Synthesis and characterisation of some novel fused thiazolo[3,2-a] pyrimidinones and pyrimido[2,1-b][1,3]thiazinones

Reactions of 7,9-bis(4-methoxyphenyl)-2-thioxo-2,3-dihydropyrido[3',2':4,5]thieno[3,2-d]pyrimidin-4(1H)-one with alpha-haloketones, chloroacetonitrile and DMAD, afforded the corresponding fused thiazolo[3,2-a]pyrimidinone derivatives. The reaction of the thione with chloroacetic acid and an appropriate aromatic aldehyde yielded the respective 2-arylidene-2H-pyrido[3',2':4,5]thieno[3,2-d]thiazolo[3,2-a]pyrimidine-3,5-diones. Also, the treatment of thione with arylidenemalononitriles gave the fused pyrimido[2,1-b][1,3]thiazine derivatives, respectively. The structures of the synthesised products were confirmed by IR, H-1 NMR and mass spectral techniques. The cytotoxic activity of the new products against breast carcinoma (MCF-7) and hepatocellular carcinoma (HepG2) cell lines were determined and the results revealed promising activity.