1-(3, 4-Dichlorobenzenesulfonyl)-3-Methyl-1H-Imidazolium Chloride: An Efficient Catalyst for the Synthesis of 1, 8-Dioxo-Octahydroxanthenes under Microwave Irradiation

The reaction of 5,5-dimethyl-1,3-cyclohexanedione with various aromatic aldehydes to give corresponding 1,8-dioxo-octahydroxanthenes in aqueous medium has been reported. These reactions were carried out under microwave irradiation and catalyzed by 1-(3, 4- dichlorobenzenesulfonyl)-3-methyl-1H-imidazolium chloride. A plausible mechanism for the synthesis of 1,8-dioxo-octahydroxanthenes catalyzed by[3, 4-dcbsmim][Cl] in water has been given

Synthesis of arylpiridines with us on bifuntional catalysts Me/SiO2-SO3H (Me= Au, Ir, Pt)

Se estudió la reacción multicomponente de Hantzsch para la obtención de compuestos derivados de la familia 2-arilpiridinas, usando catalizadores bifuncionales tipo Me/SiO2-SO3H (Me = Au, Pt, Ir). Los catalizadores se caracterizaron por distintas técnicas como fisisorción de N2 a 77K, difracción de rayos X (DRX) y capacidad ácida determinada por titulación volumétrica. Estos catalizadores bifuncionales del tipo Me/SiO2-SO3H (Me: Pt, Ir, Au) permiten la formación de arilpiridinas y se evidencia que los sitios ácidos permiten la formación de 1,4-dihidropiridinas (producto de Hantzsch) y los sitios metálicos permiten la formación de 2-arilpiridinas, actuando de esta manera como un catalizador bifuncional.The multicomponent Hantzsch reaction for obtaining compounds derived from 2-arylpyridines family, using bifunctional catalysts type Me/SiO2-SO3H (Me = Au, Pt, Ir) was studied. The catalysts were characterized by different techniques such as N2 physisorption at 77K, X-ray diffraction (XRD) and acid capacity determined by volumetric titration. These bifunctional catalysts of Me /SiO2-SO3H (I: Pt, Ir, Au) permit formation of 2-arylpyridines and evidence that acidic sites enable the formation of 1,4-dihydropyridines (product Hantzsch) and metal sites allow the formation of 2-arylpyridines acting as a bifunctional catalyst.Fil: Nope Vargas, Eliana Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Martinez, José. Universidad Pedagógica y Tecnológica de Colombia. Grupo de Catálisis; ColombiaFil: Rojas, Hugo. Universidad Pedagógica y Tecnológica de Colombia. Grupo de Catálisis; ColombiaFil: Sathicq, Angel Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

Titanium dioxide nanoparticles catalyzed synthesis of Hantzsch esters and polyhydroquinoline derivatives

1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst. The present methodology offers several advantages such as excellent yields, short reaction times (30-120 min), environmentally benign, and mild reaction conditions. The catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse

Triazolinediones as highly enabling synthetic tools

Triazolinediones (TADs) are unique reagents in organic synthesis that have also found wide applications in different research disciplines, in spite of their somewhat "exotic" reputation. In this review, we offer two case studies that demonstrate the possibilities of these versatile and reliable synthetic tools, namely, in the field of polymer science as well as in more recently emerging applications in the field of click chemistry. As the general use of triazolinediones has always been hampered by the limited commercial and synthetic availability of such reagents, we also offer a review of the available TAD reagents, together with a detailed discussion of their synthesis and reactivity. This review thus aims to serve as a practical guide for researchers that are interested in exploiting and further developing the exceptional click -like reactivity of triazolinediones in various applications

K

An efficient method for the synthesis of 1,2,4,5-tetra substituted imidazoles using K7Na3P2W18Cu4O68 as catalyst is reported. This four-component condensation of benzil, aldehydes, amines, and ammonium acetate proceeds under solvent-free conditions. The catalyst is handling and recoverable

Homogeneous and heterogeneous catalysts for multicomponent reactions

[EN] Organic synthesis performed through multicomponent reactions is an attractive area of research in organic chemistry. Multicomponent reactions involve more than two starting reagents that couple in an exclusive ordered mode under the same reaction conditions to form a single product which contains the essential parts of the starting materials. Multicomponent reactions are powerful tools in modern drug discovery processes, because they are an important source of molecular diversity, allowing rapid, automated and high throughput generation of organic compounds. This review aims to illustrate progress in a large variety of catalyzed multicomponent reactions performed with acid, base and metal heterogeneous and homogeneous catalysts. Within each type of multicomponent approach, relevant products that can be obtained and their interest for industrial applications are presented.The authors wish to gratefully acknowledge the Generalitat Valenciana for the financial support in the project CONSOLIDER-INGENIO 2010 (CSD2009-00050)Climent Olmedo, MJ.; Corma Canós, A.; Iborra Chornet, S. (2012). Homogeneous and heterogeneous catalysts for multicomponent reactions. RSC Advances. 2(1):16-58. https://doi.org/10.1039/c1ra00807bS16582

Amidoalkyl Naphthols: Trifluoroacetic Acid (TFA) Catalyzed One-Pot, Multi-Component Synthesis

Trifluoroacetic acid (TFA) was found as an efficient catalyst for the synthesis of amidoalkyl naphthols from aromatic aldehydes, β-naphthol and acetamide/benzamide under solvent free condition at 80o C. All the synthesized compounds were characterized by IR, 1H NMR and Mass spectra. The advantages of the new method were good yields, short reaction times, simple work-up, inexpensive and easily available catalyst and economical due to absence of solvent. Therefore, this method could be an attractive alternative to existing methods for the synthesis of biologically important amidoalkyl naphthols

Silica-Based materials as catalysts or supports in solvent-free organic reactions

This chapter summarizes recent developments in solvent-free organic synthesis. In particular, the chapter focuses on the reactions conducted under neat conditions and in the presence of silica-based reagents or catalysts. The chapter describes the synthesis of those materials and salient features that are responsible for the enhanced reaction rates and greater selectivity. The discussion demonstrates that silica-based solids can be used to carry out a wide range of reactions and the approach can prove beneficial, leading to no solvent waste, in line with modern green chemistry metrics