Abstract
When cyanocobalamin was heated in 0.4% NaOH at 100℃ for 10 minutes in a nitrogen atmosphere, a yellow-brown substance was formed whose absorption spectrum was similar to that of vitamin B_<12r>. The product, a mixture of neutral and mono- to tri-basic acid components, was readily oxidized by air, and it was found to be reactive with alkyl halide. Neutral components of the reaction products of the yellow-brown substance with methyl iodide and n-butyl bromide were identified respectively with Co-methyl-and Co-n-butyl-derivatives of dehydrocobalamin, by their absorption spectra and by the properties and behaviors of their photolysis and cyanide treatment products in spectra, paper chromatography and in re-treatment with alkali. Therefore, the acidic components were considered to be respectively carboxylic acids derivatives of Co-methyl- and Co-n-butyl-dehydrocobalamin. While cyanocobalamin and aquo (or hydroxo) cobalamin turned yellow-brown rapidly by this alkali treatment, cyano-dehydrocobalamin and aquo (or hydroxo)-dehydrocobalamin changed very slowly. From these facts it is considered that the occurence of the yellow-brown color was due to the reduction of cobalt atom accompanied by the dehydrogenation on the ring B in the corrin nucleus.
