(petroleum ether/ethyl acetate 9:1, UV detection)]. Purification
of the crude residue by SiO2-gel column chromatography using
petroleum ether/ ethyl acetate (9:1) as the eluent afforded 5i as
a white solid; (17.6 mg, 47% yield); IR (neat): νmax 2949, 1693,
13C NMR (100 MHz, CDCl3): δ 165, 153.5, 144.8, 139.3,
133.0, 128.9 (q, J = 33 Hz, 1C), 127.0 (2C), 125.7 (q, J = 4
Hz, 2C), 125.6, 124.3 (q, J = 270 Hz, 1C), 122.4, 119.4, 119.3,
117.6, 117.5, 107.1, 66, 59.5, 46.2, 24.5, 23.3, 19.2, 14.5; 19F
NMR (376 MHz, CDCl3): δ -62.3 ppm; HRMS (ES) m/z calcd
for C25H23F3NO3 (M+H)+ : 442.1630; found: 442.1615.
1
1493, 1468, 1331, 1136, 1114, 1064, 823 cm-1; H NMR (400
MHz, CDCl3): δ 7.44 (d, J = 2.4 Hz, 1H), 7.14 (dd, J1 = 8.8
Hz, J2 = 2.4 Hz, 1H), 6.82 (d, J = 8.4 Hz, 1H), 5.43 (s, 2H),
4.26 (q, J = 7.2 Hz, 2H), 4.20 (t, J = 6 Hz, 2H), 3.15 (t, J = 6.4
Hz, 2H), 2.05-2.02 (m, 2H), 1.89-1.84 (m, 2H), 1.34 (t, J = 7.2
Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 164.9, 152.1, 139.5,
129.1, 123.0, 121.8, 120.7, 118.8, 117.9, 113.6, 107, 65.9, 59.5,
46.1, 24.4, 23.2, 19.2, 14.5; HRMS (ES) m/z calcd for
C18H19BrNO3 (M+H)+ : 376.0548; found: 376.0543.
Ethyl 2-(furan-2-yl)-8, 9, 10, 11-tetrahydro-6H-chromeno [3,
4-b]indolizine-7-carboxylate (5m):
The title compound was prepared according to the general
procedure. [TLC profile: Rf (1m) = 0.48, Rf (5m) = 0.74
(petroleum ether/ethyl acetate 9:1, UV detection)]. Purification
of the crude residue by SiO2-gel column chromatography using
petroleum ether/ ethyl acetate (9:1) as the eluent afforded 5h as
a brown solid (24 mg, 66% yield); IR (neat): νmax 2924, 1696,
1518, 1269, 1133, 1113, 1063, 1011 cm-1; 1H NMR (400 MHz,
CDCl3): δ 7.68 (d, J = 2 Hz, 1H), 7.44 (dd, J1 = 2 Hz, J2 = 0.5
Hz, 1H), 7.34 (dd, J1 = 8 Hz, J2 = 2 Hz, 1H), 6.95 (d, J = 8 Hz,
1H), 6.52 (dd, J1 = 3.2 Hz, J2 = 0.5 Hz 1H), 6.46 (dd, J1 = 3.2
Hz, J2 = 2 Hz, 1H), 5.45 (s, 2H), 4.32-4.24 (m, 4H), 3.16 (t, J =
6.4 Hz, 2H), 2.05-2.02 (m, 2H), 1.92-1.87 (m, 2H), 1.35 (t, J =
7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 165.0, 154.1,
152.7, 141.4, 139.1, 124.5, 122.6, 122.5, 119.0, 117.33, 117.3
116, 111.6, 106.9, 103.6, 66, 59.4, 46.1, 24.5, 23.3, 19.3, 14.5;
HRMS (ES) m/z calcd for C22H22NO4 (M+H)+ : 364.1549;
found: 364.1549.
Ethyl 2-fluoro-8, 9, 10, 11-tetrahydro-6H-chromeno[3, 4-b]
indolizine-7-carboxylate (5j):
The title compound was prepared according to the general
procedure. [TLC profile: Rf (1j) = 0.54, Rf (5j) = 0.73
(petroleum ether/ethyl acetate 8:2, UV detection)]. Purification
of the crude residue by SiO2-gel column chromatography using
petroleum ether/ ethyl acetate (8:2) as the eluent afforded 5j as
a pale yellow solid; (23.4 mg, 75% yield); IR (neat): νmax 2949,
1
1697, 1517, 1444, 1261, 1173, 1125, 1102, 1006, 810 cm-1; H
NMR (400 MHz, CDCl3): δ 7.06 (dd, J1 = 9.6 Hz, J2 = 3
Hz, 1H), 6.88 (dd, J1 = 9 Hz, J2 = 5 Hz, 1H), 6.74 (td, J1
=
9 Hz, J2 = 3 Hz, 1H), 5.4 (s, 2H), 4.34 (q, J = 7.2 Hz, 2H),
4.19 (t, J = 7.2 Hz, 2H), 3.15 (t, J = 6.4 Hz, 2H), 2.04-1.99 (m,
2H), 1.90-1.86 (m, 2H), 1.34 (t, J = 7.2 Hz, 3H); 13C NMR
(100 MHz, CDCl3): δ 164.9, 157.5 (d, J = 236 Hz, 1C), 148.9,
139.4, 122.4, 119.7 (d, J = 9 Hz, 1C), 118.2, 117.8 (d, J = 9 Hz,
1C) , 112.3 (d, J = 23 Hz, 1C), 107.4 (d, J = 26 Hz, 1C), 107,
65.8, 59.4, 45.9, 24.4, 23.2, 19.2, 14.5; 19F NMR (376 MHz,
CDCl3): δ -121.8 ppm; HRMS (ES) m/z calcd for C18H19FNO3
(M+H)+ : 316.1349; found: 316.1347.
Ethyl 2-(5-(ethoxycarbonyl)thiophen-2-yl)-8, 9, 10, 11-
tetrahydro-6H-chromeno[3,
4-b]indolizine-7-carboxylate
(5n):
The title compound was prepared according to the general
procedure. [TLC profile: Rf (1n) = 0.55, Rf (5n) = 0.77
(petroleum ether/ethyl acetate 9:1, UV detection)]. Purification
of the crude residue by SiO2-gel column chromatography using
petroleum ether/ ethyl acetate (8:2) as the eluent afforded 5n as
a fluorescent green solid (26 mg, 57% yield); IR (neat): νmax
2950, 1699, 1535, 1517, 1425, 1261, 1136, 1094, 1063 cm-1;
1H NMR (400 MHz, CDCl3): δ 7.73 (d, J = 4 Hz, 1H), 7.58 (d,
J = 2.4 Hz, 1H), 7.32 (dd, J1 = 8 Hz, J2 = 2.4 Hz, 1H), 7.17 (d,
J = 4 Hz, 1H), 6.96 (d, J = 8 Hz, 1H), 5.48 (s, 2H), 4.36 (q, J
= 7.2 Hz, 2H), 4.29-4.23 (m, 4H), 3.16 (t, J = 6.4 Hz, 2H),
2.07-2.02 (m, 2H), 1.92-1.88 (m, 2H), 1.39 (t, J = 7.2 Hz, 3H),
1.34 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 165,
162.4, 153.9, 151.4, 139.4, 134.3, 131.5, 126.8, 124.6, 122.7,
122.0, 119.4, 118.4, 117.6, 117.6, 107.3, 66.2, 61.2, 59.5, 46.2,
24.5, 23.3, 19.2, 14.5, 14.4; HRMS (ES) m/z calcd for
C25H25NO5SNa (M+-Na)+ : 474.1351; found: 474.1353.
Ethyl 2-phenyl-8, 9, 10, 11-tetrahydro-6H-chromeno[3, 4-b]
indolizine-7-carboxylate (5k):
The title compound was prepared according to the general
procedure. [TLC profile: Rf (1k) = 0.50, Rf (5k) = 0.73
(petroleum ether/ethyl acetate 9:1, UV detection)]. Purification
of the crude residue by SiO2-gel column chromatography using
petroleum ether/ ethyl acetate (9:1) as the eluent afforded 5k as
a brown solid; (21 mg, 56% yield); IR (neat): νmax 2927, 1695,
1519, 1491, 1261, 1174, 1135, 1114, 1025, 762 cm-1; 1H NMR
(400 MHz, CDCl3): δ 7.56-7.54 (m, 3H), 7.46-7.42 (m, 2H),
7.36-7.32 (m, 1H), 7.29-7.26 (m, 1H), 7.24 (d, J = 8.4 Hz,
1H), 5.48 (s, 2H), 4.31-4.25 (m, 4H), 3.17 (t, J = 6.4 Hz, 2H),
2.04-2.00 (m, 2H), 1.91-1.87 (m, 2H), 1.35 (t, J = 7 Hz, 3H);
13C NMR (100 MHz, CDCl3): δ 165.0, 152.8, 141.3, 139.0,
134.6, 128.8 (2C), 126.8 (3C), 125.5, 122.8, 119.4, 119.2, 117.4,
117.3, 106.9, 65.9, 59.4, 46.2, 24.5, 23.3, 19.3, 14.5; HRMS
(ES) m/z calcd for C24H24NO3 (M+H)+ : 374.1756; found:
374.1751.
1-(8, 9, 10, 11-tetrahydro-6H-chromeno[3, 4-b]indolizin-
7-yl)ethanone (5o):
The title compound was prepared according to the general
procedure. [TLC profile: Rf (1o) = 0.62, Rf (5o) = 0.62
(petroleum ether/ethyl acetate 8:2, UV detection)]. Purification
of the crude residue by SiO2-gel column chromatography using
petroleum ether/ ethyl acetate (8:2) as the eluent afforded 5o as
a pale yellow solid; (11.2 mg, 42% yield); IR (neat): νmax 2947,
1638, 1501, 1416, 1364, 1265, 1131, 1040, 738 cm-1; 1H NMR
(400 MHz, CDCl3): δ 7.36 (dd, J1 = 7.6 Hz, J2 = 1.2 Hz,
1H), 7.08 (td, J1 = 8.4 Hz, J2 = 1.6 Hz, 1H), 6.98-6.93 (m,
2H) , 5.46 (s, 2H), 4.24 (t, J = 6 Hz, 2H), 3.15 (t, J = 6.4 Hz,
Ethyl 2-(4-(trifluoromethyl)phenyl)-8, 9, 10, 11-tetrahydro
-6H-chromeno[3, 4-b]indolizine-7-carboxylate (5l):
The title compound was prepared according to the general
procedure. [TLC profile: Rf (1l) = 0.55, Rf (5l) = 0.80
(petroleum ether/ethyl acetate 8:2, UV detection)]. Purification
of the crude residue by SiO2-gel column chromatography using
petroleum ether/ ethyl acetate (8:2) as the eluent afforded 5l as
a brown solid (16 mg, 36% yield); IR (neat): νmax 2949, 1696,
2H), 2.37 (s, 3H), 2.04-1.99 (m, 2H), 1.94-1.88 (m, 2H); 13
C
NMR (100 MHz, CDCl3): δ 193.5, 153.2, 137.8, 127, 123.4,
1
1512, 1325, 1261, 1167, 1113, 1071, 821 cm-1; H NMR (400
121.4, 120.8, 118.7, 17.8, 117.2, 116.9, 66.0, 46.3, 30.7, 25.5,
MHz, CDCl3): δ 7.68 (q, J = 8.4 Hz, 4H), 7.55 (d, J = 2.4 Hz,
1H), 7.28 (dd, J1 = 8 Hz, J2 = 2.2 Hz, 1H), 7.04 (d, J = 8.4 Hz,
1H), 5.49 (s, 2H), 4.30-4.25 (m, 4H), 3.18 (t, J = 6.4 Hz, 2H),
2.06-2.03 (m, 2H), 1.90-1.89 (m, 2H), 1.36 (t, J = 7.2 Hz, 3H);
23.0, 19.4; HRMS (ES) m/z calcd for C17H18NO2 (M+H)+
268.1338; found: 268.1327.
:
Phenyl(8, 9, 10, 11-tetrahydro-6H-chromeno[3, 4-b] indol-
izin-7-yl)methanone (5p):