
%0 Journal Article
%A Singh, H 
%A Singh, S 
%T Synthesis of heterocyclics via enamines. I. Formation of 1,4-Dihydropyrimidine-2-thiols and 2-Amino-1,3-thiazines in reactions of ethyl &#946;-aminocrotonates with &#946;-keto isothiocyanates: role of solvents
%J Australian Journal of Chemistry
%D 1973/11/01
%V 26
%N 11
%P 2453-2457
%K 
%R https://doi.org/10.1071/CH9732453
%U https://www.publish.csiro.au/paper/CH9732453 
%X Ethyl &#946;-aminocrotonate (1) on condensation with the &#946;-keto isothiocyanate (2; R = Me) in hexane, benzene, or toluene formed the 1,4-dihydropyrimidine-2-thiol (3; R = Me) as the major product and the 2-amino-1,3-thiazine (4; R = Me) as the minor component. The use of ether, acetonitrile, butan-2-one, ethyl acetate, chloroform as solvents reversed the product ratio. In the reaction with (2; R = Et), the yields of (3 and 4; R = Et) formed were similarly affected by change of solvent. 
