1428979-34-3

Upstream product

• 1665-83-4 2-(diphenylmethylene)-1-methyl-1-phenylhydrazine 
• 55816-26-7 2-chlorobenzophenone hydrazone 
• 623-00-7 4-bromobenzenecarbonitrile 
• 13097-01-3 3-phenyl-1H-indazole 
• 5162-03-8 (2-chlorophenyl)(phenyl)methanone 
• 119-61-9 benzophenone 
• 2863-98-1 4-hydrazinobenzonitrile hydrochloride 
• 17672-27-4 4-hydrazinobenzonitrile 

Relevant academic research and scientific papers

Synthesis of 1: H -indazoles by an electrochemical radical Csp2-H/N-H cyclization of arylhydrazones

The development of efficient and sustainable C-N bond-forming reactions to N-heterocyclic frameworks has been a long-standing interest in organic synthesis. In this work, we develop an electrochemical radical Csp2-H/N-H cyclization of arylhydrazones to 1H-indazoles. The electrochemical anodic oxidation approach was adopted to synthesize a variety of 1H-indazole derivatives in moderate to good yields. HFIP was not only employed as a solvent or the proton donor, but also can promote the formation of N free radicals. This synthetic methodology is operationally simple, and less expensive electrodes would be suitable for this chemistry. This journal is

Ni and Cu-catalyzed one pot synthesis of unsymmetrical 1,3-di(hetero)aryl-1: H -indazoles from hydrazine, o -chloro (hetero)benzophenones, and (hetero)aryl bromides

The nickel-catalyzed cyclization of in situ generated ortho-chlorobenzophenone hydrazone derivatives, to afford 3-(hetero)aryl-1H-indazoles, is documented for the first time. The product 1H-indazoles can be transformed subsequently in a one-pot procedure into 1,3-di(hetero)aryl-1H-indazoles via copper-catalyzed N-arylation with (hetero)aryl bromides.

[Bis-(trifluoroacetoxy)iodo]benzene-Mediated Oxidative Direct Amination C–N Bond Formation: Synthesis of 1H-Indazoles

An efficient [bis-(trifluoroacetoxy)iodo]benzene (PIFA)-mediated oxidative C-N bond formation is developed for the synthesis of 1H-indazoles from readily available arylhydrazones. The reaction tolerates a wide range of functional groups and has broad scope of substrates. Moreover, this method is a relative green and reliable method for rapid preparation of substituted 1H-indazoles under mild conditions.

Divergent Synthesis of 1H-Indazoles and 1H-Pyrazoles from Hydrazones via Iodine-Mediated Intramolecular Aryl and sp3 C–H Amination

A divergent intramolecular C–H amination of hydrazones has been developed employing molecular iodine (I2) as the sole oxidant. The required hydrazone substrates were readily obtained by condensation of hydrazines with the corresponding ketones.

Synthesis of indazoles and azaindazoles by intramolecular aerobic oxidative C-N coupling under transition-metal-free conditions

A transition-metal-free oxidative C-N coupling method has been developed for the synthesis of 1H-azaindazoles and 1H-indazoles from easily accessible hydrazones. The procedure uses TEMPO, a basic additive, and dioxygen gas as the terminal oxidant. This reaction demonstrates better reactivity, functional group tolerance, and broader scope than comparable metal catalyzed reactions. A transition-metal-free oxidative C-N coupling method has been developed for the synthesis of 1H-azaindazoles and 1H-indazoles from easily accessible hydrazones (see scheme). The procedure uses TEMPO, a basic additive, and dioxygen gas as the terminal oxidant. This reaction demonstrates better reactivity, functional group tolerance, and broader scope than comparable metal catalyzed reactions. TEMPO=2,2,6,6-tetramethyl-1-piperidinyloxy.

Copper-catalyzed aerobic C(sp2)-H functionalization for C-N bond formation: Synthesis of pyrazoles and indazoles

A simple, practical, and highly efficient synthesis of pyrazoles and indazoles via copper-catalyzed direct aerobic oxidative C(sp2)-H amination has been reported herein. This process tolerated a variety of functional groups under mild conditions. Further diversification of pyrazoles was also investigated, which provided its potential for drug discovery.