General Papers ARKIVOC 2009 (xiii) 281-286 A new metal-free protocol for oxidation of alcohols using N,N-dibromo-p-toluenesulfonamide Indranirekha Saikia, Pranita Chakraborty, and Prodeep Phukan* Department of Chemistry, Gauhati University, Guwahati 781 014, Assam, India E-mail: pphukan@yahoo.com Abstract N,N-Dibromo-p-toluenesulfonamide (TsNBr 2 ) is shown to be a reagent for oxidation of alcohols, without a catalyst. The remarkable feature of this reagent is that it oxidizes primary alcohols very efficiently in excellent yields besides other secondary and benzylic alcohols, which undergo oxidation within a short time. Keywords: Oxidation, TsNBr 2 , alcohol, carbonyl compound, metal-free oxidant Introduction Oxidation of alcohols to their corresponding carbonyl compounds is a fundamental reaction in synthetic organic chemistry. 1 Traditionally, oxidation of alcohols is carried out using stoichiometric amounts of metallic oxidants notably chromium(VI) reagents, 2 permanganates, 3 and ruthenium(VIII) oxide, 4 which produce environmentally unacceptable heavy metal wastes. 5 Both stoichiometric procedures utilizing a variety of oxidants. as well as catalytic methods based on the use of coordination compounds of transition metals. have been reported. 6 Thus developing an efficient system for oxidation of organic substrates is of great importance both economically as well as environmentally. Besides metal-based oxidizing agents, a variety of halogen-based reagents such as bromine, 7 N-bromosuccinimide, 8 pyridinium hydrobromide perbromide, 9 [Bmim][Br 3 ], 10 N-bromoacetamide, 11 N-chlorosuccinimide, 12 etc. have been developed over the past several decades. 13 Among N-halogenated reagents reported in the literature, NBS has been found to be the most versatile reagent for oxidation. But in most cases of NBS assisted oxidation, it is necessary to use a catalyst in order to carry out the reaction. 8 Secondly, oxidation with NBS is restricted to secondary or benzylic alcohols, even in the presence of a catalyst. Oxidation of primary alcohols is not effective using N-halogenated reagents. Recently we have developed a new method for the synthesis of bromohydrins, alkoxybromides and bromoazides using TsNBr 2 . 14 We report herein a rapid and efficient procedure for the oxidation of alcohols to carbonyl compounds using TsNBr 2 (Scheme 1) under mild reaction conditions. ISSN 1551-7012 Page 281 © ARKAT USA, Inc.