Approach on Pd/C/K-10 Catalyst. -The use of a premixed catalyst allows a rapid formation of pyrazoles from chalcones and hydrazines under microwave conditions. -(LANDGE, S. M.; SCHMIDT, A.; OUTERBRIDGE, V.; TOEROEK*, B.; Synlett 2007, 10, 1600-1604; Dep. Chem., Univ. Mass., Boston, MA 02125, USA; Eng.) -Mais 43-123
A new solid acid/superacid catalyzed microwave assisted synthesis of trifluoromethyl-imines is described. Various α,α,α-trifluoromethylketones react readily with primary amines to produce the corresponding imines. Two different strategies have been employed; one is the application of microwave irradiation coupled with solvent-free solid acid catalysis. The other method, for highly deactivated substrates includes the use of a pressure vessel at 175 °C temperature, with solid superacid catalysis. Using the solid acid K-10 montmorillonite or the superacidic perfluorinated resinsulfonic acid Nafion-H, a wide variety of trifluoromethylated imines have been synthesized using the above methods. The products have been isolated in good to excellent yields and high selectivities. This new environmentally friendly synthetic methodology provides significantly higher yields than traditional methods during relatively short reaction times for the preparation of the target compounds.
Trifluoropyruvate. -The first highly enantioselective organocatalytic Friedel-Crafts hydroxyalkylation reaction of indoles with ethyl trifluoropyruvate is carried out with cinchona alkaloids. Highest yields and enantioselectivities for the (R)-isomers are achieved with cinchonine, while cinchonidine gives best results for the (S)-antipodes. -(TOEROEK*, B.; ABID, M.; LONDON, G.; ESQUIBEL, J.; TOEROEK, M.; MHADGUT, S. C.; YAN, P.; PRAKASH, G. K. S.; Angew. Chem., Int. Ed. 44 (2005) 20, 3086-3089; Dep. Chem., Mich. Technol. Univ., Houghton, MI 49931, USA; Eng.) -S. Adam 38-122
Pyridine derivatives R 0380 Multicomponent Domino Cyclization-Oxidative Aromatization on a Bifunctional Pd/C/K-10 Catalyst: An Environmentally Benign Approach Toward the Synthesis of Pyridines. -The one-pot synthesis of substituted pyridines (III) proceeds via a domino cyclization of aldehydes with ethyl acetoacetate followed by oxidative aromatization. It utilizes a new bifunctional noble metal-solid acid catalyst and microwave irradiation. Substrates (IV) react with benzyl cleavage to give the 4-unsubstituted product (V). -(DE PAOLIS, O.; BAFFOE, J.; LANDGE, S. M.; TOEROEK*, B.; Synthesis 2008, 21, 3423-3428; Dep. Chem., Univ. Mass., Boston, MA 02125, USA; Eng.) -Mais 11-150
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.