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C S Koble

Publications and source records attributed to C S Koble.

6 recordsLinked to original sources
PubMed1999

Synthesis of ultra-short-acting neuromuscular blocker GW 0430: a remarkably stereo- and regioselective synthesis of mixed tetrahydroisoquinolinium chlorofumarates.

[formula: see text] The stereo- and regioselective synthesis of ultra-short-acting nondepolarizing neuromuscular blocker GW 0430 (5a) is described. Key steps involved the enantioselective transfer hydrogenation of imine 8 employing Noyori's catalyst, the stereoselective crystallization and methanolysis of trans-bataines 11 and 12, and the stereo- and regioselective trans elimination of hydrogen chloride from 14. The latter transformation allowed complete control of the position of the chloro substituent and stereochemistry at the double bond of the linker in 15.

Crystallization↗
PubMed1997

Fatty acids and eicosanoids regulate gene expression through direct interactions with peroxisome proliferator-activated receptors alpha and gamma.

Peroxisome proliferator-activated receptors (PPARs) alpha and gamma are key regulators of lipid homeostasis and are activated by a structurally diverse group of compounds including fatty acids, eicosanoids, and hypolipidemic drugs such as fibrates and thiazolidinediones. While thiazolidinediones and 15-deoxy-Delta12, 14-prostaglandin J2 have been shown to bind to PPARgamma, it has remained unclear whether other activators mediate their effects through direct interactions with the PPARs or via indirect mechanisms. Here, we describe a novel fibrate, designated GW2331, that is a high-affinity ligand for both PPARalpha and PPARgamma. Using GW2331 as a radioligand in competition binding assays, we show that certain mono- and polyunsaturated fatty acids bind directly to PPARalpha and PPARgamma at physiological concentrations, and that the eicosanoids 8(S)-hydroxyeicosatetraenoic acid and 15-deoxy-Delta12,14-prostaglandin J2 can function as subtype-selective ligands for PPARalpha and PPARgamma, respectively. These data provide evidence that PPARs serve as physiological sensors of lipid levels and suggest a molecular mechanism whereby dietary fatty acids can modulate lipid homeostasis.

Animals↗
PubMed1995

1-(Fluorobenzyl)-4-amino-1H-1,2,3-triazolo[4,5-c]pyridines: synthesis and anticonvulsant activity.

A series of (fluorobenzyl)triazolo[4,5-c]pyridines was synthesized and tested for activity against maximal electroshock-induced seizures in rodents. The most promising compound, 14 (BW 534U87), which is a carbon-nitrogen isoster of a purine anticonvulsant, has a profile in rodents that suggests 14 will be free of emesis and useful in the treatment of seizure disorders for which phenytoin is presently indicated.

Animals↗
PubMed1992

2-Acetylpyridine thiocarbonohydrazones. Potent inactivators of herpes simplex virus ribonucleotide reductase.

A series of 2-acetylpyridine thiocarbonohydrazones was synthesized for evaluation as potential antiherpetic agents. The compounds were prepared by the condensation of 2-acetylpyridine with thiocarbonohydrazide followed by treatment with isocyanates or isothiocyanates. Many were found that were potent inactivators of ribonucleotide reductase encoded by HSV-1 and weaker inactivators of human enzyme. Several thiocarbonohydrazones (e.g. 38 and 39) inactivated HSV-1 ribonucleotide reductase at rate constants as much as seven times that of lead compound 2. In general, those substituted with weak electron-attracting groups offered the best combination of potency and apparent selective activity against the HSV-1 enzyme. Seven new thiocarbonohydrazones (21, 25, 31, 36, 38, 39, and 40) were apparently greater than 50-fold more selective than 2 against HSV-1 ribonucleotide reductase versus human enzyme. The results indicated new compounds worthy of further study as potentiators of acyclovir in combination topical treatment of herpes virus infections.

Antiviral Agents↗
PubMedDate not supplied

Isolation and characterization of an ether glucuronide of zidovudine, a major metabolite in monkeys and humans.

A major metabolite of zidovudine (3'-azido-3'-deoxythymidine, AZT), which previously had not been observed in a variety of experimental animals, was identified in samples of plasma and urine from cynomolgus monkeys and a patient treated with AZT. The urinary recoveries of metabolite from the monkeys and the patient were, respectively, 1.5- and 6.9-fold higher than the recoveries of unchanged drug. The metabolite was purified in gram quantities from the urines of the monkeys and the patient and was identified enzymatically, using beta-glucuronidase and a specific inhibitor of the enzyme, as a glucuronide conjugate of AZT. The metabolite was formed in vitro by incubating AZT with preparations of human liver in the presence of UDP-glucuronic acid. In addition, the metabolite was prepared synthetically and physical characterizations--including microanalysis and UV, IR, NMR and mass spectra--of compound from all three sources were identical and confirmed the metabolite to be the 5'-O-beta-D-glucuronide of AZT.

Animals↗