| Abstract: | Methyl (1S,3S and 1R,3S)‐1‐(2, 2‐dimethoxyethyl)‐1,2,3,4‐tetrahydrocarboline‐3‐carboxylate ( 3 ) was hydrolyzed in the presence of sodium hydroxide to give (1S,3S and 1R,3S)‐1‐(2,2‐dimethoxyethyl)‐1,2,3,4‐tetrahydrocarboline‐3‐carboxylic acid ( 4 ), which was reduced with LiAlH4 to provide (1S,3S)‐ and (1R,3S)‐1‐(2,2‐dimethoxyethyl)‐3‐hydroxymethyl‐1,2,3,4‐tetrahydrocarbolines ( 10 ), and then amidated in ammonia containing methanol to obtain (1S,3S)‐ and (1R,3S)‐1‐(2,2‐dimethoxyethyl)‐1,2,3,4‐tetrahydrocarboline‐3‐carboxamide ( 14 ). Acylation of (1S,3S and 1R,3S)‐ 3 , (1S,3S and 1R,3S)‐ 4 , (1S,3S)‐ 10 , (1R, 3S)‐ 10 , (1S, 3S)‐ 14 and (1R,3S)‐ 14 afforded the corresponding methyl (1S,3S and 1R,3S)‐1‐(2,2‐dimethoxyethyl)‐ 2‐(1,3‐dioxobutyl)‐1,2,3,4‐tetrahydrocarbolines‐3‐carboxylate ( 6 ), (1S,3S and 1R,3S)‐1‐(2,2‐dimethoxyethyl)‐2‐(1,3‐dioxobutyl)‐1,2,3,4‐tetrahydrocarboline‐3‐carboxylic acid ( 5 ), (1S,3S)‐ and (1R,3S)‐1‐(2,2‐dimethoxyethyl)‐2‐(1,3‐dioxobutyl)‐3‐(1,3‐dioxobutyl)oxymethyl‐1,2,3,4‐tetrahydrocarboline ( 11 ), (1S,3S)‐ and (1R,3S)‐1‐(2,2‐dimethoxyethyl)‐2‐(1,3‐dioxobutyl)‐1,2,3,4‐tetrahydrocarboline‐3‐carboxamide ( 15 ), respectively. After Aldol reaction, dehydration and dehydrogenation the desired (6S)‐6‐substituted 4,6,7,12‐tetrahydro‐4‐oxoindolo[2,3‐a]quinolizines 8 , 9 , 12 , 13 , and 16 were obtained. Their anticancer activities in vitro were investigated. |
