Synthesis and anticancer activity of γ-(triazolyl ethylidene)butenolides and polyfunctional pyrrolinones

A series of novel γ-(triazolyl ethylidene)butenolides (4-23) were prepared from commercially available l-ascorbic acid in good yields. These butenolides on reaction with ethanolic ammonia/amines led to formation of respective 5-hydroxy pyrrolinones (24-33). The two of these pyrrolinones on dehydration with p-toluenesulfonic acid, were transformed into γ-(triazolyl ethylidene)pyrrolinones (34, 35). Among all the newly synthesized hybrid molecules tested for anticancer activity in vitro, compounds 24, 25, 26, 27, 28, 30 and 32 showed significant activity against MCF-7, MDA-MB-231, PC-3 or U-937 cells. In particular compound 25 (IC50 = 11.3 μM) exhibited most potent activity against breast cancer cells and preliminary studies revealed that potency of this compound is due to ROS generation, subsequent activation of p38, leading to apoptosis and inhibition of cancer cells.