4442-17-5Relevant academic research and scientific papers
Site-selective oxidation, amination and epimerization reactions of complex polyols enabled by transfer hydrogenation
Hill, Christopher K.,Hartwig, John F.
, p. 1213 - 1221 (2017/11/28)
Polyoxygenated hydrocarbons that bear one or more hydroxyl groups comprise a large set of natural and synthetic compounds, often with potent biological activity. In synthetic chemistry, alcohols are important precursors to carbonyl groups, which then can be converted into a wide range of oxygen- or nitrogen-based functionality. Therefore, the selective conversion of a single hydroxyl group in natural products into a ketone would enable the selective introduction of unnatural functionality. However, the methods known to convert a simple alcohol, or even an alcohol in a molecule that contains multiple protected functional groups, are not suitable for selective reactions of complex polyol structures. We present a new ruthenium catalyst with a unique efficacy for the selective oxidation of a single hydroxyl group among many in unprotected polyol natural products. This oxidation enables the introduction of nitrogen-based functional groups into such structures that lack nitrogen atoms and enables a selective alcohol epimerization by stepwise or reversible oxidation and reduction.
Biotransformation of extracted digitoxin from Digitalis lanata by Streptomyces
Keshk, Sherif,Mostafa,Tawfik,Elshemy
experimental part, p. 458 - 462 (2012/01/07)
The biotransformation of digitoxin and some of its derivatives extracted from Digitalis lanata by Streptomyces isolated species was investigated. Cultures of a Streptomyces strain designated EUSA-2003B, isolated from an Egyptian soil sample, efficiently induced selective 12β-hydroxylation of the steroid aglycone of digitoxin (DT) and its α-acetyl and β-methyl derivatives. The transformation reaction was performed within a 5-day fermentation process, products were isolated and their aglycone moiety was obtained by acid hydrolysis and their structures were elucidated by 13C and 1H NMR. The biotransformation resulted mainly digoxin (DG,～87%), meanwhile, digoxigenone (DGON,～7.0%)was also afforded as a side product. The present study revealed that: 1-Streptomyces isolate EUSA2003B harbors its specific 12β-hydroxlase and has the capability to transform DT and it's α-acetyl and α-methyl derivatives into their corresponding digoxins at reasonable yields. 2-The minor structural differences in the trisaccharide side chain seemed ineffective on the transformational capability of this organism. 3-The Streptomyces might also possess a specific glycosidase that splits the saccharidic side chain beside another dehydrogenase that oxidizes C3 at the steroid nucleus into its ketone form (DGON).
Fluorescence immunoassays using fluorescent dyes free of aggregation and serum binding
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, (2008/06/13)
Fluorescence immunoassays methods are provided which use fluorescent dyes which are free of aggregation and serum binding. Such immunoassay methods are thus, particularly useful for the assay of biological fluids, such as serum, plasma, whole blood and urine.
Genetically engineered enzymes and their conjugates for diagnostic assays
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, (2008/06/13)
This invention relates to genetically engineered enzymes, their ligand conjugates, their manufacture, and their use in qualitative or quantitative assays. A hybrid enzyme, such as an AP-epitope, has a foreign amino acid moiety (an epitope) inserted near the active site of the starting AP enzyme. The foreign amino acid moiety binds with an analyte, and, as a consequence of this binding, the enzymatic activity of the hybrid enzyme, AP-epitope, is modified. The changes in the enzymatic activity are dependent upon the presence, or the amount, of the analyte. In another embodiment, the hybrid enzyme consists of a cysteine introduced near the active site of an AP to give a hybrid enzyme. The cysteine on the hybrid enzyme serves as a point of conjugation of a ligand, such as theophylline, ferritin, thyroxine, or digoxigenin, to form the hybrid enzyme-ligand conjugate. The ligand binds with an antibody, an analyte or a binding molecule to an analyte and as a result of this binding, the enzymatic activity of the hybrid enzyme-ligand conjugate is modified or modulated.
Rearrangement of 14β-Hydroxy-12β-sulfoxy-steroids to 13,17-Seco-12,17-cyclo-steroids; a 2D-NMR Analysis
Habermehl, Gerhard G.,Hammann, Peter E.
, p. 656 - 660 (2007/10/02)
The rearrangement of 3-oxo-14β-hydroxy-12β-methanesulfoxy-card-20(22)-enolide and 14β-hydroxy-12β-methanesulfoxy-pregnane-3,20-dione during elimination of the sulfoxygroups was studied.By means of 2D-NMR analysis the structures were determined as 13,17-seco-12,17-cyclo-steroids. - Keywords: 13,17-Decyclo-12,17-cyclosteroids, Steroid Rearrangement, NMR Spectra
Cardiac glycoside enzyme conjugates
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, (2008/06/13)
Enzyme conjugates are prepared of cardiac glycosides and aglycones for use in homogeneous enzyme immunoassays. The conjugates retain a substantial degree of the original activity of the enzyme and upon binding of receptor to the steroid moiety, a substantial diminution of enzyme activity is obtained. Various linking groups are employed for linking the steroid portion of the molecule to the enzyme, such as non-oxo carbonyl groups.
Selenium-75 steroids
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, (2008/06/13)
Novel dimeric and monomeric selenium-75 derivatives of steroids are made by reacting a keto steroid with selenium-75 dioxide or selenious acid-Se75. The resulting diselenide dimers can be converted into monomeric compounds by the use of a cleaving reagent followed by an alkylating agent. The compounds are useful in saturation analyses such as radioimmunoassays.
