Etidronic Acid: a New and Efficient Catalyst for the Synthesis of Novel 5-Nitro-3,4-Dihydropyrimidin-2(1 H )-Ones
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Etidronic Acid: a New and Efficient Catalyst for the Synthesis of Novel 5-Nitro-3,4-Dihydropyrimidin-2(1H)-ones Mahesh M. Savant Æ Akshay M. Pansuriya Æ Chirag V. Bhuva Æ Naval P. Kapuriya Æ Yogesh T. Naliapara
Received: 11 July 2009 / Accepted: 19 July 2009 / Published online: 31 July 2009 Ó Springer Science+Business Media, LLC 2009
Abstract A simple, convenient and efficient one-pot cyclocondensation reaction of 1-(2-hydroxyphenyl)-2nitroethanone, arylaldehydes and urea using etidronic acid to furnish nitro dihydropyrimidine derivatives is described. A new and efficient protocol is developed as a homogenous catalyst for the synthesis of dihydropyrimidines using substituted x-nitro acetophenone. Various bisphosphonic acids were examined to synthesized pyrimidines via multicomponent cyclocondensation reaction. This methodology has the advantage of excellent yields with short reaction time. Keywords Etidronic acid Homogenous catalyst Cyclocondensation Nitro-dihydropyrimidine Multicomponent
1 Introduction The Biginelli reaction [1], one of the most useful multicomponent reactions, offers an efficient way to access multifunctionalized 3,4-dihydropyrimidin-2-(1H)-ones (DH PMs) and related heterocyclic compounds [2]. However, in biginelli reaction 1,3 diketone is used as a synthone. The ability of nitro group to enhance biological and therapeutic activities of certain organic compounds has led to widespread interest in the selective introduction of nitro groups into organic compounds [3] especially those heterocyclic molecules which possess potential biological activities. For
M. M. Savant A. M. Pansuriya C. V. Bhuva N. P. Kapuriya Y. T. Naliapara (&) Department of Chemistry, Chemical Research Laboratory, Saurashtra University, Rajkot 360005, India e-mail: [email protected]
example, DHPMs are important heterocycles in both natural and synthetic compounds, which exhibit various pharmacological properties such as calcium channel blockers, antihypertensive agents, antitumor, anti-inflammatory and neuropeptide antagonists [3, 4]. Dihydropyridines and dihydropyrimidinones contain an ester group in the position 5 of the heterocycle [2, 5]. However, Substitution of NO2 for COOAlk in the dihydropyridines alters their biological action. Reports reveal that nitro group functionalized dihydropyrimidines which might have potential biological activities were less studied [6]. A major drawback to Biginelli’s original reaction was poor to moderate yields [7]. Recently, many improved procedures have been reported using InBr3 [8], InCl3 [9], LiClO4 [10], FeCl36H2O or NiCl26H2O [11], p-TsOH [12], LaCl37H2O [13], IR radiation [14], Bi(OTf)3 [15], La(OTf)3 [16], BF3 OEt2 [17], ionic liquids (BMIm PF6 and BMIm BF4) [18], TEBA [19], natural HEU type zeolite [20], I2 [21], N-bromosuccinimide (NBS) [22], polyaniline–bismoclite complex [23] and other Lewis acids [24] heteropoly acid [25], sulfated zirconia [26], Sr(NO3)2 [27], and covalently anchored sulfonic acid onto silica [28], PPE [29], Phosphoric acid [30]. H
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