ChemInform Abstract: IMPROVED METHOD FOR OXIDATIVE CLEAVAGE OF DIHYDROXYACETONE SIDE-CHAINS OF CORTICOSTEROIDS

1983 ◽  
Vol 14 (23) ◽  
Author(s):  
V. F. SHNER ◽  
Z. V. DYBAILO
Keyword(s):  
Oxidative Cleavage ◽  
Side Chains ◽  
Improved Method

scholarly journals Anaerobic and aerobic coproporphyrinogen III oxidases of Rhodopseudomonas spheroides. Mechanism and stereochemistry of vinyl group formation

1983 ◽  
Vol 209 (3) ◽  
pp. 709-718 ◽  
Author(s):  
J S Seehra ◽  
P M Jordan ◽  
M Akhtar
Keyword(s):  
Hydrogen Atom ◽  
Group Formation ◽  
Side Chains ◽  
Improved Method ◽  
Conversion Formula ◽  
Coproporphyrinogen Iii Oxidase ◽  
Rhodopseudomonas Spheroides ◽  
Vinyl Group

An improved method for the preparation of various species of porphobilinogen stereospecifically labelled with 3H in the side chains (at C-6, C-7 and C-8) is described. These labelled samples were used to study the mechanism and stereochemistry of anaerobic as well as aerobic coproporphyrinogen III oxidase of light-grown Rhodopseudomonas spheroides. It was shown that both the oxidases catalyse the conversion of the propionate side chains of coproporphyrinogen III into the vinyl groups of protoporphyrinogen IX, (formula; see text) with the labilization of the pro-S-hydrogen atom at the beta-position. These results are similar to those previously recorded for such conversions in animal and plant systems. In the light of the cumulative information available to date, mechanisms for the conversion, (formula; see text) are discussed and doubt is cast on the participation of hydroxylated intermediates in the process.

A convenient new procedure for the oxidative cleavage of the bile acid and lanosterol side chains

Tetrahedron ◽  
1974 ◽  
Vol 30 (22) ◽  
pp. 3981-3989 ◽  
Author(s):  
M. Fetizon ◽  
F.J. Kakis ◽  
V. Ignatiadou-Ragoussis
Keyword(s):  
Bile Acid ◽  
Oxidative Cleavage ◽  
Side Chains

Cation Exchange Resin Supported Oxidation of Alkylbenzenes and Olefins using Potassium Permanganate†

2000 ◽  
Vol 2000 (1) ◽  
pp. 38-39 ◽  
Author(s):  
Padmaker L. Joshi ◽  
Braja G. Hazra
Keyword(s):  
Cation Exchange ◽  
Potassium Permanganate ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Oxidative Cleavage ◽  
Side Chains ◽  
Cation Exchange Resins ◽  
Exchange Resins

Rapid and efficient oxidation of alkylbenzene side chains at the benzylic positions as well as oxidative cleavage of olefins with potassium permanganate in presence of solid polymeric cation exchange resins in good yields is reported.

An Improved Method for the Preparation and TEM Examination of Sharp Pointed Tips used in APFIM and STM

1990 ◽  
Vol 48 (2) ◽  
pp. 102-103
Author(s):  
E.A. Fischione ◽  
P.E. Fischione ◽  
J.J. Haugh ◽  
M.G. Burke
Keyword(s):  
Atom Probe ◽  
Preparation Process ◽  
Improved Method ◽  
Ion Milling ◽  
Polishing Process ◽  
Probe Field ◽  
Scanning Tunnelling ◽  
Stm Tips ◽  
Tunnelling Microscopy ◽  
Ion Microscopy

A common requirement for both Atom Probe Field-Ion Microscopy (APFIM) and Scanning Tunnelling Microscopy (STM) is a sharp pointed tip for use as either the specimen (APFIM) or the probe (STM). Traditionally, tips have been prepared by either chemical or electropolishing techniques. Recently, ion-milling has been successfully employed in the production of APFIM tips [1]. Conventional electropolishing techniques are applicable to a wide variety of metals, but generally require careful manual adjustments during the polishing process and may also be time-consuming. In order to reduce the time and effort involved in the preparation process, a compact, self-contained polishing unit has been developed. This system is based upon the conventional two-stage electropolishing technique in which the specimen/tip blank is first locally thinned or “necked”, and subsequently electropolished until separation occurs.[2,3] The result of this process is the production of two APFIM or STM tips. A mechanized polishing unit that provides these functions while automatically maintaining alignment has been designed and developed.

Immunoelectron microscopic localization of elastic tissue in archival material using an improved method

1990 ◽  
Vol 48 (3) ◽  
pp. 794-795
Author(s):  
J. C. Fanning ◽  
J. F. White ◽  
R. Polewski ◽  
E. G. Cleary
Keyword(s):  
Normal Animal ◽  
Animal Tissue ◽  
Elastic Tissue ◽  
Human Tissues ◽  
Improved Method ◽  
Tissue Samples ◽  
Archival Material ◽  
Immuno Electron Microscopy ◽  
Arteries And Veins ◽  
Biochemical Examination

Elastic tissue is an important component of the walls of arteries and veins, of skin, of the lungs and in lesser amounts, of many other tissues. It is responsible for the rubber-like properties of the arteries and for the normal texture of young skin. It undergoes changes in a number of important diseases such as atherosclerosis and emphysema and on exposure of skin to sunlight.We have recently described methods for the localizationof elastic tissue components in normal animal and human tissues. In the study of developing and diseased tissues it is often not possible to obtain samples which have been optimally prepared for immuno-electron microscopy. Sometimes there is also a need to examine retrospectively samples collected some years previously. We have therefore developed modifications to our published methods to allow examination of human and animal tissue samples obtained at surgery or during post mortem which have subsequently been: 1. stored frozen at -35° or -70°C for biochemical examination; 2.

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