November 2010 An Efficient and Clean Synthesis of Indeno[1,2-b]pyrazolo[4,3-e]pyridin-5(1H)-one
Derivatives under Microwave Irradiation in Water
1285
Table 3
Synthesis of products 4.
Entry
4
Ar
Time (min)
Yield (%)
Mp (ꢀC)
1
2
3
4
5
6
7
8
9
4a
4b
4c
4d
4e
4f
4g
4h
4i
4-ClC6H4
4-BrC6H4
8
10
8
10
7
83
80
77
79
80
77
78
76
77
>300
>300
>300
209–210
243–244
245–246
258–259
240–242
263–264
4-CH3C6H4
2-ClC6H4
3-NO2C6H4
3,4-(CH3O)2C6H3
C6H5
8
10
10
13
3,4,5-(CH3O)3C6H2
Thien-2-yl
13.87 (s, 1H, NH), 7.94 (d, 1H, J ¼ 7.6 Hz, ArH), 7.76, (t,
1H, J ¼ 7.6 Hz, ArH), 7.67 (d, 1H, J ¼ 7.6 Hz, ArH), 7.62–
7.57 (m, 3H, ArH), 1.86 (s, 3H, CH3). IR (KBr, m, cmꢁ1):
3153, 3109, 2997, 1714, 1602, 1572, 1550, 1473, 1439, 1340,
1303, 1280, 1251, 1183, 1155, 1060, 991, 807, 752, 711.
HRMS (ESI) m/z: calc. for C20H13ClN3O: 346.0742 [MþH]þ,
found: 346.0744 [MþH]þ.
4-(4-chlorophenyl)-3-methylindeno[1,2-b]pyrazolo[4,3-e]pyri-
1
din-5(1H)-one (4a). H NMR (400 MHz, DMSO-d6) (d, ppm):
13.78 (s, 1H, NH), 7.65 (d, 2H, J ¼ 6.8 Hz, ArH), 7.40 (t, 1H,
J ¼ 7.6 Hz, ArH), 7.34–7.28 (m, 3H, ArH), 7.23 (t, 2H, J ¼
8.4 Hz, ArH), 7.19 (d, 1H, J ¼ 6.8 Hz, ArH), 1.87 (s, 3H,
CH3). IR (KBr, m, cmꢁ1): 3197, 3056, 2882, 1717, 1698, 1559,
1542, 1491, 1436, 1363, 1340, 1290, 1245, 1185, 1130, 1082,
989, 811, 777, 709. HRMS (ESI) m/z: calc. for C20H13ClN3O:
346.0742 [MþH]þ, found: 346.0793 [MþH]þ.
3-methyl-4-(3-nitrophenyl)indeno[1,2-b]pyrazolo[4,3-e]pyri-
1
din-5(1H)-one (4e). H NMR (400 MHz, DMSO-d6) (d, ppm):
13.87 (s, 1H, NH), 8.43 (d, 2H, J ¼ 9.2 Hz, ArH), 8.04
(d, 1H, J ¼ 7.6 Hz, ArH), 7.93 (d, 1H, J ¼ 7.2 Hz, ArH),
7.85 (t, 1H, J ¼ 7.6 Hz, ArH), 7.77–7.73 (m, 1H, ArH), 7.62–
7.55 (m, 2H, ArH), 1.94 (s, 3H, CH3). IR (KBr, m, cmꢁ1):
3190, 3117, 2990, 1754, 1634, 1599, 1504, 1488, 1457, 1385,
1300, 1294, 1236, 1177, 1120, 1070, 985, 800, 765, 713.
HRMS (ESI) m/z: calc. for C20H13N4O3: 357.0979 [MþH]þ,
found: 357.1005 [MþH]þ.
4-(4-bromophenyl)-3-methylindeno[1,2-b]pyrazolo[4,3-e]pyri-
1
din-5(1H)-one (4b). H NMR (400 MHz, DMSO-d6) (d, ppm):
13.80 (s, 1H, NH), 7.91 (d, 1H, J ¼ 7.2 Hz, ArH), 7.73, (d,
4H, J ¼ 8.4 Hz, ArH), 7.61–7.54 (m, 3H, ArH), 7.49 (d, 3H,
J ¼ 8.0 Hz, ArH), 1.94 (s, 3H, CH3). IR (KBr, m, cmꢁ1):
3198, 3056, 2994, 1712, 1684, 1594, 1536, 1491, 1432, 1338,
1302, 1256, 1208, 1183, 1115, 1071, 995, 811, 762, 730.
HRMS (ESI) m/z: calc. for C20H13BrN3O: 390.0237 [MþH]þ,
found: 390.0212 [MþH]þ.
4-(3,4-dimethoxyphenyl)-3-methylindeno[1,2-b]pyrazolo[4,3-
1
e]pyridin-5(1H)-one (4f). H NMR (400 MHz, DMSO-d6) (d,
3-methyl-4-p-tolylindeno[1,2-b]pyrazolo[4,3-e]pyridin-5(1H)-
1
ppm): 13.73 (s, 1H, NH), 7.90 (d, 1H, J ¼ 7.2 Hz, ArH), 7.72,
(t, 1H, J ¼ 7.2 Hz, ArH), 7.61 (d, 1H, J ¼ 7.2 Hz, ArH), 7.55
(t, 1H, J ¼ 7.6 Hz, ArH), 7.15 (d, 1H, J ¼ 1.2 Hz, ArH),
7.10–7.04 (m, 2H, ArH), 3.86 (s, 3H, CH3), 3.77 (s, 3H, CH3),
2.01 (s, 3H, CH3). IR (KBr, m, cmꢁ1): 3054, 3001, 2934, 1699,
1608, 1559, 1542, 1490, 1437, 1338, 1309, 1285, 1263, 1169,
1139, 1086, 1025, 801, 766, 726. HRMS (ESI) m/z: calc. for
C22H18N3O3: 372.1343 [MþH]þ, found: 372.1333 [MþH]þ.
3-methyl-4-phenylindeno[1,2-b]pyrazolo[4,3-e]pyridin-5(1H)-
one (4c). H NMR (400 MHz, DMSO-d6) (d, ppm): 13.74 (s,
1H, NH), 7.88 (d, 1H, J ¼ 7.2 Hz, ArH), 7.71, (t, 1H, J ¼ 7.2
Hz, ArH), 7.58–7.51 (m, 2H, ArH), 7.39 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.33 (d, 2H, J ¼ 8.0 Hz, ArH), 2.44 (s, 3H, CH3), 1.92
(s, 3H, CH3). IR (KBr, m, cmꢁ1): 3190, 3048, 2962, 1710,
1612,1562, 1511, 1475, 1449, 1338, 1300,1255, 1207, 1179,
1116, 1072, 987, 809, 786, 733. HRMS (ESI) m/z: calc. for
C21H16N3O: 326.1288 [MþH]þ, found: 326.1317 [MþH]þ.
4-(2-chlorophenyl)-3-methylindeno[1,2-b]pyrazolo[4,3-e]pyri-
1
1
one (4g). H NMR (400 MHz, DMSO-d6) (d, ppm): 13.77 (s,
din-5(1H)-one (4d). H NMR (400 MHz, DMSO-d6) (d, ppm):
1H, NH), 7.91 (d, 1H, J ¼ 7.2 Hz, ArH), 7.73 (t, 1H, J ¼ 7.2,
ArH), 7.61–7.48 (m, 8H, ArH), 1.90 (s, 3H, CH3). IR (KBr, m,
cmꢁ1): 3102, 2994, 1708, 1671, 1592, 1562, 1541, 1498, 1446,
1339, 1305, 1256, 1240, 1189, 1140, 1094, 978, 805, 760,
705. HRMS (ESI) m/z: calc. for C20H14N3O: 312.1132
[MþH]þ, found: 313.1148 [MþH]þ.
Scheme 2
3-methyl-4-(3,4,5-trimethoxyphenyl)indeno[1,2-b]pyrazolo[4,3-
1
e]pyridin-5(1H)-one (4h). H NMR (400 MHz, DMSO-d6) (d,
ppm): 13.76 (s, 1H, NH), 7.91 (d, 1H, J ¼ 7.2 Hz, ArH), 7.73, (t,
1H, J ¼ 7.6 Hz, ArH), 7.62 (d, 1H, J ¼ 6.8 Hz, ArH), 7.56 (t, 1H,
J ¼ 7.2 Hz, ArH), 6.83 (s, 2H, ArH), 3.78 (d, 9H, J ¼ 3.2 Hz,
CH3), 1.86 (s, 3H, CH3). IR (KBr, m, cmꢁ1): 3193, 3107, 2967,
1709, 1583, 1562, 1504, 1464, 1433, 1344, 1318, 1296, 1250,
1163, 1126, 1005, 967, 809, 777, 729. HRMS (ESI) m/z: calc. for
C23H20N3O4: 402.1444 [MþH]þ, found: 402.1434 [MþH]þ.
3-methyl-4-(thiophen-2-yl)indeno[1,2-b]pyrazolo[4,3-e]pyridin-
1
5(1H)-one (4i). H NMR (400 MHz, DMSO-d6) (d, ppm):
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet