نتایج جستجو برای: dioxides

تعداد نتایج: 375  

Journal: :Organic & biomolecular chemistry 2014
You-Qing Wang Xiao-Yu Cui Yuan-Yuan Ren Yongna Zhang

A highly enantioselective direct Mannich reaction of methyl alkyl ketones with cyclic imines benzo[e][1,2,3]oxathiazine 2,2-dioxides, catalyzed by the combination of cinchona alkaloid derived primary amine and TFA, is disclosed. For unsymmetrical methyl alkyl ketones, it is favoured that specific regioselective addition to the imine substrates occurs at the less-substituted methyl group by ster...

Journal: :Journal of The Electrochemical Society of Japan 1959

Journal: :Chemical communications 2011
Pradip K Maity Quirin M Kainz Saqib Faisal Alan Rolfe Thiwanka B Samarakoon Fatima Z Basha Oliver Reiser Paul R Hanson

The utilization of a monomer-on-monomer (MoM) intramolecular Mitsunobu cyclization reaction employing norbornenyl-tagged (Nb-tagged) reagents is reported for the synthesis of benzofused thiadiazepine-dioxides. Facile purification was achieved via ring-opening metathesis (ROM) polymerization initiated by one of three metathesis catalyst methods: (i) free metathesis catalyst, (ii) surface-initiat...

2012
Joanna K Loh Sun Young Yoon Thiwanka B Samarakoon Alan Rolfe Patrick Porubsky Benjamin Neuenswander Gerald H Lushington Paul R Hanson

The efficient synthesis of an 80-member library of unique benzoxathiazocine 1,1-dioxides by a microwave-assisted, intermolecular nucleophilic aromatic substitution (S(N)Ar) diversification pathway is reported. Eight benzofused sultam cores were generated by means of a sulfonylation/S(N)Ar/Mitsunobu reaction pairing protocol, and subsequently diversified by intermolecular S(N)Ar with ten chiral,...

Journal: :International journal of occupational safety and ergonomics : JOSE 2003
Pranas Baltrenas Dainius Paliulis Saulius Vasarevicius Ramutis Simaitis

Not much has been written about air cleaning from ozone. The aim of this paper was to demonstrate the possibility of adsorption air cleaning from ozone. The second aim was to investigate the dependence of the efficiency of ozone removal from the air on the height of the adsorber layer and on concentrations of ozone, and to obtain empirical formulas for calculating the efficiency of ozone treatm...

2008
Y Fu ZD Wei MB Ji L Li PK Shen J Zhang

Nanoscale cerium dioxides with shape of nanoparticles, nanorods, and nanotubes were electrochemically synthesized. The morphology of CeO2 was modulated by changing electrode potential and potential direction. CeO2 nanorods and CeO2 nanotubes were synthesized via the potentiostatic and cyclic voltammeteric methods, respectively. The morphology and structure of the obtained CeO2 were characterize...

Journal: :Molecules 2012
Amel Bendjeddou Tahar Abbaz Zine Regainia Nour-Eddine Aouf

This work reports the synthesis of novel 1,4,3,5-oxathiadiazepanes 4,4-dioxides from the reaction of N'-benzyl-N-(2-hydroxyethyl)-sarcosine or proline sulfamide with aromatic aldehydes under acid catalysis. To prepare the starting materials N-Boc-sulfamide derivatives of sarcosine or proline were alkylated with benzyl alcohol under Mitsunobu reaction conditions, the Boc group was removed chemos...

Journal: :Journal of the American Chemical Society 2006
Liqin Qiu Fuk Yee Kwong Jing Wu Wai Har Lam Shusun Chan Wing-Yiu Yu Yue-Ming Li Rongwei Guo Zhongyuan Zhou Albert S C Chan

A series of chiral diphosphine ligands denoted as PQ-Phos was prepared by atropdiastereoselective Ullmann coupling and ring-closure reactions. The Ullmann coupling reaction of the biaryl diphosphine dioxides is featured by highly efficient central-to-axial chirality transfer with diastereomeric excess >99%. This substrate-directed diastereomeric biaryl coupling reaction is unprecedented for the...

Journal: :Journal of Nuclear Science and Technology 2004

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