Two types of cycloalkeno[1,2-d]pyrimidin-2-thiones (2) reacted with chloroacetic acid and the appropriate aldehyde to give 5-aryl-2,8-bis(arylmethylene)-2,3,6,7-tetrahydro-5H,8H-cyclopenta[1,2-d]thi- azolo[3,2-a]pyrimidin-3-ones (3) and 5-aryl-2,10-bis(arylmethylene)-2,3,6,7,8,9-hexahydro-5H,10H-cyclo- hepta[1,2-d]thiazolo[3,2-a]pyrimidin-3-ones (4) respectively, which show potential anticancer activities. Structures of novel compounds 3 and 4 were determined by ¹H NMR, IR and MS spectra.

Key words: cycloalkeno[1,2-d]thiazolo[3,2-a]pyrimidin-3-one, fused heterocyclic, synthesis, deter