title: Synthesis of substituted 1H-indazoles from arynes and hydrazones.
abstract: The 1H-indazole skeleton can be constructed by a [3 + 2] annulation approach from arynes and hydrazones. Under different reaction conditions, both N-tosylhydrazones and N-aryl/alkylhydrazones can be used to afford a variety of indazoles. The former reaction affords 3-substituted indazoles either via in situ generated diazo compounds or through an annulation/elimination process. The latter reaction leads to 1,3-disubstituted indazoles likely through an annulation/oxidation process. The reactions operate under mild conditions and can accommodate aryl, vinyl, and less satisfactorily, alkyl groups.
authors.affiliation: Key Laboratory of Natural Medicine and Immuno-Engineering of Henan Province, Henan University, Jinming Campus, Kaifeng, Henan 475004, PR China.
authors.forename: Pan
authors.initials: P
authors.lastname: Li
authors.forename: Chunrui
authors.initials: C
authors.lastname: Wu
authors.forename: Jingjing
authors.initials: J
authors.lastname: Zhao
authors.forename: Donald C
authors.initials: DC
authors.lastname: Rogness
authors.forename: Feng
authors.initials: F
authors.lastname: Shi
mesh_terms: D002384:Catalysis; D006835:Hydrazones / Q000737:chemistry*; D007191:Indazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: D006835:Hydrazones; D007191:Indazoles