SYNTHESIS AND SOME REACTIONS OF 2-MERCAITO-4-HYDROXYPYRIMIDINE [3,4-b]COUMARIN

Abstract

2-Mercapto-4-hydroxypyrimidine[3,4-b]coumarin (3) was prepared by the condensation of 3-ethoxycarhonylcoumarin (1) with thiourea. Alkylation of 3 with alkyl halides (namely, methyl iodide, ethyl iodide, benzyl chloride and ethyl chloroacetate) yielded the corresponding 2-alkylthio-4-hydroxypyrimidine[3,4-b]coumarins 4a-d. Hydrolysis of 4d with 2 N NaOH gave acid derivative 6, and condensation of 4d with hydrazine hydrate gave hydrazone 7. 1,3,4-Oxadiazol derivatives 9 and 11 were obtained by the reaction of 7 with aromatic aldehydes to give aryldene derivatives 8a,b. Cyclization of 8 followed with bromine in acetic acid and treatment of 7 with ethyl chloroformate in pyridine and sodium acetate led to 11.