Epimerization of erythromycin derivatives.
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چکیده
منابع مشابه
Epimerization of erythromycin derivatives.
Dirithromycin (3) isomerizes upon dissolution in different solvents. From X-ray analysis of V-T 108, an analogue of dirithromycin, and comparative 1H and 13C NMR, and MS data, the isomer of dirithromycin was confirmed to be the C-16-(S)-epimer. The ratio of the two epimers at equilibrium conditions was approximately 8:2 (R/S) in methanol at room temperature.
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The methylmalonyl coenzyme A (methylmalonyl-CoA)-specific acyltransferase (AT) domains of modules 1 and 2 of the 6-deoxyerythronolide B synthase (DEBS1) of Saccharopolyspora erythraea ER720 were replaced with three heterologous AT domains that are believed, based on sequence comparisons, to be specific for malonyl-CoA. The three substituted AT domains were "Hyg" AT2 from module 2 of a type I po...
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We tested bile acid oxazoline derivatives of chenodeoxycholic (CDC-OX), 7-ketolithocholic (7-KLC-OX), ursodeoxycholic (UDC-OX), and deoxycholic (DC-OX) as inhibitors of the 7-epimerization of the primary bile acids cholic acid (CA) and CDC in cultures of four species of bacteria and the human fecal flora. The organisms tested elaborate a 7aand/or 7Phydroxysteroid dehydrogenase (HSDH); they were...
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A previously unknown chemical structure, 6-desmethyl-6-ethylerythromycin A (6-ethylErA), was produced through directed genetic manipulation of the erythromycin (Er)-producing organism Saccharopolyspora erythraea. In an attempt to replace the methyl side chain at the C-6 position of the Er polyketide backbone with an ethyl moiety, the methylmalonate-specific acyltransferase (AT) domain of the Er...
متن کاملRacemization and epimerization.
In recent reports (I ) the term racemization is used inappropriately. It is stated in both reports that Lisoleucine racemizes to D-alloisoleucine. This reaction is epimerization, not racemization. Racemization of L-iSOleucine results in the formation of DLisoleucine. As stated in Eliel (2): "'racemization is the process of producing a racemic modification starting with one of the pure enantiome...
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ژورنال
عنوان ژورنال: The Journal of Antibiotics
سال: 1990
ISSN: 0021-8820,1881-1469
DOI: 10.7164/antibiotics.43.1271