Synthesis of diarylamines in the benzo[b]thiophene series by palladium-catalyzed amination and structure-activity relationship as antibacterial agents

The palladium-catalyzed amination of arylhalides has become an important method for the synthesis of arylamines found in pharmaceuticals. Using this methodology we were able to synthesize several diarylamines in the benzo[b]thiophene series.Here we report the synthesis 01 differently substituted diarylamines derivatives 01 6-bromo or 6-amino- 2,3,5-trimethylbenzo[b]thiophene in good to high yields (50-90%) (Scheme), The amino precursor was prepared from the bromo compound using also a C-N palladium-catalyzed cross-coupling with benzophenone imine, followed by acidic hydrolysis in a 60% overall yield.