Acetals of lactams and acid amides
The rate constants for cyclization of N,N-dimethyl-N′-(α-cyano-β-dimethylamino)-crotonylformamidine and its five-, six-, and seven-membered analogs and N-methyl-2-[N-(α-cyano-β-dimethylamino) acryloylimino]piperidine to derivatives of 2-pyridone, pyrrolo-, and pyrido-, and azepino[3,2-c]pyridine and 1,8-naphthyridine were measured in dimethylformamide (DMF) at 120–150 deg C. It is assumed that a new C-C bond with a change in the hybridization of the C(3) atom from sp2 to sp3 develops in the rate-determining step.