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Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Facile access to C-substituted piperazin-2-ones and mianserin derivative enabled by chemoselective carbene insertion
Dharmendra Kumar1,2, Urmila Unnikrishnan1, Malleswara Rao Kuram1,2
1Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India. malleswara.kuram@cdri.res.in.
Abstract:
The chemoselective N-H insertion of unsymmetrical diamines into carbene is a longstanding challenge. A simple copper-catalyzed strategy for synthesizing C-substituted piperazinones is described, employing easily accessible diazo compounds and 1,2-diamines. The reaction proceeded via chemo-selective carbene insertion at the comparatively less nucleophilic amine, followed by instantaneous cyclization. The protocol was further extended to access NH-free piperazinone, and the synthesis of a Mianserin derivative.
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