نتایج جستجو برای: enantiomers

تعداد نتایج: 3396  

Journal: :Biochemistry 2001
M Chen-Goodspeed M A Sogorb F Wu F M Raushel

The factors that govern the substrate reactivity and stereoselectivity of phosphotriesterase (PTE) toward organophosphotriesters containing various combinations of methyl, ethyl, isopropyl, and phenyl substituents at the phosphorus center were determined by systematic alterations in the dimensions of the active site. The wild type PTE prefers the S(P)-enantiomers over the corresponding R(P)-ena...

Journal: :Antiviral chemistry & chemotherapy 2000
Y L Qiu F Geiser T Kira E Gullen Y C Cheng R G Ptak J M Breitenbach J C Drach C B Hartline E R Kern J Zemlicka

A series of R and S enantiomers of 2-aminopurine methylenecyclopropane analogues of nucleosides was synthesized. Two diastereoisomeric lipophilic phosphate prodrugs derived from R and S enantiomers of 2,6-diaminopurine analogue were also prepared. Enantioselectivity (diastereoselectivity in case of prodrugs) of in vitro antiviral effects was investigated with human and murine cytomegalovirus (H...

Journal: :Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 2006
Mahasen A Radwan Heba H Abdine Bushra T Al-Quadeb Hassan Y Aboul-Enein Kenichiro Nakashima

This investigation describes a new precise, sensitive and accurate stereoselective HPLC method for the simultaneous determination of donepezil enantiomers in tablets and plasma with enough sensitivity to follow its pharmacokinetics in rats up to 12h after single oral dosing. Enantiomeric resolution was achieved on a cellulose tris (3,5-dimethylphenyl carbamate) column known as Chiralcel OD, wit...

Journal: :European journal of pharmacology 1992
M Waelbroeck J Camus M Tastenoy E Mutschler C Strohmann R Tacke L Schjelderup A Aasen G Lambrecht J Christophe

We investigated the binding properties of the (R)- and (S)-enantiomers of the muscarinic antagonists trihexyphenidyl, procyclidine, hexahydro-difenidol, p-fluoro-hexahydro-difenidol, hexbutinol, p-fluoro-hexbutinol, and their corresponding methiodides at muscarinic M1, M2, M3 and M4 receptor subtypes. In addition, binding properties of the (R)- and (S)-enantiomers of oxyphencyclimine were studi...

Journal: :Biochemical pharmacology 1993
D S Shewach D C Liotta R F Schinazi

The two enantiomers of 2',3'-dideoxy-3'-thiacytidine (BCH-189) and their 5-fluoro analogs (FTC) were found to be good substrates for human 2'-deoxycytidine kinase with Km values in the 5.7 to 42.1 microM range. The affinity of the (-)-enantiomers was greater than that of the (+)-compounds. These results may explain the greater in vitro antiviral potency against human immunodeficiency virus and ...

2015
Marco Pistolozzi Huaqiao Du Hong Wei Wen Tan

This work describes the sequential hydrolysis of bambuterol enantiomers and their monocarbamate metabolites (MONO) catalyzed by human butyrylcholinesterase (BChE) as well as the enzyme inhibition resulting from this process. Particular emphasis is given to the contribution given by MONO to the enzyme inhibition because it was not fully characterized in previous works. Bambuterol and MONO enanti...

Journal: :Biological & pharmaceutical bulletin 2002
Shinsaku Naito Masuhiro Nishimura

The stereoselective pharmacokinetics of BOF-4272 enantiomers in rats and dogs was investigated by simultaneously measuring concentrations in arterial, portal, and venous plasma, the liver, and the kidney at 2 h after the oral administration of the racemic drug. The concentrations of BOF-4272 enantiomers were measured using high-performance liquid chromatography. The concentrations of the S(-) e...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2000
Reiko Iio Satoshi Chinaka Nariaki Takayama Kazuichi Hayakawa

A capillary electrophoresis/mass spectrometry method for the simultaneous chiral analysis of enantiomers of methamphetamine (MA), amphetamine (AP), dimethylamphetamine (DMA), ephedrine (EP), norephedrine (NE) and methylephedrine (ME) in urine has been developed. The background electrolyte was 1 M formic acid (pH 1.7). Using 0.85 mM heptakis(2,6-diacethyl-6-sulfato)-beta-cyclodextrin as the chir...

Journal: :Angewandte Chemie 2014
Heike Lorenz Andreas Seidel-Morgenstern

The provision of pure enantiomers is of increasing importance not only for the pharmaceutical industry but also for agrochemistry and biotechnology. In general, there are two rival approaches to provide pure enantiomers. The "chiral" approach is based on developing an asymmetric synthesis of just one of the enantiomers, while the "racemic" approach is based on separating mixtures of the two ena...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2009
xiaoqing chen feipeng jiao xinyu jiang

the distribution behavior of ofloxacin enantiomers was examined in the aqueous and organic solvent of a two-phase system containing chiral selector l-tartarate. the effect of extraction equilibrium time, buffer ph, organic solvents and length of alkyl chain of l-tartarate on the partition coefficients and enantioselectivity of racemic ofloxacin were investigated, respectively. the l-tartarate f...

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