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Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
PIDA-mediated oxidative ring-opening of 2H-indazoles with N-hydroxyphthalimide
Arindam Barman1, Krishna Kanta Das1, Alakananda Hajra1
1Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India. alakananda.hajra@visva-bharati.ac.in.
None:
A fast and convenient phenyliodine(III) diacetate (PIDA) mediated oxidative ring-opening of 2H-indazoles with N-hydroxyphthalimide via C-N bond cleavage has been developed under metal-free reaction conditions. The new protocol afforded a range of unsymmetrical ortho-amide substituted azobenzenes with wide functional group tolerance in good yields. Mechanistic investigations suggest that the reaction likely proceeds through the formation of a phthalimide-N-oxyl (PINO) radical adduct with 2H-indazoles, followed by a rearrangement to produce the unsymmetrical azobenzene derivatives.
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