Coumarins Preparation by Pechmann Reaction Under Ultrasound Irradiation. Synthesis of Hymecromone as Insecticide Interme
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Coumarins Preparation by Pechmann Reaction Under Ultrasound Irradiation. Synthesis of Hymecromone as Insecticide Intermediate C. Gutie´rrez-Sa´nchez Æ V. Calvino-Casilda Æ E. Pe´rez-Mayoral Æ R. M. Martı´n-Aranda Æ ˇ ejka A. J. Lo´pez-Peinado Æ M. Bejblova´ Æ J. C
Received: 15 June 2008 / Accepted: 26 September 2008 / Published online: 21 October 2008 Ó Springer Science+Business Media, LLC 2008
Abstract Hymecromone, an important insecticide intermediate, were synthesized under solvent-free conditions by Pechmann reaction upon ultrasound irradiation in the presence of acid zeolites possessing different structural features. This methodology offers significant improvements for the synthesis of coumarins with regards to yield of product, simplicity in operation, and avoiding toxic catalysts and solvents. Keywords Acid zeolites Coumarin derivatives Pechmann reaction Insecticide intermediates Hymecromone Ultrasound irradiation
C. Gutie´rrez-Sa´nchez V. Calvino-Casilda E. Pe´rez-Mayoral R. M. Martı´n-Aranda (&) A. J. Lo´pez-Peinado Departmento de Quı´mica Inorga´nica y Quı´mica Te´cnica, Facultad de Ciencias, Universidad Nacional de Educacio´n a Distancia, c/Senda del Rey, 9, 28040 Madrid, Spain e-mail: [email protected] C. Gutie´rrez-Sa´nchez V. Calvino-Casilda M. Bejblova´ (&) J. Cˇejka J. Heyrovsky´ Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejsˇkova 3, 182 23 Prague 8, Czech Republic e-mail: [email protected] E. Pe´rez-Mayoral Laboratorio de Sı´ntesis Orga´nica e Imagen Molecular por Resonancia Magne´tica, Facultad de Ciencias, Universidad Nacional de Educacio´n a Distancia, c/Senda del Rey, 9, 28040 Madrid, Spain
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1 Introduction Coumarins and their derivatives are important compounds in the synthetic organic and medicinal chemistry and are used for the preparation of coumarino-pyrones, furocumarins, chromenes, and 2-acylresorcinols [1]. These compounds find applications in synthesis of pharmaceuticals, fragrances, agrochemicals, and insecticides [2]. The Hymecromone (product 3 in Scheme 1), 7-hydroxy-4methylcoumarin or 7-hydroxy-4-methyl-2H-benzo[b]pyran-2-one, is used commercially as laser dye [3], as biliary antispasmodic [4], and it is also the starting material for the production of some insecticides [5]. The Pechmann reaction is one of the simplest methods to produce coumarins. In a classical way, the reaction consists of the condensation of phenols with b-ketoesters using sulphuric acid as a catalyst [6]. Other acid catalysts like FeCl3, P2O5, AlCl3, HCl, trifluoroacetic acid, have been used for Pechmann reaction as well [7]. The homogeneous catalysts afford generation of side-products and long reaction times are needed with the consequent corrosion problems. For these reasons, there have been some attempts to find alternative, environmentally benign synthetic routes using a simple, cheap and reusable catalyst for the synthesis of coumarins [8]. With regard to that, a large variety of heterogeneous solid acids such as zeo
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