Scolecite as a Novel Heterogeneous Acid Catalyst for an Efficient Synthesis of 3,4-Dihydropyrimidin-2(1 H )-ones Via Mul
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Scolecite as a Novel Heterogeneous Acid Catalyst for an Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Via Multi-component Biginelli Reaction Sandeep V. Shinde Æ Wamanrao N. Jadhav Æ Machindra K. Lande Æ Laxman S. Gadekar Æ Balasaheb R. Arbad Æ Jeevan M. Kondre Æ Nandkishor N. Karade
Received: 25 February 2008 / Accepted: 2 May 2008 / Published online: 28 May 2008 Ó Springer Science+Business Media, LLC 2008
Abstract Scolecite is one kind of natural zeolite. A three component Biginelli reaction using scolecite as a novel heterogeneous acid catalyst is demonstrated. The short reaction time, clean reaction conditions, consistent yields and minimum environmental effects are important features of the reaction. Keywords Biginelli reaction Heterogeneous catalysis Natural zeolite Scolecite
1 Introduction Biginelli reaction, discovered in 1893, for the synthesis of multi-functionalized 3,4-dihydropyrimidin-2(1H)-one (DHPM) is an important milestone in the history of MCRs [1]. The process consists of three component condensation of an aldehyde, urea and open chain b-dicarbonyl compound in presence of catalytic amount of HCl in ethanol at reflux temperature to afford DHPM
Electronic supplementary material The online version of this article (doi:10.1007/s10562-008-9508-3) contains supplementary material, which is available to authorized users. S. V. Shinde W. N. Jadhav Dnyanopasak College, Parbhani 431401, Maharashtra, India M. K. Lande L. S. Gadekar B. R. Arbad Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004, India J. M. Kondre N. N. Karade (&) School of Chemical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, Maharashtra, India e-mail: [email protected]
in moderate yield [2]. The DHPM nucleus exhibits a broad spectrum of biological effects such as anti-viral, anti-tumor, antibacterial and anti-inflammatory activities [3]. Furthermore, appropriately functionalized DHPMs have emerged as potent calcium channel blocker, antihypertensive agents, a1a-adrenrgic antagonists and neuropeptide Y (NPY) antagonists [4]. This great biological importance of DHPM nucleus has prompted the development of new improved methodologies for Biginelli reaction, including transition metal Lewis acid catalysis [5], solid phase synthesis [6], activation with certain additives [7], ionic liquids [8], microwave irradiation [9] and grinding techniques [10]. Recent decades have witnessed an exponential growth in the applications of heterogeneous catalysis to carry out synthetic transformations as a consequence of its significance in terms of enviro-economical and practical aspects [11]. The literature survey has revealed that there is relatively little number of reports on Biginelli reaction using heterogeneous acid catalysis. Most of the methods are based upon the impregnation of toxic acid such as HCl, H2SO4 and NaHSO4 on silica gel [12]. A truly heterogeneous acid catalyst such as montmorillonite KSF was previously demonstrated for an efficient synthesis of
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