Iminophosphorane-Mediated Synthesis of 2H-Indazole Derivatives: Preparation of 2,3-Diamino-2H-indazoles by Intramolecular Trapping of Phosphazides and 1H-1,2,4-Triazoloindazoles by a Tandem Aza-Wittig/Heterocumulene-Mediated Strategy

Article abstract of DOI:10.1021/jo00302a045

Treatment of o-azidobenzaldimines 2 with tertiary phosphines in methylene chloride at 0 deg C leads to the corresponding 2,3-diamino-2H-indazole derivatives 3 by cyclization of the intermediate phosphazide.Compounds 3 react with isocyanates, carbondioxide