1004 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 6
Notes
NMR (CDCl3) δ 2.22 (s, 3, vinylic CH3), 2.35 (s, 3, aryl CH3),
6.02 (s, 2, OCH2O), 6.73 (d, 1, ArH, J ) 8.05 Hz), 6.80 (d, 1,
ArH, J ) 8.05 Hz), 8.11 (s, 1, vinylic H). Anal. (C11H11NO4)
C, H, N.
kg). All drugs were dissolved in 0.9% saline and were injected
intraperitoneally in a volume of 1 mL/kg, 30 min before the
sessions.
None of the rats had previously received drugs or behavioral
training. Water was freely available in the individual home
cages, and a rationed amount of supplemental feed (Purina
Lab Blox) was made available after experimental sessions to
maintain approximately 80% of free-feeding weight. Lights
were on from 0700 to 1900. The laboratory and animal facility
temperature was 22-24 °C, and the relative humidity was 40-
50%. Experiments were performed between 0830 and 1700
each day, Monday through Friday.
Six standard operant chambers (model E10-10RF, Coul-
bourn Instruments, Lehigh Valley, PA) consisted of modular
test cages enclosed within sound-attenuated cubicles with fans
for ventilation and background white noise. A white house
light was centered near the top of the front panel of the cage,
which was also equipped with two response levers, separated
by a food hopper (combination dipper pellet trough, model E14-
06, module size 1/2), all positioned 2.5 cm above the floor. Solid-
state logic in an adjacent room, interfaced through a Med
Associates interface to a 486-based microcomputer, controlled
reinforcement and data acquisition with locally written soft-
ware.
Briefly, a fixed ratio (FR) 50 schedule of food reinforcement
(Bioserv, 45 mg of dustless pellets) in a two-lever paradigm
was used. At least one drug and one saline session separated
each test session. Rats were required to maintain an 85%
correct responding criterion on training days in order to be
tested. In addition, test data were discarded when the
accuracy criterion of 85% was not achieved on the two training
sessions following a test session. Test sessions were run under
conditions of extinction, with rats removed from the operant
chamber when 50 presses were emitted on one lever. If 50
presses on one lever were not completed within 5 min, the
session was ended and scored as a disruption. Treatments
were randomized at the beginning of the study.
In Vitr o [3H]-5-HT a n d [3H]DA Up ta k e In h ibition . The
procedure of Steele et al.22 was employed with minor modifica-
tions exactly as described previously.16 Briefly, three rats were
decapitated and their brains rapidly removed and dissected
over ice. The cerebellums were removed and discarded, and
the remaining brain tissue (ca. 4 g, wet weight) was pooled,
diced, and homogenized in 20 mL of ice-cold 0.32 M sucrose.
Homogenizations were done in a prechilled Potter-Elvehjem
tissue grinder with a motor-driven Teflon pestle at 0 °C, for
two periods of 1 min each, 6 strokes/min, with a 15-s interval
between periods. The tissue homogenate was subjected to
centrifugation (Beckman J 2-21 with J A-20 rotor; 4 °C) at 1090g
for 10 min. The pellet was discarded, and the supernatant
was subjected to centrifugation at 17400g for 30 min. The
resulting pellet was resuspended with a polytron (setting 5,
20 s; Kinematica) in 30-40 mL of ice-cold, aerated (5% CO2
in O2) modified Krebs-Ringer bicarbonate (KR) buffer contain-
ing the following (mM): NaCl (124.3), KCl (2.95), MgSO4
(1.30), KH2PO4 (1.25), NaHCO3 (26.0), CaCl2 (2.41), d-glucose
(10.4), Na2EDTA (0.03), and Na ascorbate (0.06), pH 7.4-7.6.
The synaptosomal suspension was stored on ice until use.
4-Meth yl-6-(2-n itr o-1-p r op en yl)-1,3-ben zod ioxole (6b).
A mixture of 11.0 g (67.1 mmol) of aldehyde 5b, 40 mL of
nitroethane, 10.9 g (134 mmol) of dimethylamine hydrochlo-
ride, 0.58 g (10 mmol) of potassium fluoride, and 40 mL of
toluene was placed in a flask equipped with a Dean-Stark
trap and heated at reflux under N2 for 24 h. Solvents were
evaporated, and the residue was partitioned between Et2O and
H2O. The Et2O fraction was dried with MgSO4 and evapo-
rated, yielding 14.12 g (95%) of product as an orange-yellow
solid. An analytical sample was recrystallized from MeOH to
1
give pale-orange crystals: mp 97-98 °C; H NMR (CDCl3) δ
2.26 (s, 3, vinylic CH3), 2.46 (s, 3, aryl CH3), 6.03 (s, 2, OCH2O),
6.80 (s, 1, ArH), 6.82 (s, 1, ArH), 8.00 (s, 1, vinylic H). Anal.
(C11H11NO4) C, H, N.
Gen er a l P r oced u r e for th e Red u ction of th e Nitr o-
p r op en es 6a -c to th e Am in op r op a n es 2a -c. A solution
of 10 mmol of the appropriate nitropropene in 20 mL of THF
was added dropwise to a suspension of 70 mmol of LiAlH4 in
35 mL of THF while stirring under N2. The reaction mixture
was stirred and heated under reflux for the specified time and
cooled to room temperature, and the reaction was quenched
carefully by the sequential addition of 2 mL of 2-propanol, 2
mL of 15% aqueous NaOH, and 7 mL of H2O. The precipitate
was removed by filtration, and the resulting solution was
evaporated. The residue was suspended in H2O, acidified with
concentrated HCl, and washed three times with Et2O. The
resulting acidic solution was then made basic with aqueous
NaOH and extracted three times with Et2O. The Et2O solution
was evaporated, and the resulting oil was purified by bulb-
to-bulb distillation. The distilled oil was dissolved in 10 mL
of 2-propanol, neutralized with ethanolic HCl, and diluted with
Et2O to yield the hydrochloride salt of the aminopropane.
1-(4-Meth yl-1,3-ben zod ioxol-5-yl)-2-a m in op r op a n e Hy-
d r och lor id e (2a ). This compound was obtained from 6a in
71% yield as fine white crystals: mp 214-215 °C; 1H NMR
(D2O) δ 1.13 (d, 3, CHCH3, J ) 7 Hz), 2.02 (s, 3, ArCH3), 2.73
(m, 2, ArCH2), 3.37 (sextet, 1, CH, J ) 7 Hz), 5.79 (p, 2,
OCH2O, J ) 1 Hz), 6.58 (s, 2, overlapping ArH). Anal. (C11H16
ClNO2) C, H, N.
-
1-(4-Meth yl-1,3-ben zod ioxol-6-yl)-2-a m in op r op a n e Hy-
d r och lor id e (2b). This compound was obtained from 6b in
1
65% yield as white crystals: mp 222-223 °C; H NMR (D2O)
δ 1.11 (d, 3, CHCH3, J ) 7 Hz), 2.03 (s, 3, ArCH3), 2.65 (m, 2,
ArCH2), 3.38 (sextet, 1, CH, J ) 7 Hz), 5.79 (s, 2, OCH2O),
6.48 (s, 1, ArH), 6.51 (s, 1, ArH). Anal. (C11H16ClNO2) C, H,
N.
1-(5-Meth yl-1,3-ben zod ioxol-6-yl)-2-a m in op r op a n e Hy-
d r och lor id e (2c). This compound was obtained in 74% yield
from 6c.14 The salt precipitated from 2-propanol/ether solution
as a clear oil which crystallized overnight as white crystals:
1
mp 157-158 °C; H NMR (D2O) δ 1.13 (d, 3, CHCH3, J ) 7
Hz), 2.07 (s, 3, ArCH3), 2.70 (m, 2, ArCH2), 3.39 (sextet, 1, CH,
J ) 7 Hz), 5.76 (tt, 2, OCH2O, J ) 1, 3 Hz), 6.59 (s, 1, ArH),
6.64 (s, 1, ArH). Anal. (C11H16ClNO2) C, H, N.
P h a r m a cology Met h od s. An im a ls. Male Sprague-
Dawley rats (Harlan, Indianapolis, IN) weighing 175-200 g
were used. Animals were group housed (for in vitro experi-
ments) or individually caged (for drug discrimination experi-
ments) in a temperature-controlled room with a 12-h day/night
lighting schedule. Animals that were used for in vitro experi-
ments were supplied with food (Lab Blox, Purina) and water
ad libitum.
Dr u g Discr im in a tion . The procedures for the drug dis-
crimination assays were exactly as described previously.16,17
Training drugs were (+)-amphetamine sulfate (1.0 mg/kg), (+)-
N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine hydrochloride
((+)-MBDB; 1.75 mg/kg), 5-methoxy-6-methyl-2-aminoindan
hydrochloride (MMAI; 1.71 mg/kg), (+)-lysergic acid diethyl-
amide tartrate (LSD; 0.08 mg/kg), and (()-1-(2,5-dimethoxy-
4-iodophenyl)-2-aminopropane hydrochloride (DOI; 0.40 mg/
The ability of synaptosomes to accumulate tritiated sero-
tonin ([3H]-5-HT), dopamine ([3H]DA), and norepinephrine
([3H]NE) was measured in the absence and presence of various
concentrations of test drugs as follows: a 200-µL aliquot of
the synaptosomal suspension was added to test tubes contain-
ing 1.65 mL of ice-cold KR buffer, 50 µL of test drugs (dissolved
in deionized water) or deionized water (for total and nonspecific
determinations), and 50 µL of pargyline HCl solution (final
concentration, 100 µM). The test tubes were preincubated in
an aerated (5% CO2 in O2) 37 °C shaking water bath for 5 min.
The tubes were then returned to the ice bath and chilled for
10-15 min. Tritiated neurotransmitter (New England Nuclear)
was added (50 mL of stock solution; final concentration, 10
nM), giving a final incubation volume of 2 mL. All tubes except
nonspecific assays were returned to the aerated 37 °C shaking
water bath for 5 min to initiate neurotransmitter uptake.