A. I. D. Alanine, K. Ichinose, D. Thibaut, L. Debussche, N. P. J. Stamford, F. J. Leeper, F. Blanche and A. R. Battersby
"Biosynthesis of Vitamin B12: Use of Specific 13C-Labelling for Structural Studies on Factor IV"
J. Chem. Soc., Chem. Commun.,1994, 193-196. Full Text
[1,10,20-13C3]Uro'gen III is unambiguously synthesised for enzymic conversion into precorrin-4 isolated after aerial oxidation as two epimers of Factor IV, the 13C NMR spectra of which rigorously confirm the presence of a C-1 acetyl group in precorrin-4; attachment of the fourth methyl group at C-17 of precorrin-4 is also confirmed by related 13C-labelling experiments.
Department of Chemistry
University of Cambridge