Hindawi Publishing Corporation ISRN Organic Chemistry Volume 2013, Article ID 132794, 5 pages http://dx.doi.org/10.1155/2013/132794 Research Article Silica-ZnCl 2 : An Efficient Catalyst for the Synthesis of 4-Methylcoumarins Bandita Datta and Mohamed Afzal Pasha Department of Studies in Chemistry, Central College Campus, Bangalore University, Bengaluru 560001, India Correspondence should be addressed to Mohamed Afzal Pasha; mafpasha@gmail.com Received 23 September 2013; Accepted 16 October 2013 Academic Editors: L. De Luca, T. C. Dinadayalane, and W. Xia Copyright © 2013 B. Datta and M. A. Pasha. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Silica-ZnCl 2 has been found to be an efcient and eco-friendly catalyst for the synthesis of substituted 4-methylcoumarins from ethyl acetoacetate and substituted phenols under “neat” conditions in an oil bath at 80 ∘ C. Te experimental procedure is simple, includes shorter reaction times (15–65min), compatible with sensitive functional groups, and results in excellent yield of the products. 1. Introduction Since long time, the use of solid phase technique has been considered to be the method of choice for application in a large number of diverse and interesting chemical manipula- tions. Reactions involving solid-supported catalysts encom- pass advantages like easy work up of the reaction by fltration of solid-supported reagent, increased reactivity, higher yields of the product, and recyclability of the reagent for subsequent reaction [1]. Te utility of the solid-supported reactions has been acknowledged in the synthesis of several chemical libraries. A large number of solid-supported reagents like SiO 2 -SO 3 H[2], PPA-SiO 2 [3], and HClO 4 -SiO 2 [4] have been developed over the period of time and have been used in many chemical reactions. In our laboratory we have developed many silica-based reagents [5], which fascinated us for the development of other solid-supported reagents. ZnCl 2 , being an inexpensive and easily available catalyst, has been demonstrated in chemical reactions as a Lewis acid catalyst [6]. Although it is a user choice catalyst, it is very hygroscopic accompanied with its nonusability. Terefore, we have prepared a silica-ZnCl 2 reagent by Paul’s method [7] which can fnd application as a user-friendly catalyst. To check its applicability, we wanted to use this catalyst in the preparation of biologically important molecules, whose synthetic preparation can be improved. Hence, we chose the synthesis of substituted coumarins which have a long list of applications. Coumarins are found to have varied bioactivities includ- ing inhibition of platelet aggregation [8], inhibition of steroid 5a-reductase [9], inhibition of HIV-1 protease [10], and antibacterial [11] and anticancer [12] activities. Suitably substituted coumarins have various applications in food additives, pharmaceutical, perfume, and cosmetic indus- tries [13]. Moreover, 7-hydroxy-4-methylcoumarin deriva- tives have also been used in the synthesis of dendrimers [14]. Since coumarins have become one of the prime molecules of investigation, several groups have started synthesizing molecules with similar moieties for further applications. Coumarins can be synthesized using several strategies like the Pechmann reaction, Perkin reaction, and Knoeve- nagel condensation. Te widely used scheme is of Pechmann using ethyl acetoacetate and a phenol in the presence of concentrated sulfuric acid as a catalyst [15]. Several other catalysts have also been used including ZnCl 2 [16] which involves harsh conditions, requires longer time, gives lesser yields, and involves tedious workup procedure. Hence, a user- friendly protocol for the synthesis of coumarins needs to be developed. In our laboratory we have been synthesizing synthons, which are used in the synthesis of biologically important molecules like -enaminones [17], nitriles [18], formamides [19], and so on. In this report, we are presenting a