A SIMPLE AND CONVENIENT SYNTHESIS OF ISOLATED FUSED HETEROCYCLES BASED ON: 6-PHENYL-2-THIOXO-2,3-DIHYDROPYRIMIDIN-4(5H)-ONE AND 5-ACETYL-6-PHENYL-2-THIOXO-2,3-DIHYDROPYRIMIDIN-4(5H)-ONE

The reaction of 6-phenyl-2-thioxo-2,3-dihydropyrimidin-4(5H)-one 1 with acetyl chloride in acetic anhydride in the presence of sodium acetate afforded 5-acetyl-6-phenyl-2-thioxo-2,3-dihydropyrimidin-4(5H)-one 2 which reacted with bromine, hydrazine hydrate, phenylhydrazine, cyanothioacetamide, aldehydes and (malononitrile/sulfur) to give 2-thioxo-2,3-dihydropyrimidine derivatives 4, 7a,b, 8, 10 and 11 respectively. In the present investigation 6-phenyl-2-thioxo-2,3-dihydropyrimidin-4(5H)-one 1 was reacted with chloroacetyl chloride to yield the corresponding compound 13. Compound 1 was reacted with some electrophilic reagents such as (benzylidene-cyanothioacetamide derivatives, 2-cyano-2-cyclopentylethanethioamide, 2-cyano-2-cyclohexyl-ethanethioamide and aromatic diazonium salts) to give compounds 23, 27a,b and 35 respectively. The newly synthesized heterocycles were characterized on the basis of their chemical properties and spectral data.