Synthesis and anticancer activity of some novel fused pyridine ring system

New series of pyrido[3',2':4,5]thieno[3,2-d]pyrimidines (7a,b) and thieno[2,3-b:4,5-b'] dipyridine (11a-c) were synthesized from 4-aryl-6-(4-chlorophenyl)-2-thioxo-1,2-dihydro pyridine-3-carbonitriles 4a,b via application of Thorpe-Zielger reaction. The novel target compounds were evaluated in vitro for their anticancer activity against human breast adenocarcinoma MCF-7 and colon carcinoma cell line (HCT 116). Most of the tested compounds exploited potent to moderate growth inhibitory activity, in particular compound 11d, which exhibited superior potency to the reference drug Doxorubicin (IC50 = 5.95, 6.09 and 8.48, 8.15 mu M, respectively). The structures of the compounds obtained were determined by spectroscopic data.