نتایج جستجو برای: disubstituted urea

تعداد نتایج: 40692  

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2005
Helena Puzanowska-Tarasiewicz Ludmiła Kuźmicka Joanna Karpińska Katarzyna Mielech-Lukasiewicz

2,10-Disubstituted phenothiazines are the best drugs in psychiatry. Several methods for their analysis have been reported in the literature. The official methods are based on non-aqueous titration or spectrophotometry. Various oxidizing agents have been used for the spectrophotometric determination of 2,10-disubstituted phenothiazines, e.g. Ce(SO4)2, NH4VO3, K2S208, KIO4, KIO3, KBrO3, FeCl3, Na...

Journal: :Molecules 2014
Rui Zhou Li Guo Cheng Peng Gu He Liang Ouyang Wei Huang

The convenient, high yielding and diastereoselective synthesis of α-amino-β-substituted-γ,γ-disubstituted butyric acid derivatives was carried out by a three-component tandem reaction of a chiral equivalent of nucleophilic glycine. The reaction was performed smoothly under mild conditions and enabled the construction of two or three adjacent chiral centers in one step, thus affording a novel an...

Journal: :Organic & biomolecular chemistry 2009
Celia Clarke Stéphanie Foussat David J Fox Daniel Sejer Pedersen Stuart Warren

The stereocontrolled synthesis of trans-disubstituted cyclopropylketones has been achieved from beta-alkyl, gamma-benzoyl phosphine oxides via a three-step cascade reaction incorporating an acyl transfer, phosphinoyl transfer and cyclisation to form the cyclopropane. Using Evans' chiral oxazolidinone auxiliary and by masking the phosphine oxide moiety as a phosphine borane we have extended the ...

Journal: :European Journal of Organic Chemistry 2022

Ethyl diazoacetate (EDA), which is easily prepared from ethyl glycinate and NaNO2, reacts in situ with alkynes a water micelle environment without organic solvent to form pyrazoles. The reaction pH dependent, as the presence of protic catalysis (H2SO4 4 %, 3.5) mixture 3,5- 4,5-disubstituted pyrazoles was obtained, while, at 5.5, only 3,5-disubstituted isomer obtained. surfactant TPGS-750-M cru...

Journal: :Molecules 2011
Zalán Kádár Dóra Kovács Éva Frank Gyula Schneider Judit Huber István Zupkó Tibor Bartók János Wölfling

A straightforward and reliable method for the regioselective synthesis of steroidal 1,4-disubstituted triazoles and 1,5-disubstituted tetrazoles via copper(I)-catalyzed cycloadditions is reported. Heterocycle moieties were efficiently introduced onto the starting azide compound 3β-acetoxy-16β-azidomethylandrost-5-en-17β-ol through use of the "click" chemistry approach. The antiproliferative act...

Journal: :Molecules 2006
Hongxia He Mengjia Liu Zhibing Zheng Ying Liu Junhai Xiao Ruibin Su Chun Hu Jin Li Song Li

A series of N,N'-disubstituted-2-nitroethene-1,1-diamine and N,N'-disubstituted- N''-cyanoguanidine derivatives were prepared and evaluated for in vivo analgesic activity. The blood brain barrier (BBB) VolSurf model was used to predict the BBB permeation profiles of our synthesized compounds. Some compounds show both remarkable analgesic activity and good BBB permeation profiles, and these comp...

2014
B. Santosh

www.experimentjournal.com 1254 Synthesis, biological activity and docking studies of N,N'-(3S,4S)bis(3,4-disubstituted pyrrolidine)-1-sulfonamide derivatives as β-gluscosidase inhibitors Abstract Starting with L-tartaric acid the chiral 3,4-disubstituted pyrrolidine analogue sulfonamide derivatives were prepared. These compounds were examined for anti-bacterial and anti-fungal activity. Further...

Journal: :Chemical communications 2014
Guillaume Pelletier Léa Constantineau-Forget André B Charette

A practical and highly stereoselective approach to access 2,6-disubstituted piperidines using an amidine auxiliary is reported. Following the diastereoselective addition of Grignard reagents at the 2-position of an activated pyridinium salt, the amidine group directs a regioselective metalation at the 6-position, enabling further functionalization. A subsequent electrophilic quench or a Negishi...

Journal: :Organic & biomolecular chemistry 2015
Ganesh Pandey Rajesh Varkhedkar Divya Tiwari

An efficient and scalable synthesis of various enantiopure 1,3- disubstituted isoindolines is reported. The base catalyzed nucleophilic fragmentation of a rigid overbred template is established with various substrates to afford the corresponding 1,3-disubstituted isoindoline ester, amide, thioate, 1,3-amino alcohol and isoindolylcarboxylic acid. The crucial rigid overbred template is synthesize...

Journal: :Organic letters 2007
Mukund P Sibi Levi M Stanley Takahiro Soeta

[reaction: see text] A general strategy for highly enantioselective 1,3-dipolar cycloaddition of diazoesters to beta-substituted, alpha-substituted, and alpha,beta-disubstituted alpha,beta-unsaturated pyrazolidinone imides is described. Cycloadditions utilizing less reactive alpha,beta-disubstituted dipolarophiles require elevated reaction temperatures, but still provide the corresponding pyraz...

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