Halogenation of 1-alkyl-7-azaisatins using N-halosuccinimides: regioselective synthesis of 1-alkyl-5-halo-7-azaisatins

A facile and regioselective protocol for the halogenation of 1-alkyl-7-azaisatins with NBS or NCS in aprotic solvents under mild conditions to synthesize 1-alkyl-5-halo-7-azaisatins was developed.