Addition reactions of heterocyclic compounds. Part 72. Dimethyl acetylenedicarboxylate with 1,2,6,7,8,9-hexahydropyrrolo[3,2,1-jk]carbazole

Abstract

1,2,6,7,8,9-Hexahydropyrrolo[3,2,1-jk]carbazole with dimethyl acetylenedicarboxylate in aqueous acetic acid gave four complex products, the structures of which have been correlated with their ¹³C n.m.r. and other spectra. The carbazole was hydrolysed as an enamine to the corresponding amino-ketone, and the reactions of the latter with the acetylenic ester examined. It is concluded that the acetylene first attacks the carbazole at position 5b, and ring-opening to an amino-ketone and conversion to the complex products follow. An intramolecular dehydrogenation of a cyclohexanone to a cyclohex-2-enone grouping by an enamine residue which is itself converted to the corresponding amine is discussed.