Synthesis of Some New Pyrimidine Derivatives of Expected Antimicrobial Activity

2-(2-Arylvinyl)-6-methyl-4-mercapto-5-acetylpyrimidine derivatives 3 a − d , were synthesized form the reaction of the appropriate isothiocyanate derivatives 1 with α, β -unsaturated aminoketone 2 . Compound 3 was alkylated with methyl iodide, ethyl chloroacetate and/or bromosugar to afford 6 , 9 , and 22 a − c respectively. Cyanoethylation of 3 b afforded 6 b which upon cyclization with hydrazine hydrate gave pyrazolopyrimidine 7 . Bromination of 6 b gave dibromo compound 8 . Thieno[2,3-d]pyrimidines 10 and 12 were obtained by ring closure of the alkylated product 9 with TEA/EtOH and/or through cyclization of the hydrazide 11 with NaOEt/EtOH. While, Thieno[2,3-d]pyrimidine 14 was obtained directly by alkylation of 3 b with chloroacetone in both TEA/EtOH and Na2CO3 solution. The cycloaddition products 15 and 16 were obtained by reaction of 3b with diethylmaleate and/or maleic anhydride. Formation of 1,3,4-oxadiazole 17 , pyrazoles 18 and 19 where obtained by treating the hydrazide 11 with carbon disulphid...