Kinetics, stoichiometry and mechanism in the bromination of aromatic heterocycles. III. Aqueous bromination of indazole

Abstract

It is inferred from the products of bromination under appropriate conditions that the sequences of reactivity of various positions in indazole species are: cationic, 5 > 7 » others; molecular, 5 > 3 > 7 » others; anionic, 3 » others. Kinetic studies lead to bimolecular rate coefficients for attack by Br₂ on molecular indazole (aq., 25ºC), as follows: Position 5 3 7 10-3kº_bi/dm³ mol^-1 s^-l 4.2 2.8 0.4 Direct and indirect syntheses of 7-bromoindazole and other derivatives are described.