Journals

Dolphin, D.H., Johnson, A.W., and Shaw, N. “Sulphitocobalamin”, Nature, 1963, 199, 170-171.

A wide range of cobalamins exist where the cyano group of the original vitamin B₁₂ is replaced, for example, by water (vitamin B₁₂), halides, nitrite, sulphur-containing groups, and alkyl groups (the coenzymes and analogues) and the nature of the ligand attached to the cobalt has a profound influence on the chemical and physical properties of the cobalamin.

MeCo(III) and EtCo(III) etioporphyrin I derivatives were prepared by the treatment of the Co(py)Br complex with RMgX in (MeO)₂C₂H₄ (R is alkyl). Spectral evidence was obtained for the Co(III) analogs with allyl, C₆H₁₁, and Ph groups. The N.M.R. spectrum of the Me compound indicates that the Co is bonded to Me and to the porphyrin ring, but not to C₅H₅N. The alkyl compounds are stable toward KCN except in light.