Synthesis, spectroscopic characterization, axial base coordination equilibrium and photolytic kinetics studies of a new coenzyme B12 analogue-3′-deoxy-2′,3′-anhydrothymidylcobalamin

Abstract

A new coenzyme B₁₂ (AdoCbl) analogue, 3′-deoxy-2′,3′-didehydrothymidylcobalamin (2′,3′-anThyCbl) was prepared by the reaction of 5′-iodo-3′-deoxy-2′,3′-dihydrothymidine with reduced B_12a, and characterized by UV-Vis, CD, ESI-MS and NMR spectroscopies. Its axial base (dbzm) coordination equilibria with pH's and temperatures were investigated and showed similar features to those of coenzyme B₁₂. Photolytic dynamics studies under homolytic and heterolytic conditions demonstrated that the Co–C bond of the analogue is slightly more photolabile relative to coenzyme B₁₂.