Novel trichloroindolizine derivatives via intramolecular acylation of a bis(chloroacyl)bipyridine

Abstract

3,3′-Bis(alkyloxycarbonyl)-2,2′-bipyridines are produced from the reaction of alcohols with 3,3′-bis(chlorocarbonyl)-2,2′-bipyridine which is generated from the corresponding dicarboxylic acid and thionyl chloride. When the dicarboxylic acid is reacted with a SOCl₂–Cl₂ mixture, significant amounts of trichloroindolizines are produced. This reaction is likely to take place via initial intramolecular N-chloroacylation of bipyridine 3.