Synthesis and Biological Evaluation of a Series of 2-(3,4,5-Trimethoxybenzoyl)-Indol-3-yl Acetic Acid Derivatives as Potential Agents against Human Leukemia K562 Cells

A series of 2-(3',4',5'-trimethoxybenzoyl)-indol-3-yl acetic acid derivatives 2a-g and 3a-j were synthesized and the effects of all the compounds on human leukemia K562 cell growth were investigated. The results showed that the presence of one or more electron-donating methoxy groups at 7- or 5- and 7- positions of N-methyl indole ring, corresponding to compounds 3d and 3f, increased antiproliferative activity against K562 cells and induced the cell apoptosis. The results demonstrated that the methylation of the nitrogen atom of indole nucleus plays an important role for the antiproliferative activities. Replacing the 3',4',5'-trimethoxybenzoyl functionality with a 3',4'-dimethoxybenzoyl, 4'- methoxybenzoy or benzoyl group (compounds 3h-j, respectively) yielded inactive compounds.