SHORT COMMUNICATION CHINESE JOURNAL OF CATALYSIS Volume 31, Issue 5, 2010 Online English edition of the Chinese language journal Cite this article as: Chin. J. Catal., 2010, 31: 518–520. Received date: 28 January 2010. *Corresponding author. Tel: +91-80-22961337; Fax: +91-80-22961331; E-mail: m_af_pasha@ymail.com Copyright © 2010, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier BV. All rights reserved. DOI: 10.1016/S1872-2067(09)60064-4 Amberlite IR-120: A Reusable Catalyst for N-Formylation of Amines with Formic Acid Using Microwaves Madhusudana Reddy MUTHUKUR BHOJEGOWD, Aatika NIZAM, Mohamed Afzal PASHA* Department of Studies in Chemistry, Central College Campus, Bangalore University, Bengaluru 560 001, India Abstract: A rapid and practical green route for the N-formylation of amines with formic acid using Amberlite IR-120 as a catalyst is de- scribed. This method provides an efficient and much improved modification over the reported methods in terms of yield, reaction time, and work-up procedure. A wide variety of substituents is tolerated, which is not the case for existing procedures. Key words: N-formylation; Amberlite IR-120; formic acid; amine; microwave Since the first report by Fieser et al. [1] on the N-formylation of amines, a number of strategies have been developed for their synthesis because of their importance as intermediates in the preparation of several fine chemicals [1] and pharmaceutically important compounds such as substituted aryl imidazoles [2], 1,2-dihydroquinolines [3], fluoroquinolines [4], nitrogen- bridged heterocycles [5], etc. Formamides act as catalysts in the allylation [6] and hydrosilylation [7] reaction of carbonyl compounds. The asymmetric allylation of aldehydes using chiral formamides has also been reported recently [8]. For- mamides serve as very useful reagents in Vilsmeier formyla- tion [9] and in the synthesis of formamidines and isocyanides [10]. In addition, a formyl group is used for the protection of the amino group during peptide synthesis [11,12]. Generally, the N-formylation of amines can be carried out using the esters of formic acid such as pentafluorophenyl formate and phenyl formate for direct N-formylation in the absence of a catalyst [13,14]. Apart from this, aryl formates and ethyl formate are useful for N-formylation in the presence of catalysts like TiCl 3 (OTf) [15] and silica-bonded N-propylsulfamic acid [16]. Chandra Shekhar et al. [17] have recently reported the N-formylation of amines using ZnCl 2 as a catalyst, where the reaction requires a longer time for comple- tion. In addition to the above-mentioned reports, a number of other methods have been documented on the N-formylation of amines [18–20]. Many of the N-formylation methods have disadvantages such as the use of expensive reagents, the for- mation of side products, thermal instability, and difficult to access reagents. Therefore, the pursuit of more convenient and practical synthetic methods for these compounds still remains an active research area. On the other hand, a “green” reaction should ideally be conducted under solvent-free conditions with minimal or no side products and with the utmost atom economy [21]. One way to achieve this is by microwave heating. It is also well known that microwave heating dramatically accelerates the rate of many organic reactions and improves yields, and the reactions are highly selective [22–27]. Because of these ad- vantages there is great interest in the use of environmentally benign reagents and procedures [28]. Recently, the use of solid acidic catalysts has gained im- portance in organic synthesis because of several advantages such as operational simplicity, non-toxicity, reusability, low cost, and ease of separation after completion of the reaction [29–32]. Amberlite IR-120[H + ] resin has emerged as an effi- cient heterogeneous catalyst for various organic reactions [33]. Because of the numerous advantages associated with this in- expensive and non-hazardous recyclable catalyst we herein report a protocol for a solvent-free reaction using microwave activation for the synthesis of N-formamides using Amberlite IR-120 as a catalyst. To the best of our knowledge this is the first report on the N-formylation of amines with formic acid where the reaction is catalyzed by a reusable resin. The method