Method F. The esters of oxygen-sensitive indolizinols, which were difficult to obtain free of small amounts of colored contaminants by method D, could be prepared in a purer state by this method. A diarylcyclopropenone, an appropriate pyridine, and an acyl chloride (152 molar ratio) were dissolved in 1, 2-dichloroethane containing a trace of ascorbic acid, and the solution was refluxed under argon for 1-5 h. When reaction was complete (IR analysis) ...