Studies on #beta#-enaminonitriles: Part III~(dagger)-Reaction of #beta#-aminocrotononitrile with unsaturated acid chlorides:Benary revisited

摘要

Acylation of #beta#-aminocrotononitrile with cinnamoyl chloride when carried out in the presence of pyridine affords, according to Benary, a mixture of C- and N-acylated products. Reinvestigation fo this reaction now firmly establish through extensive spectral analyses and comparison with authentic sample that Benary. designated N-acylated product is, in fact, 5-cyano-6-methyl-4-phneyl-3,4-dihydropyridin-2 (1H)-one 5 formed via in situ cyclisation of the corresponding N-acylated enaminonitrile. Interestingly, when this reaction is tried with other classes of unsaturated acid chlorides having triple bond or extended conjugation, exclusive preference for C-acylation of #beta#-aminocrotononitrile is observed.