4-alkyl-6-amino-4-N3,N5-diaryl-2-thioxo-1,2,3,4-tetrahydropyridine-3,5-dicarboxamides: I. Tandem synthesis and alkylation. Molecular and crystal structure of 6-allylsulfanyl-2-amino-4-isobutyl-N3,N5-di-m-tolyl-3,4-dihydropyridine-3,5-dicarboxamide

4-Alkyl-6-amino-4-N (3),N (5)-diaryl-2-thioxo-1,2,3,4-tetrahydropyridine-3,5-dicarboxamides were obtained via tandem synthesis involving the Knoevenagel reaction, Michael reaction and intramolecular condensation. Alkylation of the obtained dicarboxamides proceeds regioselectively at the S atom to form the corresponding thioethers. Structure of 6-allylsulfanyl-2-amino-4-isobutyl-N (3),N (5)-di-m-tolyl-3,4-dihydropyridine-3,5-dicarboxamide was uniquely determined by XRD analysis.