Synthesis of Hydrazides from N-Tosylhydrazones and Its Application in the Preparation of Indazolones

Transition-Metal-Free Sulfoximidation of Sulfonylhydrazones for the Synthesis of N-Sulfanylidenehydrazonamides

Herein, we report a transition-metal-free C-H bond sulfoximidation protocol of sulfonyl hydrazones with hypervalent iodine(III) reagents. A library of novel N-sulfaneylidenehydrazonamides was constructed via chemoselective C-N bond formation reactions at aldehyde C-H bonds of sulfonyl hydrazones in the presence of a base. The reaction demonstrated broad substrate group diversity under exceedingly mild reaction conditions, and excellent yields were achieved at room temperature.

Metal-Free Bisamidation of N-Tosylhydrazones with Carboxylic Acids Promoted by Tetrabutylammonium Iodide and tert-Butyl Hydroperoxide

A versatile reaction between N-tosylhydrazones and carboxylic acids to access bisamides is reported. This metal-free, room-temperature reaction was catalyzed by TBAI, while TBHP served as the oxidant. Broad substrate scope and good functional group tolerance are the key features of the strategy. Subsequent intramolecular N-arylation of suitably substituted bisamides readily afforded functionalized 3-indazolones.

Method for Preparing N-Tosylhydrazonyl Chlorides

A facile and efficient method for preparing N-tosylhydrazonyl chlorides was developed. The reaction was general for a variety of substrates and displayed wonderful compatibility to diverse substituents. A range of N-tosylhydrazonyl chlorides was prepared for the first time.