نتایج جستجو برای: tetrasubstituted imidazoles

تعداد نتایج: 4152  

Journal: :journal of nanostructures 2012
a. bamoniri s. rohani

a general synthetic route to the synthesis of imidazoles has been developed using nano sbcl5/sio2 under solvent-free conditions. the multi-component reactions of aldehydes, benzil and ammonium acetate were carried out to afford some trisubstituted imidazole derivatives. this method provides several advantages like simple work-up, environmentally benign, and shorter reaction times along with hig...

Journal: :Organic & biomolecular chemistry 2014
Feng-Lei Liu Jia-Rong Chen Bin Feng Xiao-Qiang Hu Li-Hua Ye Liang-Qiu Lu Wen-Jing Xiao

An enantioselective oxa-Michael addition of oximes to β-CF3-β-disubstituted nitroalkenes catalyzed by a chiral bifunctional cinchona alkaloid-based thiourea has been developed. A variety of trifluoromethylated oxime ethers possessing a tetrasubstituted carbon stereocenter were obtained in good yields with high enantioselectivities.

Journal: :Journal of the American Chemical Society 2003
Wenjun Tang Shulin Wu Xumu Zhang

Hydrogenation of a series of cyclic beta-(acylamino)acrylates with tetrasubstituted olefins has been accomplished successfully with the use of Ru catalysts with chiral biaryl ligands such as C3-TunaPhos, and up to over 99% ee's have been achieved. This methodology provides an efficient catalytic method for the synthesis of both cis and trans chiral cyclic beta-amino acid derivatives.

2015
Dimitra Kontokosta Daniel S Mueller Dong-Liang Mo Wiktoria H Pace Rachel A Simpson Laura L Anderson

A Chan-Lam reaction has been used to prepare N-alkenyl-α,β-unsaturated nitrones, which undergo a subsequent thermal rearrangement to the corresponding tri- and tetrasubstituted pyridines. The optimization and scope of these transformations is discussed. Initial mechanistic experiments suggest a reaction pathway involving oxygen transfer followed by cyclization.

Journal: :Organic & biomolecular chemistry 2016
Adam J Close Rhiannon N Jones Cory A Ocasio Paul Kemmitt S Mark Roe John Spencer

Nitration of three regioisomers of bromo-fluorobenzaldehyde proceeds regioselectively, notably with H2SO4/HNO3 at 0 °C. The thereby synthesized tetrasubstituted aromatics, endowed with orthogonal substituents, can be elaborated via Pd-catalysed coupling, reduction and reductive amination reactions. As a test-case, these compounds were converted into EGFR inhibitors related to Gefitinib, whose a...

Journal: :Annals of the rheumatic diseases 1969
E N Wardle

This is a study of a small group of patients with rheumatoid arthritis, in whom the urine excretion of imidazole compounds was examined by Figlu assay and chromatography of 12-hour urine collections following 15 g. histidine load, and by assay of 4 amino-imidazole-5 carboxamide (AIC) in 12hour urines with and without histidine load. Gough, McCarthy, Read, Mollin, and Waters (1964) found low ser...

Journal: :The Journal of the Society of Chemical Industry, Japan 1969

Journal: :Organic & biomolecular chemistry 2012
Pipas Saha Anup Bhunia Anil K Saikia

An efficient method for the synthesis of 2,3,5,6-tetrasubstituted tetrahydropyrans has been developed from the reaction of aldehydes and ethyl 2-(1-hydroxyalkyl/hydroxy(phenyl)methyl)-5-methylhex-4-enoate using (3,5)-oxonium-ene reaction promoted by boron trifluoride etherate in good yields under mild conditions.

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