Structural influence of indole C5-N-substitutents on the cytotoxicity of seco-duocarmycin analogs

Abstract

A series of racemic indole C5-substituted seco-cyclopropylindoline compounds (2,3 and 5-7) were prepared by coupling 1-(tert-butyloxycarbonyl)-3-(chlorocarbonyl)indoline (seg-A) with 5,6,7-trimethoxy-, 5,6-dimethoxy-, 5-amino-, 5-methylsulfonylamino- and 5-(N,N-dimethylaminosulfonylamino) indole-2-carboxylic acid as seg-B in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. The synthetic compounds (2,3 and 5-7) were tested for cytotoxic activity against human cancer cell lines (COLO 205, SK-MEL-2, A549, and JEG-3) using the MTT assay.