نتایج جستجو برای: disubstituted urea

تعداد نتایج: 40692  

Journal: :Organic & biomolecular chemistry 2014
Yi Liu Xue Sun Xing Zhang Jun Liu Yuguo Du

A novel and efficient method for the one-pot synthesis of 2,4-disubstituted thiazoles from carboxylic acids or anhydrides is presented. Based on this new method, the total synthesis of the bis-2,4-disubstituted bis(thiazoles) natural product cystothiazole C is also presented.

Journal: :Chemical communications 2013
Adele Faulkner James S Scott John F Bower

We report efficient Pd-catalyzed cyclizations of oxime esters with 1,1-disubstituted alkenes as the basis of a general entry to α,α-disubstituted pyrrolidine derivatives. We also demonstrate that catalytic asymmetric variants of this chemistry are feasible by employing a suitable chiral ligand.

Journal: :The Journal of organic chemistry 2010
Camille Oger Zsuzsanna Marton Yasmin Brinkmann Valérie Bultel-Poncé Thierry Durand Marianne Graber Jean-Marie Galano

Lipase B from Candida antarctica (CALB) has been selected as the most suitable enzyme to catalyze the regioselective monoacetylation of 1,5-diol isoprostane intermediate, using vinyl acetate as an acyl transfer reagent in THF. We next applied this reaction on linear 2-substituted, 2,2'-disubstituted-1,5-pentanediols, and cyclic 2,3-disubstituted-1,5-pentanediols. To rationalize the regioselecti...

Journal: :Organic letters 2012
Liangguang Wang Xiaoqiang Yu Xiujuan Feng Ming Bao

An efficient method for the synthesis of 3,5-disubstituted pyrazoles is described. The reactions of 1,3-dialkynes with hydrazine proceeded smoothly in dimethyl sulfoxide under mild reaction conditions to produce 3,5-disubstituted pyrazoles in satisfactory to excellent yields. A one-pot procedure of the transformation has been developed.

Journal: :Chemical communications 2009
Aurélie dos Santos Laurent El Kaïm Laurence Grimaud Caroline Ronsseray

The coupling of an acyl chloride with an isocyanide affords 2,5-disubstituted oxazoles under mild basic conditions instead of 4,5-disubstituted derivatives when using Schöllkopf conditions (butyllithium); this reaction constitutes a remarkable example of a base-induced chemoselective process in isocyanide chemistry.

2004
Ines Zug Horst Hartmann Willi Kantlehner

The reaction of N,N’-persubstituted selenoacrylamides with alkyl bromoacetates gives rise to the formation of alkyl derivatives of N,N-disubstituted 2-aminoselenophene-5-carboxylates which can be transformed by saponification into corresponding 5-carboxylic acids. These compounds decompose by heating under formation of hitherto unknown N,N-disubstituted 2-amino-5H-selenophenes their spectral an...

Journal: :Nature Communications 2021

Abstract Hydrofunctionalization, the direct addition of an X–H (e.g., X=O, N) bond across alkene, is a desirable strategy to make heterocycles that are important structural components naturally occurring molecules. Described here design and discovery “donor–acceptor”-type platinum catalysts highly effective in both hydroalkoxylation hydroamination unactivated alkenes over broad range substrates...

A. Badiei G. Mohammadi Ziarani, M. Shakiba Nahad S. Ghadim Alizadeh

In this article, simple, convenient synthesis of 2-aryl-1- arylmethyl-1H-1,3-benzimidazole (1,2-disubstituted benzimidazoles) via condensation of 1,2-phenylenediamine and aromatic aldehydes using SBA-Pr-SO3H as a nanoporous solid acid catalyst in green protocol was reported.

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1997
yousef rastgar mirzaei karim akbari dilmaghani

the 2-mono and 2,6-disubstituted methyl-1,4-dihydropyridines were synthesized by reaction of morpholine, thiophenol, 8-hydroxyquinoline, 2-naphthol and 2-mercopto-1-methyl imidazole with the 2-mono bromo and 2,6-dibromo-1,4-dihidropyridines.

Journal: :Journal of the American Chemical Society 2011
Ryosuke Matsubara Alicia C Gutierrez Timothy F Jamison

Nickel-catalyzed intermolecular benzylation and heterobenzylation of unactivated alkenes to provide functionalized allylbenzene derivatives are described. A wide range of both the benzyl chloride and alkene coupling partners are tolerated. In contrast to analogous palladium-catalyzed variants of this process, all reactions described herein employ electronically unbiased aliphatic olefins (inclu...

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