Formation of 1-bromocarbonylindazoles via cleavage of 4-bromo ortho-substituted arylsydnones with HBr
摘要:
Treatment of 4-bromo-3-arylsydnones containing an ortho-carbonyl substituent (cf. 1d-j) with HBr gas leads to the corresponding, novel 1-bromocarbonyl-3-substituted indazoles (2d-k), generally in excellent yield.