Some products from nitrosation of indoles
Abstract
Nitrosation of 1-methylindole with an equimolar amount of nitrous acid gave 5-hydroxy-6,11-dimethylpyrrolo-[2,3-b:4,5-b′]di-indole, and with an excess of nitrous acid 5,11-dimethylpyrazino[2,3-b:5,6-b′]di-indole 6-oxide. Nitrosation of 1-methylindol-3-yl phenyl sulphide gave diphenyl disulphide (23%), 1-methyl-2,3-bis(phenylthio)indole (2.5%), 1-methyl-2-nitroindol-3-yl phenyl sulphide (13%), 1-methyl-3,3-bis(phenylthio)-indolin-2-one (8%), and 1-methyl-3-nitroindole (6%). The formation of these products from nitrosation can be explained by initial electrophilic attack on both free and 3-substituted indoles at the 3-position.