Synthesis and pharmacology of 1-alkyl-3-(1-naphthoyl)indoles: Steric and electronic effects of 4- and 8-halogenated naphthoyl substituents

Article abstract of DOI:10.1016/j.bmc.2012.01.038

To develop SAR at both the cannabinoid CB₁ and CB₂ receptors for 3-(1-naphthoyl)indoles bearing moderately electron withdrawing substituents at C-4 of the naphthoyl moiety, 1-propyl and 1-pentyl-3-(4-fluoro, chloro, bromo and iodo-1-naphthoyl) derivatives were prepared. To study the steric and electronic effects of substituents at the 8-position of the naphthoyl group, the 3-(4-chloro, bromo and iodo-1-naphthoyl)indoles were also synthesized. The affinities of both groups of compounds for the CB₁ and CB₂ receptors were determined and several of them were evaluated in vivo in the mouse. The effects of these substituents on receptor affinities and in vivo activity are discussed and structure-activity relationships are presented. Although many of these compounds are selective for the CB₂ receptor, only three JWH-423, 1-propyl-3-(4-iodo-1-naphthoyl)indole, JWH-422, 2-methyl-1-propyl-3-(4-iodo-1-naphthoyl)indole, the 2-methyl analog of JWH-423 and JWH-417, 1-pentyl-3-(8-iodo-1-naphthoyl)indole, possess the desirable combination of low CB₁ affinity and good CB₂ affinity.

Full text of DOI:10.1016/j.bmc.2012.01.038

Bioorganic & Medicinal Chemistry 20 (2012) 2067–2081
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Synthesis and pharmacology of 1-alkyl-3-(1-naphthoyl)indoles: Steric
and electronic effects of 4- and 8-halogenated naphthoyl substituents
Jenny L. Wiley a,c, Valerie J. Smith b, Jianhong Chen b, Billy R. Martin c, John W. Huffman b,d,
⇑
a RTI International, PO Box 12194, Research Triangle Park, NC 27709-2194, USA
b Howard L. Hunter Laboratory, Clemson University, Clemson, SC 29634-0973, USA
c Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA
d PO Box 695, Dillsboro, NC 28725-0695, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
To develop SAR at both the cannabinoid CB1 and CB2 receptors for 3-(1-naphthoyl)indoles bearing
moderately electron withdrawing substituents at C-4 of the naphthoyl moiety, 1-propyl and 1-pentyl-
3-(4-fluoro, chloro, bromo and iodo-1-naphthoyl) derivatives were prepared. To study the steric and
electronic effects of substituents at the 8-position of the naphthoyl group, the 3-(4-chloro, bromo and
iodo-1-naphthoyl)indoles were also synthesized. The affinities of both groups of compounds for the
CB1 and CB2 receptors were determined and several of them were evaluated in vivo in the mouse. The
effects of these substituents on receptor affinities and in vivo activity are discussed and structure–activity
relationships are presented. Although many of these compounds are selective for the CB2 receptor, only
three JWH-423, 1-propyl-3-(4-iodo-1-naphthoyl)indole, JWH-422, 2-methyl-1-propyl-3-(4-iodo-1-naph-
thoyl)indole, the 2-methyl analog of JWH-423 and JWH-417, 1-pentyl-3-(8-iodo-1-naphthoyl)indole,
possess the desirable combination of low CB1 affinity and good CB2 affinity.
Received 8 December 2011
Revised 20 January 2012
Accepted 22 January 2012
Available online 30 January 2012
Keywords:
Cannabinoids
Structure–activity relationships
Cannabinoid receptors
Aminoalkylindole
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
doles, WIN-55,212-2 (3), developed by the Winthrop group, is
not only very potent in vivo, but has high affinity for both the
In the four decades since Gaoni and Mechoulam reported the
elucidation of the structure of
9-tetrahydrocannabinol (1, THC),
cannabinoid CB1 and CB2 receptors.14,15 The Winthrop group syn-
thesized more than 100 aminoalkylindoles and proposed prelimin-
ary SAR12,13,16 These SAR included the observation that a group
larger than methyl at C-2 of the indole nucleus greatly attenuates
potency and that a bicyclic aroyl group, usually 1-naphthoyl or a
substituted 1-naphthoyl group, at C-3 of the indole is essential
for potency. They also concluded that an aminoalkyl group, usually
substituted aminoethyl, attached to the indole nitrogen was essen-
tial for cannabinoid activity.
In 1994 we reported that the aminoalkyl group appended to the
indole nitrogen could be replaced by an alkyl group to provide rel-
atively simple indole derivatives that exhibit typical cannabinoid
pharmacology.17 In particular, JWH-018, 1-pentyl-3-(1-naph-
thoyl)indole (4) has high affinity (Ki = 9 5 nM) for the CB1 receptor
and exhibits typical cannabinoid pharmacology in vivo.18 1-propyl-
2-methyl-3-(1-naphthoyl)indole JWH-015 (5) has relatively high
affinity for the CB2 receptor (Ki = 13.8 4.6 nM), modest affinity
for the CB1 receptor (Ki = 164 22 nM) and was one of the first com-
pounds found to have useful selectivity for the CB2 receptor.15
In subsequent work directed toward the development of
improved CB2 cannabinoid receptor ligands and to establish SAR
for cannabimimetic indoles at both the CB1 and CB2 receptors, a
number of additional indole derivatives were prepared and their
pharmacology was evaluated.19–21 It was found that CB1 receptor
affinity is optimal with a 1-pentyl nitrogen substituent and
D
the principal psychoactive constituent of marijuana,1 comprehen-
sive structure-activity relationships (SAR) have been developed
based upon the dibenzopyran nucleus of THC.2–6 The pharmacolog-
ical effects of cannabinoids are considered to be mediated through
at least two G-protein-coupled, transmembrane receptors. One of
these, the CB1 receptor, is found predominantly in the central ner-
vous system and is thought to be responsible for most of the overt
pharmacological effects of cannabinoids.5,7–9 A second receptor,
designated CB2, was originally identified from macrophages pres-
ent in the spleen, and is expressed primarily in the periphery.10
In 1991 a group at Sterling–Winthrop reported that pravadoline
(2) and a number of other structurally similar indole derivatives
inhibited contractions of the electrically stimulated mouse vas
deferens.11 Subsequent work revealed that these compounds also
inhibit adenylate cyclase, are antinociceptive and interact with a
G-coupled protein in the brain. It was also found that these
aminoalkylindoles exhibit typical cannabinoid pharmacology
in vivo and that the G-coupled protein with which they interact
is the cannabinoid CB1 receptor.12,13 One of these aminoalkylin-
⇑
Corresponding author at: PO Box 695, Dillsboro, NC 28725-0695, USA.
Tel.: +1 828 631 3339; fax: +1 864 656 6613.
E-mail address: Huffman@clemson.edu (J.W. Huffman).
0968-0896/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2012.01.038

2068
J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
receptor affinity of electron withdrawing substituents at C-4 of the
O
CH
3
naphthoyl, 1-propyl- and 1-pentyl-3-(1-naphthoyl-4-halo)indoles
(9–12, R = C3H7 or C5H11, R0 = H or CH3) were synthesized and their
pharmacology was evaluated. In earlier work it was found that
1-propyl- and 1-pentyl-2-methyl-3-(2-methoxy-1-naphthoyl)indoles
(13) had restricted rotation about the naphthalene C-1 bond to the
carbonyl carbon, with a calculated energy barrier of 12.9 kcal/mol
and an experimentally determined barrier of 13.1 kcal/mol.20 In
addition, two of the compounds in this series were very selective
for the CB2 receptor. It seemed probable that the 3-(8-haloge-
OH
H CO
3
H C
N
3
H C
3
O
C H
5 11
H C
3
N
O
1
2
7
O
6
8
O
nated-1-naphthoyl)indole derivatives (14–16, R = C3H7 or C5H11
,
3
R0 = H or CH3) would exhibit similar restricted rotation, would be
readily available and would provide a second series of indole
derivatives with electron withdrawing groups on the naphthalene
moiety, providing additional insight into the SAR of the cannabim-
imetic indoles. The choice of the N-propyl substituent is based on
the observation that JWH-015 (5), a highly CB2 selective indole
derivative, contains this substitution pattern.15,19 The N-pentyl
group was chosen since this substituent almost invariably provides
compounds with higher CB1 receptor affinities than are observed
with other nitrogen substituents.
H C
3
N
2
2
O
4
N
1
C H
5
11
N
O
3
4
R''
O
O
2. Results
R'
H C
3
N
R
X
R'
N
R
As shown in Scheme 1, two synthetic protocols have been
developed for the preparation of various 1-alkyl-3-(1-naph-
thoyl)indoles. In one of the schemes, indole or 2-methylindole
(17, R = H or CH3) is reacted with methylmagnesium bromide
and the resulting ambident anion upon reaction with the aroyl
chloride provides 3-acylindole 18.11,17 Alkylation on nitrogen is ef-
fected using a primary alkyl halide with KOH in DMSO to afford the
target 3-acylindole (19). Although this sequence is satisfactory and
uses readily available aroyl chlorides, the yields in the first step are
quite variable and intermediate 18 is difficult to purify. Alterna-
tively, acylation of an N-substituted indole or 2-methylindole
(20) using an acyl chloride and dimethylaluminum chloride pro-
vides the 3-acylindole in from fair to good yield.20 In this proce-
dure, which was developed by Okauchi, the indole is stirred with
the Lewis acid for 30 min prior to addition of the acyl chloride.22
Although this procedure appears to be a modified Friedel–Crafts
reaction, there is evidence that it proceeds via a 3-indolylalumi-
num intermediate.23 Unless otherwise noted, cannabimimetic in-
doles 9–12 and 14–16 were prepared via the Okauchi procedure.
For the synthesis of the 4-halogenated naphthoylindoles (9–12),
4-fluoro-1-naphthoic acid (21, Scheme 2) is the only 4-halo-1-
naphthoic acid that is commercially available. 4-Chloro-, 4-bromo
5 R = C H , R', R'' = H
9
X = F
3
7
6 R = C H , R' = C H , R'' = H
10 X = Cl
11 X = Br
12 X = I
5
11
2 5
7 R = C H , R' = H, R'' = CH
5
11
3
2 5
8 R = C H , R' = H, R'' = C H
5
11
decreases dramatically with N-alkyl substituents of three or less
carbon atoms or more than six carbon atoms. In agreement with
the observations of the Winthrop group, a 2-methyl substituent
(for numbering see structure 4) slightly decreases affinity at the
CB1 receptor, while larger substituents at this position decrease
CB1 receptor affinity considerably.14,16,20 A small 4-alkyl-1-naph-
thoyl group at C-3 of the indole, as in JWH-213 (6) enhances both
CB1 (Ki = 1.5 0.2 nM) and CB2 receptor affinity (Ki =0.42
0.05 nM), while a 7-methyl or ethyl-1-naphthoyl substituent as in
JWH-048 (7) and JWH-262 (8) has relatively little effect on affinity
for either receptor.20,21 The effect upon CB1 and CB2 receptor affinity
of methoxy substituents at C-2, C-4, C-6 and C-7 of the 1-naphthoyl
moiety has also been described. A 2- or 6-methoxy-1-naphthoyl
group greatly attenuates affinity for the CB1 receptor, but has little
effect upon CB2 affinity. A 4-methoxy-1-naphthoyl group enhances
affinity for both receptors while a 6-methoxy substituent reduces
CB1 receptor affinity significantly, but has only a slight effect upon
CB2 binding. A 7-methoxy group has relatively little effect upon
affinity for either receptor.20,21
O
Ar
a
R
N
R
N
H
H
X
O
O
17
18
b
OCH3
H3C
R'
N
R
N
R
O
R
14 X = Cl
15 X = Br
16 X = I
13 R = C3H7 or C5H11
Ar
c
R
N
N
R'
R'
These studies provide some indication of the effect of various
naphthoyl substituents upon the CB1 and CB2 receptor affinities of
1-pentyl and 1-propyl-3-(1-naphthoyl)indoles. However, all of the
substituents on the naphthoyl moiety examined to date are weakly
to moderately electron releasing. In order to explore the effect upon
20
19
Scheme 1. Reagents and conditions: (a) MeMgBr, Et2O/THF, 0 °C, then ArCOCl,
reflux; (b) R0Br, KOH, DMSO, 80 °C; (c) Me2AlCl, CH2Cl2, 30 min, 0 °C, then ArCOCl,
25 °C.

J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
2069
COCH3
O
O
O
O
O
Hg
a
b
c
a
X
X
23 X = Cl, Br, I
24 X = Cl, Br, I
+
-
CO2H
COCH2N
29
b
30
I
c
X
CO2H
Cl
Hg CO2H
X
21 X = F
X
d
25 X = Cl, Br, I
22 X = Cl, Br, I
Scheme 2. Reagents and conditions: (a) CH3COCl, AlCl3, ClCH2CH2Cl, rt; (b) I2,
pyridine, 100 °C; (c) NaOH/H2O, reflux, then HCl.
31
26 X = Cl
27 X = Br
28 X = I
and 4-iodo-1-naphthoic acids (22) were synthesized as shown in
Scheme 2. Friedel-Crafts acylation of 1-chloro, 1-bromo or 1-iodo-
naphthalene (23) with acetyl chloride under standard reaction
conditions provided the corresponding 4-halogenated-1-acetyl-
naphthalene (24). Reaction of ketones 24 with iodine and pyridine
under the conditions of the King reaction gave pyridinium salts 25,
which upon basic hydrolysis and acidification provided acids 22.24
For purification acids 22 were converted to the corresponding
methyl esters under standard conditions and the esters were puri-
fied by chromatography. Basic hydrolysis and acidification pro-
vided pure acids 22.
Scheme 3. Reagents and conditions: (a) NaOH, H2O then HOAc, Hg(OAc)2;
(b) Br2/NaBr or I2/KIꢀHOAc; (c) 1 M NaOH/H2O, NaCl then HCl; (d) Cl2, HOAc.
lengthy synthesis of 8-fluoro-1-naphthoic acid, this compound
was not prepared.29
The four 3-(8-chloro-1-naphthoyl)indoles (JWH-456, JWH-461,
JWH-457, JWH-462), the 8-bromo analogs (JWH-428, JWH-429,
JWH-424, JWH-425) and the 3-(8-iodo-1-naphthoyl)indoles
(JWH-419, JWH-418, JWH-416 and JWH-417) were all prepared
by the direct acylation of the appropriately substituted indole. In
contrast to the 1-alkyl-3-(2-methoxy-1-naphthoyl)indole series,
in which only those compounds derived form 2-methylindole
(13) indicated restricted rotation about the naphthyl C-1 bond
and the carbonyl carbon,20 the 1H NMR spectra of all of the 1-al-
kyl-3-(8-halo-1-naphthoyl)indoles (14–16) showed evidence of re-
stricted rotation. Variable temperature 1H NMR experiments from
ambient temperature to 110 °C were carried out on several of these
compounds and the data for 1-propyl-3-(8-bromo-1-naph-
thoyl)indole (JWH-428, 15, R = C3H7, R0 = H) and its 2-methyl ana-
log (JWH-429, 15, R = C3H7, R0 = CH3) are typical. At ambient
temperature for 15 (R = C3H7, R0 = H) the methylene group adjacent
to nitrogen appears as a multiplet at d 4.14–4.18, while at 100 °C it
is a well resolved triplet, J = 7.5 Hz, at d 4.15. Also, in the aromatic
region of the spectrum at ambient temperature, signals for two
protons are absent. The differences in the spectra at ambient tem-
perature and 100 °C for 15 (R = C3H7, R0 = CH3) are considerably
more pronounced with several protons giving rise to signals of re-
duced intensity at ambient temperature and the signal for the C-2
methyl group was absent. The signal for this methyl group was also
absent at 75 °C, but appeared as a broadened singlet at 100 °C (see
Section 5).30
JWH-414 (9, R = C3H7, R0 = H), JWH-415 (9, R = C3H7, R0 = CH3),
JWH-412 (9, R = C5H11, R0 = H), JWH-413 (9, R = C5H11, R0 = CH3)
were prepared from the acid chloride derived from commercial
4-fluoro-1-naphthoic acid by direct acylation of the appropriate in-
dole. In the 3-(4-chloro-1-naphthoyl)indole series, the 1-propyl
compound (10, JWH-400, R = C3H7, R0 = H) was prepared both by di-
rect acylation of 1-propylindole and via alkylation of 3-(4-chloro-1-
naphthoyl)indole. JWH-399 (10, R = C3H7, R0 = CH3), JWH-398 (10,
R = C5H11, R0 = H) and JWH-397 (10, R = C5H11, R0 = CH3) were
synthesized by alkylation of the requisite 3-acylindole. The
four 3-(4-bromo-1-naphthoyl)indoles (11, JWH-386, JWH-395,
JWH-387 and JWH-394) were prepared by both routes, while the
3-(4-iodo-1-naphthoyl)indoles (12, JWH-423, JWH-422, JWH-421
and JWH-420) were prepared by the acylation of the appropriate
N-alkylindole with 4-iodo-1-naphthoyl chloride.
The substituted 1-naphthoic acids (26, 27 and 28) needed for
the synthesis of 3-(8-halo-1-napthoyl)indoles 14–16 were pre-
pared from anhydro-8-(hydroxymercuri)-1-naphthoic acid (29)
by a modification of the sequence reported by Whitmore many
years ago and developed some years later by Shechter0s group
(Scheme 3).25,26 The starting material, anhydro-8-(hydroxymercu-
ri)-1-naphthoic acid, is prepared from 1,8-naphthoic anhydride
(30) by treatment of the bis-sodium salt with mercuric acetate.
For the preparation of 8-bromo- (27) and 8-iodo-1-naphthoic acid
(28), treatment of anhydro acid 29 with an aqueous solution of so-
dium bromide (for the preparation of acid 15) or potassium iodide
(for the preparation of acid 16) followed by addition of the appro-
priate halogen provided acids 27 and 28.
The affinities of the 4- and 8-halonaphthoylindoles for the CB1
and CB2 receptors were determined by measuring their ability to
displace the potent cannabinoid [3H] CP-55,940 from its binding
site in cloned human receptor preparations using the procedure
described by Martin et al.31 The results of these determinations
are summarized in Tables 1 and 2. Also included in Table 1 are
Although Whitmore reported that reaction of 29 with chlorine in
glacial acetic acid gave 8-chloro-1-naphthoic acid (26),25 Shechter
found that this reaction afforded 5,8-dichloro-1-naphthoic acid as
the major product26 and in another early paper Rule and Barrett re-
ported that chloromercuri compound 31 gave pure acid 26 in mod-
est yield (31%) using Whitmore0s procedure.27 Acceptable yields of
8-chloro-1-naphthoic acid (26) were ultimately obtained using
chlorine in acetic acid and carrying out the reaction at ice bath tem-
peratures in acetic acid-dichloromethane.28 In view of the rather
the receptor affinities for D
9-THC (1) and WIN-55,212-2 (3). The
in vivo pharmacology was evaluated using the mouse model of
cannabinoid activity, which measures spontaneous activity (SA),
antinociception (as tail flick, TF), rectal temperature (RT) and cata-
lepsy (as ring immobility).32,33
In the 4-halo-1-naphthoyl indole series (Table 1), CB1 affinity
was consistently and substantially better for each 1-pentyl-3-(1-
naphthoyl)indole than for the corresponding 1-propyl compound.
For example, the Ki value for JWH-412, 1-pentyl-3-(4-fluoro-1-

2070
J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
Table 1
In vitro and in vivo pharmacology of 1-alkyl-3-(4-halo-1-naphthoyl)indoles (9–12),
D
9-THC (1), JWH-015 (5), JWH-018 (4) and WIN-55,212-2 (3)
O
N
R
R'
X
Compound
R
R0
X
Ki (nM)
CB2
ED50 (lmol/kg)
Tetrad tests in micef
CB1
Ratio
CB1/CB2
SA
TF
RT
RI
D
9-THC (1)
41 2a
36 10b
0.28 0.16b
13,8 4.6d
2.9 2.6d
1.1
6.8
11.9
3.2
7
3.2
4.5
4.5
4.8
WIN-55,212-2 (3)
JWH-015 (5)
JWH-018 (4)
JWH-414
1.9 0.1b
164 22d
0.23c
18.7e
0.44e
67% at 91
9.6
0.94c
28c
2.8c
84.7e
99.1e
87.2e
9
240
5d
7
0.09e
1.7e
3–9e
C3H7
C3H7
H
CH3
F
F
33
38
2
1
59% at 91
11.9
-3.3 at 91
30.1
Not active
23.2
JWH-415
530 37
14
Rimonabant (3 mg/kg) blocked or partially blocked all in vivo effects of 30 mg/kg of JWH-415
JWH-412
JWH-413
JWH-400
JWH-399
JWH-398
JWH-397
JWH-386
JWH-395
JWH-387
JWH-394
JWH-423
JWH-422
JWH-421
JWH-420
C5H11
C5H11
C3H7
H
CH3
H
CH3
H
CH3
H
CH3
H
CH3
H
CH3
H
CH3
F
F
7.2 0.5
14 0.7
3.2 0.5
2.2 0.2
44 0.4
2
6
2
9
0.8
4
6
12
1
5
<0.08
0.38
0.14
0.48
<0.08
0.54
0.58
0.99
Cl
Cl
Cl
Cl
Br
Br
Br
Br
I
93
8
Not tested
70% at 83
82% at 27
94% at 77
71% at 77
80% at 74
Not tested
Not tested
10% at 6.8
74% at 66
0.30
C3H7
187 16
2.3 0.1
8.9 0.3
161 16
373 43
1.2 0.1
14 0.2
140 10
501 48
2.5 0.2
22
1
100% at 83
90% at 27
100% at 77
75% at 77
96% at 74
ꢁ5.4 at 83
ꢁ4.9 at 27
ꢁ6.4 at 77
ꢁ3.9 at 77
ꢁ5.0 at 74
70% at 83
67% at 27
88% at 77
26% at 77
50% at 74
C5H11
C5H11
C3H7
2.8 0.2
2.3 0.02
27 1.6
C3H7
31
2
C5H11
C5H11
C3H7
C3H7
C5H11
C5H11
1.1 0.1
2.8 0.2
6.6 0.2
20 0.4
1.3 0.02
2.1 0.1
21
25
2
26% at 6.8
60% at 66
0.45
ꢁ1.7 at 6.8
ꢁ3.0 at 66
0.19
2% at 6.8
40% at 66
0.38
I
I
I
14
1
7
1.1
2.5
2.6
2.5
a
b
c
d
e
f
Ref.41
Ref.15
Ref.14
Ref.20
Ref.18
Pharmacological tests in mice included spontaneous activity (SA), tail flick test of antinociception (TF), change in rectal temperature (RT), and ring immobility (RI).
Table 2
Receptor affinities (mean SEM) of 1-alkyl-3-(8-halo-1-naphthoyl)indoles (14–16)
X
O
N
R'
R
Compound
R
R0
X
Ki (nM)
CB2
ED50
(l
mol kg)
CB1
Ratio CB1/CB2
SA
TF
RT
RI
JWH-456
JWH-461
JWH-457
JWH-462
JWH-428
JWH-429
JWH-424
JWH-425
JWH-419
JWH-418
JWH-416
JWH-417
C3H7
C3H7
C5H11
C5H11
C3H7
C3H7
C5H11
C5H11
C3H7
C3H7
C5H11
C5H11
H
CH3
H
CH3
H
CH3
H
CH3
H
CH3
H
Cl
Cl
Cl
Cl
Br
Br
Br
Br
I
642 50
>10,000
134 20
174 29
10 0.8
19 1.6
192 14
278 69
5.4 0.2
10 0.4
152 33
536 66
3.3 0.1
13 0.2
4.8
>57
2.3
6.1
>52
>36
4
5.5
19
8
68% at 86
70% at 83
94% at 80
84% at 77
76% at 77
49% at 74
1.4
79% at 6.9
ꢁ25% at 68
Not active at 66
1.8
72% at 86
42% at 83
100% at 80
100% at 77
9% at 77
72% at 74
1.8
Not active at 86
ꢁ2.3 at 83
ꢁ6.9 at 80
ꢁ5.5 at 77
ꢁ2 at 77
ꢁ2.3 at 74
2.4
15% at 83
92% at 80
86% at 77
5% at 77
4% at 74
3.7
23
1
116
7
>10,000
>10,000
21 3.4
54 11
100% at 6.9
ꢁ3.7 at 6.9
53% at 6.9
2960 240
4290 440
73 10
Not active at 68
1.3
I
I
I
22
40
ꢂ6.4
3.6
CH3
522 58
Not active at 6.2
naphthoyl)indole, was 7.2 nM compared to a Ki of 240 nM for JWH-
414, 1-propyl-3-(4-fluoro-1-naphthoyl)indole. CB1 affinities of the
1-propyl-3-(4-halo-1-naphthoyl)indoles were moderate, ranging
from 93 to 240 nM, while the 1-pentyl-3-(4-halo-1-naph-
thoyl)indoles had good affinities, ranging from 1.2 to 7.2 nM. A sim-
ilar pattern of differential affinities as a function of the length of the
alkyl substituent was observed for the 1-alkyl-2-methyl-3-(4-halo-
1-naphthoyl)indole series; however, the presence of a 2-methyl
substituent substantially decreased CB1 affinities for compounds
with either alkyl length. While the resulting CB1 affinities for the
1-propyl analogs were moderate to poor, with Kis ranging from
187 to 530 nM, the 1-pentyl compounds retained good CB1 affinity,
with Ki values ranging from 8.9 to 14 nM. Electronegativity of
the 4-halogen substituent also affected CB1 affinity. 4-Chloro substi-
tution produced the best CB1 affinity in each group, Ki = 93 nM for
JWH-400, 1-propyl-3-(4-chloro-1-naphthoyl)indole; Ki = 187 nM

J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
2071
for JWH-399, 1-propyl-2-methyl-3-(4-chloro-1-naphthoyl)indole;
Ki = 8.9 nM for JWH-397, 1-pentyl-2-methyl-3-(4-chloro-1-naph-
thoyl)indole, except for the 1-pentyl-3-(4-halo-1-naphthoyl)-
indoles, in which 3-(4-bromo-1-naphthoyl) substitution resulted
in optimal CB1 affinity (Ki = 1.2 for JWH-387). Increasing electroneg-
ativity through substitution of a 3-(4-fluoro-1-naphthoyl) substitu-
ent greatly lessened CB1 affinity, Ki = 240 nM for JWH-414, 1-
propyl-3-(4-fluoro-1-naphthoyl)indole; Ki = 7.2 nM for JWH-412,
1-pentyl-3-(4-fluoro-1-naphthoyl)indole; Ki = 530 nM for JWH-415,
1-propyl-2-methyl-3-(4-fluoro-1-naphthoyl)indole and Ki = 14 nM
for JWH-413, 1-pentyl-2-methyl-3-(4-fluoro-1-naphthoyl)indole.
Substitution of a less electronegative iodo substituent in 1-propyl-
2-methyl-3-(4-iodo-1-naphthoyl)indole, JWH-422 (Ki = 501 nM)
has a similar effect. For the other 1-propyl-3-(4-halo-1-naphthoyl)-
indoles, 1-pentyl-3-(4-halo-1-naphthoyl)indoles, and 1-pentyl-2-
methyl-3-(4-halo-1-naphthoyl)indoles, the CB1 receptor affinities
for 3-(4-chloro, bromo,iodo-1-naphthoyl) indoles do not vary
widely within each series.
JWH-415, the compound was assessed in a [35S]GTP
determine its ability to activate the CB1 receptor. JWH-415 pro-
duces G-protein activation in a concentration-dependent manner,
with an EC50 of 268 lM ( 42 SEM). Efficacy, however, is only par-
tial (Emax = 59% 3).
Table 2 presents a summary of the pharmacological results for
the 1-alkyl-3-(8-halo-1-naphthoyl)indoles. All of these compounds
possess substantially less affinity for both CB1 and CB2 receptors
than did the comparable 1-alkyl-3-(4-halo-1-naphthoyl)indoles, al-
beit some of the SAR patterns that were observed in the 4-halogen
series are also observed in the 8-halogen series. First, the 1-pen-
tyl-3-(8-halo-1-naphthoyl)indoles exhibit better CB1 and CB2 affin-
ities than the 1-propyl-3-(8-halo-1-naphthoyl)indoles. The best CB1
affinity for the 1-propyl series is a Ki of 642 nM for JWH-456, 1-pro-
pyl-3-(8-chloro-1-naphthoyl)indole. Several of the compounds fail
to demonstrate measurable binding to the CB1 receptor [Ki
>10,000 for JWH-428, 1-propyl-3-(8-bromo-1-naphthoyl)indole,
JWH-461, 1-propyl-2-methyl-3-(8-chloro-1-naphthoyl)indole, and
c
S assay to
Regardless of their CB1 affinities, all of the 3-(4-halo-1-naph-
thoyl)indoles have good CB2 affinities. Further, whereas THC shows
similar affinities for both CB1 and CB2 receptors, WIN-55,212-2 and
the majority of the 3-(4-halo-1-naphthoyl)indoles [except for two,
JWH-398 and JWH-387, 1-pentyl-3-(4-chloro-1-naphthoyl)indole
and 1-pentyl-3-(4-bromo-1-naphthoyl)indole, respectively] are
mildly to moderately CB2 selective, with CB1/CB2 ratios ranging from
2 to 25. The 1-propyl analogs exhibit better CB2 selectivity than corre-
sponding 1-pentyl compounds regardless of whether they have a
methyl substitution at the indole 2-position or are unsubstituted.
However, compared to the analogs that are unsubstituted at the 2-po-
sition of the indole group, CB2 selectivity (but not absolute affinity) is
increased with addition of the 2-methyl substituent for either the 1-
propyl or 1-pentyl indoles. The best absolute values for CB2 affinities
are exhibited by 1-pentyl-3-(4-halo-1-naphthoyl)indoles, a pattern
that was also observed for CB1 affinities. For the 1-pentyl-3-(4-halo-
1-naphthoyl)indole series, CB2 affinities ranged from 1.1 to 13 nM,
with the best affinity obtained for JWH-387, 1-pentyl-3-(4-bromo-1-
naphthoyl)indole. Decreasing electronegativity by substitution of a
4-iodo-1-naphthoyl group correspondingly decreases CB2 affinity
(JWH-421, Ki = 13 nM). Although increasing electronegativity by
4-chloro-1-naphthoyl or 4-fluoro-1-naphthoyl substitution also
decreases CB2 affinity, the magnitude of these decreases is much less
[Ki = 2.8 nM for JWH-398, 1-pentyl-3-(4-chloro-1-naphthoyl)indole
JWH-429,
1-propyl-2-methyl-3-(8-bromo-1-naphthoyl)indole].
In contrast, CB1 affinities for the 1-pentyl-3-(8-halo-1-naph-
thoyl)indoles range from 21 to 73 nM and 54 to 522 nM for the
1-pentyl-2-methyl-3-(8-halo-1-naphthoyl)indole series. CB2 affini-
ties are also better for the 1-pentyl-3-(8-halo-1-naphthoyl)indoles
than for the 1-propyl-3-(8-halo-1-naphthoyl)indoles, ranging from
Ki = 3.3–10 nM for the 1-pentyl-3-(8-halo-1-naphthoyl)indoles
and Ki = 10–19 nM for the 1-pentyl-2-methyl-3-(8-halo-1-naph-
thoyl)indoles. For the propyl analogs, CB2 affinities range from 102
to 152 nM for the 1-propyl-3-(8-halo-1-naphthoyl)indoles and
from 174 to 536 nM for the 1-propyl-2-methyl-3-(8-halo-1-naph-
thoyl)indoles. As was the case for the compounds with 4-halo-1-
naphthoyl substitutions, all compounds are CB2 selective. In
addition, methylation at the 2-position of the indole group results
in decreased CB1 affinities, as it did for the 4-halogen series. In the
1-pentyl-3-(8-halo-1-naphthoyl) series, a moderate degree of elec-
tronegativity appears to optimize CB1 affinity, with the caveat that
synthesis of the highly negative 1-alkyl-3-(8-fluoro-1-naph-
thoyl)indoles was impractical. Hence, JWH-457, 1-pentyl-3-(8-
chloro-1-naphthoyl)indole, JWH-424, 1-pentyl-3-(8-bromo-1-
naphthoyl)indole and JWH-425, 1-pentyl-2-methyl-3-(8-bromo-
1-naphthoyl)indole, have the best CB1 affinities, with Ki = 23, 21
and 54 nM, respectively. JWH-425 also has the best CB2 affinity of
the 1-pentyl-2-methyl-3-(8-halo-1-naphthoyl)indoles, with Ki =
10 nM, whereas the best CB2 affinity of the 1-pentyl-3-(8-halo-1-
naphthoyl)indoles is JWH-416, 1-pentyl-3-(8-iodo-1-naphthoyl)-
indole, with Ki = 3.3 nM. The only compound that produced the
full cannabinoid profile in vivo was JWH-424, 1-pentyl-3-(8-bro-
mo-1-naphthoyl)indole). JWH-457, 1-pentyl-3-(8-chloro-1-naph-
thoyl)indole, which also has good CB1 receptor affinity (Ki =
23 nM) is much less potent in vivo than would be expected on the
basis of its CB1 affinity.
and
Ki = 3.2 nM
for
JWH-412,
1-pentyl-2-H-3-(4-fluoro-1-
naphthoyl)indole]. CB2 affinities for the 1-pentyl-2-methyl-3-
(4-halo-1-naphthoyl)indole series vary little across 4-halogen
substitutions, ranging from 2.1 to 2.8 nM. In contrast, CB2 affinities
for the 1-propyl-3-(4-halo-1-naphthoyl)indoles range from 6.6 nM
for 1-propyl-3-(4-iodo-1-naphthoyl)indole, JWH-423, to 44 nM for
1-propyl-2-H-3-(4-chloro-1-naphthoyl)indole, JWH-400. The re-
maining 1-propyl indoles possess CB2 affinities that are similar
(20–33 nM).
Because limited yields prevented determination of full dose-
effect curves, assessment of in vivo potency was not possible for
many of the 4-halo-1-naphthoyl indoles; however, tests with
probe doses (3–30 mg/kg) suggested that compounds with good
to moderate CB1 affinity exhibit cannabinoid activity in the
in vivo test battery. Where potency calculations were possible,
compounds with good CB1 affinities also possess good potencies
in each of the four in vivo tests, with one exception. JWH-415, 1-
propyl-2-methyl-3-(4-fluoro-1-naphthoyl)indole, has poor CB1
affinity (Ki = 530 nM); yet, it produces all characteristic cannabi-
noid effects, albeit potencies are lower compared to other com-
pounds with better CB1 affinities. Further, 3 mg/kg rimonabant
blocked or partially blocked all tetrad effects of 30 mg/kg JWH-
415, suggesting that these effects were CB1 receptor-mediated.
To evaluate possible receptor mediation of the in vivo effects of
3. Discussion
The primary purpose of this study was to examine steric and elec-
tronic effects on CB1 and CB2 receptor affinities and in vivo pharmacology
of moderately electron withdrawing halogen substituents at the naph-
thoyl C-4 or C-8 positions in a series of 1-alkyl-3-(1-naphthoyl)indoles.
In addition, two electroneutral structural features (the length of the N-al-
kyl group and the presence of a methyl at the 2-indole position) were
manipulated and were found to strongly affect affinities at both cannab-
inoid receptors for this series of compounds. 1-Pentyl-3-(1-naph-
thoyl)indoles consistently exhibit more favorable CB1 affinity than 1-
propyl-3-(1-naphthoyl)indoles with the corresponding C-4 or C-8
substitutions. Whereas CB1 affinities range from good for 1-pentyl-3-
(1-naphthoyl)indoles with C-4 substitutions (1.2–14 nM) to moderate

2072
J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
or poor for those with C-8 substitutions (21–522 nM), CB1 affinities for 1-
propyl-3-(1-naphthoyl)indoles are moderate or poor (93–530 nM) for
C-4 substitutions and are consistently poor or negligible for propyl
compounds with C-8 substitutions. Absolute values obtained for CB2
affinity are also better for 1-pentyl-3-(1-naphthoyl)indoles both those
with C-4 and C-8 substituents, ranging from 1.1 nM for 1-pentyl-3
-(4-bromo-1-naphthoyl)indole (JWH-387) to 19 nM for 1-pentyl-2-
methyl-3-(8-chloro-1-naphthoyl)indole (JWH-462). However, the com-
bination of the decrease in CB1 affinities provided by a 1-propyl group
combined with relatively little decrease in CB2 affinity leads to greater
CB2 selectivity for the 1-propyl-3-(1-naphthoyl)indoles than for those in-
doles with an N-pentyl group. Greater CB2 selectivity appears to be a
function of the length of the N-alkyl group, as similar selectivity for CB2
receptors was found for JWH-015 (5), a 1-propyl-3-(1-naphthoyl)indole
derivative that is unsubstituted on the naphthoyl moiety.15,19 In addition
to the length of the alkyl group, the presence of a methyl at the indole 2-
position also affects CB1 affinity. In the compounds with C-4 substitu-
tions, the presence of a 2-methyl substituent decreases CB1 affinity with-
out having substantive effect on CB2 affinity; hence, the net result of this
substitution is increased CB2 selectivity. In contrast, 2-methyl substitu-
tion in the series of compounds with C-8 substitutions decreases CB2
affinity in the set of 1-propyl analogs, and to a lesser extent, in the set
of 1-pentyl analogs, with the most pronounced decrease seen for 1-pro-
pyl-2-methyl-3-(8-iodo-1-naphthoyl)indole (JWH-418). In summary,
the results observed with the two electroneutral structural manipula-
tions are consistent with a number of previous SAR investigations of in-
dole- and pyrrole-derived cannabinoids in which these structural
manipulations produce similar patterns of alterations of CB1 and CB2
affinities and selectivity and suggest that length of the alkyl substituent
is as crucial for this cannabinoid structural motif as it is for cannabinoids
based on the tetrahydrocannabinol structural motif.2,19,21
negative of the halogens and a C-4 fluoro substituent suppresses
CB1 affinity in the 1-propyl analogs, with or without a 2-methyl
substituent on the indole core (JWH-415 and JWH-414, respec-
tively). The least electronegative halogen is iodine and an iodo
substituent at C-4 also reduces CB1 affinity somewhat for the
1-propyl-2-methyl analog, JWH-422. However, the other 4-iodo-
naphthoyl compounds have CB1 receptor affinities that are similar
to those of the chloro and bromo analogs. Previous work has shown
that 4-fluorobenzyl moiety in place of the naphthoyl substituent in
a series of 1-pentyl-phenylacetylindoles23 or for the hydroxy group
of THC in a series of fluorinated classical cannabinoid analogs38
substantially decreases CB1 receptor affinity and in vivo potency.
CB2 affinity is less affected by electronegativity, particularly in
the 1-pentyl and 1-pentyl-2-methyl series where CB2 affinities
are uniformly good and range from 1.1 to 3.2 nM.
In the series of 3-(8-halo-1-naphthoyl)indoles, iodine, the least
electronegative halogen, decreases CB1 affinity in the 1-pentyl ana-
logs, both those with and without a methyl group at the 2-position
of the indole (JWH-417 and JWH-416, respectively). The CB1
receptor affinities for the 1-propyl analogs with halogen substitu-
ents C-8 are from negligible to very low across the entire range
of negativities evaluated (i.e., Cl, Br, and I).
In addition to electronic effects, it is likely that steric effects of
the C-8 substitutions contribute to the low CB1 affinities and CB2
selectivity of this series of compounds. In earlier work it was found
that 1-propyl- and 1-pentyl-2-methyl-3-(2-methoxy-1-naphthoyl)-
indoles (13) have restricted rotation about the naphthalene C-1
bond to the carbonyl carbon.20 In addition, two of the compounds
in this series were very selective for the CB2 receptor. While molec-
ular modeling studies of the 3-(8-halogenated-1-naphthoyl)indole
derivatives were not carried out, their consistently lower CB1 affin-
ity (compared to compounds with corresponding C-4 substitu-
tions) suggests that steric hinderance of rotation caused by the
C-8 substitution interferes with interaction with the CB1 receptor,
particularly for those compounds with an indole C-2 methyl sub-
stituent. The 1H NMR spectra of these compounds is in agreement
with this hypothesis, see above and the experimental section.30
This is particularly apparent with a relatively large iodo substitu-
ent at C-8 of the naphthoyl moiety. A possible mechanism for the
decrease in CB1 affinity is that substitution at C-8 of the naphthoyl
ring prevents optimal aromatic stacking of these compounds with
the aromatic amino acids of the CB1 receptor. These interactions
have been shown to be important for the binding of cannabimi-
metic indoles to the CB1 receptor.20,39 Similar positional biases also
occurred in series of 1-pentyl-3-phenylacetylindoles and 1-alkyl-
2-aryl-4-(1-naphthoyl)pyrroles with electron withdrawing substit-
uents.23,40 With all substituents CB1 and CB2 affinities were best
with substitution at the 2-position of the phenyl or pyrrole moie-
ties, with intermediate affinities for the 3-position and with the
least affinity for compounds with 4-substituents, suggesting that
positional substitutions following conversion of the indole tem-
plate to a pyrrole produce similar changes in affinities as deletion
of one of the naphthoyl rings (i.e., conversion to a phenylacetyl)
with the same positional substitutions on the opposite side of
the molecule. Hence, the position of substituents on either side
of the molecule appears to be important for CB1 receptor affinity
and in vivo potency for indole-derived cannabinoids, as it has been
shown to be for synthetic cannabinoids based upon a THC struc-
tural template.41 For example, compounds with halogen (e.g., iodo,
bromo, fluoro) or nitrogen substitutions at the C-2 and 4-aryl posi-
tions (on either side of the C-3 pentyl side chain of THC) had lower
CB1 receptor affinity and were less potent in vivo than compounds
with similar substitutions at the terminal end of the side chain.42 In
addition, the number of aromatic substituents also may play a role
in interaction with the CB1 receptor, as suggested by the finding
that the series of 1-pentyl-3-phenylacetylindoles shows
The in vivo evaluation of the series of naphthoylindoles with
C-4 and C-8, that was undertaken for those compounds for which
sufficient sample was available, revealed that efficacy for produc-
ing cannabimimetic effects in mice is associated with good CB1
affinity, as has been shown previously for structural analogs based
on a tetrahydrocannabinol template as well as for other indole and
pyrrole cannabinoid series.18,34 One anomaly in the current series
was JWH-415, 1-propyl-2-methyl-3-(4-fluoro-naphthoyl)indole.
Although the CB1 affinity of JWH-415 is poor (Ki = 530 nM), it
exhibited rimonabant-reversible activity in the battery of mouse
tests. Further investigation showed that JWH-415 is a low efficacy
agonist at the CB1 receptor. A similar finding was reported previ-
ously for several 1-deoxy-THC analogs, with the most prominent
being deoxy-D
9(11)-THC-dimethylheptyl (JWH-104). Similar to
the results observed here with JWH-415, JWH-104 has low CB1
affinity (Ki = 909 nM); yet, it produced cannabimimetic effects in
the battery of mouse tests that were blocked by rimonabant.35 Re-
sults of a [35S]GTP
cS binding assay showed that JWH-104 also
functions as a low efficacy agonist at CB1 receptors. Interestingly,
JWH-104 did not substitute for THC in a drug discrimination pro-
cedure in mice (an animal model of marijuana-like intoxica-
tion),36,37 suggesting that it does not produce the entire
complement of cannabinoid effects seen with THC. JWH-415 has
not been tested in the latter behavioral test.
To date, the only substituents on the naphthoyl moiety that had
been examined in indole-derived cannabinoids were weakly to
moderately electron releasing. In the present study, moderately
electron withdrawing C-4 napthoyl substituents with a range of
electronegativity (F, Cl, Br, and I) were synthesized and evaluated.
Results show that moderate electronegativity is favorable for CB1
affinity, with chloro analogs having the best, but modest, affinity
in the series of 1-propyl analogs (JWH-400 and JWH-399) and
1-pentyl-2-methyl analogs (JWH-397). The 4-bromonaphthoyl
analog (JWH-387) has the best affinity of the 1-pentyl analogs that
are unsubstituted at C-2 of the indole. Fluorine is the most electro-

J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
2073
attenuated CB1 receptor affinity compared to their 1-pentyl-3-
naphthoylindole congeners.20
ethereal solution was washed with water and 1 M KOH, dried
(MgSO4) and the solvent was removed in vacuo to give the crude
product, which was purified by column chromatography (petro-
leum ether/ether, 8:2) to give 0.076 g (52%) of 1-propyl-3-(4-flu-
oro-1-naphthoyl)indole as a tan solid: mp 166–167 °C; 1H NMR
(500 MHz, CDCl3) d 0.94 (t, J = 7.3 Hz, 3H), 1.87 (sextet, J = 7.3 Hz,
2H), 4.09 (t, J = 7 Hz, 2H), 7.21 (t, J = 8.8 Hz, 1H), 7.40–7.43 (m,
4H), 7.57 (t, J = 7 Hz, 1H), 7.62 (t, J = 7 Hz, 1H), 7.66 (t, J = 6.5 Hz,
1H), 8.22 (d, J = 8 Hz, 1H), 8.29 (d, J = 8 Hz, 1H), 8.51–8.53 (m,
1H); 13C NMR (125.77 MHz, CDCl3) d 11.3, 23.1, 48.8, 108.1,
108.3, 110.1, 117.5, 120.7, 120.7, 122.9, 122.9, 123.7, 126.0,
126.4, 126.4, 126.7, 127.0, 127.8, 137.1, 137.8, 191.1; GC/MS (EI)
m/z (rel intensity) 331 (100), 302 (66), 274 (12), 186 (95), 144
(47); HRMS (ES+) m/z calcd for C22H18FNO: 331.1372; found:
331.1367.
4. Conclusions
The major structural manipulations in the present series in-
cluded halogen substitution on the 3-naphthoyl group (i.e., fluoro,
chloro, bromo, and iodo), the position of the substituent on the
naphthoyl (i.e., C-4 or C-8), length of the N-alkyl group (i.e., propyl
or pentyl), and presence of a methyl group at the 2-position of the
indole nucleus. Of these factors, the position of the halogen substi-
tuent on the naphthoyl group and the length of the N-alkyl group
were the most critical factors affecting CB1 and CB2 affinities, with
C-4 and 1-pentyl substitutions, respectively, producing consis-
tently good affinities at both receptors. While CB2 selectivity was
enhanced by 1-propyl (vs 1-pentyl) substitution, this effect oc-
curred primarily because of a corresponding decrease in CB1 affin-
ity rather than an improvement in CB2 affinity. Together, these
results suggest that steric effects play a far more prominent role
in determining the nature of the interaction of this series of
1-alkyl-3-(1-naphthoyl)indoles with the identified cannabinoid
receptors than do electronic effects.
5.1.2. 2-Methyl-1-propyl-3-(4-fluoro-1-naphthoyl)indole
(JWH-415, 9, R = C3H7, R0 = CH3, X = F)
JWH-415 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.08 g (0.45 mmol) of 2-methyl-1-propylindole and 0.13 g
(0.68 mmol) of 4-fluoro-1-naphthoic acid there was obtained after
column chromatography (petroleum ether/ether, 8:2) 0.089 g
(56%) of 2-methyl-N-propyl-3-(4-fluoro-1-naphthoyl)indole as a
yellow oil: 1H NMR (500 MHz, CDCl3) d 0.98 (t, J = 7.5 Hz, 3H),
1.82 (sextet, J = 7.5 Hz, 2H), 2.51 (s, 3H), 4.09 (t, J = 7.5 Hz, 2H),
6.99 (t, J = 7.5 Hz, 1H), 7.16 (q, J = 8.3 Hz, 3H), 7.31 (d, J = 8.3 Hz,
1H), 7.50 (t, J = 7.4 Hz, 1H), 7.53–7.56 (m, 2H), 8.17–8.20 (m, 2H);
13C NMR (125.77 MHz, CDCl3) d 11.5, 12.6, 23.0, 44.9, 108.7,
108.8, 109.6, 114.9, 120.7, 120.8, 121.1, 121.9, 122.3, 125.7,
126.7, 126.7, 127.1, 127.9, 136.1, 136.5, 145.6, 190.5; GC/MS (EI)
m/z (rel intensity) 345 (100), 328 (34), 288 (47), 173 (73); HRMS
(ES+) m/z calcd for C23H20FNO: 345.1529; found: 345.1531.
5. Experimental
5.1. General
1H and 13C NMR spectra were recorded on a Bruker 300AC spec-
trometer or a 500 MHz Bruker Fourier Transform Spectrometer.
Mass spectral analyses were performed on a Hewlett–Packard
5890A capillary gas chromatograph equipped with a mass sensi-
tive detector or a Shimadzu QP2010 capillary gas chromato-
graph/mass spectrometer. HRMS data were obtained in the Mass
Spectrometry Laboratory, School of Chemical Sciences, University
of Illinois. Ether and THF were distilled from Na-benzophenone ke-
tyl immediately before use, and other solvents were purified using
standard procedures. Column chromatography was carried out on
5.1.3. 1-Pentyl-3-(4-fluoro-1-naphthoyl)indole (JWH-412, 9,
R = C5H11, R0 = H, X = F)
JWH-412 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.070 g (0.38 mmol) of 1-pentylindole and 0.11 g (0.58 mmol)
of 4-fluoro-1-naphthoic acid there was obtained after chromatogra-
phy (petroleum ether/ether, 7:3) 0.021 g (10%) of 1-pentyl-3-(4-flu-
oro-1-naphthoyl)indole as a brown oil: 1H NMR (500 MHz, CDCl3) d
0.89 (t, J = 7 Hz, 3H), 1.28–1.35 (m, 4H), 1.85 (p, J = 7 Hz, 2H), 4.11 (t,
J = 7 Hz, 2H), 7.22 (dd, J = 8, 10 Hz, 1H), 7.38–7.40 (m, 3H), 7.42–7.43
(m, 1H), 7.56 (t, J = 7 Hz, 1H), 7.61 (t, J = 7 Hz, 1H), 7.66 (dd, J = 5.5,
8 Hz, 1H), 8.21 (d, J = 8 Hz, 1H), 8.28 (d, J = 8.5 Hz, 1H), 8.48–8.50
(m, 1H); 13C NMR (125.77 MHz, CDCl3) d 13.9, 22.2, 28.9, 29.5,
47.2, 108.1, 108.3, 110.0, 117.5, 120.6, 120.7, 122.9, 122.9, 123.7,
126.0, 126.4, 126.7, 127.0, 127.8, 132.6, 137.1, 137.7, 191.0; GC/
MS (EI) m/z (rel intensity) 359 (50), 343 (22), 302 (54), 281 (26),
207 (100); HRMS (ES+) m/z calcd for C24H22FNO: 359.1685; found:
359.1679.
Sorbent Technologies silica gel (32–63 l) using the indicated sol-
vents as eluents. All new compounds were homogeneous to TLC
and 13C NMR. All target compounds were homogeneous to GLC
or TLC in two different solvent systems. TLC was carried out using
200 lm silica gel plates using the indicated solvents. GLC analyses
were performed on the Hewlett-Packard 5890A GC/MS or the
Shimadzu QP2010 using a 60 m carbowax column and helium
gas as a carrier. An initial column temperature of 60 °C was em-
ployed and the temperature was increased at a rate of 1.5 °C/min
to a maximum temperature of 300 °C with a total run time of
20 min.
5.1.1. 1-Propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414, 9,
R = C3H7, R0 = H, X = F)
To a solution of 0.07 g (0.44 mmol) of 1-propylindole in 5 mL of
dry dichloromethane under Ar was added 0.60 mL (0.60 mmol), of
1 M dimethylaluminum chloride in hexanes and the mixture was
stirred for 30 min at 0 °C. To this mixture was added dropwise a
solution of freshly prepared 4-fluoro-1-naphthoyl chloride in
3 mL of dry dichloromethane. The acid chloride was prepared by
the addition of 3 mL (41 mmol) of thionyl chloride to 0.12 g
(0.63 mmol) of 4-fluoro-1-naphthoic acid under Ar. The mixture
was heated at reflux for 2 h, cooled to ambient temperature and
the thionyl chloride was removed in vacuo. The acid chloride
was added to the indole mixture without further purification and
the mixture was stirred at ambient temperature overnight. The
reaction was quenched with water and extracted with ether. The
5.1.4. 2-Methyl-1-pentyl-3-(4-fluoro-1-naphthoyl)indole
(JWH-413, 9, R = C5H11, R0 = CH3, X = F)
JWH-413 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.10 g (0.48 mmol) of 2-methyl-1-pentylindole and 0.14 g
(0.74 mmol) of 4-fluoro-1-naphthoic acid there was obtained after
column chromatography (petroleum ether/ether, 9:1) 0.022 g
(12%) of 2-methyl-1-pentyl-3-(4-fluoro-1-naphthoyl)indole as a
green oil: 1H NMR (500 MHz, CDCl3) d 0.95 (t, J = 7 Hz, 3H),
1.41–1.42 (m, 4H), 1.81–1.85 (m, 2H), 2.56 (s, 3H), 4.16 (t,
J = 7.5 Hz, 2H), 7.03 (d, J = 8 Hz, 1H), 7.15–7.22 (m, 4H), 7.34 (d,

2074
J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
J = 8.5 Hz, 1H), 7.54–7.60 (m, 3H), 8.22 (d, J = 9 Hz, 1H); 13C NMR
(125.77 MHz, CDCl3) d 12.6, 13.9, 22.4, 29.1, 29.4, 43.4, 108.6,
108.8, 109.5, 114.9, 120.7, 120.7, 121.1, 121.9, 122.2, 123.9, 124.1,
125.7, 126.6, 126.7, 127.1, 127.9, 136.1, 145.5, 192.4; GC/MS (EI)
m/z (rel intensity) 373 (74), 358 (45), 316 (44), 173 (100), 145
(55); HRMS (ES+) m/z calcd for C25H24FNO: 373.1842; found:
373.1850.
Ar and stirred until it became cloudy white. A solution of 0.12 g
(1.06 mmol) of indole in 2 mL of dry ether was added and the mix-
ture was stirred at 0 °C for 30 min followed by stirring at ambient
temperature for 30 min. A solution of freshly prepared 4-chloro-1-
naphthoyl chloride in 3 mL of dry ether was added dropwise via
syringe. The acid chloride was prepared by the addition of 3 mL
(41 mmol) of thionyl chloride to 0.20 g (0.97 mmol) of chloro-1-
naphthoic acid under Ar. The mixture was heated at reflux for
2 h, cooled to ambient temperature, and the thionyl chloride was
removed in vacuo to give the acid chloride, which was added to
the indole mixture without further purification. The acid chloride
and indole mixture was stirred at ambient temperature for 4 h,
quenched with NH4Cl and extracted with ether. The ethereal solu-
tion was allowed to stand at ambient temperature for 20 min upon
which time a precipitate was filtered out to give 0.11 g (38%) of
3-(4-chloro-1-naphthoyl)indole as a cream colored solid: 1H NMR
(300 MHz, DMSO-d6) d 7.27–7.31 (m, 2H), 7.52–7.55 (m, 1H),
7.61–7.71 (m, 2H), 7.74–7.76 (m, 2H), 7.80 (d, J = 7.8 Hz, 1H),
8.08 (d, J = 8.1 Hz, 1H), 8.29–8.33 (m, 2H), 12.25 (br s, 1H); 13C
NMR (75.5 MHz, DMSO-d6) d 112.9, 117.5, 121.9, 122.8, 123.8,
124.5, 126.0, 126.3, 126.6, 128.2, 128.4, 130.5, 131.8, 132.5,
137.5, 137.7, 138.7, 190.8.
5.1.5. 1-Acetyl-4-chloro-naphthalene (24, X = Cl)
To a solution of 0.15 g (1.9 mmol) of acetyl chloride in 8 mL of
freshly distilled dichloromethane under N2 was added 0.26 g
(2.0 mmol) of AlCl3. This mixture was stirred at ambient tempera-
ture for 5 min and 0.28 g (1.72 mmol) of 1-chloronaphthalene was
added dropwise over 10 min. The mixture was heated to 40 °C and
stirred for 1 h, poured over a mixture of ice and concentrated HCl.
The product was extracted into ether, washed with brine and dried
(MgSO4). The solution was concentrated in vacuo to give 0.56 g
(84%) of 1-acetyl-4-chloro-naphthalene as a yellow oil, which
was used without further purification: 1H NMR (300 MHz, CDCl3)
d 2.58 (s, 3H), 7.33 (d, J = 7.8 Hz, 1H), 7.48–7.55 (m, 2H), 7.57 (d,
J = 7.8 Hz, 1H), 8.16 (d, J = 7.8, 1H), 8.72 (d, J = 7.2, 1H); 13C NMR
(75.5 MHz, CDCl3) d 29.8, 124.5, 124.7, 126.4, 127.4, 128.4, 128.6,
130.9, 131.2, 134.1, 136.6, 200.5; GC/MS (EI) m/z (rel intensity)
204 (69), 189 (100), 161 (75), 126 (54). The data agree in all re-
spects with those reported previously.43
5.1.8. 1-Propyl-3-(4-chloro-1-naphthoyl)indole (JWH-400, 10,
R = C3H7, R0 = H, X = Cl)
A: A solution of 0.16 g (0.52 mmol) of 3-(4-chloro-1-naph-
thoyl)indole and 0.13 g (2.35 mmol) of crushed KOH in 5 mL of
DMSO was stirred at ambient temperature for 1 h. To this mixture
was added 0.14 g (0.94 mmol) of 18 and 0.18 g (1.05 mmol) of
1-iodpropane. Stirring at ambient temperature was continued for
6 h. The reaction was quenched with H2O and the product was
extracted with ethyl acetate. After being dried (MgSO4) and con-
centrated in vacuo the product was purified by column chromatog-
raphy (petroleum ether/ethyl acetate, 7:3) to give 0.03 g (15%) of
JWH-400 as a tan solid: mp 194–195 °C; 1H NMR (500 MHz,
DMSO-d6) d 0.79 (t, J = 7.3 Hz, 3H), 1.73 (sextet, J = 7.3 Hz, 2H),
4.17 (t, J = 7.0 Hz, 2H), 7.33–7.36 (m, 2H), 7.63–7.69 (m, 3H), 7.76
(t, J = 7.5 Hz, 1H), 7.83–8.84 (m, 2H), 8.07 (d, J = 8.0 Hz, 1H), 8.33
(t, J = 8.5 Hz, 2H); 13C NMR (125.77 MHz, DMSO-d6) d 11.4, 23.2,
48.2, 111.6, 116.4, 122.2, 123.1, 123.9, 124.5, 126.1, 126.3, 126.5,
126.8, 128.3, 128.4, 130.6, 131.8, 132.5, 137.4, 138.7, 140.4,
190.4; GC/MS (EI) m/z (rel intensity) 347 (96), 330 (41), 318 (54),
186 (100); HRMS (EI+) calcd for C22H18ClNO: 347.1077; found:
347.0927.
B: JWH-400 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.13 g (0.80 mmol) of 1-propylindole and 0.15 g (0.73 mmol)
of 4-chloro-1-naphthoic acid there was obtained after chromatog-
raphy (petroleum ether/ethyl acetate, 7:3) 0.04 g (15%) of 1-pro-
pyl-3-(4-bromo-1-naphthoyl)indole (JWH-400) as a tan solid: mp
194–195 °C. The spectroscopic properties were identical to those
of material prepared by method A.
5.1.6. 4-Chloro-1-naphthoic acid (22, X = Cl)
To a solution of 2.44 g (11.9 mmol) of 1-acetyl-4-chloronaph-
thalene in 5 mL of freshly distilled pyridine under N2 was added
3.33 g (13.1 mmol) of I2 dissolved in 15 mL of freshly distilled pyr-
idine. The mixture was heated at reflux for 40 min, cooled to ambi-
ent temperature and diluted with ether until a brown precipitate
formed. The precipitate was filtered off, suspended in 12 mL of
6 M aqueous NaOH and heated at reflux for 2 h. After cooling the
solution was acidified with 10% HCl, the crude 4-chloro-1-naph-
thoic acid was extracted into ether and the ethereal extract was
washed with brine. After drying (MgSO4) the solution was concen-
trated in vacuo. The product was dissolved in 25 mL of MeOH to
which 5 mL of concentrated H2SO4 was cautiously added. The solu-
tion was heated at reflux for 3 h. After cooling to ambient temper-
ature the crude ester was extracted into ether, the ethereal
solution was washed with brine and dried (MgSO4). The solution
was concentrated in vacuo to give 1.66 g (63%) of methyl 4-
chloro-1-naphthoate as a brown oil, which was used without fur-
ther purification: 1H NMR (300 MHz, CDCl3) d 3.90 (s, 3H), 7.38
(d, J = 7.8, 1H), 7.45–7.56 (m, 2H), 7.87 (d, J = 8.1, 1H), 8.18 (d,
J = 8.4, 1H), 8.93 (d, J = 8.1, 1H); 13C NMR (75.5 MHz, CDCl3) d
52.1, 124.6, 124.9, 125.8. 126.2, 127.1, 128.3, 129.9, 130.7, 132.3,
137.2, 166.9; GC/MS (EI) m/z (rel intensity) 220 (61), 189 (100),
161 (48), 126 (42).
A mixture of 0.25 g (1.1 mmol) of methyl 4-chloro-1-naphtho-
ate and 2.10 g (37.4 mmol) of KOH in 20 mL of H2O was heated
at reflux for 12 h under N2. The reaction mixture was cooled to
ambient temperature, acidified with concentrated HCl and the
product was extracted into ether and dried (MgSO4). The organic
phase was concentrated in vacuo to give 0.27 g (88%) of
4-chloro-1-naphthoic acid as an off-white solid: mp 223–224 °C
(lit mp 220–221 °C44); 1H NMR (300 MHz, DMSO-d6) d 7.74–7.81
(m, 3H), 8.11 (d, J = 6 Hz, 1H), 8.28–8.31 (m, 1H), 8.93–8.97 (m,
1H), 13.8 (br s, 1H); 13C NMR (75.5 MHz, DMSO-d6) d 124.7,
126.1, 126.7, 127.9, 128.3, 129.0, 130.4, 130.6, 132.3, 135.7, 168.5.
5.1.9. 2-Methyl-3-(4-chloro-1-naphthoyl)indole (18, R = CH3,
Ar = 4-chloronaphthyl)
Indole 18 (Ar = 4-chloronaphthyl) was prepared using the
procedure employed for the synthesis of 3-(4-chloro-1-naph-
thoyl)indole. From 0.08 g (0.64 mmol) of 2-methylindole and
4-chloro-1-naphthoyl chloride prepared from 0.12 g (0.58 mmol)
of 4-chloro-1-naphthoic acid with 0.29 mL (0.87 mmol) of EtMgBr
(3.0 M in diethyl ether]) there was obtained 0.12 g (62%) of
2-methyl-3-(4-chloro-1-naphthoyl)indole as
a cream colored
5.1.7. 3-(4-Chloro-1-naphthoyl)indole (18, R = H, Ar = 4-
chloronaphthyl)
A solution of 0.48 mL (1.45 mmol) of EtMgBr [3.0 M in diethyl
ether]) was added with stirring to 3 mL of dry ether at 0 °C under
solid: 1H NMR (300 MHz, DMSO-d6) d 6.95 (t, J = 7.2 Hz, 1H), 7.08
(t, J = 7.5 Hz, 1H), 7.26 (d, J = 7.5 Hz, 1H), 7.39 (d, J = 7.8 Hz, 1H),
7.46–7.69 (m, 5H), 7.76 (d, J = 7.5 Hz, 2H), 7.87 (d, J = 8.4 Hz, 1H),
8.25 (d, J = 8.4 Hz, 1H), 11.1 (br s, 1H); 13C NMR (75.5 MHz,

J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
2075
DMSO-d6) d 14.7, 112.0, 114.0, 120.5, 122.0, 122.6, 124.5, 125.1,
126.0, 126.5, 127.4, 128.3, 128.4, 130.5, 131.2, 132.1, 135.5,
140.7, 146.7, 191.3.
mixture was poured over ice and concentrated HCl, extracted with
ether, washed with NaHCO3 and brine. After drying (MgSO4) the
solution was concentrated in vacuo and purified by chromatogra-
phy (petroleum ether/ether, 95:5) to give 0.75 g (62%) of 1-acet-
yl-4-bromonaphthalene as
a
brown oil: 1H NMR (300 MHz,
5.1.10. 2-Methyl-1-propyl-3-(4-chloro-1-naphthoyl)indole
(JWH-399, 10, R = C3H7, R0 = CH3, X = Cl)
CDCl3) d 2.74 (s, 3H), 7.65–7.69 (m, 2H), 7.74 (d, J = 6 Hz, 1H),
7.83 (d, J = 6 Hz, 1H), 8.32–8.35 (m, 1H), 8.72–8.75 (m, 1H); 13C
NMR (75.5 MHz, CDCl3) d 30.1, 126.4, 127.5, 127.8, 128.2, 128.4,
128.7, 128.7, 131.2, 132.3, 135.2, 201.0; GC/MS (EI) m/z (rel inten-
sity) 248 (46), 233 (100), 205 (44). The data agree in all respects
with those reported previously.43
JWH-399 was prepared by procedure A employed for the
synthesis of JWH-400. From 0.12 g (0.37 mmol) of 2-methyl-3-(4-
chloro-1-naphthoyl)indole, 0.09 g (1.69 mmol) of crushed KOH
and 0.13 g (0.75 mmol) of 1-iodopropane there was obtained after
chromatography (petroleum ether/ether; 1:1) 0.06 g (46%) of
JWH-399 as a brown oil: 1H NMR (300 MHz, CDCl3) d 1.02 (t,
J = 7.2 Hz, 3H), 1.86 (sextet, J = 7.5 Hz, 2H), 2.54 (s, 3H), 4.13 (t,
J = 7.2 Hz, 2H), 7.03 (t, J = 7.2 Hz, 1H), 7.16–7.23 (m, 2H), 7.35 (d,
J = 8.4 Hz, 1H), 7.52 (t, J = 7.5 Hz, 2H), 7.63–7.68 (m, 2H), 8.17 (d,
J = 8.4 Hz, 1H), 8.41 (d, J = 8.4 Hz, 1H); 13C NMR (75.5 MHz, CDCl3)
d 11.5, 12.7, 22.9, 44.9, 109.6, 114.7, 121.1, 122.1, 122.4, 124.7,
125.5, 126.1,126.9, 127.5, 127.7, 131.1, 131.6, 133.7, 136.2, 139.8,
145.9, 192.4; GC/MS (EI) m/z (rel intensity) 361 (100), 346 (26),
326 (56), 304 (29); HRMS (ES+) m/z calcd for C23H20ClNO:
361.1233; found: 361.1232.
5.1.14. 4-Bromo-1-naphthoic Acid (22, X = Br)
Acid 22 (X = Br) was prepared by the procedure employed for
the conversion of 1-acetyl-4-chloronaphthalene to 4-chloro-1-
naphthoic acid. From 0.52 g (2.09 mmol) of 1-acetyl-4-bromo-
naphthalene there was obtained after chromatography (petroleum
ether/ether, 95:5) 0.55 g (57%) of methyl 4-bromo-1-naphthoate as
a yellow oil: 1H NMR (500 MHz, CDCl3) d 4.00 (s, 3H), 7.63 (p,
J = 8.4 Hz, 2H), 7.77 (d, J = 7.5 Hz, 1H), 7.95 (d, J = 7.5 Hz, 1H),
8.30 (d, J = 8.0 Hz, 1H), 8.96 (d, J = 8.0 Hz, 1H)
;
13C NMR
(75.5 MHz, CDCl3) d 52.3, 126.3, 126.9, 127.6, 127.7, 128.5, 128.8,
128.9, 130.1, 132.1, 132.4, 167.4; GC/MS (EI) m/z (rel intensity)
264 (65), 233 (98), 295 (35), 126 (100).
5.1.11. 1-Pentyl-3-(4-chloro-1-naphthoyl)indole (JWH-398, 10,
R = C5H11, R0 = H, X = Cl)
JWH-398 was prepared by procedure A employed for the syn-
thesis of JWH-400. From 0.10 g (0.33 mmol) of 3-(4-chloro-1-
naphthoyl)indole, 0.08 g (1.5 mmol) of crushed KOH and 0.10 g
(0.65 mmol) of 1-bromopentane there was obtained after chroma-
tography (petroleum ether/ether, 9:1) 0.06 g (48%) of JWH-398 as a
brown oil; 1H NMR (500 MHz, CDCl3) d 0.87 (t, J = 6.8 Hz, 3H), 1.28–
1.34 (m, 4H), 1.82–1.86 (m, 2H), 4.09 (t, J = 7.0 Hz, 2H), 7.37 (s, 1H),
7.39–7.42 (m, 3H), 7.56 (t, J = 7.5 Hz, 1H), 7.59 (d, J = 7.5 Hz, 1H),
7.65–7.68 (m, 2H), 8.25 (d, J = 8.5 Hz, 1H), 8.40 (d, J = 8.5 Hz, 1H),
8.51–8.53 (m, 1H); 13C NMR (75.5 MHz, CDCl3) d 13.9, 22.2, 28.9,
29.5, 47.3, 110.1, 117.4, 122.9, 123.0, 123.8, 124.6, 125.0, 125.6,
126.5, 126.9, 127.5, 127.5, 131.0, 132.0, 133.8, 137.1, 138.0,
138.4, 191.0; GC/MS (EI) m/z (rel intensity) 375 (100), 358 (51),
318 (75), 214 (86); HRMS (ES+) m/z calcd for C24H22ClNO:
375.1390; found: 375.1383.
Saponification of 0.50 g (1.9 mmol) of methyl-4-bromo-1-naph-
thoate gave 0.35 g (73%) of 4-bromo-1-naphthoic acid as a white
solid: mp 215–217 °C (lit mp 217–219 °C44); 1H NMR (300 MHz,
DMSO-d6)
d 7.74–7.77 (m, 2H), 8.00 (q, J = 9, 12 Hz, 2H),
8.25–8.28 (m, 1H), 8.90–8.93 (m, 1H), 13.3 (br s, 1H); 13C NMR
(75.5 MHz, DMSO-d6) d 63.4, 126.7, 127.5, 127.5, 128.6, 129.0,
129.9, 130.5, 131.8, 132.3, 168.6.
5.1.15. 3-(4-Bromo-1-naphthoyl)indole (18, R = H, Ar = 4-
bromonaphthyl)
3-(4-Bromo-1-naphthoyl)indole was prepared by the procedure
employed for the synthesis of 3-(4-chloro-1-naphthoyl)indole.
From 0.14 g (1.2 mmol) of indole and 4-bromo-1-naphthoyl
chloride prepared from 0.27 g (1.07 mmol) of 4-bromo-1-naph-
thoic acid there was obtained after chromatography (petroleum
ether/ether, 2:1) 0.29 g (76%) of 3-(4-bromo-1-naphthoyl)indole
as a brown solid: 1H NMR (300 MHz, DMSO-d6) d 7.27–7.33 (m
,2H), 7.53–7.57 (m, 1H), 7.59–7.64 (m, 2H), 7.71 (d, J = 8.4 Hz,
1H), 7.75–7.80 (m, 1H), 7.98 (d, J = 7.5 Hz, 1H), 8.07 (d, J = 8.1 Hz,
1H), 8.25 (d, J = 8.4 Hz, 1H), 8.37–8.34 (m, 1H), 12.18 (br, 1H);
13C NMR (75.5 MHz, DMSO-d6) d 113.0, 117.6, 121.9, 122.8,
123.9, 124.0, 126.2, 126.6 (br), 127.3, 128.2, 128.6, 129.7, 131.8,
131.9, 137.5, 137.7, 139.4.
5.1.12. 2-Methyl-1-pentyl-3-(4-chloro-1-naphthoyl)indole
(JWH-397, 10, R = C5H11, R0 = CH3, X = Cl)
JWH-397 was prepared by procedure A employed for the syn-
thesis of JWH-400. From 0.15 g (0.47 mmol) of 2-methyl-3-(4-
chloro-1-naphthoyl)indole, 0.12 g (2.1 mmol) of crushed KOH and
0.14 g (0.94 mmol) of 1-bromopentane there was obtained after
chromatography (petroleum ether/ether, 8:2) 0.05 g (31%) of
JWH-397 as a yellow oil: 1H NMR (300 MHz, CDCl3) d 0.97 (t,
J = 6.9 Hz, 3H), 1.37–1.42 (m, 4H), 1.80–1.85 (m, 2H), 2.55 (s, 3H),
4.15 (t, J = 7.5 Hz, 2H), 7.01–7.06 (m, 1H), 7.16–7.24 (m, 2H), 7.35
(d, J = 8.1 Hz, 1H), 7.53 (t, J = 7.2 Hz, 2H), 7.63–7.68 (m, 2H), 8.17
(d, J = 8.4 Hz, 1H), 8.41 (d, J = 8.7 Hz, 1H); 13C NMR (75.5 MHz,
CDCl3) d 12.7, 14.0, 22.4, 29.1, 29.3, 43.4, 109.6, 114.7, 121.1,
122.1, 122.4, 124.7, 125.5, 126.2, 127.0, 127.4, 127.7, 131.1,
131.6, 133.7, 136.1, 139.9, 145.9, 192.4; GC/MS (EI) m/z (rel inten-
sity) 389 (100), 374 (81), 354 (43), 332 (30), 304 (27); HRMS (ES+)
m/z calcd for C25H24ClNO: 389.1546; found: 389.1541.
5.1.16. 1-Propyl-3-(4-bromo-1-naphthoyl)indole (JWH-386, 11,
R = C3H7, R0 = H, X = Br)
A: JWH-386 was prepared by procedure A employed for the syn-
thesis of JWH-400. From 0.30 g (0.86 mmol) of 3-(4-bromo-1-
naphthoyl)indole, 0.22 g (3.8 mmol) of crushed KOH and 0.31 g
(1.8 mmol) of 1-iodopropane there was obtained after chromatog-
raphy (petroleum ether/ether, 9:1) 0.040 g (12%) of JWH-386 a
white solid: mp 186–188 °C: 1H NMR (300 MHz, DMSO-d6) d 0.77
(t, J = 7.2 Hz, 3H), 1.72 (sextet, J = 7.2 Hz, 2H), 4.15 (t, J = 6.9 Hz,
2H), 7.32–7.36 (m, 2H), 7.58–7.66 (m, 3H), 7.74 (m, 1H), 7.83 (s,
1H), 8.03 (t, J = 9 Hz, 2H), 8.27 (d, J = 8.4 Hz, 1H), 8.32–8.35 (m,
1H); 13C NMR (75.5 MHz, DMSO-d6) d 11.4, 23.2, 48.1, 111.6,
116.4, 122.2, 123.1, 123.9, 124.0, 126.6, 126.7, 127.2, 128.2,
128.6, 129.8, 131.8, 131.8, 137.4, 139.3, 140.4, 162.3, 190.4; GC/
MS (EI) m/z (rel intensity) 391 (64), 376 (22), 364 (23), 207
(100), 186 (67); HRMS (EI+) m/z calcd for C22H18BrNO: 391.0572;
found: 391.0590.
5.1.13. 1-Acetyl-4-bromonaphthalene (24, X = Br)
To a stirred solution of 1.00 g (4.8 mmol) of 1-bromonaphtha-
lene in 15 mL of carbon disulfide at 0 °C in a flame-dried flask un-
der N2 was added 0.42 g (5.3 mmol) of acetyl chloride. This
solution was stirred at 0 °C for 10 min and 0.84 g (6.3 mmol) of
AlCl3 was added. The reaction was stirred at 0 °C for 3 days fol-
lowed by 2 days of stirring at ambient temperature. The reaction

2076
J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
B: JWH-386 was prepared by the procedure employed for the
137.9, 139.1, 191.0; GC/MS (EI) m/z (rel intensity) 419 (64), 402
(31), 362 (42), 334 (61), 214 (100); HRMS (EI+) m/z calcd for
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.07 g (0.44 mmol) of 1-propylindole and 0.10 g (0.40 mmol)
of 4-bromo-1-naphthoic acid there was obtained after column
chromatography (petroleum ether/ethyl acetate, 9:1) 0.12 g (72%)
of 1-propyl-3-(4-bromo-1-naphthoyl)indole as a yellow solid: mp
186–187 °C. The spectroscopic properties were identical to those
of material prepared by method A.
C24H22BrNO: 419.0885; found: 419.0086.
B: JWH-387 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.08 g (0.44 mmol) of 1-pentylindole and 4-bromo-1-naph-
thoyl chloride prepared from 0.10 g (0.40 mmol) of 4-bromo-
1-naphthoic acid there was obtained after chromatography
(petroleum ether/ethyl acetate, 9:1) 0.09 g (53%) of 1-pentyl-3-
(4-bromo-1-naphthoyl)indole as an orange oil. The spectroscopic
properties of material prepared by method B were identical to
those prepared by method A.
5.1.17. 2-Methyl-3-(4-bromo-1-naphthoyl)indole (18, R = CH3,
Ar = 4-bromonaphthyl)
2-Methyl-3-(4-bromo-1-naphthoyl)indole was prepared by the
procedure employed for the synthesis of 3-(4-chloro-1-naph-
thoyl)indole. From 0.12 g (0.88 mmol) of 2-methylindole and
freshly prepared 4-bromo-1-naphthoyl chloride from 0.20 g
(0.80 mmol) of 4-bromo-1-naphthoic acid, there was obtained
0.13 g (44%) of 2-methyl-3-(4-bromo-1-naphthoyl)indole as a yel-
low oil: 1H NMR (500 MHz, DMSO-d6) d 2.76 (s , 3H), 6.99 (d,
J = 8.0 Hz, 2H), 7.38–7.50 (m, 2H), 7.80 (d, J = 8.0 Hz, 2H), 7.84–
7.86 (m, 2H), 8.03 (d, J = 8.0 Hz, 1H), 8.36–8.38 (m, 1H), 12.09
(br, 1H); 13C NMR (75.5 MHz, DMSO-d6) d 15.8, 111.7, 114.0,
120.5, 122.6, 122.8, 125.0, 125.1, 126.0, 126.5, 128.1, 128.5,
129.0, 131.5, 131.7, 132.1, 135.9, 142.4, 148.7, 188.4.
5.1.20. 2-Methyl-1-pentyl-3-(4-bromo-1-naphthoyl)indole
(JWH-394, 11, R = C5H11, R0 = CH3, X = Br
A: JWH-394 was prepared by procedure A employed for the syn-
thesis of JWH-400. From 0.12 g (0.33 mmol) of 2-methyl-3-(4-bro-
mo-1-naphthoyl)indole, 0.08 g (1.48 mmol) of crushed KOH and
0.10 g (0.66 mmol) of 1-bromopentane there was obtained after
chromatography (petroleum ether/ether, 8:2) 0.014 g (10%) of 2-
methyl-1-pentyl-3-(4-bromo-1-naphthoyl)indole as a green oil:
1H NMR (500 MHz, CDCl3) d 0.96 (t, J = 7.0 Hz, 3H), 1.39–1.42 (m,
4H), 1.83 (p, J = 7.3 Hz, 2H), 2.55 (s, 3H), 4.15 (t, J = 7.8 Hz, 2H),
7.05 (t, J = 7.3 Hz, 1H), 7.19–7.24 (m, 2H), 7.35 (d, J = 8.0 Hz, 1H),
7.44 (d, J = 7.5 Hz, 1H), 7.52 (t, J = 8.3 Hz, 1H), 7.65 (t, J = 8.0 Hz,
1H), 7.86 (d, J = 7.5 Hz, 1H), 8.16 (d, J = 8.0 Hz, 1H), 8.39 (d,
J = 8.5 Hz, 1H); 13C NMR (125.77 MHz, CDCl3) d 12.7, 14.0, 22.4,
29.1, 29.4, 43.4, 109.6, 114.7, 121.1, 122.1, 122.4, 124.8, 125.8,
126.2, 127.0, 127.5, 127.7, 127.8, 129.3, 131.6, 132.3, 136.1,
140.7, 145.9, 192.3; GC/MS (EI) m/z (rel intensity) 433 (100), 418
(93), 377 (31), 354 (98), 348 (27), 298 (40), 254 (42), 233 (80);
HRMS (EI+) m/z calcd for C25H24BrNO: 433.1041; found: 433.1041.
B: JWH-394 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.11 g (0.57 mmol) of 2-methyl-1-pentylindole and 0.13 g
(0.52 mmol) of 4-bromo-1-naphthoic acid there was obtained after
chromatography (petroleum ether/ethyl acetate, 7:3) 0.16 g (73%)
of 2-methyl-1-pentyl-3-(4-bromo-1-naphthoyl)indole as a green
oil. The spectroscopic properties were identical to those of material
prepared by method A.
5.1.18. 2-Methyl-1-propyl-3-(4-bromo-1-naphthoyl)indole
(JWH-395, 11, R = C3H7, R0 = CH3, X = Br)
A: JWH-395 was prepared by procedure A employed for the syn-
thesis of JWH-400. From 0.22 g (0.60 mmol) of 2-methyl-1-propyl-
3-(4-bromo-1-naphthoyl)indole, 0.15 g (2.72 mmol) of crushed
KOH and 0.21 g (1.21 mmol) of 1-iodopropane there was obtained
after chromatography (petroleum ether/ether, 7:3) 0.12 g (50%) of
2-methyl-1-propyl-3-(4-bromo-1-naphthoyl)indole as
a green
solid, mp 51–53 °C: 1H NMR (300 MHz, CDCl3) d 1.02 (t, J =
7.5 Hz, 3H), 1.85 (sextet, J = 7.5 Hz, 2H), 2.54 (s, 3H), 4.11 (t,
J = 7.5 Hz, 2H), 7.04 (t, J = 7.2 Hz, 1H), 7.14–7.24 (m, 2H), 7.35 (d,
J = 8.4 Hz, 1H), 7.43 (d, J = 7.5 Hz, 1H), 7.51 (t, J = 7.2 Hz, 1H), 7.64
(t, J = 7.2 Hz, 1H), 7.86 (d, J = 7.5 Hz, 1H), 8.16 (d, J = 8.4 Hz, 1H),
8.38 (d, J = 8.4 Hz, 1H); 13C NMR (75.5 MHz, CDCl3) d 11.5, 12.7,
22.9, 44.9, 109.7, 114.7, 121.1, 122.1, 122.4, 124.8, 125.8, 126.2,
126.9, 127.5, 127.7, 127.8, 129.3, 131.6, 132.3, 136.2, 140.7,
146.0, 192.3; GC/MS (EI) m/z (rel intensity) 405 (82), 390 (31),
326 (100), 309(24): HRMS (ES+) m/z calcd for C23H20BrNO:
405.0728; found: 405.0721.
5.1.21. 1-Acetyl-4-iodonaphthalene (24, X = I)
To a stirred solution of 2.00 g (15.4 mmol) of AlCl3 in 10 mL of
freshly distilled CH2Cl2 under Ar at 0 °C was added dropwise
1.0 g (13.0 mmol) of acetyl chloride. The mixture was stirred at
0 °C for 10 min and 3.0 g (11.2 mmol) of 1-iodonaphthalene was
added dropwise over 10 min. The reaction was stirred at 0 °C for
72 h then stirred at ambient temperature for 48 h. The reaction
mixture was poured over ice and concentrated HCl, extracted into
ether and dried (MgSO4). The solvent was removed in vacuo and
the crude product was chromatographed (petroleum ether/ether,
7:3) to give 1.9 g (55%) of 1-acetyl-4-iodonaphthalene as a brown
oil, which was converted to the corresponding carboxylic acid
without further purification: 1H NMR (300 MHz, CDCl3) d 2.71 (s,
3H), 7.49 (d, J = 7.8 Hz, 1H), 7.58–7.64 (m, 2H), 8.08 (d, J = 7.5 Hz,
1H), 8.13–8.17 (m, 1H), 8.63–8.66 (m, 1H); 13C NMR (75.5 MHz,
CDCl3) d 30.2, 106.1, 126.5, 128.2, 128.6, 128.8, 130.4, 132.8,
134.6, 136.2, 136.3, 201.3; GC/MS (EI) m/z (rel intensity) 296(70),
281 (100), 253 (27), 126 (89). This compound was previously re-
ported by Rajasekaran and Gnanasekaran, however no spectro-
scopic data were presented.45
B: JWH-395 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.08 g (0.48 mmol) of 2-methyl-1-propylindole and 0.11 g
(0.45 mmol) of 4-bromo-1-naphthoic acid there was obtained after
column chromatography (petroleum ether/ethyl acetate, 8:2)
0.11 g (60%) of 2-methyl-1-propyl-3-(4-bromo-1-naphthoyl)indole
as a green oil. The spectroscopic properties were identical to those
of material prepared by method A.
5.1.19. 1-Pentyl-3-(4-bromo-1-naphthoyl)indole (JWH-387, 11,
R = C5H11, R0 = H, X = Br)
A: JWH-387 was prepared by procedure A employed for the syn-
thesis of JWH-400. From 0.10 g (0.28 mmol) of 3-(4-bromo-1-
naphthoyl)indole, 0.07 g (1.3 mmol) of crushed KOH and 0.09 g
(0.57 mmol) of 1-bromopentane there was obtained after chroma-
tography (petroleum ether/ether, 8:2) 0.022 g (18%) of JWH-387 as
an orange oil: 1H NMR (300 MHz, CDCl3) d 0.87 (t, J = 6.6 Hz, 3H),
1.25–1.31 (m, 4H), 1.80–1.85 (m, 2H), 4.09 (t, J = 7.2 Hz, 2H), 7.28
(s, 1H), 7.35–7.41 (m, 4H), 7.50–7.56 (m, 1H), 7.63–7.68 (m, 1H),
7.87 (d, J = 7.5 Hz, 1H), 8.20 (d, J = 8.4 Hz, 1H), 8.36 (d, J = 8.4 Hz,
1H), 8.48–8.51 (m, 1H); 13C NMR (75.5 MHz, CDCl3) d 13.9, 22.2,
28.9, 29.48, 47.2, 110.1, 117.4, 122.9, 123.0, 123.8, 124.8, 125.8,
126.5, 126.9, 127.4, 127.5, 127.8, 128.8, 132.0, 132.2, 137.1,
5.1.22. 4-Iodo-1-naphthoic acid (22, X = I)
Acid 22 (X = I) was prepared by the procedure employed for the
conversion of 1-acetyl-4-chloronaphthalene to 4-chloro-1-naph-
thoic acid. From 2.0 g (6.75 mmol) of 1-acetyl-4-iodonaphthalene

J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
2077
there was obtained after chromatography (petroleum ether/ether,
7:3) 1.2 g (56%) of methyl 4-iodo-1-naphthoate as a brown oil:
1H NMR (500 MHz, CDCl3) d 4.03 (s, 3H), 7.63–7.69 (m, 2H), 7.83
(d, J = 7.5 Hz, 1H), 8.17 (d, J = 7.5 Hz, 1H), 8.21 (d, J = 8.0 Hz, 2H);
13C NMR (125.77 MHz, CDCl3) d 52.4, 125.8, 126.2, 126.4, 127.8,
128.1, 128.5, 130.3, 133.0, 133.4, 136.5, 167.6; GC/MS (EI) m/z
(rel intensity) 312 (100), 281 (84), 253 (22), 126 (76).
Saponification of 1.1 g (3.5 mmol) of methyl-4-iodo-1-naphtho-
ate gave 0.90 g (86%) of 4-iodo-1-naphthoic acid as a white solid:
mp 209 °C (lit. mp 213 °C46); 1H NMR (500 MHz, DMSO-d6) d
7.72–7.74 (m, 2H), 7.84 (d, J = 8 Hz, 1H), 8.14 (dd, J = 3, 6.5 Hz,
1H), 8.27 (d, J = 7.5 Hz, 1H), 8.84 (dd, J = 3, 6.5 Hz, 1H), 13.35 (br
s, 1H); 13C NMR (125.77 MHz, DMSO-d6) d 106.1, 126.0, 126.8,
128.8, 128.9, 130.7, 131.5, 132.8, 134.4, 137.2, 168.8.
47.3, 101.9, 110.1, 117.5, 122.9, 123.0, 123.8, 126.3, 126.7, 126.9,
127.6, 128.2, 131.4, 132.5, 134.5, 136.4, 137.1, 138.0, 140.1,
191.0; GC/MS (EI) m/z (rel intensity) 467 (33), 410 (21), 214
(100), 144 (53); HRMS (ES+) m/z calcd for C24H22INO: 468.0824;
found: 468.0811.
5.1.26. 2-Methyl-1-pentyl-3-(4-iodo-1-naphthoyl)indole
(JWH-420, 12, R = C5H11, R0 = CH3, X = I)
JWH-420 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.10 g (0.50 mmol) of 2-methyl-1-pentylindole and 0.15 g
(0.50 mmol) of 4-iodo-1-naphthoic acid there was obtained after
chromatography (petroleum ether/ether, 7:3) 0.065 g (27%) of
2-methyl-1-pentyl-3-(4-iodo-1-naphthoyl)indole as a brown oil:
1H NMR (500 MHz, CDCl3) d 0.95 (t, J = 6.8 Hz, 3H), 1.39–1.42 (m,
4H), 1.81–1.84 (m, 2H), 2.55 (s, 3H), 4.15 (t, J = 7.5 Hz, 2H), 7.05
(t, J = 7.5 Hz, 1H), 7.19 (d, J = 8 Hz, 1H), 7.22 (t, J = 7.5 Hz, 1H),
7.28–7.29 (m, 1H), 7.35 (d, J = 8 Hz, 1H), 7.50 (t, J = 7.5 Hz, 1H),
7.62 (t, J = 8 Hz, 1H), 8.08 (d, J = 8.5 Hz, 1H), 8.17 (d, J = 7.5 Hz,
1H), 8.23 (d, J = 8.5 Hz, 1H); 13C NMR (125.77 MHz, CDCl3) d 12.7,
13.9, 22.4, 29.1, 29.3, 43.4, 101.7, 109.6, 114.7, 121.1, 122.2,
122.4, 126.2, 126.3, 126.9, 127.7, 128.1, 131.0, 132.6, 134.6,
136.1, 136.9, 141.6, 145.9, 192.3; GC/MS (EI) m/z (rel intensity)
481 (100), 466 (62), 354 (48), 281 (41); HRMS (ES+) m/z calcd for
5.1.23. 1-Propyl-3-(4-iodo-1-naphthoyl)indole (JWH-423, 12,
R = C3H7, R0 = H, X = I)
JWH-423 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.11 g (0.70 mmol) of 1-propylindole and 0.21 g (0.70 mmol)
of 4-iodo-1-naphthoic acid there was obtained after column chro-
matography (petroleum ether/ethyl acetate, 9:1) 0.022 g (7%) of 1-
propyl-3-(4-iodo-1-naphthoyl)indole as a pale cream powder: mp
160–161 °C; 1H NMR (500 MHz, CDCl3) d 0.79 (t, J = 7 Hz, 3H),
1.72–1.76 (m, 2H), 4.17 (t, J = 7 Hz, 2H), 7.33–7.35 (m, 2H), 7.43
(d, J = 7 Hz, 1H), 7.59 (t, J = 7.5 Hz, 1H), 7.64 (d, J = 7 Hz, 1H), 7.71
(t, J = 7.5 Hz, 1H), 7.81 (s, 1H), 7.98 (d, J = 8 Hz, 1H), 8.15 (d,
J = 8.5 Hz, 1H), 8.28 (d, J = 7.5 Hz, 1H), 8.32 (d, J = 6.5 Hz, 1H); 13C
NMR (125.77 MHz, CDCl3) d 11.3, 23.1, 48.9, 101.9, 110.1, 117.5,
122.9, 123.0, 123.8, 126.3, 126.7, 126.9, 127.6, 128.2, 131.4,
132.5, 134.5, 136.4, 137.1, 138.0, 140.1, 191.0; GC/MS (EI) m/z
(rel intensity) 439 (100), 422 (37), 410 (40), 186 (83); HRMS
(ES+) m/z calcd for C22H18INO: 440.0511; found: 440.0526.
C25H24INO: 482.0981; found: 482.0987.
5.1.27. 1-Propyl-3-(8-chloro-1-naphthoyl)indole (JWH-456, 14,
R = C3H7, R0 = H)
JWH-456 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414),
however the indole was stirred with dimethylaluminum chloride
for 1 h and the acid chloride and indole mixture was stirred for
6 h at ambient temperature. From 0.700 g (3.34 mmol) of 1-propy-
lindole and 0.549 g (2.66 mmol) of 8-chloro-1-naphthoic acid28
there was obtained after chromatography (petroleum ether/ether,
2:1) 0.425 g (46%) of 1-propyl-3-(8-chloro-1-naphthoyl)indole as
a yellow gum: 1H NMR (300 MHz, CDCl3) d 0.85 (t, J = 6 Hz, 3H),
1.75–1.87 (m, 2H), 4.00 (t, J = 6 Hz, 2H), 7.20 (s, 1H), 7.29–7.37
(m, 3H), 7.41(t, J = 9 Hz, 1H), 7.53–7.57 (m, 3H), 7.85 (d, J = 9 Hz,
1H), 7.96 (dd, J = 6 Hz, 3 Hz, 1H), 8.35 (s, 1H); 13C NMR
(75.5 MHz, CDCl3) d 11.2, 23.0, 48.7, 109.9, 118.6, 122.5, 122.7,
123.3, 125.4, 126.2, 126.7, 127.5, 127.8, 128.1, 128.7, 129.9,
130.8, 135.6, 137.0, 137.1, 139.0, 192.5; GC/MS (EI) m/z (rel inten-
sity) 347 (97), 312 (100), 270 (42); HRMS (ES+) m/z calcd for
C12H18ClNO: 348.1155; found: 348.1161.
5.1.24. 2-Methyl-1-propyl-3-(4-iodo-1-naphthoyl)indole
(JWH-422, 12, R = C3H7, R0 = CH3, X = I)
JWH-422 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.12 g (0.67 mmol) of 2-methyl-1-propylindole and 0.20 g
(0.67 mmol) of 4-iodo-1-naphthoic acid there was obtained after
column chromatography (petroleum ether/ether, 7:3) 0.039 g
(13%) of 2-methyl-1-propyl-3-(4-iodo-1-naphthoyl)indole as
a
green oil: 1H NMR (500 MHz, CDCl3) d 1.03 (t, J = 7.5 Hz, 3H), 1.86
(sextet, J = 7.5 Hz, 2H), 2.55 (s, 3H), 4.14 (t, J = 7.5 Hz, 2H), 7.04 (t,
J = 8 Hz, 1H), 7.18 (d, J = 8 Hz, 1H), 7.21 (t, J = 7.5 Hz, 1H), 7.28 (d,
J = 7.5 Hz, 1H), 7.35 (d, J = 8.5 Hz, 1H), 7.49 (t, J = 7.8 Hz, 1H), 7.62
(t, J = 7.8 Hz, 1H), 8.07 (d, J = 8.5 Hz, 1H), 8.17 (d, J = 7 Hz, 1H), 8.23
(d, J = 8.5 Hz, 1H); 13C NMR (125.77 MHz, CDCl3) d 11.5, 12.7, 22.9,
44.9, 101.7, 109.6, 114.7, 121.1, 122.1, 122.4, 126.1, 126.3, 126.9,
127.7, 128.1, 131.0, 132.5, 134.6, 136.2, 136.9, 141.6, 145.9, 192.3;
GC/MS (EI) m/z (rel intensity) 453 (100), 326 (58); HRMS (ES+) m/z
calcd for C23H20INO: 454.0668; found: 454.0665.
5.1.28. 2-Methyl-1-propyl-3-(8-chloro-1-naphthoyl)indole
(JWH-461, 14, R = C3H7, R0 = CH3)
JWH-461 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(8-chloro-1-naphthoyl)indole (JWH-456).
From 0.446 g (2.36 mmol) of 2-methyl-1-propylindole and
0.408 g (1.97 mmol) of 8-chloro-1-naphthoic acid there was ob-
tained after chromatography (petroleum ether/ether, 3:1) 0.447 g
(67%) of 2-methyl-1-propyl-3-(8-chloro-1-naphthoyl)indole as a
pale red gum: 1H NMR (300 MHz, CDCl3) d 0.95–0.99 (m, 3H),
1.78(s, 3H), 2.97 (s, 1 1/2H), 4.04 (m, 2H), 6.14 (br s, 1/2H), 6.72
(br s, 1/2H), 7.05–7.08 (m, 1H), 7.28 (d, J = 6 Hz, 1H), 7.35–7.40
(m, 1H), 7.44–7.52 (m, 3H), 7.82 (d, J = 6 Hz, 1H), 7.92 (d, J = 6 Hz,
1H), 8.69 (br s, 1/2H). 13C NMR (75.5 MHz, CDCl3) d 11.4, 12.5,
22.9, 44.7, 109.5, 114.4, 119.9, 121.5, 122.6, 126.0, 126.1, 126.8,
127.7, 127.8, 128.6, 129.7, 130.7, 134.2, 135.7, 136.0, 140.9,
145.9, 193.6. GC/MS (EI) m/z (rel intensity) 361 (23), 326 (100),
284 (68), 269 (23); HRMS (ES+) m/z calcd for C23H20ClNO:
362.1312; found: 362.1310.
5.1.25. 1-pentyl-3-(4-iodo-1-naphthoyl)indole (JWH-421, 12,
R = C5H11, R0 = H, X = I)
JWH-421 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.13 g (0.67 mmol) of 1-pentylindole and 0.20 g (0.67 mmol)
of 4-iodo-1-naphthoic acid there was obtained after chromatogra-
phy (petroleum ether/ether, 1:1) 0.047 g (15%) of 1-pentyl-3-
(4-iodo-1-naphthoyl)indole as
a
peach colored oil: 1H NMR
(500 MHz, CDCl3) d 0.89 (t, J = 7.5 Hz, 3H), 1.30–1.36 (m, 4H),
1.83–1.86 (m, 2H), 4.08 (t, J = 7.5 Hz, 2H), 7.35 (s, 1H), 7.36–7.42
(m, 4H), 7.51 (t, J = 8 Hz, 1H), 7.62 (t, J = 8 Hz, 1H), 8.15 (d,
J = 8.5 Hz, 1H), 8.19 (d, J = 7 Hz, 1H), 8.22 (d, J = 8.5 Hz, 1H), 8.48–
8.50 (m, 1H); 13C NMR (75.5 MHz, CDCl3) d 13.9, 22.2, 28.9, 29.5,

2078
J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
5.1.29. 1-Pentyl-3-(8-chloro-1-naphthoyl)indole (JWH-457, 14,
R = C5H11, R0 = H)
4.14–4.18 (m, 2H), 7.27–7.33 (m, 2H), 7.49 (t, J = 8.0 Hz, 1H), 7.61
(t, J = 7.0 Hz, 2H), 7.67 (t, J = 7.5 Hz, 1H), 7.88 (d, J = 7.0 Hz, 1H),
8.12 (d, J = 8.0 Hz, 1H), 8.16 (d, J = 8.0 Hz, 1H); 13C NMR
(125.77 MHz, DMSO-d6) d 11.3, 23.1, 48.0, 111.4, 118.3, 119.6,
122.1, 122.7, 123.5, 126.2, 126.8, 127.4, 128.4, 129.1, 129.5, 130.7,
133.5, 136.1, 137.3, 139.0, 140.0, 191.5: GC/MS (EI) m/z (rel inten-
sity) 391 (10), 312 (100), 270 (99), 254 (26), 241 (25); HRMS (ES+)
m/z calcd for C22H18BrNO: 392.0650; found: 392.0637.
JWH-457 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414),
however the indole was stirred with dimethylaluminum chloride
for 1 h and the acid chloride and indole mixture was stirred for
6 h at ambient temperature. From 0.780 g (2.90 mmol) of 1-propy-
lindole and 0.507 g (2.42 mmol) of 8-chloro-1-naphthoic acid there
was obtained after chromatography (petroleum ether/ether, 3:1)
0.304 g (33%) of 1-pentyl-3-(8-chloro-1-naphthoyl)indole (JWH-
457) as an dark brown oil: 1H NMR (300 MHz, CDCl3) d 0.79 (t,
J = 6 Hz, 3H), 1.08–1.26 (m, 4H), 1.66–1.75 (m, 2H), 3.94 (t,
J = 6 Hz, 2H), 7.15 (s, 1H), 7.26–7.32 (m, 3H), 7.34(m, 1H),
7.45–7.53 (m, 3H), 7.79 (d, J = 9 Hz, 1H), 7.90 (dd, J = 9 Hz, 3 Hz,
1H), 8.39 (s, 1H); 13C NMR (75.5 MHz, CDCl3) d 13.7, 21.9, 28.6,
29.1, 46.8, 109.8, 118.4, 122.4, 122.5, 123.2, 125.3, 126.0, 126.6,
127.4, 127.7, 127.9, 128.6, 129.8, 130.6, 135.4, 136.8, 137.0,
138.8, 192.3; GC/MS (EI) m/z (rel intensity) 375 (80), 340 (100),
270 (48); HRMS (ES+) m/z calcd for C24H22ClNO: 376.1468; found:
376.1459.
At 100 °C: 1H NMR (500 MHz, DMSO-d6) d 0.82 (t, J = 7.3 Hz,
3H), 1.78 (sextet, J = 7.3 Hz, 2H), 4.15 (t, J = 7.5 Hz, 2H), 7.24 (t,
J = 7.5 Hz, 1H), 7.29 (t, J = 7.5 Hz, 1H), 7.45 (d, J = 8.0 Hz, 1H), 7.49
(s, 1H), 7.56 (d, J = 8.5 Hz, 1H), 7.60 (d, J = 7.0 Hz, 1H), 7.65 (t,
J = 7.5 Hz, 1H), 7.86 (d, J = 7.5 Hz, 1H), 8.09 (d, J = 8.5 Hz, 1H),
8.13 (t, J = 7.8 Hz, 2H).
5.1.33. 2-Methyl-1-propyl-3-(8-bromo-1-naphthoyl)indole
(JWH-429, 15, R = C3H7, R0 = CH3)
JWH-429 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.13 g (0.66 mmol) of 2-methyl-1-propylindole and 0.15 g
(0.60 mmol) of 8-bromo-1-naphthoic acid there was obtained after
chromatography (petroleum ether/ethyl acetate, 8:2) 0.04 g (16%)
of 2-methyl-1-propyl-3-(8-bromo-1-naphthoyl)indole as a green
5.1.30. 2-Methyl-1-pentyl-3-(8-chloro-1-naphthoyl)indole
(JWH-462, 14, R = C5H11, R0 = CH3)
JWH-462 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(8-chloro-1-naphthoyl)indole (JWH-456).
From 0.746 g (3.67 mmol) of 2-methyl-1-pentylindole and 0.632 g
(3.06 mmol) of 8-chloro-1-naphthoic acid there was obtained after
column chromatography (petroleum ether/ether, 3:1) 0.644 g (54%)
of 2-methyl-1-pentyl-3-(8-chloro-1-naphthoyl)indole as a dark
brown oil: 1H NMR (300 MHz, CDCl3) d 0.85–0.88 (m, 3H),
1.31–1.41 (m, 4H), 1.74 (s, 3H), 2.96 (s, 1 1/2H), 3.96–4.07 (m,
2H), 6.15 (br s, 1/2H), 6.71 (br s, 1/2H), 7.03 (m, 1H), 7.26 (d,
J = 6 Hz, 1H), 7.33 (t, J = 9 Hz, 1H), 7.44–7.50 (m, 3H), 7.78 (d, J
= 6 Hz, 1H), 7.88 (d, J = 6 Hz, 1H), 8.71 (br s, 1/2H). 13C NMR
(75.5 MHz, CDCl3) d 12.2, 13.6, 21.9, 28.6, 28.9, 42.7, 109.3, 113.9,
119.5, 121.3, 122.2, 125.6, 125.8, 126.4, 127.3, 127.5, 128.2, 129.4,
130.2, 135.4, 135.7, 140.6, 144.1, 145.5, 193.1. GC/MS (EI) m/z (rel
intensity) 389 (21), 354 (100), 284 (81), 269 (25); HRMS (ES+) m/z
calcd for C25H24ClNO: 390.1625; found: 390.1616.
oil: 1H NMR (Ambient Temperature, 500 MHz, DMSO-d6)
d
0.81–0.90 (m, 3H), 1.65–1.76 (m, 2H), 2.89 (s, 1 1/2H), 4.23–4.24
(m, 2H), 6.63–6.66 (m, 1/2H), 7.01–7.03 (m, 1/2H), 7.26–7.27 (m,
1/2H), 7.43–7.54 (m, 2 1/2H), 7.64 (t, J = 7.5 Hz, 1H), 7.83–7.91
(m, 1H), 8.11–8.17 (m, 2H), 8.39 (br s, 1/2H); (At 100 °C: 1H NMR
(500 MHz, DMSO-d6)
d 0.89 (t, J = 7.5 Hz, 3H), 1.76 (sextet,
J = 7.3 Hz, 2H), 2.89 (br s, 3H), 4.17 (t, J = 7.0 Hz, 2H), 6.92 (br s,
1H), 7.13 (t, J = 7.5 Hz, 1H), 7.45 (t, J = 7.5 Hz, 3H), 7.63 (t,
J = 7.5 Hz, 1H), 7.83 (d, J = 7.5 Hz, 1H), 8.07 (d, J = 8.0 Hz, 1H),
8.12 (d, J = 8.5 Hz, 1H); 13C NMR (75.5 MHz, DMSO-d6) d 11.5,
14.3, 23.0, 44.7, 109.5, 120.0, 120.2, 121.4, 121.6, 122.7, 125.9,
126.6, 127.4, 127.7, 128.6, 129.2, 130.16, 132.9, 136.1, 142.2,
144.4, 146.0, 193.5. GC/MS (EI) m/z (rel intensity) 405 (10), 326
(100), 284 (79), 269 (31); HRMS (ES+) m/z calcd for C23H20BrNO:
406.0807; found: 406.0788.
5.1.34. 1-Pentyl-3-(8-bromo-1-naphthoyl)indole (JWH-424, 15,
R = C5H11, R0 = H)
5.1.31. 8-Bromo-1-naphthoic acid (27)
To a mixture of 3.9 mL (67 mmol) of acetic acid and 0.40 mL
(22.2 mmol) of H2O was added with stirring 1.0 g (2.70 mmol) of
anhydro-8-hydroxymercuri-1-naphthoic acid26 and the suspen-
sion was stirred at 0 °C for 10 min. A solution of 0.89 g (8.66 mmol)
of NaBr in 3.2 mL of water and 0.43 g (2.70 mmol) of bromine were
added sequentially and the reaction was slowly heated to 100 °C.
After cooling to ambient temperature the mixture was poured into
ice and 0.57 g (84%) of 8-bromo-1-naphthoic acid was filtered out
as a cream colored solid: mp 173–174 °C (lit. mp 174–175 °C26); 1H
NMR (500 MHz, DMSO-d6) d 7.49 (t, J = 7.8 Hz, 1H), 7.61 (t,
J = 7.3 Hz, 1H), 7.68 (d, J = 7.0 Hz, 1H), 7.96 (d, J = 7.3 Hz, 1H),
8.07 (d, J = 8.0 Hz, 1H), 8.11 (d, J = 8.0 Hz, 1H), 13.32 (s, 1H); 13C
NMR (125.77 MHz, DMSO-d6) d 119.3, 126.3, 127.6, 128.0, 128.3,
129.4, 131.2, 133.6, 133.9, 135.7, 171.3.
JWH-424 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.12 g (0.66 mmol) of N-pentylindole and 0.15 g (0.60 mmol)
of 8-bromo-1-naphthoic acid there was obtained after chromatog-
raphy (petroleum ether/ethyl acetate, 7:3) 0.20 g (78%) of
N-pentyl-3-(8-bromo-1-naphthoyl)indole as a brown oil: 1H NMR
(Ambient Temperature, 500 MHz, DMSO-d6) d 0.86 (t, J = 7.0 Hz,
3H), 1.22–1.32 (m, 4H), 1.77–1.81 (m, 2H), 4.00–4.02 (m, 2H),
7.19–7.29 (m, 1H), 7.31–7.43 (m, 4H), 7.53 (t, J = 7.5 Hz, 1H), 7.62
(d, J = 7.0 Hz, 1H), 7.80 (d, J = 8.5 Hz, 1H), 7.96 (d, J = 8.0 Hz, 1H);
13C NMR (75.5 MHz, CDCl3) d 14.0, 22.2, 28.8, 29.4, 47.1, 110.1,
119.3, 120.2, 122.7, 122.8, 123.5, 125.4, 126.7, 126.9, 128.1,
128.7, 129.5, 130.4, 133.1, 136.0, 137.1, 137.3, 140.1, 192.3; GC/
MS (EI) m/z (rel intensity) 421 (3), 340 (100), 270 (58); HRMS
(ES+) m/z calcd for C24H22BrNO: 420.0963; found: 420.0959.
5.1.32. 1-Propyl-3-(8-bromo-1-naphthoyl)indole (JWH-428, 15,
R = C3H7, R0 = H)
5.1.35. 2-Methyl-1-pentyl-3-(8-bromo-1-naphthoyl)indole
(JWH-425, 15, R = C5H11, R0 = CH3)
JWH-428 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.08 g (0.53 mmol) of N-propylindole and 0.12 g (0.48 mmol)
of 8-bromo-1-naphthoic acid there was obtained after column
chromatography (petroleum ether/ethyl acetate, 8:2) 0.09 g (48%)
of 1-propyl-3-(8-bromo-1-naphthoyl)indole as an orange solid:
mp 101–102 °C; 1H NMR (Ambient Temperature, 500 MHz,
JWH-425 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.13 g (0.66 mmol) of 2-methyl-1-pentylindole and 0.15 g
(0.60 mmol) of 8-bromo-1-naphthoic acid there was obtained after
chromatography (petroleum ether/ethyl acetate, 9:1) 0.04 g (15%)
of 2-methyl-1-pentyl-3-(8-bromo-1-naphthoyl)indole as a brown
DMSO-d6)
d
0.74 (t, J = 7.0 Hz, 3H), 1.71 (q, J = 7.0 Hz, 2H),
oil: 1H NMR (Ambient Temperature, 500 MHz, DMSO-d6)
d

J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
2079
0.83–0.88 (m, 3H), 1.25–1.34 (m, 4H), 1.64–1.77 (m, 2H), 2.91 (s, 1
5.1.39. 1-Pentyl-3-(8-iodo-1-naphthoyl)indole (JWH-416, 16,
R = C5H11, R0 = H)
1/2H), 4.21–4.27 (m, 2H), 5.89 (br s, 1/2H), 6.67 (br s, 1/2H), 7.04
(br s, 1/2H), 7.27 (br s, 1H), 7.48–7.52 (m, 2 ½H), 7.65 (t,
J = 7.5 Hz, 1H), 7.86–7.91 (m, 1H), 8.13–8.17 (m, 1 1/2H), 8.41 (br
s, 1/2H); 13C NMR (125.77 MHz, DMSO-d6) d 12.7, 14.0, 22.4,
29.1, 29.4, 43.4, 109.7, 120.1, 121.4, 121.7, 122.7, 125.9, 126.6,
127.4, 127.5, 128.6, 130.1, 132.9, 133.4, 135.4, 136.1, 142.2,
144.3, 146.0, 193.5. GC/MS (EI) m/z (rel intensity) 433 (6), 354
(78), 284 (100), 269 (28); HRMS (ES+) m/z calcd for C25H24BrNO:
434.1120; found: 434.1128.
JWH-416 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.10 g (0.57 mmol) of 1-pentylindole and 0.23 g (0.77 mmol)
of 8-iodo-1-naphthoic acid there was obtained after chromatogra-
phy (petroleum ether/ether, 1:1) 0.040 g (11%) of 1-pentyl-3-
(8-iodo-1-naphthoyl)indole as a yellow oil: 1H NMR (Ambient
Temperature, 500 MHz, DMSO-d6)
d 0.88 (t, J = 7.0 Hz, 3H),
1.26–1.32 (m, 4H), 1.81–1.83 (m, 2H), 4.04–4.14 (m, 2H), 7.20 (t,
J = 7.0 Hz, 1H), 7.38–7.43 (m, 2 1/2H), 7.54 (t, J = 7.0 Hz, 1H), 7.67
(d, J = 7.0 Hz, 1H), 7.95 (d, J = 8.0 Hz, 2H), 8.22 (d, J = 7.5 Hz, 1H);
13C NMR (125.77 MHz, CDCl3) d 13.9, 22.2, 28.8, 29.4, 47.1, 93.2,
109.9, 122.7, 123.0, 123.5, 125.1, 126.9, 127.0, 127.3, 128.5,
129.1, 129.5, 130.9, 132.0, 132.2, 135.7, 137.1, 141.6, 191.6; GC/
MS (EI) m/z (rel intensity) 341 (100), 324 (48), 284 (86), 214
(85), 144 (48); HRMS (EI+) calcd for C24H22INO: 467.0747; found:
467.0742.
5.1.36. 8-Iodo-1-naphthoic acid (28)
To 5.00 g (13.5 mmol) of anhydro-8-(hydroxymercuri)-1-naph-
thoic acid was added 9.63 g (58.0 mmol) of potassium iodide in
47 mL of H2O. After dissolution, 3.42 g (13.5 mmol) of iodine was
added and the reaction mixture was heated at reflux for 15 h.
The solution was cooled to ambient temperature and a brown pre-
cipitate was filtered out. To the filtrate was added 1.62 g (10 mmol)
of sodium thiosulfate in 9 mL of H2O to destroy excess iodine and
the solution was acidified by the dropwise addition of concd HCl.
The crude acid was filtered out, dissolved in hot acetone and con-
centrated in vacuo. Recrystallization from CHCl3 gave 2.1 g (52%) of
8-iodo-1-naphthoic acid as a white solid: mp 155–156 °C (lit. mp
164–165°C26); 1H NMR (500 MHz, CDCl3) d 7.23 (t, J = 7.8 Hz, 1H),
7.51 (t, J = 7.5 Hz, 1H), 7.90 (d, J = 8.0 Hz, 1H), 7.93 (d, J = 7.5 Hz,
2H), 8.27 (d, J = 7.5 Hz, 1H), 12.63 (br s, 1H); 13C NMR
(125.77 MHz, CDCl3) d 93.1, 125.1, 127.5, 129.5, 129.6, 131.4,
132.6, 133.5, 135.4, 141.9, 175.5.
5.1.40. 2-Methyl-1-pentyl-3-(8-iodo-1-naphthoyl)indole (JWH-
417, 16, R = C5H11, R0 = CH3)
JWH-417 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.17 g (0.84 mmol) of 2-methyl-1-pentylindole and 0.25 g
(0.84 mmol) of 8-iodo-1-naphthoic acid there was obtained after
chromatography (petroleum ether/ether, 1:1) 0.25 g (64%) of
2-methyl-1-pentyl-3-(8-iodo-1-naphthoyl)indole as a brown oil:
1H NMR (Ambient Temperature, 500 MHz, DMSO-d6) d 0.84–0.89
(m, 3H), 1.24–1.36 (m, 4H), 1.65–1.84 (m, 2H), 2.91 (s, 1 1/2H),
4.17–4.28 (m, 2H), 5.99–6.01 (m, 1/2H), 6.69–6.71 (m, 1/2H),
7.03–7.06 (m, 1/2H), 7.28–7.31 (m, 2H), 7.45–7.48 (m, 1H),
7.52–7.61 (m, 2H), 8.13–8.26 (m, 3H), 8.43 (br s, 1/2H); 13C NMR
(125.77 MHz, DMSO-d6) d 13.0, 14.3, 22.3, 28.8, 29.4, 43.1, 93.8,
110.7, 119.7, 121.5, 122.0, 122.6, 123.0, 126.4, 127.9, 130.0,
131.1, 131.6, 135.8, 136.2, 141.7, 144.0, 146.3, 191.8; GC/MS (EI)
m/z (rel intensity) 481 (3), 354 (70), 284 (100), 269 (45), 254
(28); HRMS (ES+) m/z calcd for C25H24INO: 482.0981; found:
482.0961.
5.1.37. 1-Propyl-3-(8-iodo-1-naphthoyl)indole (JWH-419, 16,
R = C3H7, R0 = H)
JWH-419 was prepared by the procedure employed for the syn-
thesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.11 g (0.69 mmol) of 1-propylindole and 0.31 g (1.0 mmol)
of 8-iodo-1-naphthoic acid there was obtained after chromatogra-
phy (petroleum ether/ether, 1:1) 0.064 g (21%) of N-propyl-3-
(8-iodo-1-naphthoyl)indole as a brown oil: 1H NMR (Ambient
temperature, 500 MHz, DMSO-d6)
d 0.78 (t, J = 7.5 Hz, 3H),
5.2. Receptor binding experiments
1.73 (q, J = 7.0 Hz, 2H), 4.15–4.22 (m, 2H), 7.28–7.33 (m, 3H),
7.62–7.65 (m, 3 1/2H), 8.11–8.14 (m, 2H), 8.23 (d, J = 7.0 Hz, 1H);
13C NMR (125.77 MHz, DMSO-d6) d 11.3, 23.1, 48.0, 94.1, 111.3,
119.3, 122.3, 122.3, 122.7, 123.5, 125.9, 126.9, 127.8, 128.7,
130.0, 131.2, 131.9, 135.8, 137.3, 141.8, 141.9, 190.9; GC/MS (EI)
m/z (rel intensity) 439 (2), 312 (100), 270 (63); HRMS (ES+) m/z
calcd for C22H18INO: 440.0511; found: 440.0491.
5.2.1. Materials
All chemicals were from Sigma (St. Louis, MO) except the
following: [35S]GTP
c
S (1250 Ci/mmol) was purchased from New
England Nuclear Group (Boston, MA), GTP S from Boehringer
c
Mannheim (New York, NY), and DMEM/F-12 from Fischer Scientific
(Pittsburg, PA). Whatman GF/B glass fiber filters were purchased
from Fisher Scientific (Pittsburgh, PA).
5.1.38. 2-Methyl-1-propyl-3-(8-iodo-1-naphthoyl)indole (JWH-
418, 16, R = C3H7, R0 = CH3)
5.2.2. Membrane preparations
JWH-418 was prepared by the procedure employed for the
synthesis of 1-propyl-3-(4-fluoro-1-naphthoyl)indole (JWH-414).
From 0.14 g (0.84 mmol) of 2-methyl-1-propylindole and 0.36 g
(1.2 mmol) of 8-iodo-1-naphthoic acid there was obtained after
chromatography (petroleum ether/ether, 3:7) 0.13 g (35%) of
2-methyl-1-propyl-3-(8-iodo-1-naphthoyl)indole as a brown oil:
1H NMR (Ambient Temperature, 500 MHz, DMSO-d6) d 0.87–0.95
(m, 3H), 1.70–1.86 (m, 2H), 2.91 (s, 1 1/2H), 4.16–4.27 (m, 2H),
5.99–6.00 (m, 1/2H), 6.69–6.72 (m, 1/2H), 7.03–7.06 (m, 1/2H),
7.28–7.31 (m, 1 1/2H), 7.44–7.46 (m, 1H), 7.54–7.62 (m, 2H),
8.12–8.15 (m, 2H), 8.20–8.28 (m, 1H), 8.42 (br s, 1/2H); 13C NMR
(125.77 MHz, DMSO-d6) d 11.5, 13.0, 23.0, 44.9, 92.9, 109.3, 109.7,
116.0, 120.5, 121.4, 121.7, 122.7, 125.7, 127.1, 128.0, 129.5, 130.7,
132.0, 135.9, 141.4, 143.8, 146.2, 192.8; GC/MS (EI) m/z (rel inten-
sity) 453 (6), 326 (100), 284 (95), 269 (54), 254 (31); HRMS (ES+)
m/z calcd for C23H20INO: 454.0668; found: 454.0662.
Human embryonic kidney-293 cells stably expressing the hu-
man CB1 receptor were cultured in DMEM with 10% fetal bovine
serum, and Chinese hamster ovary cells stably expressing the
human CB2 receptor were cultured in DMEM with 10% fetal calf
serum. Cells were harvested by replacement of the medium with
ice-cold phosphate-buffered saline containing 1 mM EDTA fol-
lowed by centrifugation at 1000g for 5 min at 4 °C. The pellet
was resuspended in 50 mM Tris–HCl containing 320 mM sucrose,
2 mM EDTA, and 5 mM MgCl2, pH 7.4 (centrifugation buffer), and
then centrifuged at 1000g for 10 min at 4 °C, and the resulting
supernatant was saved. This process was repeated twice. The
supernatant fractions were combined and centrifuged at 40,000g
for 30 min at 4 °C. The resulting P2 pellet was resuspended in assay
buffer (50 mM Tris–HCl, pH 7.4, 3 mM MgCl2, 0.2 mM EGTA, and
100 mM NaCl), and protein was measured. Membranes were
stored at ꢁ80 °C until use.

2080
J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
5.2.3. Receptor binding
interruptions of the photocell beams (16 beams per chamber) for a
Membrane homogenates (50
l
g) were incubated with 0.5 nM
10-min period using a Digiscan Animal Activity Monitor (Omnitech
Electronics Inc., Columbus, OH). Activity in the chamber was re-
corded as the total number of beam interruptions and was ex-
pressed as % inhibition of the level of activity of the vehicle group.
[3H]CP 55,940 in the presence of varying concentrations
(1 nM–10
bovine serum albumin (5 mg/mL). Nonspecific binding was mea-
sured in the presence of 1 M CP 55,940. The assay was incubated
lM) of test compounds in 0.5 mL of buffer containing
l
at 30 °C for 1 h and terminated by the addition of ice-cold 50 mM
Tris-HCl containing bovine serum albumin (1 mg/mL, pH 7.4)
followed by filtration under vacuum through Whatman GF/B glass
fiber filters with three washes with ice-cold Tris buffer. Bound
radioactivity was determined by liquid scintillation spectropho-
tometry at 50% efficiency after extraction by shaking samples for
30–60 min with Budget–Solve scintillation fluid.
5.4.3. Tail-flick latency
Antinociception was assessed using the tail-flick procedure. The
heat lamp of the tail-flick apparatus was maintained at an intensity
sufficient to produce control latencies of 2–3 s. Control values for
each animal were determined prior to drug administration. Mice
were then re-evaluated following drug administration and latency
(s) to tail-flick response was recorded. A 10-sec maximum was im-
posed to prevent tissue damage. The degree of antinociception was
expressed as the % MPE (maximum possible effect) which was cal-
culated as:
5.3. [35S]GTPcS binding
5.3.1. [35S]GTP
c
S binding assay
ꢀ
ꢁ
Prior to assays, samples were thawed on ice, centrifuged at
50,000g for 10 min at 4 °C, and resuspended in Assay Buffer
(50 mM Tris–HCl (pH 7.4), 3 mM MgCl2, 0.2 mM EGTA, and
100 mM NaCl). Concentration–effect curves were generated by
ðtest latency ꢁ control latencyÞ
ð10 s ꢁ test latencyÞ
%MPE ¼
incubating membranes (10
albumin (1 mg/mL) with various concentrations of test compounds
in the presence of 20 S in a 1 mL of
M GDP and 0.1 nM [35S]GTP
total volume. [35S]GTP
S binding stimulated by 2 M CP55,940
was used as an internal standard in each assay. Basal binding
was assessed in the absence of agonist, and nonspecific binding
lg) in assay buffer and bovine serum
5.4.4. Core temperature
Hypothermia was assessed by first measuring baseline core
temperatures prior to drug treatment with a telethermometer
(Yellow Springs Instrument Co., Yellow Springs, OH) and a rectal
thermistor probe inserted to 25 mm. Rectal temperatures were
also measured following drug administration. Rectal temperature
values were expressed as the difference between control tempera-
ture (before injection) and temperatures following drug adminis-
l
c
l
c
was measured in the presence of 10 lM GTPcS. The reaction was
incubated for 90 min at 30 °C and terminated by filtration under
vacuum through Whatman GF/B glass fiber filters with three
washes with ice-cold (4 °C) Tris buffer (50 mM Tris–HCl, pH 7.4).
Bound radioactivity was determined by liquid scintillation spectro-
photometry at 95% efficiency after extraction overnight in Scinti-
Safe Econo 1 scintillation fluid (Fisher Scientific, Hampton, NH).
tration (D°C).
5.4.5. Catalepsy
Catalepsy was determined by using a slight modification of the
ring test as developed by Pertwee.48 Mice were injected iv with
either vehicle or cannabinoid and 40 min after treatment were
placed on a ring (5.5 cm in diameter) which was attached to a ring
stand and raised to a height of 16 cm. Mice were rated for catalepsy
by observers who were blind with regard to treatment. During a
5-min test session, the amount of time (sec) for which the mouse
was motionless (except for respiratory movements) was deter-
mined. Mice that either fell or actively jumped from the ring were
allowed 5 such ‘escapes.’ If these occurred before 2.5 min, the ani-
mal’s data were disregarded. An immobility index was determined
by dividing the amount of time spent motionless by the length of
the test session (300 s) and multiplying by 100 to determine an
immobility index for each mouse.
5.3.2. Data analysis
All in vitro data are reported as the means SEM of at least
three experiments, each performed in triplicate. For the receptor
binding experiments, displacement IC50 values were originally
determined by Hill plots and then converted to Ki values using
the method of Cheng and Prusoff.47 For the [35S]GTP
cS binding
experiment, nonlinear regression analysis was conducted to obtain
EC50 and Emax values of agonist-stimulated [35S]GTP
cS binding by
iterative curve fitting with JMP (SAS, Cary, NC).
5.4. Pharmacology
5.4.1. Subjects
5.4.6. Data analysis
Male ICR mice (Harlan Laboratories, Dublin, VA) weighing
18–25 g were maintained on a 14:10 hr light:dark cycle with free
access to food and water.
When supply of a compound was sufficient to evaluate multiple
doses, potency was determined based on a scheme we have used in
numerous previous studies with cannabinoids, with maximal can-
nabinoid effects in each procedure estimated as follows: 90% inhi-
bition of spontaneous activity, 100% MPE in the tail flick procedure,
ꢁ6 °C change in rectal temperature, and 60% ring immobility. ED50
was defined as the dose at which half maximal effect occurred. For
compounds that produced one or more cannabinoid effect, ED50
was calculated separately using least-squares linear regression
on the linear part of the dose–effect curve for each measure in
the mouse tetrad, plotted against log10 transformation of the dose.
When limited supply prevented assessment of potency, a probe
dose of the compound was tested the in vivo test battery. In these
cases, the test dose is specified in the appropriate table and values
obtained in each test are reported directly as % inhibition of
locomotion, % maximal antinociceptive effect, change in rectal
temperature, and % ring immobility.
D
9-THC was obtained from the National
Institute on Drug Abuse. All compounds were dissolved in 1:1:18
(emulphor–ethanol–saline) for in vivo administration. Emulphor
(EL-620, a polyoxyethylated vegetable oil, GAF Corporation, Lin-
den, NJ) is currently available as Alkmulphor. All drug injections
were administered iv (tail vein) at a volume of 0.1 mL/10 g of body
weight. Following drug administration each animal was tested for
effects on the following procedures: spontaneous (locomotor)
activity at 5–15 min, tail-flick latency (antinociception) response
at 20 min, core (rectal) temperature at 30 min and ring immobility
(catalepsy) at 40–45 min. Separate mice were tested with each
dose of a compound (n = 6 per dose).
5.4.2. Spontaneous activity
Measurement of locomotor activity was accomplished by plac-
ing mice into individual activity cages (6.5 ꢃ 11 in), and recording

J. L. Wiley et al. / Bioorg. Med. Chem. 20 (2012) 2067–2081
2081
20. Huffman, J. W.; Zengin, G.; Wu, M.-J.; Lu, J.; Hynd, G.; Bushell, K.; Thompson, A.
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Acknowledgments
The work at Clemson was supported by Grant DA03590 to
J.W.H. and that at the Research Triangle Institute by Grants DA-
031988 and DA-03672 to J.L.W., all from the National Institute
on Drug Abuse.
22. Okauchi, T.; Itonaga, M.; Minami, T.; Owa, T.; Kitoh, K.; Yoshino, H. Org. Lett.
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