ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The recent experiments on the chloride-assisted dealkylation of alkylcobalamins by a variety of oxidants (IrCl62-, AuCl4-, Fe(H2O)5Cl2+, and PtCl62-), which are scattered in several previous publications, and their general kinetic characteristics are summarized. The kinetic studies are also extended to include the dealkylations of (methylaquo)-3,5,6-trimethylbenzimidazolylcobamide and protonated base-off ethylcobalamin by IrCl62- (1.0M Cl-) and by Fe(III) ions at 0.1M Cl-, and the demethylation of (methylaquo)-3,5,6-trimethylbenzimidazolylcobamide by AuCl4- (1.0M Cl-). This extension is in an effort to substantiate the general mechanism which has been previously proposed for these oxidative dealkylations. The general kinetic characteristics are described in terms of a preassociation of the reactants, followed by a rate-determining electron-transfer process to yield the R-B12+ radical, which then undergoes further reactions to produce the products observed. The overall reactions are discussed within the framework of chlorine-bridging inner sphere electron-transfer reactions.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550160310
