Synthesis of Diaryl Diazepines 3a-q (General Procedure). An equimolar mixture of the ethanedione
derivative, 1,3-propanediamine, and glacial acetic acid (1:1:1) was dissolved in ethanol (30 ml). The mixture was
allowed to reflux for 24-30 h. The reaction was monitored throughout by TLC, and the solvent was evaporated
under vacuum after completion. The resulting sticky compound was stripped with silica gel, and chromatography
with benzene gave a liquid product, with partial recovery of starting material, which on trituration with
petroleum ether gave a solid product. This was recrystallized from a suitable solvent to afford the desired
compounds 3a-q.
3-(4-Methylphenyl)-2-phenyl-6,7-dihydro-5H-1,4-diazepine (3a). Yield 23%; mp 82-84°C (brown
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crystals from MeOH). IR, νmax, cm-1: 1608, 1592 (C=N), 1510, 1332, 1272, 825, 780. H NMR, δ, ppm
(400 MHz): 2.32 (3H, s, CH3); 2.34-2.41 (2H, m, NCH2CH2); 3.5 (4H, br. s, NCH2CH2); 7.1-7.6 (9H, m, ArH).
Mass-spectrum, m/z: 263 [MH+]. Found, %: C 82.28; H 7.02; N 10.84. C18H18N2. Calculated, %: C 82.41;
H 6.92; N 10.68.
3-(4-Bromophenyl)-2-phenyl-6,7-dihydro-5H-1,4-diazepine (3b). Yield 6%; mp 93-95°C (white
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crystals from petr. ether). IR, νmax, cm-1: 1598 (C=N), 1585, 1392, 1272, 1068, 945, 825. H NMR, δ, ppm
(300 MHz): 2.33-2.41 (2H, m, NCH2CH2); 3.5 (4H, br. s, NCH2CH2); 7.1-7.6 (9H, m, ArH). Mass-spectrum,
m/z: 329 [M+2]. Found, %: C 62.56; H 4.60; N 8.24. C17H15BrN2. Calculated, %: C 62.4; H 4.62; N 8.56.
3-(4-Fluorophenyl)-2-phenyl-6,7-dihydro-5H-1,4-diazepine (3c). Yield 13%; mp 77-78°C (white
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crystals from petr. ether). IR, νmax, cm-1: 1598 (C=N), 1587, 1506, 1288, 1159, 1080, 943, 850, 783. H NMR,
δ, ppm (300 MHz): 2.31-2.40 (2H, m, NCH2CH2); 3.5 (4H, br. s, NCH2CH2); 6.9-7.6 (9H, m, ArH). Found, %: C
76.74; H 5.72; N 10.56. C17H15FN2. Calculated, %: C 76.67; H 5.68; N 10.52.
3-(4-Methoxyphenyl)-2-phenyl-6,7-dihydro-5H-1,4-diazepine (3d). Yield 13%; mp 106-108°C (white
crystals from MeOH–petr. ether). IR, νmax, cm-1: 1600 (C=N), 1570, 1508, 1247, 1174, 1029, 945, 813, 786. 1H
NMR, δ, ppm (400 MHz): 3.77 (3H, s, OCH3); 2.31-2.38 (2H, m, NCH2CH2); 3.2 (4H, br. s, NCH2CH2); 6.8-7.3
(9H, m, ArH). Found, %: C 77.84; H 6.38; N 10.0. C18H18N2O. Calculated, %: C 77.67; H 6.52; N 10.06.
3-(4-Methylsulfanylphenyl)-2-phenyl-6,7-dihydro-5H-1,4-diazepine (3e). Yield 29%; mp 115-117°C
(brownish-white crystals from petr. ether). IR, νmax, cm-1: 1600, 1593 (C=N), 1550, 1247, 1180, 1097, 960, 823,
785. 1H NMR, δ, ppm (400 MHz): 2.4 (3H, s, SCH3); 2.34-2.37 (2H, m, NCH2CH2); 3.5 (4H, br. s, NCH2CH2);
7.1-7.5 (9H, m, ArH). Found, %: C 73.14; H 6.08; N 9.42. C18H18N2S. Calculated, %: C 73.43; H 6.16; N 9.51.
2-(4-Chlorophenyl)-3-(4'-methylphenyl)-6,7-dihydro-5H-1,4-diazepine
(3f).
Yield
34%;
mp 102-104°C (white crystals from MeOH). IR, νmax, cm-1: 1610 (C=N), 1600, 1593, 1400, 840, 821, 761.
1H NMR, δ, ppm (300 MHz): 2.3 (3H, s, CH3); 2.32-2.39 (2H, m, NCH2CH2); 3.4 (4H, br. s, NCH2CH2); 7.1-7.5
(8H, m, ArH). Found, %: C 72.83; H 5.62; N 9.49. C18H17ClN2. Calculated, %: C 72.84; H 5.77; N 9.44.
2,3-Di-(4,4'-dichlorophenyl)-6,7-dihydro-5H-1,4-diazepine (3g). Yield 17%; mp 111-113°C (white
crystals from MeOH). IR, νmax,cm-1: 1614 (C=N), 1591, 1467, 1398, 1080, 840, 769. H NMR, δ, ppm
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(300 MHz): 2.31-2.40 (2H, m, NCH2CH2); 3.5 (4H, br. s, NCH2CH2); 7.2-7.5 (8H, m, ArH). Found, %: C 64.24;
H 4.35; N 8.98. C17H14Cl2N2. Calculated, %: C 64.37; H 4.45; N 8.83.
2-(4-Chlorophenyl)-3-(4'-fluorophenyl)-6,7-dihydro-5H-1,4-diazepine (3h). Yield 41%;
mp 104-106°C (white crystals from MeOH). IR, νmax, cm-1: 1614 (C=N), 1587, 1272, 1090, 945, 850, 763.
1H NMR, δ, ppm (400 MHz): 2.32-2.39 (2H, m, NCH2CH2); 3.5 (4H, br. s, NCH2CH2); 6.98-7.31 (8H, m, ArH).
Found, %: C 68.12; H 4.66; N 9.54. C17H14ClFN2. Calculated, %: C 67.89; H 4.69; N 9.31.
2-(4-Chlorophenyl)-3-(4'-methylsulfanylphenyl)-6,7-dihydro-5H-1,4-diazepine (3i). Yield 13%;
mp 120-122°C (white crystals from petr. ether). IR, νmax, cm-1: 1610 (C=N), 1589, 1396, 1274, 1095, 941, 835,
1
815. H NMR, δ, ppm (400 MHz): 2.45 (3H, s, SCH3); 2.28-2.43 (2H, m, NCH2CH2); 3.51 (4H, br. s,
NCH2CH2); 7.1-7.7 (8H, m, ArH). Found, %: C 65.91; H 5.15; N 8.82. C18H17ClN2S. Calculated, %: C 65.74;
H 5.21; N 8.52.
2-(4-Chlorophenyl)-3-phenyl-6,7-dihydro-5H-1,4-diazepine (3j). Yield 38%; mp 72-74°C (white
crystals from MeOH). IR, νmax, cm-1: 1611, 1592 (C=N), 1456, 1338, 1272, 1092, 1013, 944, 835, 786. 1H NMR,
δ, ppm (300 MHz): 2.32-2.41 (2H, m, NCH2CH2); 3.5 (4H, br. s, NCH2CH2); 7.2-7.6 (9H, m, ArH).
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