epimer

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Related to epimers: Mutarotation, Anomers

epimer

[′ep·ə·mər]
(organic chemistry)
A type of isomer in which the difference between the two compounds is the relative position of the H (hydrogen) group and OH (hydroxyl) group on the last asymmetric C (carbon) atom of the chain, as in the sugarsD-glucose andD-mannose.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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References in periodicals archive ?
Due to the same polarity, it's very difficult to obtain optically pure 1 and 2, so 3 and 4 were designed and prepared to enhance the polarity difference of C24 epimers. After isolation over silica gel (petroleum ether:ethyl acetate=10/1), suitable crystals of 3 and 4 were obtained from ethyl acetate and acetone, respectively.
Synthesis and Crystal Structures of 3,6-diacetylated C24 epimeric 20(R)-Ocotillol-Type Saponins
Considering the 3[alpha]/[beta]-[[sup.18]F]FCA epimers, it was found that 3[alpha]-[[sup.18]F]FCA shows a slight, yet significant decrease in time-to-peak of the liver TAC and excretion to gallbladder and intestines proceeded faster.
Evaluating Hepatobiliary Transport with [sup.18]F-Labeled Bile Acids: The Effect of Radiolabel Position and Bile Acid Structure on Radiosynthesis and In Vitro and In Vivo Performance
[71] developed a green chemistry method for extraction, chromatography, and derivatization of first-, second-, and third-generation tetracyclines and epimers from feed samples.
Tetracyclines in Food and Feedingstuffs: From Regulation to Analytical Methods, Bacterial Resistance, and Environmental and Health Implications
However, pharmacokinetic studies of ginsenosides are challenging, especially for ginsenosides epimers. Firstly, because of the UV end absorption of ginsenosides, HPLC-UV method detection performed at 200~205 nm usually caused high level of baseline noise.
Pharmacokinetic Comparison of 20(R)- and 20(S)-Ginsenoside Rh1 and 20(R)- and 20(S)-Ginsenoside Rg3 in Rat Plasma following Oral Administration of Radix Ginseng Rubra and Sheng-Mai-San Extracts
25-OH Vitamin D is a challenging analyte to accurately measure in human blood due to the presence of 25-OH Vitamin D2, Vitamin D binding proteins, 25-OH Vitamin D metabolites such as 24, 25 (OH)2 Vitamin D, and C-3 epimers of 25-OH Vitamin D.
An update on vitamin D testing: what is right for your laboratory?
Tyrakowska, "The influence of stereochemistry on the antioxidant properties of catechin epimers," European Food Research and Technology, vol.
Antioxidant and Vasodilator Activity of Ugni molinae Turcz
2002) and using the chemical shift difference of the diastereomeric protons at C-26 (Agrawal 2005) revealed that compound 1 was a 7:3 mixture of the 25R and 25S epimers. Compound 1a/b was, therefore, identified as a mixture (7:3, 25R.25S epimers) of 26-O-[beta]-D-glucopyranosyl-furost-5-ene-3,22,26-triol 3-O-[[alpha]-L-rhamnopyranosyl-(1[right arrow]-3)- [beta]-D-glucopyranosyl-(1[right arrow]2)]-[alpha]-Lrhamnopyranosyl-(1[right arrow]4)-[beta]-D-glucopyranoside (Fig.
Aldose reductase inhibition of a saponin-rich fraction and new furostanol saponin derivatives from Balanites aegyptiaca
For liquid chromatographic separation of the epimers, different stationary-phase chemistries have been investigated.
Mass spectrometric profiling of vitamin D metabolites beyond 25-hydroxyvitamin D
Gotlinger, "Resolvins, docosatrienes, and neuroprotectins, novel omega-3-derived mediators, and their endogenous aspirin-triggered epimers," Lipids, vol.
Beneficial effects of omega-3 polyunsaturated fatty acids in gestational diabetes: consequences in macrosomia and adulthood obesity
22R homohopanes are more abundant than 22S epimers and the 22S/(22S + 22R) homohopane ratio of oil shale samples is very low (Table 6).
Organic geochemical characteristics of Miocene oil shale deposits in the Eskisehir Basin, Western Anatolia, Turkey

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