Table 3 Analytical data for the oxamides 2–4, amides 6–8 and
oxalamate 9
(2.24 mmol) of 2-aminophenol and 0.010 g of the catalyst.
After crystallisation a reddish solid was yielded (0.42 g, 70%),
mp 237 ЊC (good elemental analysis from this sample could not
be obtained). νmax(KBr)/cmϪ1 3368 (NH), 1670 (CO); δH(300.08
MHz) 9.90 (1 H, s, NH), 8.20 (1 H, d, J 7.9, 3-H), 8.15 (1 H, d,
J 7.9, 11-H), 7.16 (2 H, m, 12-H, 14-H), 7.06 (1 H, t, J 7.6,
13-H), 7.05 (1 H, t, J 7.6, 4-H), 7.00 (1 H, d, J 7.6, 6-H), 6.89
(1 H, t, J 7.6, 5-H), 3.92 (3 H, s, OCH3); δC(75.46 MHz) 157.2,
157.1, 156.9, 149.0, 147.2 (C-9, C-8, C-14a, C-10a, C-1), 125.6
(C-12), 125.3 (C-13), 120.6 (C-4), 119.9 (C-3), 119.8 (C-11),
119.3 (C-5), 115.0 (C-6), 111.2 (C-14), 56.0 (OCH3).
Found (%) (required)
Compound
(formula)
Yield
(%)
Mp/ЊC
(decomp.)
C
H
N
2
68
80
60
63
50
62
90
188
(decomp.)
207
58.2
(58.5)
58.4
(58.7)
51.6
(51.7)
67.3
(67.4)
63.0
(62.7)
59.4
(59.6)
50.2
(50.4)
4.6
(4.6)
5.0
(4.9)
3.5
(3.3)
5.0
(4.9)
4.5
(4.5)
3.6
(3.6)
4.1
(4.2)
14.6
(14.6)
19.2
(19.6)
18.2
(18.5)
15.1
(15.7)
20.0
(20.9)
18.4
(19.8)
11.5
(11.8)
(C14H13N3O4)
3
(C14H14N4O3)
4
211
(decomp.)
274–275
(C13H10N4O5)
6
2-[N-(2-Methoxyphenyl)carbamoyl]-1H-benzimidazole
6.
(C15H13N3O2)
Prepared from 0.50 g (2.24 mmol) of ethyl N-(2-methoxy-
phenyl)oxalamate, 0.24 g (2.24 mmol) of 1,2-diaminobenzene,
0.010 g of the catalyst and 20 cm3 of nitrobenzene at reflux for
24 h. This solution was allowed to stand for 4 days. The result-
ing solid was filtered, washed with 20 cm3 of acetone and
crystallised from ethyl alcohol to yield a pale yellow solid
(0.38 g). νmax(KBr)/cmϪ1 3237 (NH), 1668 (CO); δH(300.08
MHz) 13.63 (1 H, br s, NH), 9.91 (1 H, br s, OCNH), 8.36 (1 H,
d, J 7.8, 3-H), 7.70 (2 H, br s, 11-H, 14-H), 7.35 (2 H, m, 12-H,
13-H), 7.16 (2 H, m, 4-H, 6-H), 7.03 (1 H, m, 5-H), 3.97 (3 H, s,
OMe); δC(75.46 MHz) 157.1 (C-8), 149.4 (C-1), 146.1 (C-9),
127.3 (C-4), 125.6 (C-2), 124.7 (br, C-12, C-13), 121.5 (C-5),
112.0 (C-6), 56.9 (OMe) (C-10a, C-14a not observed). From a
sample doped with water: δH(300.08 MHz) 7.84 (1 H, d, J 7.6,
11-H), 7.59 (1 H, d, J 7.6, 14-H), 3.39 (8 H, s, H2O) the other
signals were unchanged; δC(75.46 MHz) 143.0 (C-10a), 135.7
(C-14a), 125.3 (C-13), 123.7 (C-12), 120.8 (C-11), 113.4 (C14)
the other signals remained unchanged.
7
248–249
(C14H12N4O2)
8
314
(decomp.)
105
(C14H10N4O3)
9
(C10H10N2O5)
resulting suspension was heated for 3 days under reflux with a
Dean–Stark trap to eliminate water. The solution was cooled to
room temperature and the resulting solid was filtered and
crystallised from ethyl alcohol.
N-(3-Hydroxypyridine)-NЈ-(2-methoxyphenyl)oxamide
2.
Prepared from 0.50 g (2.24 mmol) of ethyl N-(2-methoxy-
phenyl)oxalamate, 0.25 g (2.24 mmol) of 2-amino-3-hydroxy-
pyridine, and 0.010 g of the catalyst. After crystallisation, a
slightly grey solid was obtained (0.44 g). νmax(KBr)/cmϪ1 3397
(NH), 1707 (CO); δH(399.78 MHz) 10.47 (1 H, s, NHB), 10.26
(1 H, s, OH), 9.83 (1 H, s, NHA), 8.18 (1 H, dd, J 8.3 and 1.2,
3-H), 7.93 (1 H, d, 13-H), 7.30 (1 H, dd, J 7.8 and 1.4, 15-H),
7.17 (3 H, m, 4-H, 5-H, 6-H), 7.03 (1 H, t, J 7.6, 14-H), 3.91
(3 H, s, OMe); δC(100.54 MHz) 158.4, 157.8 (C-8, C-9), 149.6
(C-1), 147.1 (C-16), 139.2 (C-11), 139.0 (C-13), 126.1 (C-4 and
C-2), 124.0 (C-15), 123.6 (C-5), 121.2 (C-14), 120.3 (C-3), 118.8
(C-6), 56.6 (OMe).
2-[N-(2-Methoxyphenyl)carbamoyl]-3H-imidazo[4,5-b]-
pyridine 7. Prepared From 0.50 g (2.24 mmol) of ethyl
N-(2-methoxyphenyl)oxalamate, 0.24 g (2.24 mmol) of 2,3-
diaminopyridine and 0.010 g of the catalyst using the same
procedure as for the synthesis of 6. Crystallisation from ethyl
alcohol yielded a pale beige solid (0.30 g). νmax(KBr)/cmϪ1 3374
(NH), 1678 (CO); δH(300.08 MHz) 14.3 and 13.9 (1 H, br, NH),
9.94 (1 H, s, NH), 8.52 (1 H, br, 13-H), 8.33 (1 H, d, J 8.6, 3-H),
8.13 (1 H, br, 11-H), 7.38 (1 H, d, J 7.9, 12-H), 7.16 (1 H, m,
4-H), 7.15 (1 H, d, 6-H), 7.03 (1 H, m, 5-H), 3.96 (3 H, s, OMe);
δC(75.46 MHz) 155.7 (C-8), 148.4 (C-1), 146.2 (C-9), 146.0
(C-13), 132.9 (br, C-10a, and or C-14a), 128 (br, C-11), 126.1
(C-2), 124.7 (C-4), 120.5 (C-5), 119.4 (C-3), 119.4 (br, C-12),
111.0 (C-6), 56.0 (OMe).
N-(3-Aminopyridine)-NЈ-(2-methoxyphenyl)oxamide 3. Pre-
pared from 0.50 g (2.24 mmol) of ethyl N-(2-methoxyphenyl)-
oxalamate, 0.24 g (2.24 mmol) of 2,3-diaminopyridine, and
0.010 g of the catalyst after reflux in 20 cm3 of anhydrous ethyl
alcohol for 24 h. After crystallisation, a slightly reddish solid
was obtained (0.51 g). νmax(KBr)/cmϪ1 3370 (NH), 1679 (CO);
δH(300.08 MHz) 10.34 (1 H, s, NHB), 9.79 (1 H, s, NHA), 8.25
(1 H, dd, J 8.1 and 1.8, 3-H), 7.88 (1 H, br d, J 1.8, 13-H), 7.46
(1 H, dd, J 7.7 and 1.7, 15-H), 7.15 (2 H, m, 4-H, 6-H), 7.03
(1 H, m, 5-H), 6.60 (1 H, dd, J 7.8 and 7.5, 14-H), 5.92 (2 H, s,
NH2), 3.91 (3 H, s, OMe); δC(75.5 MHz) 159.6, 157.8 (C-8,
C-9), 155.3 (C-11), 149.4 (C-1), 146.6 (C-13), 134.5 (C-15),
126.5 (C-2), 125.9 (C-4), 121.3 (C-5), 119.9 (C-3), 117.4 (C-16),
111.9 (C-6), 112.7 (C-14), 50.8 (OMe).
2-[N-(2-Nitrophenyl)carbamoyl]-1H-benzimidazole 8. Pre-
pared from 0.50 g (2.10 mmol) of 9, 0.23 g (2.10 mmol) of 1,2-
diaminobenzene and 0.010 g of the catalyst using the same
procedure as for the synthesis of 6. Crystallisation from ethyl
alcohol yielded a greenish yellow solid (0.37 g). νmax(KBr)/cmϪ1
3274 (NH), 1674 (CO); δH(399.78 MHz) 13.7 (1 H, s, NH), 11.8
(1 H, s, OCNH), 8.42 (1 H, dd, J 8.3 and 1.0, 3-H), 8.19 (1 H,
dd, J 8.3 and 1.5, 6-H), 7.86 (1 H, dt, J 8.3 and 1.0, 4-H), 7.85
(1 H, d, J 7.8, 11-H), 7.60 (1 H, d, J 7.8, 14-H), 7.40 (2 H, m,
12-H, 13-H), 7.43 (1 H, dt, J 8.3 and 1.5, 5-H); δC(100.54 MHz)
157.9 (C-8), 145.2 (C-9), 142.9 (C-10a), 140.2 (C-1), 135.7
(C-4), 135.5 (C-2), 132.7 (C-14a), 126.2 (C-6), 125.5 (C-5, C-12
or C-13), 124.2 (C-3), 123.7 (C-13 or C-12), 120.9 (C-11), 113.4
(C-14).
N-(3-Hydroxypyridine)-NЈ-(2-nitrophenyl)oxamide 4. From
0.50 g of 9 (2.10 mmol), 0.23 g (2.10 mmol) of 2-amino-3-
hydroxypyridine and 0.010 g of the catalyst. After crystallis-
ation, a yellowish solid was obtained (0.38 g). νmax(KBr)/cmϪ1
3290 (NH), 3096 (OH), 1702 (CO); δH(399.78 MHz) 11.63 (1 H,
s, NHA), 10.51 (1 H, s, NHB), 10.30 (1 H, br s, OH), 8.28 (1 H, d,
J 8.3, 3-H), 8.18 (1 H, d, J 8.3, 6-H), 7.94 (1 H, br d, 13-H), 7.85
(1 H, t, J 7.9, 4-H), 7.46 (1 H, t, J 7.8, 5-H), 7.31 (1 H, d, J 7.3,
15-H), 7.20 (1 H, dd, J 7.8 and 8.3, 4-H); δC(100.54 MHz) 158.1,
156.9 (C-8, C-9), 146.3 (C-16), 139.5 (C-11), 138.3 (C-1), 138.1
(C-13), 134.9 (C-4), 131.1 (C-2), 125.3 (C-5, C-6), 123.3 (C-3),
Ethyl N-(2-nitrophenyl)oxalamate 9. Prepared from 4.0 cm3
(36.2 mmol) of ethyl chlorooxoacetate and 5.0 g (36.2 mmol) of
2-nitroaniline using similar procedures as for the synthesis of
ethyl N-(2-methoxyphenyl)oxalamate.8 Crystallisation from
hexane yielded a yellow solid (7.7 g). νmax(KBr)/cmϪ1 330.9
(NH), 1740 (CO); δH(300.08 MHz) 11.38 (1 H, s, NH), 8.10
(1 H, d, J 8.5, 3-H), 8.09 (1 H, d, J 8.5, 6-H), 7.78 (1 H, t, J 8.5,
4-H), 7.42 (1 H, t, J 8.5, 5-H), 4.32 (2 H, q, J 7.00, CH2), 1.30
15
123.2 (C-15), 122.8 (C-14); δ N(40.52 MHz) Ϫ255.9 (N-7),
Ϫ261.1 (N-10).
2-[N-(2-Methoxyphenyl)carbamoyl]benzoxazole 5. From 0.50
g (2.24 mmol) of ethyl N-(2-methoxyphenyl)oxalamate, 0.24 g
J. Chem. Soc., Perkin Trans. 2, 2001, 1817–1823
1821