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I. Singh et al. / Bioorg. Med. Chem. 11 (2003) 529–538
100) and 283 ([M+H]+, 58); 1H NMR (300 MHz,
CDCl3): d 2.21 (3H, s, COCH3), 2.97 (1H, dd, J=7.5 Hz
and 15.9 Hz, C-3Ha), 3.07 (1H, dd, J=6.1 Hz and
15.9 Hz, C-3Hb), 4.31 (1H, t, J=8.0 Hz, C-4H), 6.68
(1H, d, J=2.5 Hz, C-5H), 7.01 (1H, dd, J=2.5 Hz and
8.6 Hz, C-7H), 7.11–7.20 (3H, m, C-30H, C-50H and C-
8H) and 7.26–7.38 (3H, m, C-20H, C-40H and C-60H);
13C NMR (75.5 MHz, CDCl3): d 20.94 (COCH3), 36.60
and 40.66 (C-3 and C-4), 117.94, 121.32 and 121.99 (C-
5, C-7 and C-8), 127.00 (C-10), 127.61, 127.85 and
128.95 (C-20, C-30, C-40, C-50 and C-60), 139.22 (C-10),
146.94 and 149.18 (C-6 and C-9), and 167.19 and 169.35
(2 ꢃ CO); IR (Nujol): 1766 and 1747 (2 ꢃ CO), 1462,
(1H, dd, J=8.7 Hz and 15.8 Hz, C-3Ha), 3.05 (1H, dd,
J=5.9 Hz and 15.8 Hz, C-3Hb), 3.79 (3H, s, OCH3),
4.28 (1H, dd, J=5.9 Hz and 8.6 Hz, C-4H), 6.67 (1H, d,
J=2.4 Hz, C-5H), 6.86 (2H, d, J=8.7 Hz, C-30H and C-
50H), 7.00 (1H, dd, J=2.4 Hz and 8.7 Hz, C-7H) and
7.07–7.13 (3H, m, C-20H, C-60H and C-8H); 13C NMR
(75.5 MHz, CDCl3): d 21.73 (COCH3), 37.57 and 40.49
(C-3 and C-4), 56.07 (OCH3), 115.39 (C-30 and C-50),
118.68, 122.05 and 122.66 (C-5, C-7 and C-8), 128.28
(C-10), 129.31 (C-20 and C-60), 132.26 (C-10), 147.72 and
149.91 (C-40 and C-9), 159.92 (C-6), and 168.14 and
170.16 (2 ꢃ CO); IR (Nujol): 1773 and 1775 (2 ꢃ CO),
1597, 1489, 1417, 1208, 1125, 1050, 1014, 909 and
1376, 1219, 1179, 1127, 972 and 725 cmꢁ1
.
701 cmꢁ1
.
(ꢀ)-5-Acetoxy-7-methyl-4-phenyl-3,4-dihydrocoumarin
(21). It was obtained as a brown solid (720 mg) in 81%
yield; mp 163–164 ꢂC (lit.19 mp 160 ꢂC). Rf : 0.37
(chloroform–acetone, 19:1); ESIMS, m/z (% rel. int.):
319.1 ([M+Na]+, 100) and 297 ([M+H]+, 81); 1H
NMR (300 MHz, CDCl3): d 2.17 and 2.30 (6H, 2s, 3H
each, CH3 and COCH3), 2.99 (1H, dd, J=2.7 Hz and
15.7 Hz, C-3Ha), 3.10 (1H, dd, J=6.1 Hz and 15.7 Hz,
C-3Hb), 4.37 (1H, dd, J=2.6 Hz and 6.1 Hz, C-4H),
6.76 and 6.80 (2H, 2d, 1H each, J=2.0 Hz each, C-6H
and C-8H), 7.03–7.05 (2H, m, C-30H and C-50H) and
7.20–7.31 (3H, m, C-20H, C-40H and C-60H); 13C NMR
(75.5 MHz, CDCl3): d 19.68 and 21.82 (CH3 and
COCH3), 38.23 and 38.82 (C-3 and C-4), 109.54 (C-8),
120.34 (C-6), 121.59 (C-10), 127.68, 128.37 and 129.96
(C-20, C-30, C-40, C-50 and C-60), 138.86 and 140.53 (C-10
and C-7), 151.07 and 153.30 (C-5 and C-9), and 167.43
and 169.96 (2 ꢃ CO); IR (Nujol): 1768 and 1770 (2 ꢃ
CO), 1612, 1513, 1488, 1429, 1370, 1179, 1137, 1031,
(ꢀ)-5-Acetoxy-7-methyl-4-(40-methoxyphenyl)-3,4-dihydro-
coumarin (24). It was obtained as a white solid (861 mg)
in 88% yield; mp 163–164 ꢂC. Rf=0.37 (chloroform–
acetone, 19:1); HRMS, C19H18O5 (M+ 326.1145, calcd
326.1209); ESIMS, m/z (% rel. int.): 349.3 ([M+Na]+,
82) and 327 ([M+H]+, 100); 1H NMR (300 MHz,
CDCl3): d 2.17 and 2.30 (6H, 2s, 3H each, CH3 and
COCH3), 3.01 (2H, m, C-3H), 3.74 (3H, s, OCH3), 4.33
(1H, br d, J=3.3 Hz, C-4H), 6.76–6.81 (4H, m, C-20H,
C-30H, C-50H and C-60H) and 6.94–6.97 (2H, m, C-6H
and C-8H); 13C NMR (75.5 MHz, CDCl3): d 18.82 and
21.02 (CH3 and COCH3), 36.07 and 36.83 (C-3 and C-
4), 55.19 (OCH3), 101.99 (C-8), 114.48 (C-30 and C-50),
119.07 (C-6), 121.15 (C-10), 127.95 (C-20 and C-60),
131.64 (C-10), 138.00 (C-7), 150.13 and 152.34 (C-5 and
C-9), 158.86 (C-40), and 166.88 and 169.22 (2 ꢃ CO);
IR (KBr): 1776 and 1778 (2 ꢃ CO), 1613, 1592, 1512,
1420, 1374, 1342, 1301, 1247, 1214, 1123, 829 and
758 cmꢁ1
.
918 and 830 cmꢁ1
.
(ꢀ)-7-Acetoxy-4-(30,40,50-trimethoxyphenyl)-3,4-dihydro-
coumarin (25). It was obtained as a white solid (1.03 g)
in 92% yield; mp 143–144 ꢂC. Rf : 0.38 (chloroform–
acetone, 19:1); HRMS, C20H20O7 (M+ 372.1184, calcd
372.1209); ESIMS, m/z (% rel. int.): 395.3 ([M+Na]+,
100) and 373 ([M+H]+, 6); 1H NMR (300 MHz,
CDCl3): d 2.31 (3H, s, COCH3), 2.98 (1H, dd,
J=8.5 Hz and 15.8 Hz, C-3Ha), 3.10 (1H, dd,
J=6.1 Hz and 15.8 Hz, C-3Hb), 3.81 and 3.84 (9H, 2s,
6H and 3H each, 3 ꢃ OCH3), 4.25 (1H, br t,
J=8.5 Hz, C-4H), 6.36 (2H, s, C-20H and C-60H), 6.84
(1H, dd, J=2.1 Hz and 8.3 Hz, C-6H), 6.90 (1H, d,
J=2.1 Hz, C-8H) and 7.00 (1H, d, J=8.3 Hz, C-5H);
13C NMR (75.5 MHz, CDCl3): d 25.37 (COCH3), 41.17
and 45.03 (C-3 and C-4), 60.51 and 65.17 (3 ꢃ OCH3),
108.98 (C-20 and C-60), 115.22 (C-8), 122.25 (C-6),
127.69 (C-10), 133.17 (C-5), 139.84 (C-10), 154.96,
156.25 and 158.08 (C-30, C-40, C-50, C-7 and C-9), and
171.37 and 173.46 (2 ꢃ CO); IR (Nujol): 1766 and
1738 (2 ꢃ CO), 1617, 1591, 1463, 1377, 1216, 1145,
(ꢀ)-7-Acetoxy-4-(40-methoxyphenyl)-3,4-dihydrocoumarin
(22). It was obtained as a light yellow solid (786 mg) in
84% yield; mp 90–91 ꢂC. Rf : 0.37 (chloroform–acetone,
19:1); HRMS, C18H16O5 (M+ 312.1006, calcd
312.0998); ESIMS, m/z (% rel. int.): 335.1 ([M+Na]+,
1
12); APCI, m/z (% rel. int.): 313.2 ([M+H]+, 100); H
NMR (300 MHz, CDCl3): d 2.30 (3H, s, COCH3), 2.99
(1H, dd, J=6.7 Hz and 15.7 Hz, C-3Ha), 3.08 (1H, dd,
J=5.9 Hz and 15.7 Hz, C-3Hb), 3.77 (3H, s, OCH3),
4.28 (1H, br t, J=6.8 Hz, C-4H), 6.57 (1H, d, J=2.4 Hz,
C-8H), 6.61 (1H, dd, J=2.4 and 8.2 Hz, C-7H), 6.86–
6.92 (3H, m, C-30H, C-50H and C-5H) and 7.10–7.17
(2H, m, C-20H and C-60H); 13C NMR (75.5 MHz,
CDCl3): d 21.00 (COCH3), 36.93 and 39.22 (C-3 and C-
4), 55.25 (OCH3), 110.78, 114.49 and 117.78 (C-30, C-50,
C-6 and C-8), 123.82 (C-10), 128.61 and 128.77 (C-20, C-
60 and C-5), 131.76 (C-10), 150.43 and 151.88 (C-40 and
C-9), 163.07 (C-7), and 167.22 and 169.14 (2 ꢃ CO); IR
(KBr): 1775 and 1777 (2 ꢃ CO), 1614, 1511, 1427, 1368,
1254, 1205, 1126, 1011 and 906 cmꢁ1
.
1126, 1112, 984 and 849 cmꢁ1
.
(ꢀ)-6-Acetoxy-4-(40-methoxyphenyl)-3,4-dihydrocoumarin
(23). It was obtained as an oil (796 mg) in 85% yield.
Rf : 0.38 (chloroform–acetone, 19:1); HRMS, C18H16O5
(M+ 312.0984, calcd 312.0998); ESIMS, m/z (% rel.
int.): 335.3 ([M+Na]+, 100) and 313 ([M+H]+, 22); 1H
NMR (300 MHz, CDCl3): d 2.22 (3H, s, COCH3), 2.99
(ꢀ)-6-Acetoxy-4-(30,40,50-trimethoxyphenyl)-3,4-dihydro-
coumarin (26). It was obtained as an oil (993 mg) in 89%
yield. Rf : 0.35 (chloroform–acetone, 19:1); HRMS,
C20H20O7 (M+ 372.1163, calcd 372.1209); ESIMS, m/z
(% rel. int.): 395.3 ([M+Na],+ 100) and 373 ([M+H]+,
22); 1H NMR (300 MHz, CDCl3): d 2.26 (3H, s,