A new kind of analogues of coenzyme B-12 base-off form, which are cobi
namides containing 2'-deoxynucleosides, were synthesized by an improve
d method. They are 2',5' dideoxyuridinylcobinamide , 2',5'-dideoxyaden
osylcobinamide, 2',5'-dideoxycytidylcobin amde, and 5'-deoxythymidylco
binamide. All the four analogues were investigated by UV-Vis and 2D H-
1 NMR spectroscopies. The spectroscopic properties with those of their
corresponding cobalamins were compared.