Synthesis and antitumor screening of new series of pyrimido-[4,5-b]quinolines and [1,2,4]triazolo[2′,3′:3,4]pyrimido[6,5-b]quinolines

New series of pyrimido[4,5-b]quinolines and [1,2,4]triazolo[2',3':3,4]pyrimido[6,5-b]quinolines have been synthesized. Compounds 4a, 4e, 4f, 4h, 5b, 5d, 6a, 6d, 6e, 8c, 8d, 10c-e, 10h, 11a, 11b, and 12a were tested for in vitro antitumor activity against human breast carcinoma (MCF-7) cell line, where compound 8d was found to be the most active member with IC50 value of 3.62 mu M. The DNA-binding affinity for the same compounds showed that compounds 8d and 10d exhibited the highest affinity to DNA. The detailed synthesis, spectroscopic, and biological data are reported.