Synthesis of 1-(1-Aroyl-2-arylvinyl)-2-dicyanomethylen-1,2-dihydropyridines from 2-Chloropyridinium Salts and Unsaturated Nitriles

1-(1-Aroyl-2-arylvinyl)-2-dicyanomethylene-1,2-dihydropyridines are formed from 1-(aroylmethyl)-2-chloropyridinium bromides and arylmethylenemalonitriles in ethanol at room temperature in the presence of a twofold excess of triethylamine. The products are converted into 2-amino-3-aroyl-1-cyanoindolizines on boiling in acetic acid.