Unprecedented SnCl2-mediated cyclization of nitro arenes via N-N bond formation
Devesh Sawant1, Rishi Kumar, Prakas R Maulik
1Medicinal Chemistry Division and Molecular and Structural Biology Division, Central Drug Research Institute, Lucknow 226 001, India.
Abstract:
[reaction: see text] A mild, efficient, one-pot protocol for the cyclization of nitro-aryl substrates using SnCl(2) has been described. The mechanistic course of the reaction suggests the involvement of a hydroxylamine intermediate leading to an intramolecular cyclization via N-N bond formation. The versatility of the methodology has been demonstrated by using two nitro-aryl substrates derived from dihydroisoquinolines and dihydro-beta-carbolines. The intramolecular cyclization led to the formation of indazoles in high yields and purities.
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