Identification of the b, d, and e analogs of vitamin B12 as monocarboxylic acids by 15N NMR spectroscopy

Abstract
15N NMR spectra of b−, d−, and e‐cyanocobalamin (vitamin B12) and the products of their amidation with 15N‐labeled ammonia show that these analogs are monocarboxylic acids of vitamin B12 which result from hydrolysis at the respective propionamide groups.