Indole derivatives. 129. Reaction of 5-vinylindole with brominating agents

The bromination of 5-vinylindole at two reaction centers, viz., the carbon-carbon multiple bond of the vinyl group and the pyrrole ring, was realized. In the case of the reaction with pyridinium bromide perbromide it was shown that the pyrrole ring is the most reactive with respect to electrophilic agents. It was established that the introduction of an electron-acceptor acetyl group into the pyrrole ring leads to a decrease in the reactivity of the pyrrole ring, and bromination takes place at the double bond.