Scholarly article on 3,5-di-tert-butyl-4-hydroxyphenylacetyl chloride 40056-42-6 from Bioorganic and Medicinal Chemistry p. 4827

Bioorganic & Medicinal Chemistry 11 (2003) 4827–4845

Inhibitors of Lipoprotein(a) Assembly

Karen E. Sexton,^aHelen T. Lee,^a,* Mark Massa,^cJanak Padia,^dWilliam C. Patt,^a

Peggy Liao,^eJason K. Pontrello,^fBruce D. Roth,^a

Mark A. Spahr^band Randy Ramharack^b

^aDepartment of Medicinal Chemistry, Pﬁzer Global Research and Development, 2800 Plymouth Road,

Ann Arbor, MI, 48105, USA

^bDepartment of Molecular Biology, Pﬁzer Global Research and Development, 2800 Plymouth Road,

Ann Arbor, MI, 48105, USA

^cMonsanto, St. Louis, MO, USA

^dChemRX Advanced Technologies, Phoenix, AZ, USA

^eDuke University, Raleigh, NC, USA

^fUniversity of Wisconsin-Madison, Madison, WI, USA

Received 26 July 2001; accepted 5 April 2002

Abstract—Compounds of the general structure A and B were investigated for their activity as lipoprotein(a), [Lp(a)], assembly

(coupling) inhibitors. SAR around the amino acid derivatives (structure A) gave compound 14-6 as a potent coupling inhibitor.

Oral dosing of compound 14-6 to Lp(a) transgenic mice and cymologous monkeys resulted in a>30% decrease in plasma Lp(a)

levels after 1–2 weeks of treatment at 100 mg/kg/day.

Introduction

Lp(a) consists of two particles, apolipoprotein(a),

[apo(a)], and apolipoproteinB-100, (apoB-100), of low

density lipoprotein (LDL).¹Apo(a) is highly related to

plasminogen. However, unlike plasminogen, apo(a)

contains multiple and variable amounts of the kringleIV

domain.⁴Both apo(a) and apoB-100 are synthesized

predominantly by the liver and coupled through a single

disulﬁde bond to form Lp(a). The coupling reaction is

thought to occur extracellularly.¹Unlike LDL, plasma

Lp(a) levels are genetically determined and unaﬀected

by diet, exercise and commonly used lipid lowering

agents.⁴A suitable treatment for elevated plasma Lp(a)

would have great potential in treating those that do not

respond to current therapies.

Current therapies for the treatment and prevention of

premature atherosclerotic vascular disease (i.e., cor-

onary heart disease and stroke) are changes in diet,

exercise and administration of lipid lowering agents.

However, there still remains a signiﬁcant number of

patients who do not beneﬁt from the latter protective

measures.¹This suggests the presence of additional risk

factors that are not modiﬁed by existing therapies. One

of these additional risk factors may be lipoprotein(a),

[Lp(a)], for which there is no suitable treatment.¹Some

epidemiological studies have demonstrated that plasma

Lp(a) levels >20–30 mg/dL is an independent risk fac-

tor for the development of premature atherosclerotic

vascular disease.¹Consistent with the latter ﬁndings,

Lp(a) accumulates in the arterial wall at a concentration

proportional to its plasma concentration.²Furthermore,

recent studies using transgenic rabbits have directly

demonstrated that Lp(a) is atherosclerotic.³

Previous studies have demonstrated that inhibition of

the apo(a)/apoB-100 coupling reaction may be a poten-

tial means of lowering Lp(a).^5,6Therefore, it was our

goal to develop compounds which would reduce plasma

Lp(a) levels by blocking the disulﬁde bond formation

between apo(a)/apoB-100. Our eﬀorts were directed at

two series of compounds, the amino acid (general

structure A) and the sulfonamide (general structure B)

derivatives. The sulfonamide series gave a ﬂat SAR and

*Corresponding author. Tel.: +1-734-622-7874; fax: +1-734-622-

3171; e-mail: helen.lee2@pﬁzer.com

doi:10.1016/j.bmc.2002.04.001

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K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

Scheme 1. (a) H₂SO₄, R₃OH; Note: when R₃=t-Bu, H₂SO₄, isobutylene, aq KOH, Et₂O, dioxane; (b) NBS, cat (PhCO)₂O₂, CCl₄; (c) NHR₅R₆,

Et₃N, THF; (d) (COCl)₂, cat DMF; NH(R₄)₂, Et₃N, CH₂Cl₂or HOBt, DCC, NH(R₄)₂, CH₂Cl₂; (e) NH₂R₅, Et₃N, THF; (f) R₆CHO, NaHB(OAc)₃,

DCE; (g) KOH, K₃Fe(CN)₆, C₆H₆, H₂O; (h) NHR₅R₆, THF.

was inactive in vivo so most of our eﬀorts focused on

the amino acid derivatives. Compound 14-6, an amino

acid derivative, was taken forward for in vivo studies. In

Lp(a) transgenic mice, plasma Lp(a) levels were

decreased 21ꢀ3.2% after a single week of dosing and

30.7ꢀ3.2% after 2 weeks of oral dosing. Due to the

eﬃcacy of compound 14-6 in the Lp(a) transgenic mice,

it was administered to cynomolgus monkeys. After 1

week of treatment (100 mg/kg/day), monkey plasma

Lp(a) levels were decreased 34.7ꢀ5.6%. In this paper

we discuss the chemistry, SAR and biological activity of

these compounds.

pling reagents. The amide (6) was either brominated

with NBS (7) followed by displacement with an amine

to give the ﬁnal compound (8) or oxidized to the qui-

none methine (5) and then coupled with an amine to

give 8. If the amine was not commercially available

(Scheme 1, step e), it was prepared using reductive ami-

nation conditions with the appropriate amine and alde-

hyde. Quinone derivatives (5) were obtained by

oxidizing the ester (2) or amide (6) with potassium fer-

ricyanide (III).

In Scheme 2, the desired compounds were made by a

Friedel–Craft acylation of the appropriate 2,6-di-

substituted phenol (9) with ethyl oxalyl chloride, fol-

lowed by condensation with phenylhydrazine (11) and

reduction to the amine (12) with 10% palladium on

carbon. This amine (12) was subjected to reductive

amination conditions in 1,2-dichloroethane (DCE) to

obtain secondary and tertiary amines (13, 14).

Sulfonamides

All sulfonamides were prepared as shown in Scheme 3,

except 24 and 27. For compounds in Table 9, the

penultimate amine (18) [2,6-di-tert-butyl-4-(pyridin-3-

ylaminomethyl)phenol] was prepared according to

Scheme 3, method A by reﬂuxing 3-aminopyridine (16)

with 3,5-di-tert-butyl-4-hydroxybenzaldehyde (15) in

toluene and catalytic amounts of p-toluenesulfonic acid

(PTSA) to form the corresponding imine (17). This

imine (17) was reduced by catalytic hydrogenation using

Raney nickel in a methanol/THF solution at room

temperature. Amine (18) was coupled with various sul-

fonyl chlorides (19) by heating in pyridine at 60 ^ꢁC with

catalytic amounts of 4-dimethylaminopyridine (4-

DMAP) to obtain the desired product (20).

Chemistry

Amino acid derivatives

All amino acid derivatives were prepared according to

Scheme 1 or 2. The ester analogues (Scheme 1) were

prepared by Fischer esteriﬁcation of a 4-hydroxyphenyl

acetic acid derivative (1), followed by bromination (3)

with N-bromosuccinimide (NBS) and displacement by

the appropriate amine to give the desired product (4).

The amide analogues were also prepared according to

Scheme 1. Amide (6) was made from carboxylic acid (1)

via the acid chloride or using HOBt and DCC as cou-

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4829

Scheme 2. (a) AlCl₃, ethyloxalyl chloride, CH₂Cl₂; (b) PhNHNH₂, EtOH; (c) H₂, 10% Pd/C, 1.5:1 THF/EtOH; (d) 2 equiv R₅CHO, NaB(OAc)₃H,

DCE: (e) equiv R₅CHO, NaB(OAc)₃H, DCE; (f) 1 equiv R₆CHO, NaB(OAc)₃H, DCE.

Scheme 3. (a) Cat PTSA, PhCH₃; (b) RaNi, THF/MeOH or 20%Pt/C, MeOH, AcOH; (c) NaB(OAc)₃H, DCE; (d) K₂CO₃, CH₃CN; (e) cat.

4-DMAP, pyridine.

For compounds in Table 10, 4-toluenesulfonyl chloride

was coupled with various amines (18) to form the sul-

fonamides (20). Three methods (A, B, C) were used to

make amines (18). Only imine (17) formation was

observed with heterocyclic amines under reductive ami-

nation conditions. For this reason, amines containing

heterocycles were subjected to condensation/reduction

conditions (Scheme 3, method A). For aniline and sub-

stituted anilines, reductive amination conditions gave

the desired penultimate amine, 18 (Scheme 3, method

B). In one case, nucleophilic displacement was utilized

(Scheme 3, method C).

For compounds in Table 11, the penultimate amine (18)

was prepared as shown in Scheme 3, method A, unless

otherwise noted, then coupled with various sulfonyl

chlorides (19) to give the sulfonamides, 20. To prepare

compound 24 (Scheme 4), 3,5-di-tert-butyl-4-hydroxy-

phenylacetic acid was converted to the acid chloride,

reduced with lithium aluminum hydride (LAH), bromi-

nated with phophorus tribromide and coupled with 3-

aminopyridine in reﬂuxing toluene to give amine 23.

This was coupled with 4-toluenesulfonyl chloride to give

sulfonamide, 24. Compound 27 (Scheme 5) was pre-

pared from 2,6-di-tert-butyl-1,4-benzoquinone and 3-

4830

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

Scheme 4. (a) (COCl)₂, cat DMF; (b) LAH, Et₂O; (c) PBr₃, Et₂O; (d) Et₃N, Kl, PhCH₃; (e) TsCl, cat 4-DMAP, pyridine.

Scheme 5. (a) NaB(OAc)₃H, AcOH, DCE; (b) pyridine, DCE.

aminopyridine as described by Reiker and Kessler⁷to

form imine, 26, which was subsequently reduced with

sodium triacetoxyborohydride and coupled with 2-thio-

phenesulfonyl chloride to give the desired product, 27.

by ELISA as described above. The cell-based LpA3

assay is used to test the activity of the compounds in a

more physiological setting than LpABC (e.g., presence

of plasma proteins). Compounds active in the cellular

assay (LpA3) but not the biochemical assay (LpABC)

(i.e., those that are not coupling inhibitors) could aﬀect

any other aspect of apo(a) and/or apoB-100 synthesis.

Biological Methods

The Lp(a) biochemical coupling assay, LpABC, consists

of incubating recombinant apo(a), [r-apo(a)], with

apoB-100 of LDL. Lp(a) generated from the latter

reaction is analyzed by a previously described ELISA.⁸

The source of r-apo(a) is conditioned media from

human 293 cells permanently expressing a human 17-

kringle IV apo(a) cDNA expression construct.⁹Condi-

tioned media from HepG2 cells is used as a source of

LDL. To analyze the inﬂuence of compounds on the

Lp(a) coupling reaction, 45 mL of conditioned media

from the 293 cells is added to a 0.5 mL test tube followed

by the addition of 10 mL of compound at concentra-

tions ranging from 0.03 to 50 mM and 45 mL of HepG2

conditioned media (LDL source). The mixture is incu-

bated at 37 ^ꢁC for 30 min and Lp(a) measured by

ELISA as described above. Optical density at l_{450 nm}

(OD₄₅₀) from the Lp(a) ELISA plates is used as a

direct measure of the amount of Lp(a) generated by the

coupling of r-apo(a) and apoB-100.

In vivo studies

For in vivo testing, Lp(a) transgenic mice, generated

essentially as described,¹⁰and cynomolgus monkeys¹¹

were used. Mice were dosed by oral gavage with the

compound delivered in a solution consisting of carboxy

methlycellulose and 0.3% Tween-20. Monkeys were

dosed by placing the compound in their meal. Animals

were bled and plasma Lp(a) levels were determined on a

COBAS MIRA Plus (Roche) chemistry system using

Wako reagents.

Results and Discussion

Amino acid derivatives—in vitro data

The ﬁrst structure–activity relationship (SAR) studied

was replacements of the 3,5-di-tert-butyl-4-phenol moi-

ety. Table 1 shows that all replacements for the tert-

butyl groups were detrimental to the activity in the bio-

chemical (LpABC) assay. For this reason, the 3,5-di-

tert-butyl-4-phenol moiety was retained.

The Lp(a) cellular assay, LpA3, uses HepG2 cells per-

manently transfected with the apo(a) cDNA construct

described above. The expressed r-apo(a) couples to the

endogenously made apoB-100 from the HepG2 cells to

form Lp(a). In the assay, compounds are incubated with

the cells for 8 h. Lp(a) is measured in the culture media

The structure of the compounds may suggest that they

work as antioxidants. While this may be one possible

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4831

mechanism, it is not the only one, as shown by several

lines of evidence. If the compounds worked as anti-

oxidants, derivatives without the tert-butyl groups

should still be active. Our results show that any changes

to the tert-butyl groups gave inactive compounds (Table

1). The activity changed as the substitution on the

amine was varied, both from primary to secondary to

tertiary (Table 6) and also among the diﬀerent tertiary

amines (Tables 3 and 6). This shows that the substitu-

tion on the amine also contributed to the activity.

groups and carbamates. It was observed that bulky

substituents on the amine were inactive [(13-45–13-48,

except compound 13-44 (21.99 mM)],as well as carba-

mates (13-49, 13-50). The phenethyl amine (13–43) and

furyl amine (13-55) exhibited moderate activity while

the pyridyl amine (13-51) and methyl pyridyl amines

(13-9, 13-10, 13-12) were the most active of the second-

ary amines.

Compounds containing tertiary amines are summarized

in Table 5. It was found that in the biochemical

(LpABC) assay, compounds with alkyl groups gave

submicromolar activity, although little change was

observed in in vitro potency among the diﬀerent alkyl

groups (4-2, 4-4, 4-7–4-9). Tertiary amines with a benzyl

group exhibited only moderate activity or were inactive

(14-2, 14-13, 14-14), the most potent compound con-

taining a methylene-2-pyridine moiety (14-5). It was

Several quinone methine derivatives (5) were synthe-

sized and are shown in Table 2. These quinone methine

derivatives (5) were some of the potent analogues in the

biochemical (LpABC) assay.

Tables 3 and 4 summarize SAR on secondary amines.

Table 3 highlights secondary amines containing alkyl,

cycloalkyl, benzyl and substituted benzyl amines. In the

biochemical (LpABC) assay, alkyl and cycloalkylamines

showed moderate activity with cyclohexyl derivatives

being the more potent of these compounds (4-6, 13-1).

Most of the benzyl and substituted benzyl compounds

were inactive in the biochemical (LpABC) assay. Of the

ones that exhibited activity, only moderate (10–50 mM)

activity was observed. Table 4 displays secondary

amines with various aromatic and heteroaromatic

Table 3. Eﬀect of R₅on in vitro activity

Compd

R₅

LpABC IC₅₀

(mM)

LpA3

IC₅₀(mM)

Table 1. Eﬀect of R₁, R₂on in vitro activity

4-1

4-5

4-2

4-6

13-1

13-13

13-8

Me

Et

n-Bu

19.04

10.89

11.22

4.16

6.52

12.17

10.27

ia

29.18

54.30

29.63

ia

33.41

53.94

43.40

12.48

ia

50.16

46.68

ia

53.99

ia

47.94

ia

16

13

40

49

ia

25

ia

4.6

9.3

ia

Cyclohexyl

CH₂-cyclohexyl

CH₂-cyclopropyl

Bn

3-(OH)Bn

4-(OH)Bn

2-(OMe)Bn

4-(OMe)Bn

4-(OBn)Bn

2-(CF₃)Bn

3-(CF₃)Bn

2-(Cl)Bn

3-(Cl)Bn

4-(Cl)Bn

2-(F)Bn

3-(NO₂)Bn

4-(NO₂)Bn

4-(NH₂)Bn

4-(NMe₂)Bn

4-(NBu₂)Bn

4-(CN)Bn

2-(Me)Bn

3-(Me)Bn

13-14^a

13-15^a

13-16^a

13-17^a

13-18^a

13-19^a

13-20^a

13-21^a

13-22

13-23^a

13-24^a

13-25^a

13-26^a

13-27^a

13-28^a

13-29^a

13-30^a

13-31^a

13-32^a

13-33^a

13-34^a

13-35^a

13-36^a

13-37^a

13-38^a

13-39

13-40

13-41

13-42^a

Compd

R₁

R₂

LpABC

IC₅₀(mM)

LpA3

IC₅₀(mM)

13-1

13-2

13-3^a

13-4

13-5

13-6

13-7

t-Bu

H

Cl

Ph

t-Bu

Me

H

Cl

6.52

ia

NA

ia

Ph

s-Bu

60.18

67.39

ia

35.2

s-Bu

ia, inactive (no dose–responsive curve was obtained up to 100 mM);

NA, not available; p<0.05.

^aHCl salt.

Table 2. In vitro activity of quinone methine derivatives

2,4-(diCl)Bn

3,4-(diCl)Bn

3,5-(diCl)Bn

3-(Me)-4-(OMe)Bn

4-(OH)-3-(OMe)Bn

4-(OH)-3-(OEt)Bn

3,4,5-(OMe)Bn

3-(OH)-4,5-(OMe)Bn

3,5-(di-t-Bu)-4-(OH)Bn

3,5-(diCl)-2-(OH)Bn

14.98

59.08

10.26

10.59

ia

Compd

X

LpABC

IC₅₀(mM)

LpA3

IC₅₀(mM)

5-1

5-2

5-3

O-n-Bu

N(n-Bu)₂

OMe

0.30

0.38

1.03

0.9

NA

3.80

15.87

ia, inactive (no dose–response curve was obtained up to 100 mM);

p<0.05.

^aParallel synthesis.

NA, not available.

4832

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

found that the di(methylene-2-pyridine) moiety gave

submicromolar activity (14-3). In general, tertiary

amines substituted with two pyridyl groups were more

active than those with only one pyridyl group (14-3, 14-

4, 14-6, 14-7 vs 14-5, 14-13, 14-14, 14-9). Enantiomic

separation for compound 14-6 di(methylene-3-pyridine)

was performed and the activities of the two enantiomers

were comparable. For this reason, only the racemates

were synthesized in further studies.

on the amino portion of the molecule (4-2 vs 8-1–8-3,

14-6 vs 8-4 through 8-6, 4-17 vs 8-7–8-10). Based on this

data, the amide was considered a suitable replacement

for the ethyl ester.

In general, the activity decreased in the cell-based assay

(LpA3) compared to the biochemical assay (LpABC).

This may be attributed to one of two reasons. In the

cellular assay (LpA3), the compound could have been

bound to other cellular components or possibly meta-

bolized into less active or inactive metabolites. It should

be noted that, in most cases, the rank order of potency

was similar in the two assays. In some cases, the com-

pounds are more active in the cellular (LpA3) assay

compared to the biochemical (LpABC) assay (4-1, 4-15,

4-20, 13-7, 13-39, 13-52, 12). This may be due to possi-

ble formation of more active metabolites.

Table 6 compares the activities of primary, secondary

and tertiary amines. It was found that in the biochem-

ical (LpABC) assay, the primary amine was inactive

(12) and that tertiary amines were, in general, more

potent than secondary amines (4-1 vs 4-2, 4-3 vs 4-4, 13-

8 vs 14-2, etc.).

SAR studies on the ester (R₃) are summarized in Table

7. It was possible that the ethyl ester would be metabo-

lized in vivo and a more hindered ester, such as the tert-

butyl ester, or an amide, would prevent such metabo-

lism. The carboxylic acid was found to be inactive (13-

11). In general, in the biochemical (LpABC) assay, ester

modiﬁcation of compounds containing a tertiary amine

resulted in little change in activity (4-12, 4-14–4-16),

although the ethyl ester was always the most active. For

compounds containing secondary amines, changing the

ethyl ester to a bulkier group, such as the tert-butyl

ester, resulted in decreased activity (13-1 vs 4-19, 13-10

vs 4-20, 4-21).

Sulfonamides—in vitro data

Table 9 outlines SAR studies done on R₇, the sulfona-

mide portion of the molecule. Little variation in activity

in the biochemical (LpABC) assay was observed among

the diﬀerent substitution patterns—from small alkyl

groups (20-1) to aromatic and heteroaromatic groups

(20-2, 20-3, 20-19, 20-20, 20-21) to electron donating

and withdrawing groups (20-7, 20-4, 20-9). Changing

the position of substituents on the phenyl ring (20-4, 20-

5, 20-6, 20-9, 20-10) resulted in minor changes in in vitro

Table 5. Eﬀect of R₅, R₆on in vitro activity

Table 8 outlines SAR around compounds containing

either an amide or an ester. Replacing the ester with an

amide had little eﬀect on in vitro potency in the bio-

chemical (LpABC) assay, regardless of the substituents

Table 4. Eﬀect of R₅on in vitro activity

Compd

R₅

R₆

LpABC

LpA3

IC₅₀(mM) IC₅₀(mM)

4-2

4-7

Me

n-Bu

n-Oct

0.40

0.65

1.48

0.95

0.63

1.58

0.53

0.80

1.65

B

1.40

NA

2.40

2.70

1.80

1.30

2.50

4-8^a

4-9^a

4-4^a

4-10

4-11

4-12

4-13

14-2

14-5

14-13

14-14

(CH₂)₂-NMe₂

n-Bu

Compd

R₅

LpABC

IC₅₀(mM)

LpA3

IC₅₀(mM)

–(CH₂)₄—

–(CH₂)₅—

–(CH₂)₂O(CH₂)₂—

13-43

13-44^a

13-45^a

13-46^a

13-47^a

13-48^a

13-49

13-50

13-51

13-52

13-9

13-10

13-12

13-53

13-54^a

13-55^a

(CH₂)₂Ph

CH₂CH(Ph)₂

8.54

21.99

ia

n

ia

3.05

ia

6.48

5.90

7.27

20.21

34.47

9.37

64.4

ia

–(CH₂)₂NMe(CH₂)₂—

n

B

n

ia

CH₂-4-diphenyl ether

CH₂-1-naphthyl

CH₂-1-(4-OMe)naphthyl

CH₂-2-anthracene

CO₂B

CH₂-2-pyridyl

CH₂-3-pyridyl

CH₂-4-pyridyl

CH₂-2-pyridyl

CH₂-3-pyridyl

CH₂-4-pyridyl

CH₂-2-pyridyl

CH₂-3-pyridyl

CH₂-2-thiophene CH₂-3-pyridyl

CH₂-3-thiophene CH₂-3-pyridyl

CH₂-2-furyl

CH₂-cyclohexyl

Bn

3.20

NA

ia

20

0.55

NA

ia

14-3

ia

CH₂-2-pyridyl

CH₂-3-pyridyl

CH₂-4-pyridyl

CH₂-3-pyridyl

CH₂-4-pyridyl

CH₂-cyclohexyl

ia

14-6

14-12

14-4

14-7

14-8

14-9

14-10

14-11

14-1

1.30

2.32

0.85

2.88

1.48

20.26

8.08

3.91

2.14

3.90

CO₂t-Bu

3-Pyridyl

CO-3-pyridyl

CH₂-2-pyridyl

CH₂-3-pyridyl

CH₂-4-pyridyl

CH₂-2-thiophene

CH₂-3-thiophene

CH₂-3-furan

ia

7.60

44

9.10

20

25.4

65.6

ia

NA

3.70

NA

20

CH₂-3-pyridyl

SO₂Me

22

ia, inactive (no dose-response curve was obtained up to 100 mM); NA,

not available; p<0.05.

^aHCl salt.

ia, inactive (no dose-response curve was obtained up to 100 mM);

p<0.05.

^aParallel synthesis.

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4833

activity. However, when the para substituent on the

phenyl group changed from methyl to ethyl, n-propyl,

or tert-butyl, the activity decreased more than two fold

(20-12, 20-13, 20-14, 20-15). Bulky substituents on the

sulfonamide portion were detrimental to activity as

shown by the decrease in activity with the naphthyl

group (20-18). Extending the chain length more than

Table 6. Eﬀect of R₅, R₆on in vitro activity

Compd

R₅

R₆

LpABC

LpA3

Table 8. In vitro activity comparison of amides and esters

IC₅₀(mM) IC₅₀(mM)

12

4-1

4-2

H

Me

n-Bu

H

Me

H

n-Bu

H

SO₂Me

ia

46

16

1.40

40

2.40

ia

20

ia

19.04

0.40

11.22

0.63

6.52

2.14

10.27

B

6.48

0.55

0.85

3.20

5.90

1.30

2.88

1.48

20.26

8.08

3.91

7.27

2.32

4-3

4-4^a

13-1

14-1

13-8

14-2

13-9

14-3

14-4

14-5

13-10

14-6

14-7

14-8

14-9

14-10

14-11

13-12

14-12

CH₂-cyclohexyl

Bn

H

Compd

ia

R₅=R₆

NA

X

LpABC

IC₅₀(mM) IC₅₀(mM)

LpA3

B

n

CH₂-2-pyridyl

CH₂-3-pyridyl

CH₂-3-pyridyl CH₂-2-thiophene

CH₂-3-pyridyl CH₂-3-thiophene

CH₂-3-pyridyl

CH₂-4-pyridyl

H

9.10

CH₂-2-pyridyl

CH₂-3-pyridyl

Bn

NA

20

3.90

NA

3.70

NA

25.40

NA

4-2

Me

OEt

N(Me)₂

N(n-Bu)₂

NMe(n-Bu)

OEt

N(Me)₂

N(Et)₂

N(n-Bu)₂

OEt

0.40

1.49

1.03

1.48

1.30

0.98

1.08

0.50

0.80

1.59

1.17

0.74

1.55

1.40

NA

8-1^a

8-2^a

8-3^a

14-6

8-4

H

CH₂-3-pyridyl

CH₂-4-pyridyl

CH₂-cyclohexyl

CH₂-3-pyridyl

–(CH₂)₂O(CH₂)₂–

3.90

NA

1.30

10.98

5

8-5

8-6^a

4-17

8-7

CH₂-2-furyl

H

CH₂-4-pyridyl

N(Me)₂

N(Et)₂

N(n-Bu)₂

8-8

8-9^a

8-10^a

NA

–(CH₂)₂O(CH₂)₂– NMe(n-Bu)

ia, inactive (no dose-response curve was obtained up to 100 mM); NA,

not available, p<0.05.

^aHCl salt.

NA, not available; p<0.05.

^aHCl salt.

Table 9. Eﬀect of R₇on in vitro potency

Table 7. Eﬀect of ester modiﬁcation (R₃) on in vitro activity

Compd

R₇

LpABC

IC₅₀(mM)

LpA3

IC₅₀(mM)

20-1

20-2

20-3

20-4

20-5

20-6

20-7

20-8

Me

Ph

CH₂Ph

2-(Br)Ph

3-(Br)Ph

4-(Br)Ph

4-(OMe)Ph

4-(F)Ph

4-(NO₂)Ph

3-(NO₂)Ph

4-(NH₂)Ph

4-(Me)Ph

4-(Et)Ph

4-(n-Pr)Ph

4-(t-Bu)Ph

5.58

4.12

3.49

2.43

2.76

3.16

3.70

2.6

4

4.78

2.38

8.6

7.6

11.8

3.5

16.84

7.07

2.64

1.66

2.3

41.2

16.2

NA

12

11.13

NA

5.80

7.50

9.4

7.4

16.3

6.9

7.7

10

23.6

12.5

NA

13

8.9

24.3

ia

Compd R₃

R₅

R₆

LpABC

IC₅₀(mM) IC₅₀(mM)

LpA3

4-14

4-12

4-15

4-2

Me

Et

n-Bu

Et

–(CH₂)₂O(CH₂)₂–

Me

1.79

0.80

1.18

0.40

0.41

0.84

1.30

2.10

2.14

ia

10.83

4.16

9.04

ia

5.90

24.67

20.61

1.95

1.30

0.50

1.40

0.60

1.98

3.90

NA

20

NA

54.7

49.2

NA

ia

20

Me

CH₂-3-pyr

20-9

4-16

4-17

14-6

14-15

14-1

14-16

4-18

13-1

4-19

13-11

13-10

4-20

4-21

n-Bu

t-Bu

Et

t-Bu

Et

20-10

20-11

20-12

20-13

20-14

20-15

20-16

20-17

20-18

20-19

20-20

20-21

Me

CH₂-3-pyr

CH₂-3-py

CH₂-cyclohexyl SO₂Me

t-Bu

Me CH₂-cyclohexyl

Et CH₂-cyclohexyl

t-Bu CH₂-cyclohexyl

H

Et

H

4-(Acetamido)Ph

CH¼CHPh

2-Naphthyl

2-Thiophene

2-Thiophene-5-pyrid-2-yl

2-Acetamido-4-(Me)thiazole

CH₂-3-pyr

i-Pr

t-Bu

9.60

NA

ia, inactive (no dose–response curve was obtained up to 100 mM);

NA=not available; p<0.05.

ia, inactive (no dose–response curve was obtained up to 100 mM); NA,

not available; p<0.05.

4834

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

Table 11. Eﬀect of chain length (n₁, n₂) on in vitro activity

Table 10. Eﬀect of R₈on in vitro potency

Compd

R₇

n₁

n₂

LpABC

IC₅₀(mM)

LpA3

IC₅₀(mM)

20-19

20-35

27-1^a,c

20-18

20-36

20-12

20-37

24-1^b

2-Thiophene

2-Naphthyl

4-Tolyl

1

0

1

0

1

2

0

1

0

1

0

1

2.64

ia

7.07

ia

2.38

ia

8.9

53.8

ia

13

ia

7.50

ia

NA

Compd

R₈

LpABC

IC₅₀(mM)

LpA3

IC₅₀(mM)

20-22

20-23

20-24

20-25

20-26

20-27

20-28

20-12

20-29

20-30

20-31

20-32

20-33

20-34

Cyclohexyl

Ph

3-(Cl)Ph

3,5-(diCl)Ph

3-(NO₂)Ph

4-(OMe)Ph

2-Pyridyl

3-Pyridyl

4-Pyridyl

ia

27.86

ia

2.38

ia

1.63

5

ia

4-Tolyl

ia

ia, inactive (no dose–response curve was obtained up to 100 mM); NA,

not available; p<0.05.

6.9

NA

7.6

39.1

ia

^aScheme 5.

^bScheme 4.

2-(Cl)-3-pyridyl

6-(Cl)-3-pyridyl

2-(OMe)-3-pyridyl

2,6-(diMe)-3-pyridyl

6-(OEt)-2-benzothiazole

^cHCl salt.

24.2

77.91

ia

8.5

ia

in Lp(a) transgenic mice. The mice were dosed at a

concentration of 100 mg/kg/day for 2 weeks. At the end

of each week of dosing, the mice were bled 2 h after

dosing and plasma Lp(a) levels were measured.

ia, inactive (no dose–response curve was obtained up to 100 mM); NA,

not available; p<0.05.

one carbon between the aromatic and sulfonyl group

resulted in a signiﬁcant drop in activity (20-17).

Compounds 4-2, 4-17 and 20-19 were not active in

Lp(a) transgenic mice after 1 week of dosing. Com-

pound 14-6 showed a 21ꢀ3.2% decrease in plasma

Lp(a) levels after 1 week and a 30.7ꢀ3.2% decrease

after 2 weeks in a group of ﬁve animals.

Maintaining one of the better substitution patterns in

both the biochemical (LpABC) and cellular assays

(LpA3) for R₇(4-tolyl), the SAR for R₈was investi-

gated. The results are displayed in Table 10. It was

found that 3-pyridine (20-12) was most desirable for in

vitro activity in the biochemical (LpABC) assay. Elec-

tron withdrawing substituents to the 3-pyridine ring

were tolerated (20-30, 20-31) while electron donating

substituents led to a signiﬁcant drop in activity (20-32,

20-33). Moving the nitrogen of the pyridine ring to

either an ortho or para position resulted in inactive

compounds (20-28, 20-29). Replacement of the pyridine

ring with a phenyl ring, either substituted or unsub-

stituted, saturated system or other heterocycle, also

gave inactive compounds (20-22, 20-23, 20-24, 20-26,

20-34).

Compound 14-6 was tested in monkeys at a dose of 100

mg/kg/day. After one week of treatment with 14-6,

monkey plasma Lp(a) levels were decreased 34.7ꢀ5.6%

(n=7). All seven monkeys tested responded to treat-

ment.

Conclusion

We have identiﬁed a potent Lp(a) coupling inhibitor,

14-6, that was eﬀective in lowering plasma Lp(a) levels

in Lp(a) transgenic mice and in monkeys. Further in

vivo studies are ongoing in our laboratory.

Table 11 summarizes studies done on the methylene

linkers, n₁and n₂. The optimal compounds had n₁=1

and n₂=0 (20-19, 20-18, 20-12). All other permutations

resulted in inactive compounds. (20-35, 20-36, 20-37, 24-

1, 27-1).

Experimental

All melting points were recorded on a Thomas Hoover

1

melting point apparatus and are uncorrected. H NMR

spectra were recorded on a Varian INOVA 400 MHz

spectrometer. Positive and negative ion atmospheric

pressure chemical ionization (APCI) mass spectra were

obtained on a Micromass Platform LC mass spectro-

meter. Silica gel TLC was performed on silica gel 60

F₂₅₄precoated sheets and column chromatography on

silica gel 60 (70–230 mesh). Elemental analyses were

performed by Quantitative Technologies, Inc., NJ, USA.

Again, compounds were less active in the cellular assay

(LpA3) compared to the biochemical assay (LpABC).

This may be due to the reasons discussed previously for

the amino acid derivatives.

In vivo data

Base on the in vitro results, compounds from both the

amino acid derivatives (4-2, 4-17, 14-6) and the sulfo-

namides (20-19) were taken forward for in vivo studies

Esters (2) were obtained by Fischer esteriﬁcation except

for the tert-butyl ester.

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4835

Procedure for 3,5-di-tert-butyl-4-hydroxyphenyl acetic

acid tert-butyl ester (2). To a solution of concentrated

H₂SO₄(30 mL) in 300 mL dioxane under nitrogen was

added 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid

(29.76 g, 113 mmol) followed by isobutylene (300 mL).

The cold mixture was sealed and stirred at room tem-

perature for 4 days and poured into a rapidly stirred

mixture of 85% potassium hydroxide (75 g), water, ice

and ether. The organic layer was separated, washed with

brine and evaporated at reduced pressure to give a yel-

low oil (23.02 g, 64%). MS m/z 320.3 (M+H)^{+; 1}H

NMR (CDCl₃) d 1.43 (s, 18H) 1.45 (s, 9H) 3.43 (s, 2H)

5.11 (s, 1H) 7.06 (s, 2H).

solution was then concentrated in vacuo and the residue

dissolved in CH₂Cl₂. It was washed with water and

brine, dried (MgSO₄) and concentrated in vacuo. The

product was obtained by column chromatography

(MeOH/CH₂Cl₂). The amino acid was dissolved in ether

and treated with 4 N HCl in dioxane (4 mL) and stirred

for 1 h. The resultant hydrochloride salt was collected

by ﬁltration.

Method 2. To a solution of compound 7 (1 equiv) in

THF was added the amine (1 equiv) and Et₃N (1 equiv).

The reaction was stirred at room temperature for 18 h.

The solvent was removed in vacuo. The residue was

dissolved in EtOAc, washed with water and brine, dried

(MgSO₄) and concentrated. The intermediate was

obtained by column chromatography.

General procedure for synthesis of 2-phenylacetamides (6)

Method 1. The carboxylic acid, 1, was converted to the

acid chloride using excess oxalyl chloride and a catalytic

amount of DMF at room temperature. The solvent was

removed in vacuo, redissolved in THF and the appro-

priate amine (excess) was added. The reaction was stir-

red at room temperature until all the starting material

was consumed. The solvent was removed in vacuo and

the solid was triturated to obtain the desired product.

To this intermediate (1 equiv) in 1,2-dichloroethane was

added the appropriate aldehyde (1.05 equiv) and

sodium triacetoxyborohydride (2 equiv). The reaction

was heated to 50 ^ꢁC for 1 h. Water was added and the

organic layer was separated, washed with brine, dried

(MgSO₄) and concentrated. The desired product was

obtained by column chromatography.

Method 2. Carboxylic acid, 1, N-hydroxybenzotriazole

(1.07 equiv) and dicyclohexylcarbodiimide (1.07 equiv)

in CH₂Cl₂was stirred for 5 min and then treated with

the appropriate amine (1.1 equiv). The mixture was

stirred at room temperature for 24 h then ﬁltered. The

organic solution was washed with water and brine. The

organic phase was dried (MgSO₄) and solvent removed

in vacuo. The pure product was obtained by column

chromatography.

Amino-(3,5-di-tert-butyl-4-hydroxy-phenyl)-acetic acid

ethyl ester (12). Aluminum chloride (24 g, 180 mmol)

was added to a solution of ethyloxalyl chloride (24.6 g,

180 mmol) in CH₂Cl₂(350 mL) and then cooled to 0 ^ꢁC.

The mixture then treated, dropwise over 15 min, with

2,6-di-tert-butyl phenol, 9, (30.9 g, 150 mmol) in

CH₂Cl₂(125 mL). The mixture was stirred cold for 1 h

and then warmed to room temperature and stirred an

additional h. The solution was cooled to 0 ^ꢁC and

quenched with water. The organic phase was separated

and washed with 1 N HCl and brine. The organic phase

was dried (MgSO₄) and concentrated in vacuo to give

the ketoester, 10, as an oil, 44.6 g (97%). The ketoester,

10, (44.6 g, 146 mmol) and phenylhydrazine (20.5 g, 190

mmol) were dissolved in 150 mL ethanol. The mixture

was heated to reﬂux for 18 h. The solution was cooled

to room temperature and the hydrazone, 11, allowed to

precipitate. The solid was collected by ﬁltration and

washed twice with ethanol. The resultant hydrazone, 11,

was dried at 65 ^ꢁC for 3 h at reduced pressure to give,

41.5 g (72%). The hydrazone, 11, (19.6 g, 49.4 mmol)

was dissolved in a mix of ethanol (100 mL) and THF

(150 mL). This solution was treated with 10% Pd/C and

subjected to hydrogen gas for 14 h. The mixture was

ﬁltered and the solvents removed in vacuo to give a

white solid. The solid was recrystallized from hexanes to

give a white crystalline solid (12, 12.7 g, 84%, 58% over-

all). MS m/z 308.2 (M+H)⁺. ¹H NMR (CDCl₃) d 1.20 (t,

3H), 1.39 (s, 18H), 4.07–4.21 (m, 2H), 4.47 (s, 1H), 5.17 (s,

1H), 7.11 (s, 2H). Calcd for C₁₈H₂₉NO₃: C, 70.32; H,

9.51; N, 4.56. Found: C, 70.10; H, 9.53; N, 4.46.

General procedure for synthesis of 2-bromo acetates and

acetamides (3, 7)

To a solution of 2 or 6 in CCl₄was added N-bromo-

succinimide (1.5 equiv) and a catalytic amount of ben-

zoyl peroxide. The reaction was heated to 60 ^ꢁC for 18

h. The solvent was removed in vacuo. The residue was

dissolved in EtOAc, washed with water and brine, dried

(MgSO₄) and the solvent removed in vacuo to give the

crude product as an orange oil which was taken on to

the next step without further puriﬁcation.

General procedure for oxidation of 2-phenylacetates (2) or

2- phenylacetamides (6) to quinone methine derivatives (5)

To a 1:1 mixture of benzene/water was added 2 or 6,

KOH (9 equiv) and potassium ferricyanide (III) (2

equiv). The reaction was heated at 40 ^ꢁC for 3–18 h. The

reaction was cooled, the layers were separated and the

organic layer was washed with water and brine, dried

(MgSO₄) and the solvent removed in vacuo to give the

product.

General procedure for the synthesis of amino acid deriva-

tives (4, 13, 14)

General procedure for synthesis of 2-aminoacetamides (8)

Method 1. To the quinone methine (5, 1 equiv) in THF

was added a solution of amine (2 equiv) in THF. The

solution was stirred at room temperature for 18 h. The

Method 1 (compound 4). To a solution of bromide, 3, in

THF was added the appropriate amine (excess). The

reaction was stirred at room temperature until all start-

4836

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

ing material was consumed. The reaction mixture was

concentrated in vacuo, dissolved in EtOAc, washed with

brine, dried (MgSO₄) and concentrated. The pure pro-

duct was obtained by column chromatography.

Cyclohexylamino(3,5-di-tert-butyl-4-hydroxyphenyl)ace-

1

tic acid ethyl ester (4-6). MS m/z 390.2 (M+H)⁺; H

NMR (CDCl₃) d 1.12–1.90 (m, 13H), 1.42 (s, 18H),

2.31–2.39 (m, 1H), 4.07–4.26 (m, 2H), 4.39 (s, 1H), 5.16

(s, 1H), 5.29 (s, 1H), 7.14 (s, 2H). Calcd for C₂₄H₃₉NO₃:

C, 73.99; H, 10.09; N, 3.60. Found: C, 73.71; H, 9.87; N,

3.49.

Method 2 (compounds 13). To a solution of 12 in 1,2-

dichloroethane was added the appropriate aldehyde (4

equiv) and sodium triacetoxyborohydride (4 equiv). The

reaction was stirred at room temperature until all start-

ing material was consumed. The reaction was con-

centrated in vacuo. The residue was dissolved in EtOAc,

washed with water and brine, dried (MgSO₄) and the

solvent removed in vacuo. The pure product was obtained

by column chromatography. This procedure was followed

for all compounds made by parallel synthesis.

(Butylmethylamino)-(3,5-di-tert-butyl-4-hydroxyphenyl)

acetic acid ethyl ester (4-7). MS m/z 378.3 (M+H)⁺;

¹H NMR (CDCl₃) d 0.82 (t, 3H), 1.20–1.45 (m, 4H),

1.24 (s, 3H), 1.42 (s, 18H), 2.25 (s, 3H), 2.20–2.50 (m,

2H), 4.07 (s, 1H), 4.10–4.25 (m, 2H), 5.18 (s, 1H), 7.18

(s, 2H). Calcd for C₂₃H₃₉NO₃: C, 73.17; H, 10.41; N,

3.71. Found: C, 73.20; H, 10.07; N, 3.82.

Method 3(compounds 14). To a solution of 4 (R₆=H),

12, or 13 in 1,2-dichloroethane was added the appro-

priate aldehyde (1.05–2.1 equiv) and sodium triacetoxy-

borohydride (1.4–3.0 equiv). The reaction was stirred at

room temperature until all starting material was con-

sumed. The reaction was concentrated in vacuo. The

residue was dissolved in EtOAc, washed with water and

brine, dried (MgSO₄) and concentrated. The pure pro-

duct was obtained by column chromatography.

(3,5-Di-tert - butyl - 4 - hydroxyphenyl) - (methyloctylami-

no)acetic acid ethyl ester, hydrochloride (4-8). MS m/z

1

434.4 (M+H)⁺; H NMR (DMSO-d₆) d 0.78–0.86 (m,

6H), 1.35 (s, 18H), 2.20–2.85 (m, 3H), 2.80–3.40 (m,

2H), 4.22 (q, 2H), 5.20–5.40 (m, 1H), 7.24 (s, 2H), 7.47–

7.49 (m, 1H), 10.3–10.7 (m, 1H). Calcd for

.

C₂₇H₄₇NO₃HCl 0.25H₂O: C, 68.32; H, 10.30; N, 2.95; Cl,

7.47. Found: C, 68.35; H, 10.42; N, 2.70; Cl, 6.90.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(2-dimethylaminoe-

thyl)methylamino]acetic acid ethyl ester, hydrochloride

(3,5-Di-tert - butyl - 4 - hydroxyphenyl)methylaminoacetic

acid ethyl ester (4-1). MS m/z 322.2 (M+H)⁺; ¹H

NMR (CDCl₃) d 1.25 (t, 3H), 1.42 (s, 18H), 2.42 (s, 3H),

4.12–4.29 (m, 3H), 5.19 (s, 1H), 7.14 (s, 2H). Calcd for

C₁₉H₃₁NO₃: C, 70.99; H, 9.72; N, 4.36. Found: C,

71.05; H, 9.72; N, 4.21.

1

(4-9). MS m/z 393.4 (M+H)⁺; H NMR (DMSO-d₆) d

1.14 (t, 3H), 1.36 (s, 18H), 2.40–2.80 (m, 9H), 3.30–3.60

(m, 4H), 4.18–4.26 (m, 2H), 5.30 (s, 1H), 7.25 (s, 2H),

.

7.41 (s, 1H). Calcd for C₂₃H₄₀N₂O₃2.0HCl 2.0H₂O: C,

55.08; H, 9.25; N, 5.59; Cl, 14.14. Found: C, 55.23; H,

9.22; N, 5.31; Cl, 13.49.

(3,5-Di-tert-butyl-4-hydroxyphenyl)dimethylaminoacetic

acid ethyl ester (4-2). MS m/z 336.3 (MÀH)⁺; ¹H

NMR (CDCl₃) d 1.24 (t, 3H), 1.42 (s, 18H), 2.1–2.4 (br.

s, 6H), 3.7–3.8 (m, 1H), 4.10–4.30 (m, 2H), 5.22 (s, 1H),

7.19 (s, 2H). Calcd for C₂₀H₃₃NO₃: C, 71.60; H, 9.91;

N, 4.17. Found: C, 71.05; H, 9.72; N, 4.21.

(3,5-Di-tert-butyl-4-hydroxyphenyl)pyrrolidin-1-yl-acetic

acid ethyl ester (4-10). MS m/z 362.2 (M+H)⁺; ¹H

NMR (CDCl₃) d 1.22 (t, 3H), 1.43 (s, 18H), 1.75–1.85

(m, 4H), 2.40–2.60 (m, 4H), 3.81 (s, 1H), 4.18-4.27 (m,

2H), 5.19 (s, 1H), 7.21 (s, 2H). Calcd for C₂₂H₃₅NO₃: C,

73.09; H, 9.76; N, 3.87. Found: C, 73.25; H, 9.71; N,

3.70.

Butylamino(3,5-di-tert-butyl-4-hydroxyphenyl)acetic acid

ethyl ester (4-3). MS m/z 364.2 (M+H)⁺; ¹H NMR

(CDCl₃) d 0.89 (t, 3H), 1.24 (t, 3H), 1.25–1.60 (m, 4H),

1.42 (s, 18H), 2.50–2.65 (m, 2H), 4.08–4.25 (m, 2H),

4.26 (s, 1H), 5.19 (s, 1H), 7.15 (s, 2H). Calcd for

C₂₂H₃₇NO₃: C, 72.68; H, 10.26; N, 3.85. Found: C,

72.83; H, 10.10; N, 3.76.

(3,5-Di-tert-butyl-4-hydroxyphenyl)piperidin-1-yl-acetic

acid ethyl ester (4-11). MS m/z 376.2 (M+H)⁺; ¹H

NMR (CDCl₃) d 1.22 (t, 3H), 1.43 (s, 18H), 1.50–1.70

(m, 6H), 2.25–2.45 (m, 4H), 3.88 (s, 1H), 4.1–4.3 (m,

2H), 5.18 (s, 1H), 7.17 (s, 2H). Calcd for C₂₃H₃₇NO₃: C,

73.56; H, 9.93; N, 3.73. Found: C, 73.27; H, 9.57; N,

3.90.

Dibutylamino(3,5-di-tert-butyl-4-hydroxyphenyl)acetic

acid ethyl ester, hydrochloride (4-4). MS m/z 420.3

(M+H)⁺; ¹H NMR (CDCl₃) d 0.60–0.70 (m, 3H),

0.85–0.95 (m, 3H), 1.10–1.18 (m, 3H), 1.25–1.70 (m,

8H), 1.35 (s, 18H), 2.8–3.5 (m, 4H), 4.2–4.3 (m, 2H),

5.20 (d, 1H), 7.28 (s, 2H), 7.51 (s, 1H). Calcd for

(3,5-Di-tert-butyl-4-hydroxyphenyl)morpholin-4-yl-acetic

acid ethyl ester (4-12). MS m/z 378.2 (M+H)⁺. ¹H

NMR (CDCl₃) d 1.22 (t, 3H), 1.43 (s, 18H), 2.40–2.55

(m, 4H), 3.65–3.80 (m, 4H), 3.88 (s, 1H), 4.1-4.3 (m,

2H), 5.21 (s, 1H), 7.18 (s, 2H). Calcd for C₂₂H₃₅NO₄: C,

69.99; H, 9.34; N, 3.71. Found: C, 69.94; H, 9.23; N,

3.61.

.

C₂₆H₄₅NO₃HCl: C, 68.47; H, 10.17; N, 3.07. Found: C,

68.50; H, 10.25; N, 2.91.

(3,5-Di-tert-butyl-4-hydroxyphenyl)ethylaminoacetic acid

ethyl ester (4-5). MS m/z 336.2 (M+H)⁺; ¹H NMR

(DMSO-d₆) d 0.98 (t, 3H), 1.12 (t, 3H), 1.34 (s, 18H),

2.10–2.50 (m, 2H), 4.0–4.15 (m, 2H), 4.20 (s, 1H), 6.91

(s, 1H), 7.07 (s, 2H). Calcd for C₂₀H₃₃NO₃: C, 71.60; H,

9.91; N, 4.17. Found: C, 71.91; H, 9.99; N, 4.11.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(4-methylpiperazin-

1-yl)acetic acid ethyl ester (4-13). MS m/z 391.2

1

(M+H)⁺; H NMR (CDCl₃) d 1.21 (t, 3H), 1.41 (s,

18H), 2.29 (s, 3H), 2.40–2.60 (m, 8H), 3.92 (s, 1H), 4.1–

4.25 (m, 2H), 5.19 (s, 1H), 7.16 (s, 2H). Calcd for

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4837

.

C₂₃H₃₈N₂O₃0.25 EtOAc: C, 69.81; H, 9.70; N, 6.79.

Found: C, 69.54; H, 9.67; N, 7.18.

.

1H). Calcd for C₂₆H₃₈N₂O₃0.167H₂O: C, 72.62; H,

8.92; N, 6.52. Found: C, 72.73; H, 8.99; N, 6.36.

(3,5-Di-tert-butyl-4-hydroxyphenyl)morpholin-4-yl-acetic

1

(3,5-Di-tert-butyl-4-oxo-cyclohexa-2,5-dienylidene)acetic

acid butyl ester (5-1). MS m/z 319.3 (M+H)⁺. ¹H

NMR (CDCl₃) d 0.95 (t, 3H), 1.27 (s, 9H), 1.30 (s, 9H),

1.36–1.48 (m, 2H), 1.63–1.70 (m, 2H), 4.2 (t, 2H), 6.15

(s, 1H), 6.78 (m, 1H), 8.27 (m, 1H). Calcd for C₂₀H₃₀O₃:

C, 75.43; H, 9.50. Found: C, 75.50; H, 9.86.

acid methyl ester (4-14). MS m/z 364.2 (M+H)⁺; H

NMR (CDCl₃) d 1.42 (s, 18H), 2.30–2.55 (m, 4H), 3.60–

3.80 (m, 4H), 3.69 (s, 3H), 3.89 (s, 1H), 5.23 (s, 1H), 7.26

(s, 2H). Calcd for C₂₁H₃₃NO₄: C, 69.39; H, 9.15; N,

3.85. Found: C, 69.51; H, 9.18; N, 3.80.

(3,5-Di-tert-butyl-4-hydroxyphenyl)morpholin-4-yl-acetic

acid butyl ester (4-15). MS m/z 406.3 (M+H)⁺; ‘p¹H

NMR (CDCl₃) d 0.84 (t, 3H), 1.20–1.30 (m, 2H), 1.42 (s,

18H), 1.50–1.65 (m, 2H), 2.40–2.55 (m, 4H), 3.65–3.80

(m, 4H), 3.86 (s, 1H), 4.05–4.15 (m, 2H), 5.20 (s, 1H),

N,N-Dibutyl-2-(3,5-di-tert-butyl-4-oxo-cyclohexa-2,5-di-

1

enylidene)acetamide (5-2). MS m/z 374.3 (M+H)⁺; H

NMR (CDCl₃) d 0.93–1.0 (m, 6H), 1.27 (s, 9H), 1.29 (s,

9H), 1.20–1.65 (m, 8H), 3.25–3.35 (m, 2H), 3.4-3.5 (m,

2H), 6.49 (s, 1H), 6.82 (m, 1H), 7.48 (m, 1H). Calcd for

C₂₄H₃₉NO₂: C, 77.16; H, 10.52; N, 3.75. Found: C,

77.52; H, 10.73; N, 3.74.

.

7.18 (s, 2H). Calcd for C₂₄H₃₉NO₄0.167 H₂O: C, 70.48;

H, 9.63; N, 3.43. Found: C, 70.47; H, 9.69; N, 3.33.

(3,5-Di-tert-butyl-4-hydroxyphenyl)dimethylaminoacetic

acid butyl ester (4-16). MS m/z 364.3 (M+H)⁺; ¹H

NMR (CDCl₃) d 0.84 (t, 3H), 1.20-1.35 (m, 2H), 1.42 (s,

18H), 1.50–1.65 (m, 2H), 2.2–2.3 (m, 6H), 3.7–3.8 (br.s,

1H), 4.05–4.20 (m, 2H), 5.21 (s, 1H), 7.18 (s, 2H). Calcd

for C₂₂H₃₇NO₃: C, 72.68; H, 10.26; N, 3.85. Found: C,

72.78; H, 10.07; N, 3.79.

(3,5-Di-tert-butyl-4-oxo-cyclohexa-2,5-dienylidene)acetic

acid methyl ester (5-3). MS m/z 277.1 (M+H)⁺. ¹H

NMR (CDCl₃) d 1.27 (s, 9H), 1.29 (s, 9H), 3.80 (s, 3H),

6.13 (s, 1H), 6.77 (m, 1H), 8.29 (m, 1H). Calcd for

C₁₇H₂₄O₃: C, 73.88; H, 8.75. Found: C, 73.55; H, 8.77.

2-(3,5-Di-tert-butyl-4-hydroxyphenyl)-2-dimethylamino-

N,N-dimethyl-acetamide, hydrochloride (8-1, Method 1).

1

N,N-dimethylamino(3,5-di-tert-butyl-4-hydroxyphenyl)

acetic acid tert-butyl ester (4-17). Mp 74À76 ^ꢁC; MS m/

MS m/z 335.2 (M+H)⁺; H NMR (DMSO-d₆) d 1.35

(s, 18H), 2.33–2.35 (m, 3H), 2.81–2.82 (m, 3H), 2.86–

2.88 (m, 6H), 5.54 (d, 1H), 7.27 (s, 2H), 7.43 (s, 1H),

1

z 364.3 (M+H)⁺; H NMR (CDCl₃) d 1.42 (s, 18H)

2.24 (s, 6H) 3.68 (s, 1H) 5.17 (s, 1H) 7.16 (s, 2H). Calcd

.

10.0 (s, 1H). Calcd for C₂₀H₃₄N₂O₂HCl: C, 64.76; H,

.

for C₂₂H₃₇NO₃0.33H₂O: C, 71.44; H, 10.19; N, 3.79.

Found: C, 71.45; H, 9.82; N, 3.49.

9.51; N, 7.55; Cl, 9.56. Found: C, 64.43; H, 9.82; N,

7.27; Cl, 9.46.

(Cyclohexylmethylamino)-(3,5-di-tert-butyl-4-hydroxy-

phenyl)acetic acid methyl ester (4-18). MS m/z 390.2

N,N-Dibutyl-2-(3,5-di-tert-butyl-4-hydroxyphenyl)-2-di-

methylamino-acetamide, hydrochloride (8-2, Method 1).

1

(M+H)⁺; H NMR (CDCl₃) d 0.80–1.0 (m, 2H), 1.10–

MS m/z 419.4 (M+H)⁺. H NMR (DMSO-d₆) d 0.7–

1.80 (m, 9H), 1.43 (s, 18H), 2.40–2.55 (m, 2H), 3.74 (s,

3H), 5.26 (s, 1H), 7.16 (s, 2H). Calcd for C₂₄H₃₉NO₃: C,

73.99; H, 10.09; N, 3.60. Found: C, 74.19; H, 10.30; N,

3.38.

0.95 (m, 6H), 1.00–1.50 (m, 8H), 1.34 (s, 18H), 2.36–

2.38 (m, 3H), 2.80–2.82 (m, 3H), 3.00–3.50 (m, 4H),

5.40–5.47 (m, 1H), 7.25 (s, 2H), 7.44 (s, 1H), 9.9 (s, 1H).

Calcd for C₂₆H₄₆N₂O₂HCl: C, 68.62; H, 10.41; N, 6.16;

Cl, 7.79. Found: C, 68.76; H, 10.68; N, 6.06; Cl, 7.79.

.

(Cyclohexylmethylamino)-(3,5-di-tert-butyl-4-hydroxy-

phenyl)acetic acid tert-butyl ester (4-19, Method 1). Mp

75–77 ^ꢁC; MS m/z 432.5 (M+H)⁺; ¹H NMR (CDCl₃) d

0.8–1.0 (m, 2H) 1.10–1.30 (m, 3H) 1.42 (d, 27H) 1.6–

1.85 (m, 6H) 2.40 (m, 2H) 4.10 (s, 1H) 5.13 (s, 1H) 7.13

(s, 2H). Calcd for C₂₇H₄₅NO₃: C, 75.13; H, 10.51; N,

3.24. Found: C, 75.15; H, 10.53; N, 3.24.

N-Butyl-2-(3,5-di-tert-butyl-4-hydroxyphenyl)-N-methyl-

2-morpholin-4-yl-acetamide, hydrochloride (8-3, Method

1). MS m/z 419.4 (M+H)^{+ 1}H NMR (DMSO-d₆) d

0.61–1.15 (m, 7H), 1.35 (s, 18H), 2.80 (d, 3H), 2.9–3.1 (m,

2H), 3.15–3.40 (m, 2H), 3.65–4.0 (m, 6H), 5.60–5.67 (m,

1H), 7.29 (s, 2H), 7.43–7.45 (m, 1H), 10.35 (s, 1H). Calcd

.

for C₂₅H₄₂N₂O₃HCl 0.6H₂O: C, 64.45; H, 9.56; N, 6.01;

Cl, 7.61. Found: C, 64.85; H, 9.75; N, 5.83; Cl, 7.50.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(pyridin-3-ylmethy-

l)amino]acetic acid isopropyl ester (4-20). MS m/z 413.2

1

(M+H)⁺. H NMR (CDCl₃) d 1.12 (d, 3H), 1.22 (d,

2-(Bis-pyridin-3-ylmethylamino)-2-(3,5-di-tert-butyl-4-

hydroxyphenyl)-N,^N-dimethylacetamide (8-4, Method 1).

3H), 1.38 (s, 18H), 3.68–3.79 (m, 2H), 4.19 (s, 1H),

5.01–5.05 (m, 1H), 5.16 (s, 1H), 7.08 (s, 2H), 7.21–7.23

(m, 2H), 7.66–7.69 (m, 1H), 8.46–8.52 (m, 2H). Calcd

for C₂₅H₃₆N₂O₃: C, 72.78; H, 8.80; N, 6.79. Found: C,

72.61; H, 8.88; N, 6.45.

1

MS m/z 489.3 (M+H)⁺; H NMR (CDCl₃) d 1.40 (s,

18H), 2.55 (s, 3H), 3.03 (s, 3H), 3.80–4.02 (m, 4H), 4.58

(s, 1H), 5.21 (s, 1H), 7.05 (s, 2H), 7.20–7.26 (m, 2H),

7.59–7.62 (m, 2H), 8.45–8.48 (m, 4H). Calcd for

C₃₀H₄₀N₄O₂: C, 73.74; H, 8.25; N, 11.46. Found: C,

72.82; H, 8.32; N, 11.21.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(pyridin-3-ylmethy-

l)amino]acetic acid tert-butyl ester (4-21). Mp 116–

118 ^ꢁC; MS m/z 427.4 (M+H)⁺; H NMR (CDCl₃) d

2-(Bis-pyridin-3-ylmethylamino)-2-(3,5-di-tert-butyl-4-

hydroxyphenyl)-N,N-diethylacetamide (8-5, Method 2).

Mp 159–160 ^ꢁC; MS m/z 517.3 (M+H)⁺; ¹H NMR

1

1.42 (d, 27H) 3.78 (q, 2H) 4.15 (s, 1H) 5.17 (s, 1H) 7.11

(s, 2H) 7.26 (m, 1H) 7.75 (m, 1H) 8.55 (dd, 1H) 8.56 (d,

4838

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

(CDCl₃) d 0.64–0.69 (t, 3H) 1.19–1.23 (t, 3H) 1.41 (s,

18H) 2.69–3.06 (m, 3H) 3.80–4.04 (m, 5H) 4.53 (s, 1H)

5.20 (s, 1H) 7.09 (s, 2H) 7.20 (m, 2H) 7.61 (d, 2H) 8.44

(dd, 2H) 8.52 (d, 2H). Calcd for C₃₂H₄₄N₄O₂: C, 74.38;

H, 8.58; N, 10.84. Found: C, 74.26; H, 8.32; N, 10.86.

1.35 (m, 2H), 1.23 (t, 3H), 1.40 (s, 9H), 1.45–1.82 (m,

8H), 2.23 (s, 3H), 2.41–2.44 (m, 2H), 4.05–4.28 (m, 2H),

4.30–4.55 (br.s., 1H), 4.81 (s, 1H), 7.04 (s, 1H), 7.13 (s,

1H). Calcd for C₂₂H₃₅NO₃: C, 73.09; H, 9.76; N, 3.87.

Found: C, 72.73; H, 9.49; N, 4.06.

2-(Bis-pyridin-3-ylmethylamino)-N,N-dibutyl-2-(3,5-di-

tert - butyl - 4 - hydroxy-phenyl)-acetamide, hydrochloride

(8-6, Method 1). MS m/z 573.5 (M+H)⁺; ¹H NMR

(DMSO-d₆) d 0.60–0.95 (m, 9H), 1.00–1.60 (m, 9H),

1.29 (s, 18H), 2.78–2.95 (m, 3H), 3.50–3.60 (m, 1H),

4.05–4.12 (m, 1H), 4.88 (s, 1H), 7.01 (s, 2H), 7.81–7.86

(m, 2H), 8.34–8.36 (m, 2H), 8.66–8.73 (m, 4H). Calcd

for C₃₆H₅₂N₄O₂2.5HCl 0.7H₂O: C, 63.94; H, 8.33; N,

8.29; Cl, 13.11. Found: C, 63.76; H, 8.48; N, 7.97; Cl,

12.72.

(3-tert-Butyl - 4 - hydroxyphenyl) - (cyclohexylmethylami-

no)acetic acid ethyl ester, hydrochloride (13-3). MS m/z

1

348.2 (M+H)⁺; H NMR (DMSO-d₆) d 0.75–0.88 (m,

2H), 1.05–1.20 (m, 6H), 1.28 (s, 9H), 1.5–1.75 (m, 6H),

2.45–2.65 (m, 2H), 4.1–4.2 (m, 2H), 5.05 (s, 1H), 6.83 (d,

1H), 7.10 (d, 1H), 7.25 (s, 1H), 9.3 (s, 1H), 9.45 (s, 1H),

.

9.93 (s, 1H). Calcd for C₂₁H₃₃NO₃HCl: C, 65.69; H,

8.93; N, 3.65; Cl, 9.23. Found: C, 65.82; H, 9.10; N,

3.40; Cl, 8.90.

.

(Cyclohexylmethylamino) - (4 - hydroxyphenyl)acetic acid

1

2-(3,5-Di-tert-butyl-4-hydroxyphenyl)-N,N-dimethyl-2-

morpholin - 4 - yl - acetamide (8-7, Method 1). MS m/z

377.3 (M+H)⁺. ¹H NMR (CDCl₃) d 1.42 (s, 18H), 2.4–

2.6 (m, 4H), 2.92 (s, 3H), 2.99 (s, 3H), 3.65–3.80 (m,

4H), 4.1–4.18 (m, 1H), 5.2 (s, 1H), 7.14 (s, 2H). Calcd

ethyl ester (13-4). MS m/z 292.1 (M+H)⁺; H NMR

(DMSO-d₆) d 0.7–0.92 (m, 2H), 1.0–1.18 (m, 6H), 1.20–

1.35 (m, 1H), 1.55–1.70 (m, 5H), 2.09–2.21 (m, 3H),

3.91–4.06 (m, 2H), 4.07–4.11 (m, 1H), 6.64 (d, 2H), 7.09

(d, 2H), 9.35 (s, 1H). Calcd for C₁₇H₂₅NO₃: C, 70.07; H,

8.65; N, 4.81. Found: C, 70.12; H, 8.76; N, 4.71.

.

for C₂₂H₃₆N₂O₃0.15H₂O: C, 69.67; H, 9.65; N, 7.34.

Found: C, 69.59; H, 9.71; N, 7.32.

(Cyclohexylmethylamino)-(3,5-dichloro-4-hydroxyphenyl)

acetic acid ethyl ester (13-5). MS m/z 360.0 (M+H)⁺;

¹H NMR (DMSO-d₆) d 0.70–0.90 (m, 2H), 1.0–1.75 (m,

14H), 2.2 (dd, 2H), 3.96–4.15 (m, 2H), 4.24 (s, 1H), 7.36

(s, 2H). Calcd for C₁₇H₂₃Cl₂NO₃: C, 56.67; H, 6.43; N,

3.89; Cl, 19.68. Found: C, 56.76; H, 6.28; N, 3.79; Cl,

19.60.

2-(3,5-Di-tert-butyl-4-hydroxy-phenyl)-N,N-diethyl-2-

morpholin - 4 - yl - acetamide (8-8, Method 1). MS m/z

405.3 (M+H)⁺; ¹H NMR (CDCl₃) d 0.91–1.14 (m, 3H),

1.05–1.14 (m, 3H), 1.41 (s, 18H), 2.4–2.65 (m, 4H), 3.10–

3.60 (m, 4H), 3.65–3.80 (m, 4H), 4.10–4.15 (m, 1H), 5.20

(s, 1H), 7.25 (s, 2H). Calcd for C₂₄H₄₀N₂O₃: C, 71.25; H,

9.97; N, 6.92. Found: C, 70.97; H, 9.79; N, 6.82.

(Cyclohexylmethylamino) - (2⁰- hydroxy - [1,1⁰;3⁰,1⁰⁰] ter-

N,N-Dibutyl-2-(3,5-di-tert-butyl-4-hydroxyphenyl)-2-

morpholin-4-yl-acetamide, hydrochloride (8-9, Method

phenyl-5⁰-yl)acetic acid ethyl ester (13-6). MS m/z 444.2

1

(M+H)⁺; H NMR (CDCl₃) d 0.8–1.0 (m, 2H), 1.1–

1

1). MS m/z 461.5 (M+H)⁺; H NMR (DMSO-d₆) d

1.35 (m, 3H), 1.25 (t, 3H), 1.40–1.60 (m, 1H), 1.6–1.82

(m, 5H), 2.38–2.50 (m, 2H), 4.1–4.30 (m, 2H), 4.34 (s,

1H), 5.42 (s, 1H), 7.29–7.56 (m, 12H). Calcd for

0.70-0.85 (m, 6H), 0.97–1.50 (m, 8H), 1.35 (s, 18H), 2.97–

3.10 (m, 5H), 3.40–3.55 (m, 3H), 3.68–4.0 (m, 4H), 5.5–

5.55 (m, 1H), 7.27 (s, 2H), 7.46 (s, 1H), 10.25 (s, 1H).

.

C₂₉H₃₃NO₃0.25H₂O: C, 77.73; H, 7.54; N, 3.12.

Found: C, 77.75; H, 7.63; N, 2.95.

.

Calcd for C₂₈H₄₈N₂O₃HCl: C, 67.65; H, 9.93; N, 5.63;

Cl, 7.13. Found: C, 67.27; H, 10.04; N, 5.50; Cl, 7.06.

(Cyclohexylmethylamino)-(3,5-di-s-butyl-4-hydroxyphe-

nyl)acetic acid ethyl ester (13-7). MS m/z 404.2

N - Butyl - 2 - (3,5 - di - tert - butyl - 4 - hydroxyphenyl) - 2 -

dimethylamino-N-methyl-acetamide, hydrochloride (8-10,

Method 1). MS m/z 377.3 (M+H)⁺; ¹H NMR

(DMSO-d₆) d 0.85–1.1 (m, 7H), 1.35 (s, 18H), 2.34–2.37

(m, 3H), 2.77–2.83 (m, 6H), 2.95–3.10 (m, 1H), 3.65–

3.75 (m, 1H), 5.40–5.55 (m, 1H), 7.24 (s, 2H), 7.39–7.41

(m, 1H), 9.95 (s, 1H). Calcd for C₂₃H₄₀N₂O₂HCl: C,

66.88; H, 10.01; N, 6.78; Cl, 8.58. Found: C, 66.90; H,

10.21; N, 6.63; Cl, 8.24.

1

(M+H)⁺; H NMR (CDCl₃) d 0.75–0.9 (m, 8H), 1.0–

1.20 (m, 12H), 1.5–1.70 (m, 7H), 1.70–1.85 (m, 3H), 2.5–

2.62 (m, 2H), 2.90–3.05 (m, 2H), 4.23 (q, 2H), 4.85–4.92

(m, 1H), 7.06–7.08 (m, 2H), 8.85 (s, 1H), 10.9 (s, 1H);

HPLC: 94%, C18 column, 1:1 CH₃CN/H₂O, l=254 nm.

.

Benzylamino(3,5 - di - tert - butyl - 4 - hydroxyphenyl)acetic

aci_ꢁd ethyl ester (13-8). 66356x16c PD 189107; mp

1

95 C; MS m/z 398.3 (M+H)⁺; H NMR (CDCl₃) d

(Cyclohexylmethylamino)-(3,5-di-tert-butyl-4-hydroxy-

phenyl)acetic acid ethyl ester (13-1). MS m/z 404.2

1.25 (t, 3H) 1.42 (s, 18H) 3.70–3.80 (q, 2H) 4.10–4.25

(m, 2H) 4.27 (s, 1H) 5.19 (s, 1H) 7.14 (s, 2H) 7.20–7.40

(m, 5H). Calcd for C₂₅H₃₅NO₃: C, 75.53; H, 8.87; N,

3.52. Found: C, 75.36; H, 8.78; N, 3.41.

1

(M+H)⁺; H NMR (CDCl₃) d 0.8–1.8 (m, 14H), 1.38

(s, 18H), 2.35 (dd, 2H), 4.02–4.11 (m, 2H), 4.18 (s, 1H),

5.13 (s, 1H), 7.11 (s, 2H). Calcd for C₂₅H₄₁NO₃: C,

74.40; H, 10.24; N, 3.47. Found: C, 74.42; H, 10.44; N,

3.39.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(pyridin-2-ylmethyl)

amino]acetic acid ethyl ester (13-9). MS m/z 399.2

1

(M+H)⁺; H NMR (CDCl₃) d 1.21 (t, 3H), 1.38 (s,

(3-tert-Butyl-4-hydroxy-5-methylphenyl)-(cyclohexylme-

thylamino)acetic acid ethyl ester (13-2). MS m/z 362.2

18H), 3.79–3.91 (m, 2H), 4.06–4.22 (m, 2H), 4.30 (s,

1H), 5.15 (s, 1H), 7.07–7.12 (m, 3H), 7.28–7.30 (m, 1H),

7.56–7.61 (m, 1H), 8.5–8.52 (m, 1H). Calcd for

1

(M+H)⁺; H NMR (CDCl₃) d 0.8–1.0 (m, 2H), 1.1-

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4839

C₂₄H₃₄N₂O₃: C, 72.33; H, 8.60; N, 7.03. Found: C,

72.50; H, 8.66; N, 6.92.

Mp 110–112 ^ꢁC; MS m/z 526.3 (M+H)⁺; ¹H NMR

(CDCl₃) d 1.20 (t, 3H) 1.41 (d, 36H) 3.60 (q, 2H) 4.00–

4.20 (m, 2H) 4.25 (s, 1H) 5.05 (s, 1H) 5.15 (s, 1H) 7.05 (s,

2H) 7.10 (s, 2H). Calcd for C₃₃H₅₁NO₄H₂O: C, 72.89;

H, 9.75; N, 2.57. Found: C, 72.71; H, 9.82; N, 2.36.

.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(pyridin-3-ylmethyl)

amino]acetic acid ethyl ester (13-10). MS m/z 399.3

(M+H)⁺. ¹H NMR (CDCl₃) d 1.20 (t, 3H) 1.41 (s,

18H) 3.75 (q, 2H) 4.10–4.25 (m, 2H) 4.25 (s, 1H) 5.10 (s,

1H) 7.10 (s, 2H) 7.20–7.25 (m, 1H) 7.70 (m, 1H) 8.50–

8.60 (m, 2H). Calcd for C₂₄H₃₄N₂O₃: C, 72.33; H, 8.60;

N, 7.03. Found: C, 72.39; H, 8.50; N, 6.83.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-phenethylaminoace-

tic acid ethyl ester (13-43). MS m/z 412.2 (M+H)⁺; ¹H

NMR (CDCl₃) d 1.21 (t, 3H), 1.41 (s, 18H), 2.77–2.92 (m,

4H), 4.05–4.23 (m, 2H), 4.30 (s, 1H), 5.19 (s, 1H), 7.26 (s,

2H), 7.28–7.31 (m, 5H). Calcd for C₂₆H₃₇NO₃: C, 75.87;

H, 9.06; N, 3.40. Found: C, 75.86; H, 8.81; N, 3.28.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(pyridin-3-ylmethyl)

amino]acetic acid, hydrochloride (13-11). Compound 13-

10 was hydrolyzed with aqueous sodium hydroxide. MS

Benzyloxycarbonylamino(3,5-di-tert-butyl-4-hydroxyphe-

nyl)acetic acid ethyl ester (13-49). Compound 13-49 was

synthesized by reacting compound 12 with benzyl-

chloroformate; MS m/z 442.2 (M+H)⁺; ¹H NMR

(CDCl₃) d 1.24 (t, 3H), 1.41 (s, 18H), 4.1–4.3 (m, 3H),

5.12 (m, 2H), 5.25–5.29 (m, 1H), 5.6–5.65 (m, 1H), 7.13 (s,

2H), 7.26–7.40 (m, 5H). Calcd for C₂₆H₃₅NO₅: C, 70.72;

H, 7.99; N, 3.17. Found: C, 70.83; H, 8.03; N, 3.20.

1

m/z 371.2 (M+H)⁺; H NMR (DMSO-d₆) d 1.31 (t,

18H), 3.80–3.85 (m, 2H), 4.14 (s, 1H), 6.99 (s, 1H), 7.05

(s, 2H), 7.30–7.35 (m, 1H), 7.70–7.78 (m, 1H), 8.46 (s,

.

2H). Calcd for C₂₂H₃₀N₂O₃0.7HCl: C, 66.73; H, 7.81;

N, 7.07. Found: C, 67.06; H, 7.77; N, 7.34.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(pyridin-4-ylmethyl)

amino]acetic acid ethyl ester (13-12). MS m/z 400.2

1

(M+H)⁺; H NMR (CDCl₃) d 1.20 (t, 3H), 1.38 (s,

tert-Butoxycarbonylamino-(3,5-di-tert-butyl-4-hydroxy-

phenyl)-acetic acid ethyl ester (13-50). Compound 13-50

was synthesized by reacting compound 12 with tert-

18H), 3.66–3.78 (m, 2H), 4.10–4.19 (m, 2H), 4.20 (s,

1H), 5.22 (s, 1H), 7.09 (s, 1H), 7.22–7.25 (m, 1H), 8.49–

8.51 (m, 1H). Calcd for C₂₄H₃₄N₂O₃: C, 72.33; H, 8.60;

N, 7.03. Found: C, 72.43; H, 8.60; N, 6.95.

1

butylchloroformate; MS m/z 406.2 (MÀH)^À; H NMR

(CDCl₃) d 1.24 (t, 3H), 1.41 (s, 18H), 1.44 (s, 9H), 4.1–

4.3 (m, 2H), 5.15–5.22 (m, 2H), 5.30–5.40 (m, 1H), 7.12

(s, 2H). Calcd for C₂₃H₃₇NO₅: C, 67.78; H, 9.15; N,

3.44. Found: C, 67.69; H, 8.99; N, 3.34.

(Cyclopropylmethylamino)-(3,5-di-tert-butyl-4-hydroxy-

phenyl)acetic acid ethyl ester (13-13). MS m/z 362.2

1

(M+H)⁺. H NMR (CDCl₃) d 0.0–0.09 (m, 2H), 0.37–

0.45 (m, 2H), 0.87–0.97 (m, 1H), 1.16 (t, 3H), 1.35 (s,

18H), 2.28–2.46 (m, 2H), 4.02–4.19 (m, 2H), 4.26 (s, 1H),

5.11 (s, 1H), 7.08 (s, 2H). Calcd for C₂₂H₃₅NO₃: C, 73.09;

H, 9.76; N, 3.87. Found: C, 72.87; H, 9.79; N, 3.83.

(3,5-Di-tert-butyl-4 - hydroxy - phenyl) - [(pyridine - 3- car-

bonyl)-amino]-acetic acid ethyl ester (13-52). Compound

13-52 was made by reacting compound 12 with nicotinyl

1

chloride. MS m/z 413.2 (M+H)⁺; H NMR (CDCl₃) d

1.24 (t, 3H), 1.39 (s, 18H), 4.16–4.27 (m, 2H), 5.27 (s,

1H), 5.64 (d, 1H), 6.92–6.94 (m, 1H), 7.17 (s, 2H), 7.34–

7.38 (m, 1H), 8.08–8.11 (m, 1H), 8.69–8.70 (m, 1H), 9.00

(s, 1H). Calcd for C₂₄H₃₂N₂O₄: C, 69.88; H, 7.82; N,

6.79. Found: C, 69.68; H, 7.93; N, 7.02.

(3-Chloro-benzylamino)-(3,5-di-tert-butyl-4-hydroxyphe-

nyl)acetic acid ethyl ester (13-22). MS m/z 432.2

1

(M+H)⁺; H NMR (CDCl₃) d 1.20 (t, 3H), 1.39 (s,

18H), 3.68–3.71 (m, 2H), 4.10–4.21 (m, 2H), 4.22 (s,

1H), 5.19 (s, 1H), 7.10 (s, 2H), 7.20–7.22 (m, 3H), 7.31

(s, 1H). Calcd for C₂₅H₃₄ClNO₃: C, 69.51; H, 7.93; N,

3.24. Found: C, 69.55; H, 8.13; N, 3.31.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(thiophen-2-ylme-

thyl)amino]acetic acid ethyl ester (13-53). MS m/z 404.1

1

(M+H)⁺; H NMR (CDCl₃) d 1.17 (t, 3H), 1.36 (s,

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(3,4,5-trimethoxy-

benzylamino)acetic acid ethyl ester (13-39). MS m/z

488.2 (M+H)⁺; ¹H NMR (CDCl₃) d 1.18–1.22 (m,

3H), 1.39 (s, 18H), 3.62–3.72 (m, 2H), 3.80–3.82 (s, 9H),

4.05–4.22 (m, 2H), 4.24 (s, 1H), 5.16 (s, 1H), 6.54 (s,

2H), 7.11 (s, 2H). Calcd for C₂₈H₄₁NO₆: C, 68.97; H,

8.47; N, 2.87. Found: C, 68.96; H, 8.45; N, 2.80.

18H), 3.91 (s, 2H), 4.0–4.20 (m, 2H), 4.29 (s, 1H), 5.14

(s, 1H), 6.88–6.89 (m, 2H), 7.08 (s, 2H), 7.16–7.18 (m,

1H). Calcd for C₂₃H₃₃NO₃S: C, 68.45; H, 8.24; N, 3.47.

Found: C, 68.49; H, 8.04; N, 3.39.

The following compounds were synthesized using the

parallel synthesis method (compounds 13).

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(3-hydroxy-4,5-di-

methoxybenzylamino)-acetic acid ethyl ester (13-40). MS

(3,5-Di-tert-butyl-4 - hydroxyphenyl) - (3- hydroxybenzyl-

amino)acetic acid ethyl ester (13-14). MS m/z 414.4

(M+H)⁺; HPLC purity=88%.

1

m/z 474.2 (M+H)⁺; H NMR (CDCl₃) d 1.24 (t, 3H),

1.42 (s, 18H), 3.60–3.71 (m, 2H), 3.84 (s, 3H), 3.88 (s,

3H), 4.08–4.25 (m, 2H), 4.27 (s, 1H), 5.19 (s, 1H), 5.68–

5.80 (m, 1H), 6.51–6.54 (d, 2H), 7.14 (s, 2H). Calcd for

C₂₇H₃₉NO₆: C, 68.47; H, 8.30; N, 2.96. Found: C,

68.37; H, 8.33; N, 2.89.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(4 -hydroxybenzyl-

amino)acetic acid ethyl ester (13-15). MS m/z 414.4

(M+H)⁺; HPLC purity=91%.

(3,5-Di-tert-butyl-4-hydroxyphenyl) - (2 - methoxybenzyl-

amino)acetic acid ethyl ester (13-16). MS m/z 428.4

(M+H)⁺; HPLC purity=93%.

(3,5-Di-tert-butyl-4-hydroxy - benzylamino) - (3,5 - di-tert-

butyl-4-hydroxy-phenyl)acetic acid ethyl ester (13-41).

4840

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

(3,5-Di-tert-butyl-4 - hydroxyphenyl) - (4 - methoxybenzyl-

amino)acetic acid ethyl ester (13-17). MS m/z 428.4

(M+H)⁺; HPLC purity=86%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(3,5-dichlorobenzyl-

amino)acetic acid ethyl ester (13-35). MS m/z 466.3

(M+H)⁺; HPLC purity=92%.

(4-Benzyloxy-benzylamino)-(3,5-di-tert-butyl-4-hydroxy-

phenyl)acetic acid ethyl ester (13-18). MS m/z 504.4

(M+H)⁺; HPLC purity=89%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(4-methoxy-3-me-

thylbenzylamino)-acetic acid ethyl ester (13–36). MS m/z

442.4 (M+H)⁺; HPLC purity=87%.

(3,5-Di-tert-butyl-4-hydroxyphenyl) - (2 - triﬂuoromethyl-

benzylamino)acetic acid ethyl ester (13-19). MS m/z

466.3 (M+H)⁺; HPLC purity=76%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(4-hydroxy-3-meth-

oxybenzylamino)-acetic acid ethyl ester (13-37). MS m/z

444.4 (M+H)⁺; HPLC purity=93%.

(3,5-Di-tert-butyl-4-hydroxyphenyl) - (3- triﬂuoromethyl-

benzylamino)acetic acid ethyl ester (13-20). MS m/z

466.3 (M+H)⁺; HPLC purity=88%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(3-ethoxy-4-hydro-

xybenzylamino)acetic acid ethyl ester (13-38). MS m/z

458.4 (M+H)⁺; HPLC purity=97%.

(2-Chloro-benzylamino)-(3,5-di-tert-butyl-4-hydroxyphe-

nyl)acetic acid ethyl ester (13-21). MS m/z 432.3

(M+H)⁺; HPLC purity=89%

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(3,5-dichloro-2-hy-

droxybenzylamino)-acetic acid ethyl ester (13-42). MS

m/z 482.3 (M+H)⁺; HPLC purity=91%.

(4-Chloro-benzylamino)-(3,5-di-tert-butyl-4-hydroxyphe-

nyl)acetic acid ethyl ester (13-23). MS m/z 432.3

(M+H)⁺; HPLC purity=95%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(2,2-diphenylethyl-

amino)acetic acid ethyl ester (13-44). MS m/z 488.4

(M+H)⁺; HPLC purity=84%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(2-ﬂuoro-benzylami-

no)acetic acid ethyl ester (13-24). MS m/z 416.4

(M+H)⁺; HPLC purity=76%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(4-phenoxybenzyla-

mino) - acetic acid ethyl ester (13-45). MS m/z 490.4

(M+H)⁺; HPLC purity=79%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(3-nitro-benzylami-

no)acetic acid ethyl ester (13-25). MS m/z 443.3

(M+H)⁺; HPLC purity=83%

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(naphthalen-1-ylme-

thyl)amino]acetic acid ethyl ester (13-46). MS m/z 448.4

(M+H)⁺; HPLC purity=88%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(4-nitro-benzylami-

no)acetic acid ethyl ester (13-26). MS m/z 443.3

(M+H)⁺; HPLC purity=78%

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(4-methoxynaphtha-

len-1-ylmethyl)amino]acetic acid ethyl ester (13-47). MS

m/z 478.4 (M+H)⁺; HPLC purity=92%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(4-dimethylamino-

benzylamino)acetic acid ethyl ester (13-28). MS m/z

441.4 (M+H)⁺; HPLC purity=81%.

[(Anthracen-9-ylmethyl)amino]-(3,5-di-tert-butyl-4-hydro-

xyphenyl)acetic acid ethyl ester (13-48). MS m/z 498.4

(M+H)⁺; HPLC purity=96%.

(4-Dibutylamino-benzylamino)-(3,5-di-tert-butyl-4-hydro-

xyphenyl)acetic acid ethyl ester (13-29). MS m/z 525.4

(M+H)⁺; HPLC purity=86%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(thiophen-3-ylme-

thyl)amino]acetic acid ethyl ester (13-54). MS m/z 404.3

(M+H)⁺; HPLC purity=100%.

(4-Cyano-benzylamino)-(3,5-di-tert-butyl-4-hydroxyphe-

nyl)acetic acid ethyl ester (13-30). MS m/z 423.4

(M+H)⁺; HPLC purity=87%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-[(furan-3-ylmethyl)

amino]acetic acid ethyl ester (13-55). MS m/z 388.4

(M+H)⁺; HPLC purity=73%.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(2-methyl-benzylami-

no)acetic acid ethyl ester (13-31). MS m/z 412.4

(M+H)⁺; HPLC purity=84%.

(Cyclohexylmethylmethanesulfonylamino) - (3,5 - di - tert -

butyl - 4 - hydroxyphenyl)acetic acid ethyl ester (14-1,

Method 3). Compound 14-1 was synthesized by react-

ing compound 13-1 with methanesulfonyl chloride; MS

1

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(3-methyl-benzylami-

no)acetic acid ethyl ester (13-32). MS m/z 412.4

(M+H)⁺; HPLC purity=89%.

m/z 480.2 (MÀH)^À; H NMR (CDCl₃) d 0.4–0.9 (m,

6H), 1.1–1.19 (m, 1H), 1.25 (t, 3H), 1.38 (s, 18H), 1.4–

1.55 (m, 4H), 2.87 (s, 3H), 3.03 (d, 2H), 4.13–4.35 (m,

2H), 5.29 (s, 1H), 5.67 (s, 1H), 7.02 (s, 2H). Calcd for

C₂₆H₄₃NO₅S: C, 64.83; H, 9.00; N, 2.88. Found: C,

64.93; H, 8.92; N, 2.88.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(2,4-dichloro-benzy-

lamino)acetic acid ethyl ester (13-33). MS m/z 466.3

(M+H)⁺; HPLC purity=87%.

Dibenzylamino(3,5-di-tert-butyl-4-hydroxyphenyl)acetic

acid ethyl ester (14-2, Method 3). Mp 101–102 ^ꢁC; MS

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(3,4-dichloro-benzy-

lamino)acetic acid ethyl ester (13-34). MS m/z 466.3

(M+H)⁺; HPLC purity=94%.

1

m/z 488.3 (M+H)⁺; H NMR (CDCl₃) d 1.31 (t, 3H)

1.40 (s, 18H) 3.75 (q, 4H) 4.25 (q, 2H) 4.50 (s, 1H) 5.15

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4841

(s, 1H) 7.10–7.40 (m, 12H). Calcd for C₃₂H₄₁NO₃: C,

78.81; H, 8.47; N, 2.87. Found: C, 78.91; H, 8.68; N,

2.81.

2H) 7.16 (s, 1H) 7.21–7.26 (m, 2H) 7.75 (m, 1H) 8.46 (dd,

.

1H) 8.57 (d, 1H). Calcd for C₂₉H₃₈N₂O₃S 0.167H₂O: C,

69.92; H, 7.70; N, 5.63. Found: C, 69.91; H, 7.86; N,

5.51.

(Bis-pyridin-2-ylmethylamino)-(3,5-di-tert-butyl-4-hydro-

xyphenyl)acetic acid ethyl ester (14-3, Method 3). MS

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(pyridin-3-ylmethyl-

thiophen-3-ylmethylamino)acetic acid ethyl ester (14-10,

Method 3). Mp 148–150 ^ꢁC. MS m/z 495.4 (M+H)⁺.

¹H NMR (CDCl₃) d 1.31 (t, 3H) 1.41 (s, 18H) 3.68–3.82

(m, 4H) 4.27 (q, 2H) 4.49 (s, 1H) 5.19 (s, 1H) 7.00 (dd,

1H) 7.12 (m, 3H) 7.18–7.27 (m, 2H) 7.61 (m, 1H) 8.45

(dd, 1H) 8.51 (d, 1H). Calcd for C₂₉H₃₈N₂O₃S H₂O: C,

67.88; H, 7.80; N, 5.46. Found: C, 67.79; H, 7.47; N,

5.35.

1

m/z 490.3 (M+H)⁺. H NMR (CDCl₃) d 1.31 (t, 3H)

1.40 (s, 18H) 3.90–4.10 (q, 4H) 4.25 (q, 2H) 4.60 (s, 1H)

5.20 (s, 1H) 7.10 (m, 2H) 7.19 (s, 2H) 7.50 (d, 2H) 7.60

(m, 2H) 8.45 (m, 2H). Calcd for C₃₀H₃₉N₃O₃: C, 73.59;

H, 8.03; N, 8.58. Found: C, 73.28; H, 8.07; N, 8.31.

.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(pyridin-2-ylmethyl-

pyridin - 3- ylmethylamino)acetic acid ethyl ester (14 - 4,

Method 3). Mp 102–103^ꢁC. MS m/z 490.4 (M+H)⁺;

¹H NMR (CDCl₃) d 1.30 (t, 3H) 1.41 (s, 18H) 3.80–4.00

(m, 4H) 4.25 (q, 2H) 4.52 (s, 1H) 5.20 (s, 1H) 7.05–7.20

(m, 2H) 7.40 (d, 1H) 7.60 (m, 2H) 8.40 (m, 2H) 8.50 (d,

1H). Calcd for C₃₀H₃₉N₃O₃: C, 73.59; H, 8.03; N, 8.58.

Found: C, 73.44; H, 8.00; N, 8.46.

(3,5-Di-tert-butyl-4-hydroxyphenyl) - (furan - 2 - ylmethyl-

pyridin-3-ylmethylamino)acetic acid ethyl ester (14-11,

Method 3). Mp 118–119 ^ꢁC; MS m/z 479.4 (M+H)⁺.

¹H NMR (CDCl₃) d 1.29 (t, 3H) 1.41 (s, 18H) 3.66–3.80

(m, 4H) 4.25 (m, 2H) 4.46 (s, 1H) 5.19 (s, 1H) 6.14 (d,

1H) 6.30 (m, 1H) 7.20 (m, 3H) 7.38 (m, 1H) 7.71 (m,

1H) 8.45 (dd, 1H) 8.54 (d, 1H). Calcd for C₂₉H₃₈N₂O₄:

C, 72.77; H, 8.00; N, 5.85. Found: C, 72.62; H, 8.10; N,

5.62.

(Benzyl-pyridin-2-ylmethylamino)-(3,5-di-tert-butyl-4-hy-

droxyphenyl)acetic acid ethyl ester (14-5, Method 3).

1

MS m/z 489.4 (M+H)⁺. H NMR (CDCl₃) d 1.27 (t,

3H) 1.41 (s, 18H) 3.80–4.04 (m, 4H) 4.20–4.29 (q, 2H)

4.54 (s, 1H) 5.16 (s, 1H) 7.08–7.38 (m, 8H) 7.54–7.65 (m,

(Bis-pyridin-4-ylmethylamino)-(3,5-di-tert-butyl-4-hydro-

xyphenyl)acetic acid ethyl ester (14-12, Method 3). Mp

90–92 ^ꢁC. MS m/z 490.3 (M+H)⁺; p¹H NMR (CDCl₃)

d 1.30 (t, 3H) 1.41 (s, 18H) 3.75 (t, 4H) 4.25 (q, 2H) 4.45

(s, 1H) 5.20 (s, 1H) 7.10 (d, 2H) 7.20 (s, 4H) 8.55 (d,

.

2H) 8.46 (m, 1H). Calcd for C₃₁H₄₀N₂O₃0.25H₂O: C,

75.43; H, 8.21; N, 5.68. Found: C, 75.51; H, 7.89; N,

5.51.

.

(Bis-pyridin-3-ylmethylamino)-(3,5-di-tert-butyl-4-hydro-

xyphenyl)acetic acid ethyl ester (14-6, Method 3). Mp

125–127 ^ꢁC; MS m/z 490.4 (M+H)⁺; ¹H NMR

(CDCl₃) d 1.31 (t, 3H) 1.41 (s, 18H) 3.77 (s, 4H) 4.25 (q,

2H) 4.46 (s, 1H) 5.23 (s, 1H) 7.09 (s, 2H) 7.20 (m, 2H)

7.60 (m, 2H) 8.45–8.50 (m, 4H). Calcd for C₃₀H₃₉N₃O₃:

C, 73.59; H, 8.03; N, 8.58. Found: C, 73.32; H, 8.07; N,

8.43.

4H). Calcd for C₃₀H₃₉N₃O₃0.33H₂O: C, 72.75; H, 8.08;

N, 8.48. Found: C, 72.60; H, 8.14; N, 8.13.

(Benzylpyridin-3-ylmethylamino)-(3,5-di-tert-butyl-4-hy-

droxyphenyl)acetic acid ethyl ester (14-13, Method 3).

Mp 120–121 ^ꢁC; MS m/z 489.3 (M+H)⁺; ¹H NMR

(CDCl₃) d 1.31 (t, 3H) 1.41 (s, 18H) 3.75 (d, 2H) 3.78 (s,

2H) 4.27 (q, 2H) 4.49 (s, 1H) 5.18 (s, 1H) 7.11 (s, 2H)

7.18-7.33 (m, 6H) 7.60 (m, 1H) 8.45 (dd, 1H) 8.52 (d,

1H). Calcd for C₃₁H₄₀N₂O₃: C, 76.19; H, 8.25; N, 5.73.

Found: C, 76.15; H, 8.31; N, 5.62.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(pyridin-3-ylmethyl-

pyridin - 4 - ylmethylamino)acetic acid ethyl ester (14-7,

Method 3). MS m/z 490.4 (M+H)⁺; ¹H NMR

(CDCl₃) d 1.31 (t, 3H) 1.41 (s, 18H) 3.77 (s, 4H) 4.26–

4.29 (q, 2H) 4.46 (s, 1H) 5.22 (s, 1H) 7.09 (s, 2H) 7.20–

7.23 (m, 3H) 7.61 (m, 1H) 8.47–8.53 (m, 4H). Calcd for

(Benzylpyridin-4-ylmethylamino)-(3,5-di-tert-butyl-4-hy-

droxyphenyl)acetic acid ethyl ester (14-14, Method 3).

1

MS m/z 489.4 (M+H)⁺. H NMR (CDCl₃) d 1.28 (t,

3H) 1.41 (s, 18H) 3.75 (s, 2H) 3.78 (s, 2H) 4.25 (q, 2H)

4.49 (s, 1H) 5.18 (s, 1H) 7.10 (s, 2H) 7.22–7.33 (m, 7H)

.

C₃₀H₃₉N₃O₃0.5H₂O: C, 72.19; H, 8.02; N, 8.42. Found:

C, 72.19; H, 8.09; N, 8.12.

.

8.49 (dd, 2H). Calcd for C₃₁H₄₀N₂O₃0.25H₂O: C,

(Cyclohexylmethylpyridin-3-ylmethylamino)-(3,5-di-tert-

butyl - 4 - hydroxyphenyl)acetic acid ethyl ester (14-8,

Method 3). MS m/z 495.2 (M+H)⁺; ¹H NMR

(CDCl₃) d 0.45–0.90 (m, 3H), 1.00–1.40 (m, 7H), 1.41 (s,

18H), 1.50–1.85 (m, 4H), 2.28–2.51 (m, 2H), 3.63–3.83

(m, 2H), 4.21–4.30 (m, 2H), 4.57 (s, 1H), 5.17 (s, 1H),

7.11 (s, 2H), 7.16–7.21 (m, 1H), 7.56–7.59 (m, 1H),

8.43–8.47 (m, 2H). Calcd for C₃₁H₄₆N₂O₃: C, 75.26; H,

9.37; N, 5.66. Found: C, 75.03; H, 9.30; N, 5.50.

75.43; H, 8.21; N, 5.68. Found: C, 75.51; H, 8.27; N,

5.54.

(Bis-pyridin-3-ylmethylamino)-(3,5-di-tert-butyl-4-hydro-

xyphenyl)acetic acid tert-butyl ester (14-15, Method 3).

Mp 152–153 ^ꢁC. MS m/z 518.4 (M+H)⁺. ¹H NMR

(CDCl₃) d 1.42 (s, 18H) 1.54 (s, 9H) 3.78 (q, 4H) 4.35 (s,

1H) 5.19 (s, 1H) 7.12 (s, 2H) 7.20 (q, 2H) 7.59 (d, 2H) 8.47

(d, 2H) 8.51 (d, 2H). Calcd for C₃₂H₄₃N₃O₃: C, 74.24; H,

8.37; N, 8.12. Found: C, 74.32; H, 8.56; N, 7.98.

(3,5-Di-tert-butyl-4-hydroxyphenyl)-(pyridin-3-ylmethyl-

thiophen-2-ylmethylamino)acetic acid ethyl ester (14-9,

Method 3). Mp 141–142 ^ꢁC; MS m/z 495.3 (M+H)⁺;

¹H NMR (CDCl₃) d 1.31 (t, 3H) 1.42 (s, 18H) 3.73–4.07

(m, 4H) 4.30 (q, 2H) 4.56 (s, 1H) 5.19 (s, 1H) 6.91 (m,

(Cyclohexylmethylmethanesulfonylamino) - (3,5 - di - tert -

butyl - 4 - hydroxyphenyl)acetic acid tert-butyl ester (14-

16). Compound 14-16 was synthesized by reacting

compound 4-21 and methanesulfonyl chloride; Mp

4842

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

134–136 ^ꢁC. MS m/z 508.3 (MÀH)^À. ¹H NMR (CDCl₃)

d 0–1.2 (m, 11H) 1.42 (s, 18H) 1.49 (a, 9H) 2.89 (s, 3H)

3.10 (m, 2H) 5.30 (s, 1H) 5.57 (s, 1H) 7.07 (s, 2H). Calcd

for C₂₈H₄₇NO₅S: C, 65.98; H, 9.29; N, 2.75. Found: C,

65.59; H, 8.97; N, 2.52.

.

(d, 1H) 8.55 (dd, 1H). Calcd for C₂₁H₃₀N₂O₃S H₂O: C,

61.73; H, 7.83; N, 6.85. Found: C, 61.86; H, 7.26; N,

6.67.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-N-pyridin-3-ylben-

zenesulfonamide (20-2). Mp 143–145 ^ꢁC; MS m/z 453.3

1

(M+H)⁺; H NMR (CDCl₃) d 1.35 (s, 18H) 4.70 (s,

Sulfonamides

2H) 5.15 (s, 1H) 6.85 (s, 2H) 7.20 (m, 1H) 7.35 (d, 1H)

7.55 (t, 2H) 7.60 (t, 1H) 7.65 (d, 2H) 8.15 (d, 1H) 8.43

(dd, 1H). Calcd for C₂₆H₃₂N₂O₃S: C, 69.00; H, 7.13; N,

6.19. Found: C, 68.62; H, 6.86; N, 5.95.

Amine (18). Method A. A mixture of the appropriate

aldehyde, 15 (1 equiv), amine, 16 (1.1 equiv), and cata-

lytic p-toluenesulfonic acid in toluene was heated to

reﬂux until the starting material was consumed and the

product observed by mass spec. Water was removed via

molecular sieves and a Dean-Stark trap. The molecular

sieves were ﬁltered oﬀ and the reaction evaporated at

reduced pressure and the crude product (imine, 17) was

recrystallized from EtOAc. Imine, 17, can be reduced to

amine, 18, with Raney nickel or with 20% Pt/C. The

reaction was subjected to hydrogen gas and stirred at

room temperature until all starting material was con-

sumed and the product was observed by tlc. The cata-

lyst was ﬁltered oﬀ and the ﬁltrate was removed in

vacuo to obtain the product which was puriﬁed by col-

umn chromatography.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-N-pyridin-3-ylben-

zylsulfonamide (20-3). Mp 139–140 ^ꢁC. MS m/z 467.3

1

(M+H)⁺; H NMR (CDCl₃) d 1.33 (s, 18H) 4.32 (s,

2H) 4.52 (s, 2H) 5.18 (s, 1H) 6.88 (s, 2H) 7.15 (m, 1H)

7.23 (m, 1H) 7.38 (s, 4H) 8.21 (d, 1H) 8.42 (dd, 1H).

Calcd for C₂₇H₃₄N₂O₃S: C, 69.50; H, 7.34; N, 6.00.

Found: C, 69.70; H, 7.43; N, 6.18.

2-Bromo-N-(3,5-di-tert-butyl-4-hydroxybenzyl)-N-pyridin

-3-ylbenzenesulfonamide (20-4). Mp 103–107 ^ꢁC; MS m/z

533.1 (M+H)⁺; ¹H NMR (CDCl₃) d 1.34 (s, 18H) 4.91

(s, 2H) 5.17 (s, 1H) 6.93 (s, 2H) 7.16 (m, 1H) 7.33 (t, 2H)

7.43 (m, 1H) 7.76 (d, 1H) 7.92 (d, 1H) 8.27 (d, 1H) 8.40

.

(dd, 1H). Calcd for C₂₆H₃₁N₂O₃SBr 0.33H₂O: C, 58.04;

H, 5.89; N, 5.21. Found: C, 58.12; H, 5.90; N, 4.74.

Method B (18). To a solution of the appropriate

aldehyde, 15 (1 equiv), in 1,2-dichloroethane was added

amine, 16 (1.08 equiv) and sodium triacetoxyborohy-

dride (1.5 equiv). The reaction was stirred at room

temperature for 18 h. The reaction was washed with

water and brine, dried (MgSO₄) and concentrated in

vacuo. The pure product was obtained by column

chromatography.

3-Bromo-N-(3,5-di-tert-butyl-4-hydroxybenzyl)-N-pyridin-

3-ylbenzenesulfonamide (20-5). Mp 129–131 ^ꢁC; MS m/z

533.1 (M+H)⁺. ¹H NMR (CDCl₃) d 1.33 (s, 18H) 4.70

(s, 2H) 5.16 (s, 1H) 6.88 (s, 2H) 7.26 (m, 1H) 7.40 (t, 2H)

7.54 (d, 1H) 7.74 (d, 1H) 7.83 (t, 1H) 8.18 (d, 1H) 8.48

.

(dd, 1H). Calcd for C₂₆H₃₁N₂O₃SBr 0.33H₂O: C, 58.04;

H, 5.89; N, 5.21. Found: C, 58.10; H, 5.71; N, 4.89.

Method C (18). A mixture of bromide, 21 (1 equiv),

amine, 16 (10 equiv) and potassium carbonate (1 equiv)

in acetonitrile was heated to 70 ^ꢁC until all starting

material was consumed and the product was observed

by mass spec. The reaction was cooled and ﬁltered. The

ﬁltrate was concentrated in vacuo, redissolved in

EtOAc, washed with water and brine, and dried

(MgSO₄) to give the ﬁnal product.

4-Bromo-N-(3,5-di-tert-butyl-4-hydroxybenzyl)-N-pyridin-

3-ylbenzenesulfonamide (20-6). Mp 129–130 ^ꢁC; MS m/z

533.2 (M+H)⁺; ¹H NMR (CDCl₃) d 1.32 (s, 18H) 4.67

(s, 2H) 5.14 (s, 1H) 6.87 (s, 2H) 7.20 (q, 1H) 7.33 (m,

1H) 7.50–7.65 (dd, 4H) 8.13 (d, 1H) 8.46 (dd, 1H).

Calcd for C₂₆H₃₁N₂O₃SBr: C, 58.75; H, 5.88; N, 5.27.

Found: C, 58.93; H, 5.83; N, 5.17.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-methoxy-N-pyr-

idin-3-ylbenzenesulfonamide (20-7). Mp 142–143 ^ꢁC; MS

General procedure for sulfonamide formation. To a solu-

tion of amine, 18, in pyridine was added the appropriate

sulfonyl chloride, 19, and a catalytic amount of 4-dime-

thylaminopyridine. The reaction was heated to 60 ^ꢁC for

18 h. The reaction was cooled and the solvent evapo-

rated in vacuo. The residue was dissolved in EtOAc,

washed with water (3X) and brine, dried (MgSO₄) and

evaporated at reduced pressure. The pure product, 20,

was obtained by column chromatography.

1

m/z 483.2 (M+H)⁺; H NMR (CDCl₃) d 1.32 (s, 18H)

3.88 (s, 3H) 4.66 (s, 2H) 5.12 (s, 1H) 6.88 (s, 2H) 6.95 (d,

2H) 7.20 (m, 1H) 7.39 (m, 1H) 7.60 (d, 2H) 8.13 (d, 1H)

8.42 (d, 1H). Calcd for C₂₇H₃₄N₂O₄S: C, 67.19; H, 7.10;

N, 5.80. Found: C, 66.93; H, 7.18; N, 5.66.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-ﬂuoro-N-pyridin-

3-ylbenzenesulfonamide (20-8). Mp 137–138 ^ꢁC; MS m/z

471.2 (M+H)⁺; ¹H NMR (CDCl₃) d 1.32 (s, 18H) 4.67

(s, 2H) 5.14 (s, 1H) 6.88 (s, 2H) 7.20 (m, 3H) 7.37 (m,

1H) 7.66 (q, 2H) 8.13 (d, 1H) 8.45 (dd, 1H). Calcd for

C₂₆H₃₁N₂O₃SF: C, 66.36; H, 6.64; N, 5.95. Found: C,

66.46; H, 6.54; N, 5.87.

Sulfonamides. Compounds 20-1 to 20-21 use amine 18

(R₁=3-pyridine, n₂=0) as starting material. This amine

was synthesized as described in Scheme 3, method A.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-N-pyridin-3-ylme-

1

thanesulfonamide (20-1). MS m/z 391.1 (M+H)⁺; H

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-nitro-N-pyridin-

3-ylbenzenesulfonamide (20-9). Mp 157–158 ^ꢁC; MS m/z

498.2 (M+H)⁺; ¹H NMR (CDCl₃) d 1.29 (s, 18H) 4.68

NMR (CDCl₃) d 1.35 (s, 18H) 2.95 (s, 3H) 4.80 (s, 2H)

5.20 (s, 1H) 6.95 (s, 2H) 7.28 (t, 1H) 7.55 (m, 1H) 8.45

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4843

1

(s, 2H) 5.15 (s, 1H) 6.84 (s, 2H) 7.20 (s, 1H) 7.30 (d, 1H)

7.80 (d, 2H) 8.10 (s, 1H) 8.30 (d, 2H) 8.46 (d, 1H). Calcd

for C₂₆H₃₁N₃O₅S: C, 62.76; H, 6.28; N, 8.44. Found: C,

62.85; H, 6.30; N, 8.25.

MS m/z 510.2 (M+H)⁺; H NMR (CDCl₃) d 1.32 (s,

18H) 1.36 (s, 9H) 4.69 (s, 2H) 5.13 (s, 1H) 6.88 (s, 2H)

7.53 (dd, 4H) 8.18 (m, 1H) 8.44 (m, 1H); LCMS: 96.98%,

retention time: 4.250 min, gradient: 60% CH₃CN/40%

H₂O, column: Alltech Alltima C18 150ꢂ4.6 5m.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-3-nitro-N-pyridin-

3-ylbenzenesulfonamide (20-10). Mp 99–107 ^ꢁC; MS m/z

498.1 (M+H)⁺; ¹H NMR (CDCl₃) d 1.32 (s, 18H) 4.74

(s, 2H) 5.17 (s, 1H) 6.89 (s, 2H) 7.26 (m, 1H) 7.33 (m,

1H) 7.71 (t, 1H) 7.91 (d, 1H) 8.13 (d, 1H) 8.50 (m, 3H).

2-Phenylethenesulfonic acid (3,5-di-tert-butyl-4-hydroxy-

benzyl)pyridin-3-ylamide (20-17). Mp 215–216 ^ꢁC; MS

m/z 479.3 (M+H)⁺; H NMR (DMSO-d₆) d 1.23 (s,

18H) 4.77 (s, 2H) 6.86 (s, 1H) 6.89 (s, 2H) 7.35–7.60 (m,

5H) 7.74–7.80 (m, 3H) 8.40 (m, 2H). Calcd for

.

C₂₈H₃₄N₂O₃S 0.167H₂O: C, 69.76; H, 7.13; N, 5.81.

Found: C, 69.38; H, 7.12; N, 5.79.

1

.

Calcd for C₂₆H₃₁N₃O₅S 0.33H₂O: C, 61.95; H, 6.29; N,

8.33. Found: C, 62.11; H, 6.41; N, 8.21.

4-Amino-N-(3,5-di-tert-butyl-4-hydroxybenzyl)-N-pyridin-

3- ylbenzenesulfonamide (20-11). Compound 20-9 was

stirred in acetic acid (2 mL) and zinc dust (7:1 w/w, zinc/

compound) at room temperature. The reaction was

complete after 1.5 h and ﬁltered through Celite, rinsing

with EtOAc. The ﬁltrate was washed with saturated

aqueous NaHCO₃, evaporated at reduced pressure and

puriﬁed by column chromatography to obtain 20-11.

Naphthalene-2-sulfonic acid (3,5-di-tert-butyl-4-hydroxy-

benzyl)pyridin-3-ylamide (20-18). Mp 169–171 ^ꢁC; MS

m/z 503.2 (M+H)⁺; ‘p¹H NMR (CDCl₃) d 1.30 (s,

18H) 4.74 (s, 2H) 5.13 (s, 1H) 6.89 (s, 2H) 7.22 (m, 1H)

7.41 (m, 1H) 7.65 (m, 3H) 7.97 (m, 3H) 8.17 (d, 1H) 8.27

(d, 1H) 8.44 (d, 1H). Calcd for C₃₀H₃₄N₂O₃S: C, 71.68;

H, 6.82; N, 5.57. Found: C, 71.29; H, 6.74; N, 5.36.

Mp 169–170 ^ꢁC; MS m/z 468.2 (M+H)⁺; ¹H NMR

(CDCl₃) d 1.32 (s, 18H) 4.15 (s, 2H) 4.64 (s, 2H) 5.10 (s,

1H) 6.64 (d, 2H) 6.89 (s, 2H) 7.18 (m, 1H) 7.41 (d, 2H) 8.16

(s, 1H) 8.40 (s, 1H). Calcd for C₂₆H₃₃N₃O₃S 0.33H₂O: C,

65.87; H, 7.11; N, 8.87. Found: C, 66.24; H, 7.12; N, 8.38.

Thiophene-2-sulfonic acid (3,5-di-tert-butyl-4-hydroxy-

benzyl)pyridin-3-ylamide (20-19). Mp 137–138 ^ꢁC; MS

1

m/z 459.2 (M+H)⁺; H NMR (CDCl₃) d 1.33 (s, 18H)

.

4.73 (s, 2H) 5.15 (s, 1H) 6.91 (s, 2H) 7.12 (q, 1H)

7.22 (q, 1H) 7.40 (m, 1H) 7.43 (dd, 2H) 8.63 (dd, 1H)

8.20 (d, 1H) 8.47 (dd, 1H). Calcd for C₂₄H₃₀N₂O₃S₂: C,

62.85; H, 6.59; N, 6.11. Found: C, 63.17; H, 6.69; N,

6.01.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-methyl-N-pyri-

din - 3- ylbenzenesulfonamide (20-12). Mp 129–130 ^ꢁC;

1

MS m/z 467.2 (M+H)⁺; H NMR (CDCl₃) d 1.32 (s,

18H) 2.44 (s, 3H) 4.67 (s, 2H) 5.12 (s, 1H) 6.88 (s, 2H)

7.20 (q, 1H) 7.30 (d, 2H) 7.38 (m, 1H) 7.56 (d, 2H) 8.11

(d, 1H) 8.43 (dd, 1H). Calcd for C₂₇H₃₄N₂O₃S: C, 69.50;

H, 7.34; N, 6.00. Found: C, 69.49; H, 7.43; N, 5.92.

5-Pyridin-2-ylthiophene-2-sulfonic acid (3,5-di-tert-butyl-

4-hydroxybenzyl)pyridin-3-ylamide (20-20). MS m/z

536.3 (M+H)⁺; ¹H NMR (CDCl₃) d 1.33 (s, 18H) 4.81

(s, 2H) 5.17 (s, 1H) 6.93 (s, 2H) 7.29 (m, 1H) 7.37 (d,

2H) 7.52 (d, 1H) 7.67 (m, 2H) 7.79 (m, 1H) 8.30 (d, 1H)

8.47 (dd, 1H) 8.61 (d, 1H). Calcd for

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-ethyl-N-pyridin-

3-ylbenzeneulfonamide (20-13). Mp 113–116 ^ꢁC; MS m/z

.

C₂₉H₃₃N₃O₃S₂1.5H₂O: C, 61.84; H, 6.39; N, 7.46.

Found: C, 61.95; H, 6.23; N, 6.87.

1

481.2 (M+H)⁺; H NMR (CDCl₃) d 1.31 (t, 3H) 1.32

(s, 18H) 2.73 (q, 2H) 4.68 (s, 2H) 5.13 (s, 1H) 6.88 (s,

2H) 7.26 (m, 2H) 7.35 (d, 2H) 7.59 (d, 2H) 8.14 (m, 1H)

8.44 (dd, 1H). Calcd for C₂₈H₃₆N₂O₃S: C, 69.97; H,

7.55; N, 5.83. Found: C, 70.21; H, 7.61; N, 5.78.

N-{5-[(3,5-Di-tert-butyl-4-hydroxybenzyl)pyridin-3-yl-

sulfamoyl] -4- methylthiazol-2-yl}acetamide (20-21). Mp

175–177 ^ꢁC; MS m/z 531.2 (M+H)⁺; ¹H NMR

(CDCl₃) d 1.33 (s, 18H) 2.17 (s, 3H) 2.27 (s, 3H) 4.81 (s,

2H) 5.15 (s, 1H) 6.93 (s, 2H) 7.29 (m, 1H) 7.56 (m, 1H)

8.34 (d, 1H) 8.47 (dd, 1H). Calcd for C₂₆H₃₄N₄O₄S₂: C,

58.84; H, 6.46; N, 10.56. Found: C, 59.11; H, 6.46; N,

10.42.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-propyl-N-pyri-

din-3-ylbenzenesulfonamide (20-14). Mp 93–95 ^ꢁC; MS

1

m/z 495.2 (M+H)⁺; H NMR (CDCl₃) d 0.96 (t, 3H)

1.32 (s, 18H) 1.67 (q, 2H) 2.67 (t, 2H) 4.67 (s, 2H) 5.12

(s, 1H) 6.91 (s, 2H) 7.20 (m, 1H) 7.29 (d, 2H) 7.38 (m,

1H) 7.58 (d, 2H) 8.13 (d, 1H) 8.44 (dd, 1H). Calcd for

N-Cyclohexyl-N-(3,5-di-tert-butyl-4-hydroxybenzyl)-4-

methylbenzenesulfonamide

.

C₂₉H₃₈N₂O₃S 0.33H₂O: C, 69.50; H, 7.72; N, 5.59.

Found: C, 69.55; H, 7.76; N, 5.40.

(20-22).

Amine

18

(R₁=cyclohexane, n₂=0) was synthesized as described

for Scheme 3, Method C. Mp 175–177 ^ꢁC; MS m/z 254.1

(MÀ218)⁺; ¹H NMR (CDCl₃) d 1.39 (s, 18H) 1.20–1.80

(m, 10H) 2.38 (s, 3H) 3.72 (m, 1H) 4.31 (s, 2H) 5.11 (s,

1H) 7.08 (s, 2H) 7.21 (d, 2H) 7.58 (d, 2H). Calcd for

4-tert-Butyl-N-(3,5-di-tert-butyl-4-hydroxybenzyl)-N-pyr-

idin-3-yl-benzenesulfonamide (20-15). Mp 155–156 ^ꢁC;

1

MS m/z 509.3 (M+H)⁺; H NMR (CDCl₃) d 1.32 (s,

.

18H) 1.36 (s, 9H) 4.69 (s, 2H) 5.13 (s, 1H) 6.88 (s, 2H)

7.53 (dd, 4H) 8.18 (m, 1H) 8.44 (m, 1H). Calcd for

C₃₀H₄₀N₂O₃S: C, 70.83; H, 7.93; N, 5.51. Found: C,

70.59; H, 7.91; N, 5.41.

C₂₈H₄₁NO₃S 0.167H₂O: C, 70.78; H, 8.71; N, 2.95.

Found: C, 70.71; H, 8.49; N, 2.77.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-methyl-N-phe-

nylbenzenesulfonamide (20-23). Amine 18 (R₁=C₆H₅,

n₂=0) was synthesized as described for Scheme 3,

N-{4-[(3,5-Di-tert-butyl-4-hydroxybenzyl) - pyridin - 3- yl-

sulfamoyl]phenyl}acetamide (20-16). Mp 163–165 ^ꢁC;

1

Method B(MS, NMR); MS m/z 248.1 (MÀ218)⁺; H

4844

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

NMR (CDCl₃) d 1.25 (s, 18H) 2.36 (s, 3H) 4.57 (s, 2H)

5.01 (s, 1H) 6.81 (s, 2H) 6.86 (m, 2H) 7.14 (m, 3H) 7.21

(m, 2H) 7.49 (d, 2H). Calcd for C₂₈H₃₅NO₃S: C, 72.22;

H, 7.58; N, 3.01. Found: C, 71.95; H, 7.56; N, 3.07.

Mp 215 ^ꢁC; MS m/z 467.3 (M+H)⁺; ¹H NMR (CDCl₃)

d 1.40 (s, 18H) 2.36 (s, 3H) 4.91 (s, 2H) 5.38 (s, 1H) 6.95

(s, 2H) 7.07 (d, 2H) 7.23 (d, 2H) 7.42 (d, 2H) 7.85 (d,

2H). Calcd for C₂₇H₃₄N₂O₃S: C, 69.50; H, 7.34; N, 6.00.

Found: C, 69.46; H, 7.24; N, 5.93.

N-(3-Chlorophenyl)-N-(3,5-di-tert-butyl-4-hydroxyben-

zyl) - 4 - methylbenzenesulfonamide (20-24). Amine 18

(R₁=3-Cl–C₆H₄, n₂=0) was synthesized as described

for Scheme 3, method B(MS); Mp 105–107 ^ꢁC; MS

m/z 282.1 (MÀ218)⁺; ¹H NMR (CDCl₃) d 1.33

(s, 18H) 2.43 (s, 3H) 4.40 (s, 2H) 5.10 (s, 1H)

6.85 (s, 2H) 6.87 (m, 2H) 7.15 (m, 2H) 7.28

(d, 2H) 7.55 (d, 2H). Calcd for C₂₈H₃₄NO₃SCl:

C, 67.25; H, 6.85; N, 2.80. Found: C, 67.16; H, 6.91;

N, 2.69.

N-(2-Chloropyridin-3-yl)-N-(3,5-di-tert-butyl-4-hydroxy-

benzyl)-4-methylbenzenesulfonamide (20-30). Amine 18

(R₁=2-Cl-3-pyridine, n₂=0) was synthesized as descri-

bed for Scheme 3, Method A. Mp 117–119 ^ꢁC; MS m/z

501.2 (M+H)^{+ 1}H NMR (CDCl₃) d 1.31 (s, 18H) 2.44

(s, 3H) 4.54–4.89 (dd, 2H) 5.14 (s, 1H) 6.86 (s, 2H) 7.07

(q, 1H) 7.28 (dd, 3H) 7.65 (d, 2H) 8.24 (dd, 1H). Calcd

for C₂₇H₃₃N₂O₃SCl: C, 64.72; H, 6.64; N, 5.59. Found:

C, 64.72; H, 6.68; N, 5.49.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-N-(3,5-dichloro-

phenyl)-4-methylbenzenesulfonamide (20-25). Amine 18

(R₁=3,5-diCl–C₆H₃, n₂=0) was synthesized as_ꢁdescri-

bed for Scheme 3, method B(MS). Mp 143–145 C; MS

m/z 316.0 (MÀ218)⁺; ¹H NMR (CDCl₃) d 1.34 (s, 18H)

2.46 (s, 3H) 4.57 (s, 2H) 5.14 (s, 1H) 6.85 (m, 4H) 7.19

(t, 1H) 7.30 (d, 2H) 7.56 (d, 2H). Calcd for

C₂₈H₃₃NO₃SCl₂: C, 62.91; H, 6.22; N, 2.62. Found: C,

62.91; H, 6.26; N, 2.46.

N-(6-Chloropyridin-3-yl)-N-(3,5-di-tert-butyl-4-hydroxy-

benzyl)-4-methylbenzenesulfonamide (20-31). Amine 18

(R₁=6-chloro-3-pyridine, n₂=0) was synthesized as

described for Scheme 3, Method A. Mp 152–153 ^ꢁC; MS

m/z 501.1 (M+H)^{+ 1}H NMR (CDCl₃) d 1.33 (s, 18H)

2.45 (s, 3H) 4.63 (s, 2H) 5.15 (s, 1H) 6.88 (s, 2H) 7.18 (d,

1H) 7.29 (m, 3H) 7.53 (d, 2H) 7.86 (d, 1H). Calcd for

C₂₇H₃₃N₂O₃SCl: C, 64.72; H, 6.64; N, 5.59. Found: C,

65.03; H, 6.82; N, 5.42.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-methyl-N-(3-ni-

trophenyl)benzenesulfonamide (20-26). Amine 18

(R₁=3-NO₂–C₆H₄, n₂=0) was synthesized as described

for Scheme 3, Method B(MS).

N-(3,5-Di-tert-butyl-4-hydroxybenzyl) - N - (6 - methoxy -

pyridin - 3- yl) - 4 - methylbenzenesulfonamide (20-32).

Amine 18 (R₁=6-OMe-3-pyridine, n₂=0) was synthe-

sized as described for Scheme 3, Method A. Mp 127–

129 ^ꢁC; MS m/z 497.2 (M+H)⁺; H NMR (CDCl₃) d

1

Mp 128–130 ^ꢁC; MS m/z 291.1 (MÀ218)^À; H NMR

1.33 (s, 18H) 2.44 (s, 3H) 3.87 (s, 3H) 4.60 (s, 2H) 5.13

(s, 1H) 6.57 (d, 1H) 6.88 (s, 2H) 7.11 (dd, 1H) 7.30 (d,

2H) 7.56 (d, 2H) 7.62 (d, 1H). Calcd for C₂₈H₃₆N₂O₄S:

C, 67.71; H, 7.31; N, 5.64. Found: C, 67.81; H, 7.35; N,

5.53.

1

(CDCl₃) d 1.30 (s, 18H) 2.45 (s, 3H) 4.65 (s, 2H) 5.15 (s,

1H) 6.85 (s, 2H) 7.30 (d, 2H) 7.40 (m, 2H) 7.55 (d, 2H)

7.70 (m, 1H) 8.05 (m, 1H). Calcd for C₂₈H₃₄N₂O₅S: C,

65.86; H, 6.71; N, 5.49. Found: C, 65.83; H, 6.75; N,

5.32.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-N-(2,6-dimethyl-

pyridin - 3 - yl) - 4 - methylbenzenesulfonamide (20-33).

Amine 18 (R₁=2,6-diMe-3-pyridine, n₂=0) was syn-

thes_ꢁized as described for Scheme 3, Method A. Mp 147–

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-N-(3-methoxyphe-

nyl) - 4 - methylbenzenesulfonamide (20-27). Amine 18

(R₁=3-OMe–C₆H₄, n₂=0) was synthesized as described

for Scheme 3, method B. Mp 119–121 ^ꢁC; MS m/z 278.1

1

148 C; MS m/z 495.2 (M+H)⁺; H NMR (CDCl₃) d

1

(MÀ218)⁺; H NMR (CDCl3) d 1.32 (s, 18H) 2.43 (s,

1.29 (s, 18H) 2.15 (s, 3H) 2.45 (d, 6H) 4.20–4.80 (dd,

2H) 5.14 (s, 1H) 6.76 (s, 2H) 6.81 (d, 2H) 7.29 (d, 2H)

7.60 (d, 2H). Calcd for C₂₉H₃₈N₂O₃S: C, 70.41; H, 7.74;

N, 5.66. Found: C, 70.56; H, 7.80; N, 5.62.

3H) 3.64 (s, 3H) 4.62 (s, 2H) 5.09 (s, 1H) 6.45 (m, 1H)

6.50 (m, 1H) 6.73 (m, 1H) 6.88 (s, 2H) 7.08 (t, 1H)

7.29 (s, 1H) 7.57 (d, 2H). Calcd for C₂₉H₃₇NO₄S: C,

70.27; H, 7.52; N, 2.83. Found: C, 70.11; H, 7.44; N,

2.66.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-N-(6-ethoxy-ben-

zothiazol - 2 - yl) - 4 - methyl - benzenesulfonamide (20-34).

Amine 18 (R₁=6-OEt-2-benzothiazole, n₂=0) was syn-

thes_ꢁized as described for Scheme 3, Method A. Mp 214–

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-methyl-N-pyri-

din-2-ylbenzenesulfonamide (20-28). Amine 18 (R₁=2-

pyridine, n₂=0) was synthesized as described for

Scheme 3, Method A. Mp 117 ^ꢁC; MS m/z 249.1 (M-

1

216 C; MS m/z 567.3 (M+H)⁺; H NMR (CDCl₃) d

1.29 (s, 18H) 1.38 (t, 3H) 2.37 (s, 3H) 4.00 (q, 2H) 5.16

(s, 1H) 5.22 (s, 2H) 6.87 (dd, 1H) 7.02 (s, 2H) 7.06 (d,

1H) 7.15 (d, 3H) 7.82 (d, 2H). Calcd for C₃₁H₃₈N₂O₄S₂:

C, 65.69; H, 6.76; N, 4.94. Found: C, 65.63; H, 6.85; N,

4.77.

1

218)⁺; H NMR (CDCl₃) d 1.32 (s, 18H) 2.40 (s, 3H)

4.88 (s, 2H) 5.06 (s, 1H) 7.03 (s, 2H) 7.08 (m, 1H) 7.25

(d, 2H) 7.47 (q, 3H) 7.62 (m, 1H) 8.31 (dd, 1H). Calcd

for C₂₇H₃₄N₂O₃S: C, 69.50; H, 7.34; N, 6.00. Found: C,

69.32; H, 7.26; N, 5.94.

Thiophene-2-sulfonic acid (3,5-di-tert-butyl-4-hydroxy-

benzyl) - pyridin - 3- ylmethylamide (20-35). Amine 18

(R₁=3-pyridine, n₂=1) was synthesized as described

for Scheme 3, Method B. Mp 110–112 ^ꢁC; MS m/z 473.2

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-methyl-N-pyri-

din-4-ylbenzenesulfonamide (20-29). Amine 18 (R₁=4-

pyridine, n₂=0) was synthesized as described for

Scheme 3, method A.

1

(M+H)⁺. H NMR (CDCl₃) d 1.33 (s, 18H) 4.27 (d,

K. E. Sexton et al. / Bioorg. Med. Chem. 11 (2003) 4827–4845

4845

4H) 5.19 (s, 1H) 6.85 (s, 2H) 7.13 (m, 2H) 7.57 (m, 3H)

8.16 (s, 1H) 8.42 (d, 1H). Calcd for C₂₅H₃₂N₂O₃S₂: C,

63.53; H, 6.82; N, 5.93. Found: C, 63.27; H, 6.86; N,

5.87.

(s, 1H) 6.67 (s, 2H) 6.99 (m, 1H) 7.19 (d, 3H) 7.88 (d,

.

3H) 8.31 (s, 1H). Calcd for C₂₈H₃₆N₂O₃S 0.33H₂O: C,

69.04; H, 7.53; N, 5.75. Found: C, 68.64; H, 7.30; N,

5.66.

Naphthalene-2-sulfonic acid (3,5-di-tert-butyl-4-hydroxy-

benzyl) - pyridin - 3- ylmethylamide (20-36). Amine 18

(R₁=3-pyridine, n₂=1) was synthesized as described

for Scheme 3, Method B. Mp 164–165 ^ꢁC; MS m/z 517.2

(M+H)⁺; ¹H NMR (DMSO-d₆) d 1.16 (s, 18H) 4.24 (s,

2H) 4.32 (s, 2H) 5.74 (s, 1H) 6.73 (s, 2H) 7.13 (q, 1H)

7.40 (m, 1H) 7.68 (m, 2H) 7.87 (dd, 1H) 8.06 (m, 1H)

8.14 (m, 3H) 8.30 (m, 1H) 8.57 (s, 1H). Calcd for

Thiophene-2-sulfonic acid (3,5-di-tert-butyl-4-hydroxy-

phenyl) - pyridin - 3- ylmethylamide (27-1). A mixture of

2,6-di-tert-butyl-1,4-benzoquinone (2.2 g, 10 mmol) and

3-amino-methylpyridine (1.08 g, 10 mmol) and two

drops acetic acid in 15 mL toluene was heated to reﬂux

for 30 min. The solvent was removed in vacuo and the

desired product (25) obtained by column chromato-

graphy.

.

C₃₁H₃₆N₂O₃S 0.33H₂O: C, 71.16; H, 7.02; N, 5.36.

Found: C, 71.41; H, 7.11; N, 5.32.

To a solution of the imine (25, 2.0 g, 6.5 mmol) in 1,2-

dichloroethane was added sodium triacetoxyborohy-

dride (1.65 g, 7.8 mmol) and a catalytic amount of acetic

acid. The reaction was stirred at room temperature for

two h. The reaction was washed with saturated

NaHCO₃, dried (MgSO₄) and concentrated in vacuo.

The product, 26, was puriﬁed by column chromato-

graphy.

N-(3,5-Di-tert-butyl-4-hydroxybenzyl)-4-methyl-N-pyri-

din - 3- ylmethylbenzenesulfonamide (20-37). Amine 18

(R₁=3-pyridine, n₂=1) was synthesized described for

Scheme 3, Method B. Mp 164–166 ^ꢁC; MS m/z 481.2

(M+H)⁺; ¹H NMR (DMSO-d₆) d 1.22 (s, 18H) 2.40 (s,

3H) 4.15 (s, 2H) 4.22 (s, 2H) 5.74 (s, 1H) 6.80 (s, 2H)

7.12 (q, 1H) 7.40 (m, 3H) 7.75 (d, 2H) 8.18 (d, 1H) 8.30

.

(dd, 1H). Calcd for C₂₈H₃₆N₂O₃S 1.25H₂O: C, 66.71;

H, 7.64; N, 5.56. Found: C, 66.81; H, 7.36; N, 5.45.

Yield 1.6 g (80%). To a solution of the amine (26, 312

mg, 1 mmol) in 1,2-dichloroethane was added two drops

of pyridine and 2-thiophenesulfonyl chloride (269 mg,

1.5 mmol). The mixture was stirred at room tempera-

ture for 18 h. The reaction was evaporated at reduced

pressure. Trituration with hexanes resulted in a crystal-

line product (27-1).

N-[2-(3,5-Di-tert-butyl-4-hydroxyphenyl)-ethyl]-4-methyl

-N-pyridin-3-ylbenzenesulfonamide (24-1). 3,5-Di-tert-

butyl-4-hydroxyphenyl acetic acid (1, 5.72 g, 22 mmol)

was converted to the acid chloride in excess oxalyl

chloride and a catalytic amount of DMF. The solvent

was removed under vacuum and the residue redis-

solved in ether (100 mL) and treated with lithium

aluminum hydride (1.15 g, 30 mmol) and stirred at

room temperature for 18 h. The reaction was then

heated to reﬂux for 2 h. The reaction was cooled,

treated with Na₂SO₄and ﬁltered through Celite. The

ether ﬁltrate was washed with brine, dried (MgSO₄),

concentrated in vacuo and the residue triturated with

hexanes to obtain 3.80 g (70%) of 2-(3,5-di-tert-butyl-

4-hydroxyphenethyl)alcohol.

Mp 135–140 ^ꢁC; MS m/z 459.2 (M+H)⁺; ¹H NMR

(CDCl₃) d 1.26 (s, 18H) 4.80 (s, 2H) 5.30 (s, 1H) 6.63 (s,

2H) 7.10 (q, 1H) 7.36 (dd, 1H) 7.65 (dd, 1H) 7.72 (m,

1H) 8.41 (d, 1H) 8.49 (s, 1H) 8.59 (d, 1H). Calcd for

.

C₂₄H₃₀N₂O₃S₂HCl 0.83H₂O: C, 56.45; H, 6.40; N,

5.49. Found: C, 56.24; H, 6.00; N, 5.20.

References and Notes

1. Koschinsky, M. L.; Ramharack, R. Curr. Pharm. Des.

1996, 2, 121, and references cited within.

2. Huby, T.; Chapman, J.; Thillet, J. Atherosclerosis 1997,

133, 1, and references cited within.

3. Fan, J.; Shimoyamada, H.; Sun, H.; Marcovina, S.; Honda,

K.; Watanabe, T. Arterioscler. Thromb. Vasc. Biol. 2001, 21, 88.

4. Kronenberg, F.; Steinmetz, A.; Kostner, G. M.; Dieplinger,

H. Crit. Rev. Clin. Lab. Sci. 1996, 33, 495, and references cited

within.

To a solution of the alcohol (3.80 g, 15 mmol) in ether

(25 mL) was added dropwise a solution of phosphorus

tribromide (0.71 mL, 7.5 mmol) in 10 mL ether. The

reaction was stirred at room temperature for 3 days.

The reaction was concentrated in vacuo. The residue

was dissolved in EtOAc, washed with saturated Na₂CO₃

and brine, dried (MgSO₄) and concentrated in vacuo.

The pure product, 22, was obtained by column chro-

matography (45%).

5. Trieu, V. N.; Olsson, U.; McConathy, W. J. Biochem. J.

1995, 307, 17.

6. Frank, S.; Durovic, S.; Kostner, K.; Kostner, G. M. Arter-

ioscler Thromb. Vasc. Biol. 1995, 15, 1774.

7. Rieker, A.; Kessler, H. Tetrahedron 1967, 23, 3723.

8. Taddei-Peters, W. C.; Butman, B. T.; Jones, G. R.;

Venetta, T. M.; Macomber, P. F.; Ransom, J. H. Clin. Chem.

1993, 39, 1382.

9. Ramharack, R.; Bocan, T. M.; Imperiale, M. J.; Spahr,

M. A. Biochim Biophys Acta 1999, 1438, 322.

10. Callow, M. J.; Verstuyft, J.; Tangirala, R.; Palinski, W.;

Rubin, E. M. J. Clin. Invest. 1995, 96, 1639.

11. Ramharack, R.; Spahr, M. A.; Hicks, G. W.; Kieft, K. A.;

Brammer, D. W.; Minton, L. L.; Newton, R. S. J. Lipid Res.

1995, 36, 1294.

To a solution of the bromide (22, 2.11 g, 6.7 mmol) in

20 mL toluene was added 3-aminopyridine (0.65 g, 6.8

mmol) and Et₃N (0.96 mL, 6.8 mmol). The reaction was

heated to reﬂux for one week. The solvent was removed

in vacuo. The residue was partitioned between EtOAc

and water. An insoluble tan solid was collected by ﬁl-

tration to give 23 in 45% yield. The general procedure for

sulfonamides was followed to obtain 24-1 (R₁=3-pyri-

dine, R₂=4-Me–C₆H₄, n₁=2, n₂=0). Yield: 22% mp

224–227 ^ꢁC; MS m/z 481.2 (M+H)⁺; ¹H NMR (CDCl₃)

d 1.34 (s, 18H) 2.35 (s, 3H) 3.02 (t, 2H) 4.30 (t, 2H) 5.19

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