z Catalysis Synthesis of 2-Arylbenzoxazoles by Hetereogeneous g-MnO 2 Catalyzed Redox Reaction of o-Nitrophenol with Benzyl Alcohols or Benzyl Amines Chiranjit Sen , [a, c] Tapan Sahoo, [a, c] Sunil M Galani , [a, c] A. B Panda ,* [b, c] and Subhash C. Ghosh * [a, c] Hetereogeneous g-MnO 2 Catalyzed Redox Reaction of o-Nitro- phenol with Benzyl Alcohols/ benzyl amines for the synthesis of 2-Arylbenzoxazoles is described here. Surface active Mn +3 spe- cies and the surface O À & O 2 À species were found to play an important role in the catalytic activity. Catalyst is easy to pre- pare, economic and can be reused for several times. The proce- dure is very simple and general and applicable for wide range of substrates to afford 2-aryl benzoxazole in good to excellent yield. Aryl benzoxazole play an important role in synthetic organic chemistry. They are present in many natural products and im- portant building blocks in pharmaceutical and agrochemical compounds [1] and also used in various organic materials [2] (Fig- ure 1). 2-substituted benzoxazole are traditionally synthesized by condensation of amino phenol with aldehyde, alcohol or carboxylic acid derivatives [3] , Transitions metal (TM) catalysed intramolecular or intermolecular coupling reactions of o-hal- oanilides or their analogues [4] , direct C ÀH activation at C2-car- bon of benzoxazole, [5] TM-catalysed hydrogen transfer meth- ods [6] . Despite the improvement of these methods mostly required harsh reaction conditions like high temperature, strong oxidizing agent, use of expensive transition metal cata- lyst and ligands etc. Recently, redox condensations of o-substituted nitro arenes with suitable reducing components provide a direct and atom economic approach for the synthesis of benzazoles. [7] Deng et al. reported dppf catalysed redox condensation of o-nitro- phenol with benzylic alcohols for the synthesis of 2-aryl ben- zoxazole. [7a] Nguyen et al reported iron sulphide catalysed re- dox condensation of o-substituted nitro benzenes with alkyl or benzyl amines and 2-or-4 methyl heteroarenes for benzoxazole [a] C. Sen , T. Sahoo , S. M. Galani, Dr. S. C. Ghosh Natural Products and Green Chemistry Division [b] Dr. A. B. Panda Inorganic Materials and Catalysis Division [c] C. Sen, T. Sahoo, S. M. Galani, Dr. A. B. Panda, Dr. S. C. Ghosh Academy of Scientific and Innovative Research, CSIR-Central Salt and Marine Chemicals Research Institute, G.B. Marg, Bhavnagar-364002, Gujarat, India. Fax: (+) 91 278–2567562 E-mail: scghosh@csmcri.org Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/slct.201600450 Figure 1. example of some important 2-aryl benzoxazole. Communications DOI: 10.1002/slct.201600450 2542 ChemistrySelect 2016, 1, 2542 – 2547  2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim