The styrlpyridinethione la-c reacted with several halogenated compounds; w-bromoacetophenone, methyl chloroacetate, a-chloroacetylacetone and ethyl-a-chloroacetoacetate to give the corresponding thieno[2,3-b]pyridines 3a-c, 1 la-c and the thiazolo[3.2-a]pyridines 1 4 -c .

Pyrimidin-4-one-2-thione (3) was synthesized via the reaction of thiourea (1) with ethyl benzoylacetate (2) and was taken as a starting material for the present study via its reactions with the halogen-containing reagents 6a-d and lOa-c to give the corresponding thiazolopyri midines 8, 9 and 12a-c. The 2-hydrazino derivatives 5 were synthesized either via the reaction of 3 or 4 with hydrazine hydrate. Compound 5 reacted with 6a-c and lOa-c to give the corre sponding pyrimidotriazines 17a-c and 19 respectively. A lso, compound 5 reacted with the active methylene-containing reagents 13 and 2a,b to give the corresponding 2-pyrazolopyrimidines 15 and 22a,b respectively. On the other hand, the triazolopyrimidines 21a,b and 30a,b were also obtained via the reaction of 5 with each of formic acid, acetic anhydride, ethyl chloroformate and carbon disulfide respectively. Some o f the newly synthesized heterocyclic derivatives were tested for their biological activity.

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6-Aryl-5-cyano-4-pyrimidinon-2-thione derivatives1a-c reacted with ethyl iodide to give the corresponded 2-S-ethylpyrimidin-4-one derivatives2a-c. Compounds2a-c was, in turn, reacted with hydrazine hydrate to give the sulfur free reaction products,3a-c. These reaction products were taken as the starting materials for the synthesis of several newly synthesized heterocyclic derivatives. Reactions with several halogenated ketones, esters, chloroacetic acid and chloroacetamide give pyrimidotriazines8, 12 and15 while their reactions with formic acid, acetic acid and carbon disulfide gave the corresponded triazolopyrimidines17 and21. The reaction with both acetyl acetone and ethylacetoacetate gave the corresponded 2-(3', 5'-dimethyl-1'-pyrazoly) pyrimidine derivatives20a-c and24a-c respectively while the reaction with cinnamonitriles25a-h afforded the corresponded aryl hydrazopyrimidines27a-f. The structures of these reaction products were established based on both elemental analyses and spectral data studies.