Synthesis of Benz[b]indolizinies and related compounds

Abstract

Ethyl 2-pyridylacetate reacted with p-benzoquinone and p-toluoquinone in acetic acid to give 3-hydroxy- and 1-methyl-3-hydroxy-10- ethoxycarbonylbenz[b]-indolizine respectively, while 1,4-naphthoquinone yielded the known 12-ethoxy-carbonyl-6,11-dioxo-6,11-dihydronaphth[2,3- b]indolizine. Ethyl 2-pyridylacetate reacted with 2-chlorocyclohexanone and 2-bromocyclohexane-1,3-dione to give small yields of 10- ethoxycarbonyl- and 10-ethoxycarbonyl-4-oxo-1,2,3,4-tetrahydrobenz- [b]indolizine respectively.