Procedures for the preparation of 3-substituted 1H- and 2H-indazoles and 2-substituted indoles were developed based on cross-coupling of o-iodoarylhydrazines with copper acetylenides in pyridine or dimethylforamide. An alternative procedure for the synthesis of 3-substituted 1H-indazoles involves cyclocondensation of (2-chloroaryl)acetylenes with hydrazine hydrate in butanol.
Procedures for the preparation of 3-substituted 1H- and 2H-indazoles and 2-substituted indoles were developed based on cross-coupling of o-iodoarylhydrazines with copper acetylenides in pyridine or dimethylforamide. An alternative procedure for the synthesis of 3-substituted 1H-indazoles involves cyclocondensation of (2-chloroaryl)acetylenes with hydrazine hydrate in butanol.