نتایج جستجو برای: disubstituted urea

تعداد نتایج: 40692  

Journal: :Chemical communications 2011
Mingzong Li Cong Wang Ping Fang Haibo Ge

A novel Pd-catalyzed decarboxylative cross-coupling of oxamic acids with potassium phenyltrifluoroborates has been realized under mild reaction conditions. This method provides an efficient access to N-mono- or N,N-disubstituted benzamides and benzoates.

Journal: :Chemical science 2015
Alan R Burns Amaël G E Madec Darryl W Low Iain D Roy Hon Wai Lam

2,2-Disubstituted cyclic 1,3-diketones containing a tethered electron-deficient alkene undergo chiral phosphoric acid-catalyzed desymmetrizing Michael cyclizations to give bridged bicyclic products in high enantioselectivities. Both bicyclo[3.2.1]octanes and bicyclo[3.3.1]nonanes are accessible using this methodology.

Journal: :journal of sciences islamic republic of iran 0

a number of 3-amino-1, 2, 4-triazin-5 (2h)- ones(1) were synthesized and condensed with a-haloketones to give 2,6-disubstituted imidazo [1, 2-b] [1, 2, 4]-triazin-3 (4h)-ones (2). these compounds were reacted further with a - haloketones to yield n-alkylated products (3).

Journal: :Organic & biomolecular chemistry 2011
Hung-Chou Wu Long-Chih Hwang Ming-Jung Wu

2,7-Disubstituted pyrazolo[1,5-a]pyridines were synthesized in good chemical yields by the reaction of enediynones with hydrazine, followed by addition of copper chloride. This reaction can tolerate many functional groups.

Journal: :Chemical communications 2005
Jadranka Cubrilo Rainer F Winter Dietrich Gudat

We report the highly selective assembly of unprecedented eta5-1-methylene-1,2-dihydronaphthalenide ligands from the stoichiometric coupling of a phenyl group and two equivalents of disubstituted propargylic alcohols; in this reaction, tetraphenylborate acts as a phenylating agent.

Journal: :Dalton transactions 2009
Slawomir Urban Matyas Tursky Roland Fröhlich Frank Glorius

The investigation of the electronic and steric properties of 4,5-disubstituted imidazolylidenes is reported, as well as their successful application as organocatalysts in the formation of gamma-butyrolactones by conjugate Umpolung.

Journal: :Organic & biomolecular chemistry 2009
Omar Boutureira Joanna F McGouran Robert L Stafford Daniel P G Emmerson Benjamin G Davis

A systematically varied series of conformationally restricted ketones, readily prepared from N-acetyl-D-glucosamine, were tested against representative olefins as asymmetric epoxidation catalysts showing useful selectivities against terminal olefins and, in particular, typically difficult 2,2-disubstituted terminal olefins.

Journal: :Chemical communications 2007
Naoki Hayashi Kazunao Kusano Shingo Sekizawa Ikuya Shibata Makoto Yasuda Akio Baba

Regio- and stereoselective hydrostannation of allenes by using di-n-butyliodotin hydride (Bu2SnIH) was accomplished to give alpha,beta-disubstituted vinyltins, which induced the synthesis of multi-substituted alkenes in a one-pot procedure.

Journal: :The Journal of organic chemistry 2008
Mercedes Amat Maria Pérez Annamaria T Minaglia Joan Bosch

A synthetic route to enantiopure cis-2,4-disubstituted and 2,4-bridged piperidines is reported, the key step being a stereoselective conjugate addition of an organocuprate to a phenylglycinol-derived unsaturated lactam bearing a substituent at the 8a-position.

Journal: :Organic & biomolecular chemistry 2005
Jin-Wen Huang Min Shi

A novel carbolithiation of gem-aryl disubstituted methylenecyclopropanes was disclosed by the treatment with BuLi in THF at -78 degree C. The corresponding addition products can be obtained in good to high yields by quenching with various electrophiles.

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