Short communication A rapid and easy method for the synthesis of azoxy arenes using tetrabutylammonium peroxymonosulfate Abdolreza Rezaeifard * , Maasoumeh Jafarpour * , Mohammad Ali Naseri, Raheleh Shariati Department of Chemistry, Faculty of Science, University of Birjand, P. O. Box 414, Birjand, Iran Received 7 December 2006; received in revised form 14 February 2007; accepted 20 February 2007 Available online 6 March 2007 Abstract A simple and efficient method for the selective oxidation of aromatic amines to azoxy arenes using tetrabutylammonium peroxymonosulfate in high/excellent yield (75e95%) after short reaction times (2e10 min) has been developed. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Azoxy arenes; Oxidation; Aromatic amines; Tetrabutylammonium peroxymonosulfate Azoxy arenes are key materials for electronic devices due to their liquid crystalline properties [1]; they have also been utilized as therapeutic medicines, polymer inhibitors, stabi- lizers, dyes, reducing agents and analytical reagents [2]. Hence, the development of an efficient and selective method for the preparation of these valuable compounds is a worth- while goal. Although the oxidation of amines is a fundamen- tal reaction in the case of the synthesis of oxygen-containing amines such as azoxy compounds, as outlined in Scheme 1, a variety of oxidation products such as N-arylhydroxylamine (A), nitroso; (B), nitro (C) derivatives and also azo arene (D) are frequently observed together with azoxy arene (E) [3]. Thus, selectivity in this reaction is required in order to obtain the desired product. Relatively few general methods exist for the oxidation of aromatic amines to azoxy arenes. Aqueous peracids oxidize aniline to a mixture of azo- and azoxybenzene and oxidize ortho-substituted anilines to nitrobenzene [4]. t-BuOOH in O Ar-NH 2 Ar-NO 2 Ar-NHOH Ar-NO Ar-N=N-Ar Ar-N=N-Ar A B C D E [O] [O] [O] Scheme 1. * Corresponding authors. Tel.: þ98 561 2230516; fax: þ98 561 2230515. E-mail addresses: rrezaeifard@birjand.ac.ir (A. Rezaeifard), mjafarpour@ birjand.ac.ir (M. Jafarpour). 0143-7208/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.dyepig.2007.02.008 Dyes and Pigments 76 (2008) 840e843 www.elsevier.com/locate/dyepig