Synthesis of novel isoxazole functionalized pyrazolo[3,4-b]pyridine derivatives; their anticancer activity

A series of novel isoxazole functionalized pyrazolo[3,4-b]pyridine derivatives 5a-n were prepared, respectively, initiated from 6-thiophenyl-4-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine 3 through selective N-propargylation, and these N-propargylated compounds 4 were cyclized with aryloximes by using of sodium hypochlorite, and obtained the title products 5a-n. All the final products 5a-n were submitted for anticancer activity against four cancer cell lines such as HeLa-cervical cancer (CCL-2); COLO 205-colon cancer (CCL-222); HepG2-liver cancer (HB-8065); MCF7-breast cancer (HTB-22); Compounds 5c, 5d, and 5h are found to have more prominent anticancer activity at micro molar concentration.