Reaction of ethyl chloroformate with 3-(2-aryl-1-hydroxyethylidene)indol-2(3H)-ones 3 affords the corresponding ethyl 3-[(2-aryl-1-ethoxycarbonyloxy)ethenyl]-2-(ethoxycarbonyloxy)indole-1-carboxylates 4 from which ethyl 6-(ethoxycarbonyloxy)-11H-benzo[a]carbazole-11-carboxylates 5a,b, the corresponding 3H,10H-pyrrolo[3,2-a]- 5c, 10H-thieno[3,2-a]- 5d and 10H-thieno [2,3-a]carbazole-10-carboxylate 5e are obtained via 6Ï-electrocyclization.
氯甲酸乙酯与 3-(2-芳基-1-羟基亚乙基)
吲哚-2(3H)-酮 3 反应,得到相应的 3-[(2-芳基-1-乙氧基羰基氧基)
乙烯基]-2-(乙氧基羰基氧基)
吲哚-1-
羧酸乙酯 4,由此得到 6-(乙氧基羰基氧基)-11H-苯并[a]
咔唑-11-
羧酸乙酯 5a、b,通过 6Ï-电环化反应得到相应的 3H、10H-
吡咯并[3,2-a]- 5c、10H-
噻吩并[3,2-a]- 5d 和 10H-
噻吩并[2,3-a]
咔唑-10-
羧酸 5e。