Recyclization of 1-amino-3.5-diaryl-2.6,6-tricyanocyclohexa-1,3,-dienes to pyridine derivatives

The base-catalyzed recyclization of 1-amino-3,5-diaryl-2,6, 6-tricyanocyclohexa-1,3-dienes to 2,4-diaryl-5-cyano-6-dicyanomethylene-1,2,3,6-tetrahydropyridines, 4,6-diaryl-3-cyano-2-dicyanomethylene-1,2-dihydropyridines, and 4,6-diaryl-3-cyano-2-dicyanomethylpyridines has been investigated. The intermediate products of this reaction — cis, trans-2-amino,4,6-diaryl-1,1,3-tricyanohexa-1,3,5-trienes —have been isolated; on heating these are transformed reversibly into the initial cyclohexadienes or they isomerize irreversibly into trans, trans-hexatrienes, while in the presence of a base (piperidine, diethylamine, triethylamine, KOH), they cyclize to form the above-mentioned' pyridine derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, PP. 621–625, May, 1986.