Vol. 30, No. 1, 2019
Marçal and Garden
29
1
1176, 1150, 1104, 768, 759, 708; H NMR (200 MHz,
CDCl3) d 9.29 (1H, s), 7.30 (1H, dd, J 1.1, 7.7 Hz), 7.25
(1H, td, J 1.1, 7.7 Hz), 7.05 (1H, td, J 1.1, 7.7 Hz), 6.95
(1H, d, J 7.7 Hz), 4.93 (1H, t, J 8.3 Hz), 3.92 (2H, s), 3.77
(3H, s), 2.66 (1H, dd, J 8.3, 13.3 Hz), 2.30 (1H, dd, J 8.3,
13.3 Hz), 2.10 (3H, s); 13C NMR (50 MHz, CDCl3) d 180.9
(CO), 172.6 (CO), 169.5 (CO), 141.2 (C), 129.2 (CH),
129.1 (C), 123.3 (CH), 123.1 (CH), 110.5 (CH), 58.9 (CH),
55.7 (CH), 52.9 (C), 52.5 (OCH3), 39.0 (CH2), 22.4 (CH3).
Mass spectrum (ESI(+)) m/z C15H16N2O4 [M + Na]+ calcd.
311.1003, obs. 311.0999; [2M + Na]+ calcd. 599.2113,
obs. 599.2113.
(C), 123.1 (CH), 122.9 (CH), 110.7 (CH), 69.1 (CH), 55.8
(C), 55.7 (CH), 52.8 (CH3), 41.4 (CH2), 32.6 (CH2), 19.6
(CH2). Mass spectrum (ESI(+)) m/z C16H16N2O4 [M + Na]+
calcd. 323.1002, obs. 323.0997.
(3S,3’S,7’aR) 3’,7’a-Dimethyl 1,2,2’,3’,6’,7’-hexahydro-
2,5’-dioxo-spiro[3H-indole-3,1’-[1H]pyrrolizine]-
3’,7’a(5’H)-dicarboxylate (27)
A single diastereoisomer was isolated in 80% yield.
IR (ATR) ν / cm-1 3244, 2956, 2926, 2854, 1721, 1713,
1699, 1620, 1472, 1438, 1333, 1232, 1192, 1078, 756;
1H NMR (500 MHz, CDCl3) d 9.23 (1H, s), 7.24 (1H, td,
J 7.6, 1.3 Hz), 7.05-6.97 (2H, m), 6.86 (1H, d, J 7.4 Hz),
5.01 (1H, t, J 8.4 Hz), 3.80 (3H, s), 3.75 (3H, s), 3.01 (1H,
dd, J 7.9, 13.8 Hz), 2.71 (1H, dd, J 8.9, 13.8 Hz), 2.75-2.60
(2H, m), 2.52-2.47 (1H, m), 2.06-2.02 (1H, m); 13C NMR
(125 MHz, CDCl3) d 179.4 (CO), 177.6 (CO), 171.6 (CO),
171.0 (CO), 141.7 (C), 129.8 (CH), 124.6 (C), 123.8 (CH),
122.8 (CH), 110.9 (CH), 78.1 (C), 58.9 (C), 56.9 (CH), 52.7
(CH3), 52.5 (CH3), 38.6 (CH2), 32.4 (CH2), 23.7 (CH2).
Mass spectrum (ESI(+)) m/z C18H18N2O6 [M + Na]+ calcd.
381.1062, obs. 381.1057.
(3’S,7’aR) 3’-Methyl 1,2,2’,3’,6’,7’-hexahydro-2,5’-dioxo-
spiro[3H-indole-3,1’-[1H]pyrrolizine]-3’(5’H)-carboxylate
(26a/b)
A part of the crude product mixture of 25a/b and 26a/b
(0.550 g) was hydrolyzed to give a mixture of 26a/b. This
was chromatographically separated using CH2Cl2:EtOAc
(9:1 v/v) to give the apolar 26a (347 mg) and the polar
26b (131 mg).
Apolar (3R,3’S,7’aR) 3’-methyl 1,2,2’,3’,6’,7’-hexahydro-
2,5’-dioxo-spiro[3H-indole-3,1’-[1H]pyrrolizine]-
3’(5’H)-carboxylate (26a)
(3S,3’S,7’aR) 3’-Methyl 1,2,2’,3’,6’,7’-hexahydro-
7’a-methyl-2,5’-dioxo-spiro[3H-indole-3,1’-[1H]pyrrolizine]-
3’(5’H)-carboxylate (28)
1H NMR (500 MHz, CDCl3) d 9.04 (1H, s, NH), 7.28
(1H, td, J 7.7, 1.1 Hz), 7.04 (1H, td, J 7.6, 1.0 Hz), 6.99
(1H, d, J 7.8 Hz), 6.86 (1H, dd, J 7.6, 1.1 Hz), 4.80 (1H,
t, J 8.8 Hz), 4.53 (1H, dd, J 8.5, 4.7 Hz), 2.82 (1H, dd,
J 13.3, 9.1 Hz), 2.73-2.61 (m, 2H), 2.25 (1H, ddd, J 17.6,
11.0, 4.2 Hz), 2.08 (1H, dddt, J 17.1, 8.7, 7.0, 4.4 Hz),
1.26 (1H, dddd, J 13.7, 11.0, 7.6, 4.7 Hz); 13C NMR
(125 MHz, CDCl3) d 177.3 (CO), 176.0 (CO), 171.3
(CO), 140.8 (C), 129.3 (C), 129.2 (CH), 123.5 (CH), 123.5
(CH), 110.7 (CH), 69.1 (CH), 56.9 (C), 54.9 (CH), 52.9
(CH3), 41.9 (CH2), 33.1 (CH2), 18.9 (CH2). Mass spectrum
(ESI(+)) m/z C16H16N2O4 [M + Na]+ calcd. 323.1002,
obs. 323.0989.
A single diastereoisomer was isolated in 67% yield. IR
(ATR) ν / cm-1 3250, 2983, 2958, 2926, 1709, 1680, 1666,
1619, 1472, 1435, 1334, 1241, 1178, 1110, 754; 1H NMR
(200 MHz, CDCl3) d 8.69 (1H, s), 7.35-7.15 (2H, m),
7.04 (1H, t, J 7.6 Hz), 6.94 (1H, d, J 7.6 Hz), 4.88 (1H, t,
J 8.7 Hz), 3.79 (3H, s), 2.80-2.65 (3H, m), 2.47 (1H, ddd,
J 3.7, 11.1, 17.5 Hz), 2.10-1.90 (1H, m), 1.85-1.60 (1H,
m), 1.58 (3H, s); 13C NMR (50 MHz, CDCl3) d 180.6 (CO),
177.0 (CO), 172.7 (CO), 141.8 (C), 129.3 (CH), 126.4
(C), 125.7 (CH), 122.6 (CH), 110.5 (CH), 72.6 (C), 59.2
(C), 54.6 (CH), 52.7 (OCH3), 39.6 (CH2), 33.0 (CH2), 29.2
(CH2), 26.5 (CH3). Mass spectrum (ESI(+)) m/z C17H18N2O4
[M + Na]+ calcd. 337.1211, obs. 337.1158; [2M + Na]+
calcd. 651.2525, obs. 651.2425.
Polar (3S,3’S,7’aR) 3’-methyl 1,2,2’,3’,6’,7’-hexahydro-
2,5’-dioxo-spiro[3H-indole-3,1’-[1H]pyrrolizine]-
3’(5’H)-carboxylate (26b)
(3R,3’S,7’aR) 3’-Methyl 1,2,2’,3’-tetrahydro-2,5’-dioxo-
spiro[3H-indole-3,1’-benzo[6’,7’][1H]pyrrolizine]-
3’(5’H)-carboxylate (29)
Yield 75% (approximately 5:1 ratio of diastereoisomers);
IR (ATR) ν / cm-1 3263, 2953, 2923, 2848, 1744, 1724, 1681,
1472, 1370, 1307, 1174, 757, 723. Data for the principal
isomer: 1H NMR (500 MHz, CDCl3) d8.63 (1H, s), 7.73 (1H,
d, J 7.4 Hz), 7.31 (1H, t, J 7.4 Hz), 7.28 (1H, d, J 7.4 Hz),
7.03 (1H, d, J 7.4 Hz), 7.02 (1H, t, J 7.6 Hz), 6.82 (1H, d,
J 7.6 Hz), 6.69 (1H, t, J 7.6 Hz), 6.48 (1H, d, J 7.6 Hz), 5.42
IR (ATR) ν / cm-1 3209, 3041, 3000, 2944, 1703, 1669,
1619, 1472, 1466, 1432, 1288, 1234, 1183, 756; 1H NMR
(500 MHz, CDCl3) d 9.12 (1H, s), 7.28-7.24 (1H, m), 7.22
(1H, dd, J 7.5, 1.1 Hz), 7.07 (1H, td, J 7.6, 0.9 Hz), 6.98
(1H, d, J 7.8 Hz), 4.92 (1H, t, J 8.4 Hz), 4.45 (1H, dd, J 8.7,
4.3 Hz), 3.80 (3H, s), 2.84 (1H, dd, J 13.7, 8.5 Hz), 2.70-
2.60 (1H, m), 2.58-2.49 (2H, m), 2.19-2.08 (1H, m), 1.80-
1.68 (1H, m); 13C NMR (125 MHz, CDCl3) d 180.1 (CO),
177.4 (CO), 172.4 (CO), 141.4 (C), 129.3 (CH), 127.2