Studies on the Chemical Reactivity of Ethyl 4-sulfanyl-6-methyl-2-phenylpyrimidine-5-carboxylate

S-Alkyl pyrimidine derivatives 2-5 were obtained by the reactions of ethyl 4-sulfanyl-6-methyl-2-phenylpyrimidine-5- carboxylate (1) with allyl bromide, propargyl bromide, epichlorohydrin and vinyl acetate (Scheme 1). On reaction of sulfanylpyrimidine 1 with iodine, hydrogen peroxide under different conditions afforded bisdisulphide, desulphrization, and 4-hydroxypyrimidines 6-8. Treatment of the sulfanylpyrimidine 1 with ethylbromoacetate followed by oxidation, and hydrazonlysis gave the thienopyrimidine dioxide derivative 10 and pyrazolopyrimidine 11, respectively (Scheme 2). Reaction of 1 with benzalidene derivatives in ethanol/TEA yielded pyridopyrimidine derivatives 12a,b and 13. On reaction with ethyl acrylate afforded thienopyrimidine 14 under the same condition. Furthermore, reaction of 1 with dimethyl amine/sulfur in absolute ethanol and with 4-chlorobenzaldhyde afforded the dihydrothienopyrimidine, and 6-styrylpyrimidinthione 15 and 16, respectively (Scheme 3). N-alkylated pyrazolopyrimidine 18 and pyridazinopyrimidine 19 were obtained by the reaction of 4-chloropyrimidine 17 with acetophenonehydrazone and hydrazones derivative of malononitrile in the presence of TEA (Scheme 4). All of the newly synthesized compounds were characterized by IR, 1H, 13C NMR and microanalysis. Keywords: pyrimidine-4-thiol, S-alkyl pyrimidine, pyrazolopyrimidine, thienopyrimidine, pyrido and pyridazinopyrimidine, analgesic activities, COX inhibitor, antiallergic, anti-inflammatory, IR spectra, C NMR