Acetals of lactams and amides. 44. Synthesis of derivatives of aminocyanopyridines from enamino amides and enamino nitriles
It has been established that in the reaction of a tertiary enamino amide with a primary amine a substantial influence is exerted by the basicity of the amine and the steric hindrance of its amino group. The secondary enamino amides obtained interact with the diethyl acetal of dimethylformamide to form enamino amides substituted at the amide nitrogen or 1-substituted pyramidin-4-ones, depending on the degree of steric hindrance of the NH group. Compounds of both these types, on being heated in an alkaline medium, are converted into derivatives of 4-amino-3-cyano-2-pyridone. An enamino dinitrile — α-cyano-β-dimethylaminocrotonitrile — condenses with acetals of amides and lactams to form dienic diamines which can be converted into derivatives of 3-cyano-4-dimethylaminopyridine.