Synthesis and reactions of Di- and Tetra-hydrobenz[b]indolizines

Abstract

Treatment of 1-(4?,4?-diethoxybutyl)-3-methoxycarbonylindole with ethanolic hydrogen chloride gives in high yield 9-chloro-10- methoxycarbonyl-6,7,8,9-tetra-hydrobenz[b]indolizine which is readily converted into the 6,7-dihydro compound and the fully aromatic 10- methoxycarbonylbenz[b]indolizine. Substitution and addition reactions of these compounds have been studied. A mechanism for the formation of the chlorotetrahydrobenz[b]indolizines is discussed.