Collect. Czech. Chem. Commun. 1993, 58, 893-901

New Preparation of 2-N-Alkyl(aryl)amino-5-methyl-4H-1,3-thiazin-4-ones and 3,4-Dihydro-5-methyl-2,4-dioxo-2H-1,3-thiazine

Dušan Koščík, Milan Dzurilla and Peter Kutschy

Department of Organic Chemistry, Šafárik University,041 67 Košice, Slovak Republic


Addition-cyclization reactions of 3-bromo- and 3-chloro-2-methylpropenoylisothiocyanates with primary and secondary amines and alcohols have been studied. The formed addition products, thioureas, underwent cyclization of heating with ethanolic KOH or in dimethylformamide in the presence of lithium hydride. This method represents a new approach to 2-dialkyl(aryl)amino-5-methyl-4H-1,3-thiazin-4-ones. Addition reactions with alcohols afforded 3,4-dihydro-5-methyl-2,4-dioxo-2H-1,3-thiazine as the sole product. The structure of the synthesized compounds was confirmed by 1H NMR, 13C NMR, IR and mass spectroscopy.