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

Supported ionic liquid silica nanoparticles (SILnPs) as an efficient and recyclable heterogeneous catalyst for the dehydration of fructose to 5-hydroxymethylfurfural

Supported ionic liquid nanoparticles (SILnPs) having particle size ranging from 293 ± 2 to 610 ± 11 nm have been prepared by immobilization of ionic liquid, 1-(tri-ethoxy silyl-propyl)- 3-methyl-imidazolium hydrogen sulfate (IL-HSO4) on the surface of silica nanoparticles. The catalytic activity of the prepared SILnPs was investigated for the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in the presence of dimethylsulfoxide (DMSO) as a solvent. The reaction temperature and amount of catalyst have been optimized for dehydration of fructose over SILnPs using experimental design leading to 99.9% fructose conversion and 63.0% HMF yield using silica SILnPs (d = 610 ± 11) nm at 130.0 ◦C in 30 min reaction time. The SILnPs catalysts developed in this study present improved performances over other zeolites and strong acid ion exchange resin catalysts, and they have been efficiently and very easily recycled over seven times without any significant loss in fructose conversion and HMF yield

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

Molybdatophosphoric acid as an efficient catalyst for the catalytic and chemoselective oxidation of sulfides to sulfoxides using urea hydrogen peroxide as a commercially available oxidant

An efficient procedure for the chemoselective oxidation of alkyl (aryl) sulfides to the corresponding sulfoxides using urea hydrogen peroxide (UHP) in the presence of a catalytic amount of molybdatophosphoric acid at room temperature is described. The advantages of described method are: generality, high yield and chemoselectivity, short reaction time, low cost and compliment with green chemistry protocols

Enantioselective Total Synthesis of (—)-Acetylaranotin, a Dihydrooxepine Epidithiodiketopiperazine

The first total synthesis of the dihydrooxepine-containing epidithiodiketopiperazine (ETP) (−)-acetylaranotin (1) is reported. The key steps of the synthesis include an enantioselective azomethine ylide (1,3)-dipolar cycloaddition reaction to set the absolute and relative stereochemistry, a rhodium-catalyzed cycloisomerization/chloride elimination sequence to generate the dihydrooxepine moiety, and a stereoretentive diketopiperazine sulfenylation to install the epidisulfide. This synthesis provides access to (−)-1 in 18 steps from inexpensive, commercially available starting materials. We anticipate that the approach described herein will serve as a general strategy for the synthesis of additional members of the dihydrooxepine ETP family

Green Synthesis & Biological Evaluation of Novel Benzimidazole Derivatives as Antianxiety Agents

Benzimidazole is one of the most important heterocyclic compound, having varied biological activities and still of great scientific interest now a days. They are widely found in bioorganic and medicinal chemistry with application in drug discovery. In the present study some novel benzimidazole derivatives were synthesized under green synthesis by solvent free conditions by using catalytic amount of silica supported sodium hydrogen sulphate according to the scheme. All the synthesized benzimidazole derivatives have been characterized by using elemental analysis, FT-IR, 1HNMR, 13C NMR spectroscopy and further supported by Mass spectroscopy. Purity of all the compounds has been checked on thin layer chromatographic plate and HPLC technique. All the synthesized compounds were tested for their anti anxiety and neurotoxicity activities by elevated plus maze test in mice. Test compounds and diazepam was administered intraperitoneally in antianxiety study at dose of 2 mg/kg. Compounds BZ-6 & BZ-7 showed highest antianxiety activity compared to diazepam and did not show neurotoxicity in rotarod test. All the compounds exhibited moderate to significant antianxiety activity

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