Elemental Sulfur-Promoted Oxidative Rearranging Coupling between o-Aminophenols and Ketones: A Synthesis of 2-Alkyl benzoxazoles under Mild Conditions

Thanh Binh Nguyen* and Pascal Retailleau

*Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Sud, Université Paris-Saclay, 1, avenue de la Terrasse, 91198 Gif-sur-Yvette, France, Email: nguyenicsn.cnrs-gif.fr

T. B. Nguyen, P. Retailleau, Org. Lett., 2017, 19, 3887-3890.

DOI: 10.1021/acs.orglett.7b01775

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Abstract

Elemental sulfur is an excellent oxidant for an oxidative rearranging coupling between o-aminophenols and ketones in the presence of N-methylpiperidine to provide a wide range of 2-alkylbenzoxazoles under mild conditions.

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proposed mechanism

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Benzazoles from Aliphatic Amines and o-Amino/Mercaptan/Hydroxyanilines: Elemental Sulfur as a Highly Efficient and Traceless Oxidizing Agent

T. B. Nguyen, L. Ermolenko, W. A. Dean, A. Al-Mourabit, Org. Lett., 2012, 14, 5948-5951.

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Key Words

benzoxazoles, sulfur

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ID: J54-Y2017