Catalytic asymmetric synthesis of indole derivatives as novel α-glucosidase inhibitors in vitro

Indole containing compounds have acquired conspicuous significance due to their wide spectrum of biological activities. Synthesis of a series of enantiomerically pure indole derivatives 3a-r via Friedel-Crafts alkylation of indole 1 with enones 2a-r were described here. The products were isolated in a moderate to excellent yields (upto 89%) with excellent enantioselectivities (upto 99.9% ee). These compounds 3a-r were evaluated for their in vitro alpha-glucosidase inhibitory activity and some of them were identified as potent inhibitors (IC50 = 4.3 +/- 0.13-43.9 +/- 0.51 mu M) with several fold higher activity than the clinically used alpha-glucosidase inhibitor, acarbose (IC50 = 840 +/- 1.73 mu M). To the best of knowledge, this is the first report of the propanone substituted indole ring containing compounds by in vitro alpha-glucosidase enzyme inhibition.