Efficient Synthesis of Symmetrical and Unsymmetrical Acyclic Imides
General Procedure for the Synthesis of Acyclic
1535, 1415, 1170, 780, 710 cm-1. 1H NMR (500 MHz, CDCl3)
δ 0.99 (6H, t, J = 7.40 Hz, 2CH3), 1.67-1.73 (4H, m, 2CH2),
2.57 (4H, t, J = 7.4 Hz, 2CH2), 7.81 (1H, br s, NH). MS (EI)
m/z: 157.07 (6.43) [M+], 129.05 (18.29), 90.99 (47.66), 88.02
(88.24), 71.03 (100).
Imides by the Reaction of Solid Aromatic Nitriles
with Aliphatic Anhydrides in the Presence of
H3PW12O40 under Thermal Conditions and MW
Irradiation
A mixture of nitrile (1 mmol), aliphatic anhydride (2
mmol) and H3PW12O40 (0.2 mmol) was heated at 80 °C or
irradiated under MW (1000 W) at 40 °C. The progress of the
reaction was monitored by TLC. After completion of the
reaction, the mixture was cooled to room temperature and
Et2O (15 ml) was added. The catalyst was filtered and washed
with Et2O (10 ml). The filtrates were evaporated and the crude
product was purified by chromatography on a short column of
silica-gel (ethyl acetate:petroleum ether, 1:6) to afford the pure
imide (Table 5).
N-Acetyl-4-methylbenzamide (Table 3, entry 1). White
solid, m.p.: 111-113 °C. IR (KBr) ν
3291, 1742, 1675,
max
1597, 1482, 1240 cm-1. H NMR (500 MHz, CDCl3) δ 2.43
(3H, s, CH3), 2.61 (3H, s, CH3) 7.30 (2H, d, J = 8.25 Hz,
ArH), 7.76 (2H, d, J = 8.25 Hz, ArH), 8.72 (1H, br s, NH).
N-Acetyl-2-thiophenamide (Table 3, entry 2). White
1
solid, m.p.: 134-135 °C. IR (KBr) ν
3280, 3097, 2926,
max
1708, 1680, 1530, 1480, 1375, 1250, 1100, 840, 720 cm-1. 1H
NMR (500 MHz, CDCl3) δ 2.61 (3H, s, CH3), 7.16 (1H, J =
4.35 Hz, CH), 7.67 (1H, d, J = 4.8 Hz, CH), 7.83 (1H, d, J =
3.38 Hz, CH), 9.32 (1H, br s, NH). MS (EI) m/z: 171.06 (3)
[M+2], 169.07 (57.40) [M+], 141.06 (16.42), 136.09 (37.87),
111.03 (100).
Spectral Data
N-Acetylacetamide (Table 2, entry 1). White solid, m.p.:
73 °C. IR (KBr) ν
3270, 3120, 2991, 1738, 1550, 1240
N-Acetylbenzamide (Table 3, entry 3). White solid, m.p.:
max
cm-1. 1H NMR (500 MHz, CDCl3) δ 2.31 (6H, s, 2CH3), 8.63
(1H, br s, NH).
109-110 °C. IR (KBr) ν
3290, 2940, 1725, 1680, 1600,
max
1520, 1220 cm-1. H NMR (500 MHz, CDCl3) δ 2.63 (3H, s,
CH3), 7.52 (2H, t, J = 7.8 Hz, ArH), 7.62 (1H, t, J = 7.65 Hz,
ArH), 7.86 (2H, d, J = 7.8 Hz, ArH), 8.63 (1H, br s, NH).
N-Propionyl-2-thiophenamide (Table 3, entry 4). White
1
N-Acetyl-2-chloroacetamide (Table 2, entry 2). White
solid, m.p.: 113-114 °C. IR (KBr) ν
3254, 3180, 2998,
max
1740, 1545, 1225, 1160 cm-1. 1H NMR (500 MHz, CDCl3) δ
2.42 (3H, s, CH3), 4.27 (2H, s, CH2), 8.63 (1H, br s, NH).
N-Acetylbutyramide (Table 2, entries 3 and 6). White
solid, m.p.: 137-138 °C. IR (KBr) ν
3248, 3055, 2970,
max
1667, 1493, 1330, 1219, 1168, 950, 770 cm-1. H NMR (500
MHz, CDCl3) δ 1.21 (3H, t, J = 7.30 Hz, CH3), 3.02 (2H, q,
J = 7.30 Hz, CH2), 7.15 (1H, t, J = 4.65 Hz, CH), 7.66 (1H, d,
J = 4.50 Hz, CH), 7.79 (1H, d, J = 3.80 Hz, CH), 9.05 (1H, br
s, NH). MS (EI) m/z: 185.11 (5.34) [M+2], 183.11 (75.81)
[M+], 155.14 (56.99), 150.16 (88.17), 128.13 (85.48), 111.13
(100), 83.13 (74.73).
1
solid, m.p.: 56-57 °C. IR (KBr) ν 3260, 3175, 2984, 1740,
max
1540, 1240, 1160 cm-1. H NMR (500 MHz, CDCl3) δ 0.99
1
(3H, t, J = 7.4 Hz, CH3), 1.67-1.72 (2H, m, CH2), 2.36 (3H, s,
CH3), 2.48 (2H, t, J = 7.35 Hz, CH2), 7.83 (1H, br s, NH).
N-Acetylpropionamide (Table 2, entry 4). White solid,
m.p.: 84-85 °C. IR (KBr) ν 3265, 3236, 1727, 1538, 1510
max
1
cm-1. H NMR (500 MHz, CDCl3) δ 1.18 (3H, t, J = 7.35 Hz,
N-Propionyl-4-methylbenzamide (Table 3, entry 5).
CH3), 2.36 (3H, s, CH3), 2.55 (2H, q, J = 7.35 Hz, CH2), 8.09
(1H, br s, NH).
White solid, m.p.: 109-111 °C. IR (KBr) ν
3284, 3035,
max
2950, 1740, 1605, 1500, 1210, 1020, 840, 740 cm-1. H NMR
(500 MHz, CDCl3) δ 1.23 (3H, t, J = 7.35 Hz, CH3), 2.44 (3H,
s, CH3), 3.03 (2H, q, J = 7.35 Hz, CH2), 7.31 (2H, d, J = 3.65
Hz, ArH), 7.75 (2H, d, J = 6.65 Hz, ArH), 8.57 (1H, br s, NH).
MS (EI) m/z: 191.15 (19.91) [M+], 136.11 (13.27), 119.11
(100), 91.09 (78.40), 65.11 (35.80).
1
N-Propionylbutyramide (Table 2, entry 5). White solid,
m.p.: 107-108 °C. IR (KBr) ν
3226, 3170, 2991, 1689,
max
1510, 1112 cm-1. H NMR (500 MHz, CDCl3) δ 0.98 (3H, t,
J = 7.35 Hz, CH3), 1.16 (3H, t, J = 7.40 Hz, CH3), 1.67-1.71
(2H, m, CH2), 2.56 (2H, t, J = 7.37 Hz, CH2), 2.64 (2H, q, J =
7.35 Hz, CH2), 8.37 (1H, br s, NH).
1
N-Acetyl-4-chlorobenzamide (Table 5, entry 1). White
N-Butyrylbutyramide (Table 2, entry 7). White solid,
m.p.: 103-104 °C. IR (KBr) νmax 3280, 3190, 2990, 1740,
solid, m.p.: 136-137 °C. IR (KBr) ν
3260, 1760, 1685,
max
1593, 1468 cm-1. H NMR (500 MHZ, CDCl3) δ 2.62 (3H, s,
1
403