نتایج جستجو برای: enantiomers

تعداد نتایج: 3396  

Journal: :Organic & biomolecular chemistry 2012
Atul Goel Amit Kumar Yasmin Hemberger Ashutosh Raghuvanshi Ram Jeet Govind Tiwari Michael Knauer Jyoti Kureel Anuj K Singh Abnish Gautam Ritu Trivedi Divya Singh Gerhard Bringmann

A convenient synthesis of natural and synthetic pterocarpans was achieved in three steps. Optical resolution of the respective enantiomers was accomplished by analytical and semi-preparative HPLC on a chiral stationary phase. For medicarpin and its synthetic derivative 9-demethoxymedicarpin, the absolute configuration was confirmed by a combination of experimental LC-ECD coupling and quantum-ch...

2006
Junko WAKAI

13-Cyclodextrin (CD)/diol phase silica materials have been designed for direct serum injection assays of drug enantiomers. The mixed functional phase (MFP) materials having /3-CD and diol phases were synthesized in four steps: introduction of a 3-chloropropyl phase, introduction of a /3-CD phase by ether linkage, introduction of a 3glycidoxypropyl phase and hydrolysis of the oxirange ring to a ...

2006
Mohamed M. Hefnawy Maha A. Sultan Mona M. Al-Shehri

A high-performance liquid chromatographic (HPLC) method has been developed for the separation and determination of S- and R-enantiomers of betaxolol in tablets and ophthalmic preparations. Baseline resolution was achieved by using teicoplanin macrocyclic antibiotic chiral stationary phase (CSP) known as Chirobiotic T with fluorescence detection at excitation/emission wavelengths 275/305 nm. The...

Journal: :Planta medica 2012
Yan-Hong Wang Bharathi Avula Xiang Fu Mei Wang Ikhlas A Khan

In natural product chemistry, it is often crucial to determine sugar composition as well as the absolute configuration of each monosaccharide in glycosides. An ultra-performance liquid chromatography method using both photodiode array (PDA) and mass spectrometry detectors (UPLC-UV/MS) was developed for qualitative analysis of the absolute configuration of monosaccharide enantiomers. Within a si...

Journal: :Journal of clinical pharmacology 1997
N Janiczek D E Smith T Chang A J Sedman K A Stringer

The pharmacokinetics and pharmacodynamics of pirmenol were investigated in 12 patients with premature ventricular contractions (PVCs) after oral administration of racemic pirmenol, 100 mg and 200 mg every 12 hours. Holter monitoring was performed and serial blood samples were collected after the seventh doses. Plasma concentrations of pirmenol enantiomer were determined using a stereospecific l...

Journal: :Acta crystallographica. Section B, Structural science 2010
László Fábián Carolyn Pratt Brock

A list of 181 organic kryptoracemates has been compiled. This class of crystallographic oddities is made up of racemic compounds (i.e. pairs of resolvable enantiomers) that happen to crystallize in Sohnke space groups (i.e. groups that include only proper symmetry operations). Most (151) of the 181 structures could have crystallized as ordered structures in non-Sohnke groups. The remaining 30 s...

Journal: :Electrophoresis 2002
Xuejun Peng Ethan Sternberg David Dolphin

A method for the separation of benzoporphyrin derivative mono- and diacid (BPDMA, BPDDA) enantiomers by laser induced fluorescence-capillary electrophoresis (LIF-CE) has been developed. By using 300 mM borate buffer, pH 9.2, 25 mM sodium cholate and 10% acetronitrile as electrolyte, +10 kV electrokinetic sampling injection of 2 s and an applied +20 kV voltage across the ends of a 37 cm capillar...

Journal: :Electrophoresis 2006
Fang Chen Shufeng Zhang Li Qi Yi Chen

Chiral separation of 19 pairs of amino acid (AA) enantiomers derivatized with 9-fluorenylmethylchloroformate (FMOC) was successfully conducted by capillary electrophoresis using the mixture of beta-CD and sodium taurodeoxycholate (STDC) as selectors. Resolution was considerably superior to that obtained by using either beta-CD or STDC alone. After a systematic inspection, a buffer composed of 1...

Journal: :Drug metabolism and disposition: the biological fate of chemicals 2004
Marion L Williams Donald E Mager Heli Parenteau Girish Gudi Timothy S Tracy Mike Mulheran Irving W Wainer

The effect of protein calorie malnutrition (PCM) on the pharmacokinetics of ketamine (KET) enantiomers has been investigated. Six control and six PCM rats were administered 85 mg/kg racemic KET by intramuscular injection, and plasma concentrations of (S)- and (R)-KET, norketamine (NKET), and 5,6-dehydronorketamine (DNK) were measured using enantioselective gas chromatography. Pharmacokinetic pr...

Journal: :Acta biochimica Polonica 2009
Marek Komisarski Zuzanna Kaczmarska Jarosław T Kuśmierek

Oxidative stress enhances lipid peroxidation (LPO) implicated in cancer promotion and progression. (E)-4-Hydroxynon-2-enal 1 (trans-4-hydroxy-2-nonenal, HNE) is one of the most abundant products of LPO. Reactions of HNE with DNA and proteins are responsible for its mutagenic and toxic effects. On the other hand, HNE is regarded as a key molecule in stress mediated cell cycle signaling. LPO gene...

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