Enantioselective chemoenzymatic synthesis of oseltamivir (tamiflu)(r) intermediates

Eşiyok, Hacı
The objective of this presented study was to synthesize optically active compounds considered to be key intermediates in the synthesis of Oseltamivir (Tamiflu) by performing chemical and biotechnological methods. Thereof, the carboethoxy cyclohexenone skeleton first was synthesized utilizing easily available substances. The synthesis of alpha-hydroxy ketones in enantiomerically pure form offers a great importance in the synthesis of biologically active compounds. Toward this fact, the enantioselective synthesis of alpha-hydroxy carboethoxy cyclohexenone scaffold has been accomplished by following the routes which were manganese(III) acetate-mediated chemical oxidation followed by enzyme-mediated hydrolysis and additionally microbial direct biooxidation by whole cells of fungi expressly A. oryzae and A. flavus. A very satisfying results have been obtained by both of the methods.


Covalent immobilization of invertase on chemically activated poly(2-hydroxyethyl methacrylate) microbeads
Altinok, H.; Aksoy, S.; Tumturk, H.; Hasırcı, Nesrin (2006-10-01)
Properties of invertase immobilized on poly(2-hydroxyethyl methacrylate) microbeads activated by epichlorohydrin or cyanuric chloride were studied. After 20 repeated uses for 3 days, the activity of the immobilized enzyme was 92-93%.
CpG DNA: recognition by and activation of monocytes.
Klinman, DM; Takeshita, F; Gursel, I; Leifer, C; Ishii, KJ; Verthelyi, D; Gürsel, Mayda (2002-07-01)
Unmethylated CpG motifs present in bacterial DNA rapidly trigger an innate immune response characterized by the activation of Ig- and cytokine-secreting cells. Synthetic oligonucleotides (ODNs) containing CpG motifs mimic this activity, triggering monocytes to proliferate, secrete and/or differentiate. Analysis of hundreds of novel ODNs led to the identification of two structurally distinct classes of CpG motif that differentially activate human monocytes. ODNs of the "K"-type interact with Toll-like recept...
Aromatic amino acid synthesis performance of bacillus acidocaldarius
Kocabaş, Pınar; Çalık, Pınar; Department of Chemical Engineering (2004)
In this study, the effects of bioprocess operation parameters on aromatic amino acid synthesis performance of Bacillus acidocaldarius were investigated. Firstly, in laboratory scale shake-bioreactors, a defined medium was designed in terms of its carbon and nitrogen sources, to achieve the highest cell concentration. Thereafter, the effects of bioprocess operation parameters, i.e., pH and temperature were investigated; and the optimum medium contained (kg m-3): fructose, 8; (NH4)2HPO4, 5; CaCl2, 0.2; KH2PO4...
Speciation of Selenium in Supplements by High Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometry
BAKIRDERE, Sezgin; Volkan, Mürvet; Ataman, Osman Yavuz (2015-06-13)
Anion and cation exchange high-performance liquid chromatography (HPLC) combined with inductively coupled plasma-mass spectrometry (ICP-MS) were used for speciation of selenium in supplements. All the parameters in the extraction, separation, and determination procedures were optimized. Recovery studies for the selenium species from the anion and cation exchange columns were performed and there were no analyte losses. Limits of detection for selenium(IV), selenium(VI), Se in selenomethionine, and Se in sele...
Fluorine determination in human and animal bones by particle-induced gamma-ray emission
Sastri, CS; Iyengar, V; Blondiaux, G; Tessier, Y; Petri, H; Hoffmann, P; Aras, NK; Zaichick, V; Ortner, HM (2001-08-01)
Fluorine was determined in the iliac crest bones of patients and in ribs collected from post-mortem investigations by particle-induced gamma-ray emission based on the (19)F(p,p ' gamma)(19)F reaction, using 2.0/2.5 MeV protons. The results indicate that for 68% of the human samples the F concentration is in the range 500-1999 mug g(-1). For comparison purposes fluorine was also determined in some animal bones; in some animal tissues lateral profiles of fluorine were measured.
Citation Formats
H. Eşiyok, “Enantioselective chemoenzymatic synthesis of oseltamivir (tamiflu)(r) intermediates,” M.S. - Master of Science, Middle East Technical University, 2008.