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HETEROCYCLES, Vol. 60, No. 1, 2003
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Sodium salt of 9d (monohydrate): mp 170-171℃. IR (KBr) 3480, 2160, 1665, and 1560 cm . Anal. Calcd for C H N
5
7
4
O Na: C, 30.94; H, 3.64; N, 28.86. Found: C, 31.07; H, 3.53; N, 29.08.
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General procedure for catalytic hydrogenation of 9. A stirred solution of 9 (0.01 mol) in methanol (50 mL) and 1 M
hydrochloric acid (10 mL) was hydrogenated over 10% Pd/C (1.20 g) at atmospheric pressure for 20 h. After filtration, the
11
filtrate was neutralized with 2 M ammonia to afford 11a. Yield: 68%. mp 237-238℃ (deccomp, lit., 241-243℃).
In the case of 11b, after neutralization, the solution was evaporated to dryness and residue was extracted with hot acetone.
The filtrate was dried up and the residue was recrystallized with acetonitrile to afford pure 11b. Yield: 58%. mp 183-184℃
12
(
lit., 183℃).
Acid Hydrolysis of 9.
After cooling, 1.24 g (54%) of 11 was obtained and recrystallized from water. mp 204.5-205℃. IR (KBr) 3400, 3225,
Compound (9a) (1.86 g, 0.01 mol) in 0.25 M hydrochloric acid (150 mL) was refluxed for 1.5 h.
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1
1
700, 1645, 1610, 1530, 1490, and 710 cm . H NMR (DMSO-d ) δ=6.82 (2H, s, NH ) 7.17-8.17(5H, m, Ph), 8.78(1H, s,
6
2
NH), 8.93(1H, s, NH), 10.2(1H, s, NH). MS (70 ev) m/z136(PhCONHNH ). Anal. Calcd for C H N O : C, 48.65; H, 4.54;
2
9
10
4
3
N, 25.21. Found: C, 48.84; H, 4.56; N, 25.57%.
Compound (9a) (1.86 g, 0.01 mol) in 1 M hydrochloric acid (50 mL) was refluxed for 3.5 h. After cooling, 0.90 g (74%)
of benzoic acid was collected by filtration. The filtrate was extracted with benzene to obtain an additional benzoic acid
(
0.13 g,10%).
Concentration of the aqueous layer afforded 0.79 g (78%) of 15, which was identified, after
1
3
recrystallization from 1-propanol, by comparing its IR spectrum with that of authentic sample. mp 243℃ (lit., 244 ℃).
Compound (9b) (1.24 g, 0.01 mol) in 2 M hydrochloric acid (30 mL) was also refluxed for 4 h. Solvent was removed in
vacuo and 0.90 g ( 89%) of 15 (mp 236-237℃) was obtained after washing residual solid.
14
Independent Preparation of 11. To a stirred suspension of 1.36 g (0.01 mol) of 12 and 1.34 g (0.01 mol) of 13 together
with triethylamine (1.4 mL, 0.01 mol) in acetonitrile (40 mL) was added dropwise a solution of silver nitrate (1.70 g,
0
.01 mol) in acetonitrile (15 mL) at rt.
cooling, the extract deposited 11 (1.45 g, 65.3%), which was identical with the compound obtained from acid hydrolysis of
b. mp 203-204℃.
The precipitates were collected and extracted with hot water (150 mL × 3). On
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Preparation of 16 To 0.01 mol of 9c,d in 100 mL methanol was added 0.01 mol of 36% hydrochloric acid. The mixture
was allowed to stand for 3 days at rt and neutralized with 2 M ammonia. The whole was then evaporated and the product
extracted with 100 mL of hot acetone. The extract was dried up and recrystallized from acetonitrile providing 31-32% of 16
as granules (mp 213-214℃), which was identified by direct comparison with an authentic sample prepared according to
the method in literature (mp 219-220℃).15
1
Preparation of 17a, 17a',and 18d To a solution of 0.01 mol of N -acylguanidine in acetone (50 mL) was added 0.82 g
(0.02 mol) of sodium hydroxide, then 0.01 mol of benzenesulfonyl chloride (or p-nitrobenzenesulfonyl chloride dissolved in
acetone) was added dropwise with stirring at 0℃. After stirring for 8-15 h, 20mL of water was added to dissolve
precipitation. The solution was acidified with acetic acid and a precipitate was collected by filtration and recryatallized
from appropriate solvent. In case of ethyl 18d, the crude product was obtained after the precipitation was extracted with 12
mL of chloroform and dried up.
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6
1
1
1
7a : needles (acetonitrile). mp 219-220℃ (decomp, depending on heating rate. lit., ,233-234℃). IR (KBr) 3375, 3250,
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680, 1565, 1270, 1150, and 1090 cm . MS (70 ev) m/z 303(M).
7a': yellow needles (acetonitrile). mp 223-224. IR (KBr) 3380,3290, 1680, 1615, 1565, 1285, 1150, and 1085 cm . Anal.
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1
Calcd for C H N O S : C, 48.27; H, 3.47; N, 16.08. Found : C, 48.24; H, 3.52; N, 16.22.
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12
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