Rapid and Efficient Synthesis of 1,4-Dihydropyridines
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bis-Ethyl 4,5,6,7,8-Hexahydro-4-(4-ethoxyphenyl)-2,7,7-trimethyl-5-oxoquinoline-3-
carboxylate (6a)
White powder, IR (KBr. cm−1): 3300, 3200, 3080, 2950, 1700, 1600; 1H-NMR (400 MHz,
CDCl3): δ 0.94 (s, 3H, CH3), 0.96 (s, 3H, CH3), 1.08 (s, 6H, CH3), 1.23 (t, J = 7.0, 6H,
CH2-CH3), 1.90 (br s, 4H), 2.14–2.32 (m, 8H, CH2), 2.39 (s, 3H, CH3), 2.40 (s, 3H, CH3),
3.95 (br s, 4H, OCH2-CH2), 4.09 (q, J = 7.0, 4H, OCH2CH3), 5.01 (s, 2H, CH), 6.45 (br s,
2H, NH), 6.74 (d, J = 8.6, 4H, Ar-H), 7.21 (d, J = 8.6, 4H, Ar-H); 13C-NMR (100 MHz,
CDCl3): δ 13.8, 14.3, 19.4, 19.5, 26.0, 26.1, 27.2, 28.2, 29.5, 32.6, 32.7, 35.6, 35.7, 41.1,
41.2, 48.3, 50.7, 53.7, 59.8, 61.9, 67.3, 67.5, 106.4, 112.4, 112.5, 113.8, 113.9, 114.0,
128.9, 129.0, 139.5, 143.1, 143.2, 143.3, 147.8, 148.1, 157.2, 167.6, 195.5, 195.6.
Anal. Cald. for C46H56N2O8 (764.95): C, 72.23; H, 7.38; N, 3.66. Found: C, 72.10; H,
7.21; N, 3.52.
bis-Ethyl 4-(4-Ethoxyphenyl)-1,4,5,6,7,8-hexahydro-2-methyl-5-oxoquinoline-3-
carboxylate (6b)
White powder, IR (KBr. cm−1): 3300, 3200, 3080, 2940, 1695, 1600; 1H-NMR (400 MHz,
DMSO): δ 1.14 (t, J = 7.0, 6H, OCH2CH3), 1.80–2.30 (m, 16H, CH2, OCH2-CH2), 2.28
(s, 6H, CH3), 3.93 (br s, 4H, OCH2-CH2), 3.98 (q, J = 7.0, OCH2-CH3), 4.83 (s, 2H, CH),
6.74 (d, J = 8.6, 4H, Ar-H), 7.03 (d, J = 8.6, 4H, Ar-H), 9.08 (br s, 2H, N-H); 13C-NMR
(100 MHz, CDCl3-d6): δ 14.7, 18.7, 21.3, 26.0, 26.6, 35.1, 37.2, 59.5, 67.4, 104.3, 111.8,
114.2, 128.8, 140.5, 1450, 151.6, 157.2, 167.4, 195.2.
Anal. Cald. for C42H48N2O8 (708.84): C, 71.17; H, 6.82; N, 3.95. Found: C, 71.05; H,
6.64; N, 3.86.
bis-Ethyl 1,4,5,6,7,8-Hexahydro-4-(2-ethoxyphenyl)-2,7,7-trimethyl-5-oxoquinoline-3-
carboxylate (8)
1
White powder, IR (KBr. cm−1): 3300, 3085, 2950, 1700, 1680, 1646, 1600; H-NMR
(400 MHz, CDCl3): δ 0.99 (s, 3H, CH3), 1.00 (s, 3H, CH3), 1.03 (s, 3H, CH3), 1.04 (s, 3H,
CH3), 1.19 (t, J = 7.0, 3H, OCH2-CH3), 1.20 (t, J = 7.2, 3H, OCH2-CH3), 2.01–2.20 (m,
8H, CH2), 2.22–2.27 (m, 4H, OCH2-CH2), 2.29 (s, 3H, CH3), 2.31 (s, 3H, CH3), 4.00–4.09
(m, 8H, OCH2-CH2, OCH2-CH3), 5.37 (s, 2H, CH), 6.83 (d, J = 7.6, 2H, Ar-H), 6.84
(t, J = 7.2, 2H, Ar-H), 7.10 (td, J = 7.8, 1.5, 2H, Ar-H), 7.35 (d, J = 7.2, 2H, Ar-H);
13C-NMR (100 MHz, CDCl3): δ 14.3, 19.0, 20.4, 26.8, 27.2, 29.6, 32.5, 40.8, 50.9, 59.6,
68.3, 105.3, 111.5, 120.0, 127.3, 128.8, 131.5, 135.0, 143.7, 149.9, 156.8, 168.0, 196.1.
Anal. Cald. for C46H56N2O8 (764.95): C, 72.23; H, 7.38; N, 3.66. Found: C, 72.16; H,
7.23; N, 3.71.
Ethyl 4,5-Dihydro-2-methyl-5-oxo-4-p-tolyl-1H-indeno[1,2-b]pyridine-3-
carboxylate (10a)
Red powder, IR (KBr. cm−1): 3250, 3080, 1700, 1630, 1580; 1H-NMR (400 MHz, CDCl3):
δ 1.17 (t, J = 7.0, 3H, OCH2-CH3), 2.28 (s, 3H, CH3), 2.51 (s, 3H, Ar-CH3), 4.07 (q, 2H,
J = 7.0, OCH2-CH3), 5.00 (s, 1H, CH), 6.75 (br s, 1H, NH), 7.06 (d, J = 7.6, 2H, Ar-H),
7.24 (d, J = 7.6, 2H, Ar-H), 7.29–7.39 (m, 4H, Ar-H); 13C-NMR (100 MHz, CDCl3): δ