| Abstract: | Condensation of a ternary mixture of ethyl cyanoacetate, S-methylisothiourea and aromatic aldehydes in pyridine afforded directly the 4-aryl-5-cyano-2-methylthio-6-oxopyrimidines IV in good yields. Alkylation of IV with alkyl halides in alkaline medium yielded the 1-alkyl derivatives V. The methylthio group in IV and V could be eliminated by aniline, hydrazine and phenylhydrazine and the corresponding 2-anilino, VII, 2-hydr-azino, VIIIa,b, and 2-phenylhydrazino, VIIIc,d, derivatives were obtained. Compounds VIIIa,b could be cyclised with nitrous acid to give the 3-cyano-4-phenyltetrazolo1,5-a]pyrimidine-2-one (Xa) and the 1-methyl analogue Xb, respectively. Some derivatives of VIII were prepared to help in elucidating the structures. |
