The preparation and characterization of the diaquo- forms of several incomplete corrinoids: cobyric acid, cobinamide, and three isomeric cobinic acid pentaamides.
The preparation of the diaquo- forms of the incomplete corrinoids, cobyric acid, cobinamide, and three isomeric cobinic acid pentaamides, from the corresponding aquocyanocorrinoids has been accomplished. The compounds were characterized by electronic absorption spectra, pka values, and HPLC/TLC behavior. Upon titration, the acids exhibited three pKa values, but only the pKa corresponding to the carboxylic acid involved the transfer of a full equivalent of protons. In addition, the progress of diaquo- to dihydroxo-titration, and the spectrum of the final products indicated a complex process. These diaquocorrinoids appear to be unstable, and should be stored in solution, frozen, under an inert atmosphere.
Ford
S H
SH
Department of Chemistry and Physics, Chicago State University, Illinois 60628.
Nichols
A
A
Shambee
M
M
D002851:Chromatography, High Pressure Liquid; D003038:Cobamides / Q000138:chemical synthesis / Q000737:chemistry*; D007536:Isomerism; D007700:Kinetics; D015394:Molecular Structure; D010084:Oxidation-Reduction; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
D003038:Cobamides; C017142:cobinamide; C012851:cobyric acid; D014805:Vitamin B 12