Addition reactions of heterocyclic compounds. Part LX. Reactions of 2-substituted pyridines with acetylenic esters leading to quinolizines and pyrrolo2,1,5-cdindolizines

The reaction of methyl (2-pyridyl)acetate with methyl propiolate gave quinolizine derivatives; (2-pyridyl)acetone and 1-(2-pyridyl)butan-2-one reacted similarly. 2-Acetylpyridine and ethyl pyridine-2-carboxylate reacted with methyl propiolate to yield pyrrolo2,1,5-cdindolizines. The structures of the products were deduced mainly from their u.v. and n.m.r. spectra.