CHEMICAL PROPERTIES OF YLIDENE DERIVATIVES OF AZINES. 2. THE METHYLATION OF DIHYDROPYRIMIDINYLIDENECYANOACETIC ESTERS AND THEIR ANIONS

Article abstract of DOI:10.1007/BF00505721

The methylation of dihydropyrimidinylidenecyanoacetic esters by various methylating reagents leads to better yields when anions of ylidene derivatives of pyrimidine are used.The structure of the products of N- and C-methylation formed and their ratio were established with the aid of the IR and UV spectra and by 1H and 13C NMR spectroscopy.The product of C-methylation contains a methyl group at the C₍₇₎ atom of the side chain, while the product of N-methylation contains a methyl group at the nitrogen atom of the pyrimidine ring.For 6-ylidene derivatives, N-methylation occurs at the heterocyclic atom distant from the tautomerizing chain.For 2- and 6-ylidene derivatives of pyrimidine, the ratio of the products of N- and C-methylation can be changed by varying the alkylating reagent.