Conjugated azoalkenes. Part 14. Synthesis of new 1-amino- and 1,2-diaminopyrrole derivatives by reaction of some conjugated azoalkenes with activated methylene compounds RCH2Ac and RCH2CN (R = aryl, heteroaryl)

Abstract

1-Amino- and 1,2-diamino-pyrrole derivatives are obtained in high yield by reaction of conjugated azoalkenes with ketones and cyanides containing methylene groups further activated by a 4-nitrophenyl, 2-fluorophenyl, benzothiazol-2-yl or benzimidazol-2-yl group. In some cases the heterocycles can be prepared in a one flask procedure, while in others a two step sequence is required, namely, formation of the 1, 4-conjugate adduct and then cyclization. Reaction of 2,4-dichloro- and 2,3,6-trichlorophenylacetonitrile with the azoalkenes gave the 1,4-conjugate adducts, but these could not be successfully cyclized.