Background:

Methylcobalamin (CH3-B12), a cobalamin, is a form of vitamin B12.

Methylcobalamin (CH3-B12) is a cobalamin, a form of vitamin B12. It differs from cyanocobalamin in that the cyanide is replaced by a methyl group. Methylcobalamin (CH3-B12) features an octahedral cobalt(III) centre. Methylcobalamin (CH3-B12) can be obtained as bright red crystals. From the perspective of coordination chemistry, Methylcobalamin (CH3-B12) is notable as a rare example of a compound that contains metal-alkyl bonds. Methylcobalamin (CH3-B12) is equivalent physiologically to vitamin B12, and can be used to prevent or treat pathology arising from a lack of vitamin B12 (vitamin B12 deficiency), such as pernicious anemia. Methylcobalamin (CH3-B12) is also used in the treatment of peripheral neuropathy, diabetic neuropathy, and as a preliminary treatment for amyotrophic lateral sclerosis. From Wikipedia.

参考文献:
[1]. http://en.wikipedia.org/wiki/Methylcobalamin