G. Yin et al. / Tetrahedron 69 (2013) 8353e8359
8357
1106, 909, 734, 700 cmꢁ1. HRMS (EI) m/z calcd for C34H27NO4
513.1940, found: 513.1937.
(400 MHz, CDCl3)
d
7.34e7.16 (m, 10H), 7.13 (d, J¼7.6 Hz, 2H),
7.09e7.01 (m, 3H), 6.96 (d, J¼7.6 Hz, 2H), 6.78 (d, J¼4.8 Hz, 2H), 5.70
(s, 1H), 4.54e4.33 (m, 2H), 3.73 (s, 3H), 3.30 (s, 3H), 2.26 (s, 3H). 13
NMR (100 MHz, CDCl3) 166.4, 166.1, 149.5, 143.6, 141.0, 140.5, 137.8,
137.3, 135.2, 128.7, 128.5, 128.4, 127.8, 127.7, 127.5, 127.4, 126.8, 126.5,
126.2, 123.2, 101.5, 70.8, 53.3, 52.7, 50.6, 20.9. IR (KBr) 2948, 1736,
1694, 1529, 1301, 1216, 910, 733, 700 cmꢁ1. HRMS (EI) m/z calcd for
35H31NO4 529.2253, found: 529.2255.
C
4.2.5. Dimethyl 1,4,6,6-tetraphenyl-1,6-dihydropyridine-2,3-
d
dicarboxylate (3e). White solid, mp 153e154 ꢀC. 1H NMR
(400 MHz, CDCl3)
d
7.34 (t, J¼7.2 Hz, 1H), 7.29e7.21 (m, 2H),
n
7.12e6.94 (m, 11H), 6.88 (d, J¼7.3 Hz, 2H), 6.78 (d, J¼6.4 Hz, 4H),
5.36 (s, 1H), 3.61 (d, J¼4.2 Hz, 6H). 13C NMR (100 MHz, CDCl3)
C
d
166.3, 160.3, 140.6, 137.8, 137.2, 133.2, 130.3, 129.2, 128.7, 128.6,
128.3,127.8, 127.2,126.5,126.3,124.3, 123.6,122.1, 52.0, 51.7, 48.3. IR
4.3.5. Dimethyl 1-benzyl-6,6-diphenyl-1,6-dihydropyridine-2,3-
(KBr)
n
3027, 1722, 1716, 1496, 1268, 1150, 765, 698 cmꢁ1. HRMS (EI)
dicarboxylate (6e). Yellow solid, mp 139e140 ꢀC. 1H NMR
m/z calcd for C33H27NO4 501.1940, found: 501.1940.
(500 MHz, CDCl3)
d
7.30 (d, J¼7.0 Hz, 4H), 7.26e7.12 (m, 6H),
7.10e6.93 (m, 3H), 6.72 (d, J¼5.6 Hz, 2H), 6.58 (d, J¼9.7 Hz, 1H), 5.59
4.2.6. Dimethyl 1-(4-methoxyphenyl)-4,6,6-triphenyl-1,6-
(d, J¼9.7 Hz, 1H), 4.45 (s, 2H), 3.66 (s, 6H). 13C NMR (125 MHz,
dihydropyridine-2,3-dicarboxylate (3f). White solid, mp 172e173 ꢀC.
CDCl3) d 165.9, 165.7, 147.9, 143.5, 137.4, 128.5, 128.0, 127.6, 127.5,
1H NMR (400 MHz, CDCl3)
d
7.39 (d, J¼7.8 Hz, 4H), 7.32e7.12 (m,
11H), 6.90 (d, J¼7.9 Hz, 2H), 6.47 (d, J¼8.4 Hz, 2H), 5.71 (s, 1H), 3.63
(s, 3H), 3.56 (s, 3H), 3.34 (s, 3H). 13C NMR (100 MHz, CDCl3)
165.9,
165.7, 158.2, 147.2, 143.3, 140.6, 135.1, 133.8, 131.1, 128.9, 127.8, 127.7,
126.5, 126.3, 121.9, 119.9, 99.3, 71.0, 53.0, 52.8, 51.2. IR (KBr) n 2949,
1733, 1698, 1548, 1299, 1244, 909, 732, 702 cmꢁ1. HRMS (EI) m/z
d
calcd for C28H25NO4 439.1784, found: 439.1780.
127.4, 127.3, 126.9, 124.0, 112.8, 103.6, 72.6, 55.1, 52.4, 50.8. IR (KBr)
n
4.3.6. Dimethyl 1-benzyl-4-butyl-6,6-diphenyl-1,6-dihydropyridine-
3022, 1738, 1694, 1608, 1508, 1235, 1096, 751, 702 cmꢁ1. HRMS (EI)
2,3-dicarboxylate (6f). White solid, mp 107e108 ꢀC. 1H NMR
m/z calcd for C34H29NO5 531.2046, found: 531.2045.
(500 MHz, CDCl3) d 7.31e7.23 (m, 4H), 7.23e7.14 (m, 6H), 7.04 (d,
J¼3.9 Hz, 3H), 6.75 (d, J¼4.4 Hz, 2H), 5.52 (s,1H), 4.39 (s, 2H), 3.62 (d,
J¼2.9 Hz, 6H), 2.50 (t, J¼7.3 Hz, 2H), 1.52e1.42 (m, 2H), 1.36 (dd,
J1¼14.6, J2¼7.3 Hz, 2H), 0.93 (t, J¼7.2 Hz, 3H). 13C NMR (125 MHz,
4.3. General procedure for the preparation of dihydropyridines6
To a solution of amine 4 (0.5 mmol) in dry dichloromethane
(3 mL) was added 2-butynedioate (0.5 mmol) and the solution was
stirred for 10 min at room temperature. Then, propargylic alcohol 1
CDCl3) d 166.7, 166.4, 148.3, 144.0, 138.0, 133.4, 128.5, 127.8, 127.7,
127.3, 126.5, 126.3, 121.3, 102.6, 70.5, 52.9, 52.5, 51.0, 33.7, 31.7, 22.4,
14.0. IR (KBr)
2951,1733,1707,1524,1297,1200,1116, 735, 701 cmꢁ1
HRMS (EI) m/z calcd for C32H33NO4 495.2410, found: 495.2413.
n
.
ꢀ
(0.5 mmol), 4 A MS (200 mg) and BF3$Et2O (0.5 mmol) were
added in a sequence. After stirred at 0 ꢀC for 1 h, the mixture was
evaporated on vacuum. The product was isolated by column chro-
matography, using silica gel as stationary phase and hexane
eEtOAceEt3N (10:1:0.1, v/v/v) as eluent.
4.3.7. Dimethyl 1-benzyl-6-methyl-4,6-diphenyl-1,6-dihydropyridine-
2,3-dicarboxylate(6g). Yellow solid, mp 77e78 ꢀC.1H NMR (400 MHz,
CDCl3)
7.15 (d, J¼7.3 Hz, 2H), 5.16 (s, 1H), 4.51 (q, J¼17.3 Hz, 2H), 3.70 (s, 3H),
3.33 (s, 3H), 1.69 (s, 3H). 13C NMR (100 MHz, CDCl3)
166.3, 166.2,
150.1, 145.2, 141.0, 138.5, 134.7, 128.3, 127.5, 127.2, 127.1, 126.7, 126.4,
126.1, 122.6, 100.7, 64.3, 52.6, 51.9, 50.7, 26.7. IR (KBr) 2948, 1738,
1694, 1530, 1300, 1221, 1133, 734, 699 cmꢁ1. HRMS (EI) m/z calcd for
C29H27NO4 453.1940, found: 453.1936.
d
7.50 (d, J¼7.4 Hz, 2H), 7.35e7.22 (m, 10H), 7.22e7.17 (m, 1H),
4.3.1. Dimethyl 1-benzyl-4,6,6-triphenyl-1,6-dihydropyridine-2,3-
d
dicarboxylate (6a). White solid, mp 183e184 ꢀC. 1H NMR
(400 MHz, CDCl3)
(m, 3H), 6.88e6.71 (m, 2H), 5.71 (s, 1H), 4.45 (s, 1H), 3.75 (s, 3H),
3.30 (s, 3H). 13C NMR (100 MHz, CDCl3)
166.4, 166.1, 149.5, 143.4,
140.9,137.7, 135.3, 128.6, 127.83, 127.75, 127.54, 127.50, 127.47, 126.8,
d
7.35e7.23 (m, 9H), 7.22e7.11 (m, 6H), 7.09e7.00
n
d
126.6, 126.2, 123.1, 101.6, 71.0, 53.3, 52.8, 50.7. IR (KBr)
n
2949, 1735,
4.3.8. Dimethyl 1-benzyl-6,6-dimethyl-4-phenyl-1,6-dihydropyridine-
1694, 1617, 1529, 1301, 1217, 1111, 909, 734, 700 cmꢁ1. HRMS (EI) m/z
2,3-dicarboxylate (6h). Yellow solid, mp 133e134 ꢀC. 1H NMR
calcd for C34H29NO4 515.2097, found: 515.2097.
(500 MHz, CDCl3)
(s, 3H), 3.38 (s, 3H), 1.32 (s, 6H). 13C NMR (125 MHz, CDCl3)
166.4, 150.3, 141.1, 138.9, 135.4, 128.5, 127.6, 127.3, 127.2, 126.7, 126.3,
121.7, 100.7, 58.6, 52.7, 50.6, 50.5, 26.3. IR (KBr) 2924, 1739, 1693,
1525, 1434, 1303, 1126, 734, 700 cmꢁ1. HRMS (EI) m/z calcd for
24H25NO4 391.1784, found: 391.1782.
d
7.37e7.18 (m, 10H), 4.90 (s, 1H), 4.50 (s, 2H), 3.78
d
166.5,
4.3.2. Dimethyl 1-benzyl-4-phenyl-6,6-di-p-tolyl-1,6-dihydropyridine-
2,3-dicarboxylate (6b). White solid, mp 155e156 ꢀC. 1H NMR
n
(400 MHz, CDCl3)
3H), 6.98 (d, J¼6.9 Hz, 4H), 6.79 (s, 2H), 5.68 (s, 1H), 4.43 (s, 2H), 3.72
(s, 3H), 3.29 (s, 3H), 2.27 (s, 6H). 13C NMR (100 MHz, CDCl3)
166.4,
166.2, 149.5, 141.1, 140.6, 137.8, 137.2, 135.0, 128.5, 127.6, 127.5, 126.7,
d
7.34e7.21 (m, 5H), 7.16 (d, J¼6.3 Hz, 4H), 7.06 (s,
C
d
4.3.9. Dimethyl 1-(4-chlorobenzyl)-4,6,6-triphenyl-1,6-
126.5, 126.3, 123.3, 101.4, 70.6, 53.2, 52.7, 50.6, 20.9. IR (KBr)
n
2948,
dihydropyridine-2,3-dicarboxylate (6i). Yellow solid, mp 156e157 ꢀC.
1737, 1693,1531, 1302, 1216, 910, 733, 703 cmꢁ1. HRMS (EI) m/z calcd
1H NMR (400 MHz, CDCl3)
d
7.33e7.22 (m, 9H), 7.21e7.16 (m, 6H),
7.01 (d, J¼8.4 Hz, 2H), 6.71 (d, J¼8.4 Hz, 2H), 5.71 (s, 1H), 4.39 (s, 2H),
3.79 (s, 3H), 3.30 (s, 3H). 13C NMR (100 MHz, CDCl3)
166.3, 166.1,
149.2,143.2,140.8, 136.3, 135.2, 132.4, 128.6,127.9,127.8, 127.7, 127.54,
for C36H33NO4 543.2410, found: 543.2406.
d
4.3.3. Dimethyl 1-benzyl-6,6-bis(4-chlorophenyl)-4-phenyl-1,6-
dihydropyridine-2,3-dicarboxylate
172e173 ꢀC. 1H NMR (400 MHz, CDCl3)
7.20e7.04 (m, 11H), 6.76 (d, J¼6.4 Hz, 2H), 5.61 (s, 1H), 4.38 (s, 2H),
3.81 (s, 3H), 3.31 (s, 3H). 13C NMR (100 MHz, CDCl3)
166.3, 165.9,
149.3,141.5,140.5,137.3,136.2,133.8,129.9,128.1,128.0,127.6,127.4,
(6c). White
solid,
mp
127.51, 127.4, 126.9, 123.1, 101.7, 71.0, 52.9, 52.7, 50.7. IR (KBr) n 3023,
d
7.34e7.21 (m, 5H),
1736,1694,1530,1493,1216,1101, 758, 701 cmꢁ1. HRMS (EI) m/z calcd
for C34H28ClNO4 549.1707, found: 549.1704.
d
4.3.10. Dimethyl1-(3-methoxybenzyl)-4,6,6-triphenyl-1,6-
127.1, 126.9, 126.1, 122.0,102.0, 69.9, 53.4, 53.0, 50.8. IR (KBr)
n
2949,
dihydropyridine-2,3-dicarboxylate (6j). White solid, mp 151e152 ꢀC.
1737, 1694, 1530, 1302, 1217, 1093, 733, 701 cmꢁ1. HRMS (EI) m/z
1H NMR (400 MHz, CDCl3)
d 7.33e7.23 (m, 9H), 7.22e7.16 (m, 6H),
calcd for C34H27Cl2NO4 583.1317, found: 583.1313.
6.96 (t, J¼7.9 Hz,1H), 6.61 (dd, J1¼8.1, J2¼2.1 Hz,1H), 6.39 (d, J¼7.6 Hz,
1H), 6.31 (s,1H), 5.73 (s,1H), 4.41 (s, 2H), 3.78 (s, 3H), 3.67 (s, 3H), 3.30
4.3.4. Dimethyl 1-benzyl-4,6-diphenyl-6-(p-tolyl)-1,6-dihydropyridine-
(s, 3H). 13C NMR (100 MHz, CDCl3)
d
166.4, 166.1, 159.1, 149.5, 143.4,
2,3-dicarboxylate (6d). Yellow solid, mp 156e157 ꢀC. 1H NMR
140.9, 139.4, 135.4, 128.8, 128.7, 127.8, 127.53, 127.51, 127.45, 126.8,