Acetone Cyanohydrin: A Convenient Alternative of Toxic Sodium Cyanide/Acetic Acid for Oxidative Cyanation of Tertiary Am
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Acetone Cyanohydrin: A Convenient Alternative of Toxic Sodium Cyanide/Acetic Acid for Oxidative Cyanation of Tertiary Amines Sanny Verma • Suman L. Jain • Bir Sain
Received: 15 December 2010 / Accepted: 19 March 2011 / Published online: 8 April 2011 Ó Springer Science+Business Media, LLC 2011
Abstract Acetone cyanohydrin was found to be a facile, convenient and comparatively safer alternative to toxic sodium cyanide/acetic acid system for generating in situ HCN for the oxidative cyanation of tertiary amines to a-aminonitriles in high yields with hydrogen peroxide using RuCl3 as catalyst. In addition organic nature of acetone cyanohydrin makes it more suitable for an organic transformation since it is readily soluble in reaction medium and can be added in a controlled manner. Keywords Acetone cyanohydrin Cyanation Oxidation Tertiary Amine Ruthenium
1 Introduction a-Aminonitriles are highly useful and versatile intermediates which exhibit dual reactivity and widely used in the preparation of a variety of biologically important compounds such as alkaloids [1–4] and functional materials. Further, they can readily be converted into other useful products such as in a-amino acids either via hydrolysis or by nucleophilic additions to the nitrile group [5]. Therefore, the synthesis of these a-aminonitriles is significantly
Electronic supplementary material The online version of this article (doi:10.1007/s10562-011-0582-6) contains supplementary material, which is available to authorized users. S. Verma S. L. Jain (&) B. Sain Chemical Sciences Division, Indian Institute of Petroleum (Council of Scientific and Industrial Research), Mohkampur, Dehradun 248005, India e-mail: [email protected] B. Sain e-mail: [email protected]
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important both in synthetic as well as medicinal chemistry. The classic method known as Strecker reaction [6] involving the one pot condensation of a carbonyl compound, an amine and cyanide in presence of homogeneous [7–9] or heterogeneous [10–13] catalysts is well documented albeit provide poor product yields. Alternatively, the oxidation of tertiary amines with stoichiometric oxidants such as chlorine dioxide [14], m-chloroperbenzoic acid [14, 15], hydrogen peroxide [16, 17] or mercuric acetate [18], followed by the reaction of the iminium intermediate by cyanide ion represents a simple approach for their synthesis. However, the use of stoichiometric oxidants and production of huge amounts of hazardous waste is undesirable from environmental viewpoints. Metal-catalyzed oxidative of tertiary amines by using oxidants such as O2, H2O2, TBHP with NaCN in acetic acid is one of recently developed approaches for the direct synthesis of a-aminonitriles [19–24]. The generation of in situ HCN from the reaction of sodium cyanide and acetic acid is the common and critical feature of these methods. However, the major limitations with the use of sodium cyanide/acetic acid system are its hazardous nature, high cost and also the excess of dissolved cyanide ions in the reaction mixture may cause the d
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