Dhanapalan Nagarathnam. Department of Medicinal Chemistry and Pharmacognosy, (M/C 781), University of Illinois at Chicago, PO Box 6998, Chicago, Illinois 60680, USA.
A simple preparation of 2-(dimethylaminomethyl)-indole, indole-2-acetonytrile and 2-(2-arylvinyl)-indoles from 2-methylindole is described.
2-Substituted indoles are potential intermediates for many alkaloids and pharmacologically important substances and 2-vnylindoles are used in Diels-Alder reaction. While the methods for preparation of 3-substituted indoles are well established, there is a need for yet easier access to 2-substituted indoles. Recently, 2-methylindoles have been elaborated into many 2-substituted indole derivates using an allylic bromination reaction. All these methods involve protection of the indole 3-position with an ester, phenylthio or benzoyl group and masking the indole nitrogen as a benzenesulfonamide or benzamide during bromination.