7beta,8beta-Lactocyanocobalamin (Crude)

7β,8β-Lactocyanocobalamin (Crude) is a cyanocobalamin derivative featuring a cyclic ester (lactone) formed between the 7β-hydroxyl and 8β-carboxyl groups of the corrinoid core. This structural modification introduces a five-membered γ-lactone ring, altering the parent vitamin B12's coordination chemistry and redox properties. The compound arises as a synthetic byproduct during cobalamin lactonization processes, reflecting partial cyclization of the 7,8-diol intermediate. Functions as an HPLC reference standard for quantifying lactonization impurities in cyanocobalamin manufacturing.