نتایج جستجو برای: disubstituted urea

تعداد نتایج: 40692  

2016
Michael Brown Ravi Kumar Julia Rehbein Thomas Wirth

A stereoselective hypervalent iodine-promoted oxidative rearrangement of 1,1-disubstituted alkenes has been developed. This practically simple protocol provides access to enantioenriched α-arylated ketones without the use of transition metals from readily accessible alkenes.

2015
Justyna Szudkowska-Frątczak Mariusz Taczała Piotr Pawluć

A convenient methodology for the highly stereoselective synthesis of unsymmetrical (1E,3E)-1,4-disubstituted 1,3-dienes based on palladium-catalyzed Hiyama cross-coupling reaction of 1-(triethoxysilyl)-substituted buta-1,3-dienes with aryl iodides is reported.

Journal: :Chemical communications 2012
Chong Kiat Tan Chencheng Le Ying-Yeung Yeung

A facile, highly regio- and enantioselective amino-thiocarbamate-catalyzed bromolactonization of cis-1,2-disubstituted olefinic acids has been developed. The use of the enantio-enriched lactones in the synthesis of chiral synthetic intermediates is also demonstrated.

Journal: :Chemical communications 2004
Dolores Caras-Quintero Peter Bäuerle

Novel disubstituted EDOT monomers were synthesized in good yields from 3,4-dimethoxythiophene and (chiral) glycols by transetherification. The stereochemistry of the monomers affects the electronic properties of the corresponding chiral PEDOT derivatives.

2012
A. N. Solankee K. P. Patel A N. Solankee

Condensation of 4-amino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one with different aromatic and heterocyclic aldehydes in dry toluene give schiff bases 3(a-g), which on reaction with thioglycolic acid and thiolactic acid in dry toluene give the corresponding 2,3-disubstituted-4-thiazolidinones 4(a-g) and 2,3-disubstituted-5-methyl-4thiazolidinones 5(a-g). The methylene carbon atom at the position ...

Journal: :Angewandte Chemie 2013
Chong Liu Jian-Hua Xie Ya-Li Li Ji-Qiang Chen Qi-Lin Zhou

Chiral diols with three contiguous stereocenters were synthesized by a highly enantioselective ruthenium-catalyzed asymmetric hydrogenation of racemic α,α'-disubstituted cycloketones involving dynamic kinetic resolution. This new catalytic asymmetric method provides a concise route to the alkaloid (+)-γ-lycorane.

Journal: :Organic & biomolecular chemistry 2010
Zhaoming Su Steven A Rogers W Steve McCall Alicia C Smith Sindhu Ravishankar Trey Mullikin Christian Melander

A library of 4,5-disubstituted-2-aminoimidazoles was synthesized using a nitroenolate route and then screened for antibiofilm and antimicrobial activity. These compounds displayed notable biofilm dispersal and planktonic microbicidal activity against various Gram-positive and Gram-negative bacteria.

Journal: :Chemical communications 2007
José Alemán Efraím Reyes Bo Richter Jacob Overgaard Karl Anker Jørgensen

The first organocatalytic "anti-Michael" reaction of cyclic-beta-ketoesters to unsaturated double bonds is described in a highly asymmetric version leading to the synthesis of alpha,alpha'-disubstituted branched double bonds as optically active Baylis-Hillman-like adducts.

Journal: :Organic letters 2014
Chen Zhu Ji-Bao Xia Chuo Chen

Bleach oxidizes trimethylsilyl cyanide to generate an electrophilic cyanating reagent that readily reacts with an amine nucleophile. This oxidative N-cyanation reaction allows for the preparation of disubstituted cyanamides from amines without using highly toxic cyanogen halides.

Journal: :Chemical communications 2010
David R Williams Akshay A Shah

The regioselective Stille cross-coupling reactions of 3-tri-n-butylstannyl-1-trimethylsilyl-1-propyne demonstrate isomerization following the initial transmetalation step resulting in allenyl palladium intermediates for reductive coupling to yield conjugated 1,1-disubstituted allenylsilanes.

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