R. Nongrum, G. K. Kharmawlong, J. W. S. Rani, N. Rahman, A. Dutta, and R. Nongkhlaw
Vol 000
Ar–H), 6.85 (d, 1H, J = 6.4 Hz, Ar–H), 6.55–6.48 (m, 2H,
Ar–H), 6.39 (t, 1H, J = 7.2 Hz, Ar–H), 6.06 (d, 1H,
J = 6.0 Hz, NH), 5.89 (d, 1H, J = 6.0 Hz, 6H), 2.67 (bs,
2H), 2.20 (d, 1H, J = 15.6 Hz), 2.04 (d, 1H, J = 16.0 Hz),
1.10 (s, 3H), 1,04 (s, 3H) ppm. 13C NMR (100 MHz,
DMSO-d6): δ 192.1, 155.3, 139.4, 137.7, 133.4, 131.7,
128.4, 126.9, 125.9, 124.5, 123.9, 122.9, 122.5, 120.2,
119.9, 119.8, 110.6, 52.7, 49.5, 44.1, 31.9, 28.3,
27.4 ppm. ESI–MS: m/z 368 [M]+. Anal. Calcd for
C25H24N2O: C 81.49, H 6.57, N 7.60%; found C 81.34, H
154.8, 143.7,138.2, 131.0, 129.0, 127.6, 122.7, 120.5,
120.0, 119.7, 109.5, 55.4, 49.3, 43.9, 31.7, 28.3,
27.5 ppm. ESI–MS: m/z 378 [M]+. Anal. Calcd for
C23H26N2O3: C 72.99, H 6.92, N 7.40%; found C 72.40,
H 7.02, N 7.28%.
General method for the synthesis of compound 6(a–o) and
7(a–l).
To 10 mL of ethanol–water (1:3) mixture,
1.0 mmol of 1,2-phenylenediamine, 1.0 mmol of the
corresponding aldehyde (in case of 6)/1,2 diketone (in
case of 7), and 8 mol% of meglumine were ultrasonicated
at 50°C for the given time. On completion of reaction,
monitored by TLC, the solution was cooled, and the
precipitated product was filtered, washed, and collected. In
some cases, the precipitate was further recrystallized from
hot ethanol.
6.59, N 7.58%.
3,3-Dimethyl-11-styryl-2,3,4,5,10,11-hexahydro-1H-
dibenzo[b,e][1,4]diazepin-1-one (5m). Light brown solid, m.
p. 250–252°C. IR (KBr): ν 3390, 3313, 2919, 1677, 1638,
1611, 1608, 1377 cmÀ1. 1H NMR (400 MHz, DMSO-d6):
δ 8.74 (s, 1H, NH), 7.12–7.07 (m, 3H, Ar–H), 6.99 (d, 1H,
J = 7.6 Hz, Ar–H), 6.77–6.71 (m, 2H, Ar–H), 6.66–6.62
(m, 1H, Ar–H), 6.17 (d, 1H, J = 15.6 Hz, CH), 6.01
(d, 1H, J = 6.4 Hz, NH), 5.98–5.96 (m, 1H, CH), 5.23 (d,
1H, J = 5.6 Hz, CH), 2.48 (m, 2H, CH2), 2.17 (d, 1H,
J = 16.0 Hz, CH2), 2.07 (d, 1H, J = 15.6 Hz, CH2),
1.03 (s, 3H, CH3), 0.99 (s, 3H, CH3) ppm. 13C NMR
(100 MHz, DMSO-d6): δ 192.2, 154.4, 138.9, 137.2,
132.9, 130.8, 129.0, 128.7, 127.5, 126.2, 123.2, 120.7,
120.6, 119.9, 110.5, 53.7, 49.9, 44.4, 32.2, 28.8,
27.7 ppm. ESI–MS: m/z 344 [M] +. Anal. Calcd for
C24H26N2O: C 80.41, H 7.31, N 7.81%; found C 80.26, H
Spectral data of selected products. 2-Phenyl-1H-benzo[d]
imidazole (6a). Light brown solid, m.p. 286–288°C. IR
1
(KBr): ν 3411, 1590, 1541, 1410, 1276 cmÀ1. H NMR
(400 MHz, DMSO-d6): δ 13.0 (s, 1H, NH), 8.30 (d, 2H,
J = 8.0 Hz, Ar–H), 7.70–7.62 (m, 5H, Ar–H), 7.34–7.32
(m, 2H, Ar–H) ppm. 13C NMR (100 MHz, CDCl3/DMSO-
d6): δ 146.5, 133.9, 124.8, 124.3, 123.3, 121.3, 116.8,
109.6 ppm. ESI–MS: m/z 194[M]+. Anal. Calcd for
C13H10N2: C 80.39, H 5.19, N 14.42%; found C 80.25, H
5.21, N 14.38%.
2-(p-Tolyl)-1H-benzo[d]imidazole (6b).
Light yellow
solid, m.p. 270–272°C. IR (KBr): ν 3444, 1621, 1500,
1430, 1274 cmÀ1 1H NMR (400 MHz, DMSO-d6): δ
7.33, N 7.79%.
11-(4-Hydroxy-3-methoxyphenyl)-3,3-dimethyl-2,3,4,5,10,11-
hexahydro-1H-dibenzo[b,e][1,4]diazepin-1-one (5n). Yellow
.
12.84 (s, 1H, NH), 8.07 (d, 2H, J = 7.6 Hz, Ar–H), 7.65
(d, 1H, J = 7.2 Hz. Ar–H), 7.51 (d, 1H, J = 7.2 Hz, Ar–H),
7.36 (d, 2H, J = 8.0 Hz, Ar–H), 7.22–7.16 (m, 2H, Ar–H),
2.38 (s, 3H, CH3) ppm. 13C NMR (100 MHz, DMSO-d6):
δ 151.3, 143.7, 139.5, 134.9, 129.4, 127.4, 126.3, 122.2,
121.5, 118.6, 111.1, 20.9 ppm. ESI–MS: m/z 208 [M].+
Anal. Calcd for C14H12N2: C 80.74, H 5.81, N 13.45%;
found C 80.48, H 5.85, N 13.37%.
solid, m.p. 208–210°C. IR (KBr): ν 3435, 3307, 2961, 1602,
1517, 1464, 1380, 1335, 1279 cmÀ1. 1H NMR (400 MHz,
DMSO-d6): δ 8.68 (s, 1H, NH), 8.57 (s, 1H, OH), 6.87 (d,
1H, J = 7.2 Hz, Ar–H), 6.74 (s, 1H, Ar–H), 6.58–6.52 (m,
2H, Ar–H), 6.43–6.34 (m, 2H, Ar–H), 6.04 (d, 1H,
J = 5.2 Hz, NH), 5.58 (d, 1H, J = 4.8 Hz, CH), 3.57 (s,
3H,OCH3), 2.59–2.54 (m, 2H, CH2), 2.18 (d, 1H,
J = 16.0 Hz, CH2), 2.05 (d, 1H, J = 15.6 Hz, CH2), 1.05
(s, 3H, CH3), 1.02 (s, 3H, CH3) ppm. 13C NMR
(100 MHz, DMSO-d6): δ 192.3, 155.0, 147.3, 144.8,
139.3, 136.1, 131.6, 122.9, 121.0, 120.2, 119.7, 114.8,
112.2, 111.0, 55.9, 55.6, 49.9, 44.4, 32.1, 29.1, 27.5 ppm.
ESI–MS: m/z 364 [M]+. Anal. Calcd for C22H24N2O3: C
2-(4-Methoxyphenyl)-1H-benzo[d]imidazole (6c).
Light
yellow solid, m.p. 210–212°C. IR (KBr): ν 3433, 1612,
1502, 1437, 1252 cmÀ1 1H NMR (400 MHz,
.
DMSO-d6): δ 12.74 (s, 1H, NH), 8.10 (d, 2H, J = 8.8 Hz,
Ar–H), 7.60 (d, 1H, J = 7.2 Hz, Ar–H), 7.48 (d, 1H,
J = 6.8 Hz, Ar–H), 7.19–7.14 (m, 2H, Ar–H), 7.10 (d,
2H, J = 9.2 Hz, Ar–H), 3.83 (s, 3H, OCH3) ppm. 13C
NMR (100 MHz, DMSO-d6): δ 160.5, 151.2, 127.9,
122.5, 114.3, 55.2 ppm. ESI–MS: m/z 224 [M]+. Anal.
Calcd for C14H12N2O: C 74.98, H 5.39, N 12.49%;
found C 74.71, H 5.44, N 12.40%.
72.51, H 6.64, N 7.69%; found C 72.44, H 6.65, N 7.67%.
11-(3,4-Dimethoxyphenyl)-3,3-dimethyl-2,3,4,5,10,11-
hexahydro-1H-dibenzo[b,e][1,4]diazepin-1-one (5o). Yellow
solid, m.p. 238–240°C. IR (KBr): ν 3415, 3309, 2932, 1638,
1584, 1428, 1281 cmÀ1. 1H NMR (400 MHz, DMSO-d6): δ
8.81 (s, 1H, NH), 7.16–7.15 (m, 2H, Ar–H), 7.07–7.05 (m,
2H, Ar–H), 6.92–6.90 (m, 1H, Ar–H), 6.60–6.59 (m, 1H,
Ar–H), 6.50–6.48 (m, 1H, Ar–H), 6.19 (d, 1H, J = 5.6 Hz,
NH), 5.66 (d, 1H, J = 5.2 Hz, CH), 3.35 (s, 6H, OCH3),
2.57 (s, 2H, CH2), 2.18 (d, 1H, J = 15.2 Hz, CH2), 2.07 (d,
1H, J = 15.6 Hz, CH2), 1.06 (s, 3H, CH3), 1.01 (s, 3H,
CH3) ppm. 13C NMR (100 MHz, DMSO-d6): δ 192.0,
2-(4-Bromophenyl)-1H-benzo[d]imidazole (6d).
Light
brown solid, m.p. 258–260°C. IR (KBr): ν 3433, 1622,
1539, 1427, 1273 cmÀ1 1H NMR (400 MHz,
.
DMSO-d6): δ 13.01 (s, 1H, NH), 8.11 (d, 2H, J = 8.8 Hz,
Ar–H), 7.76 (d, 2H, J = 8.8 Hz, Ar–H), 7.63–7.54 (m,
2H, Ar–H), 7.21–7.20 (m, 2H, Ar–H) ppm. 13C NMR
(100 MHz, DMSO-d6): δ 155.6, 136.6, 134.2, 133.1,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet