Synthesis and assignment of novel [125I]-labeled 1 alpha,25-dihydroxyvitamin D3 derivatives

This paper describes the synthesis and structural assignment of noval 125I-1 alpha,25-dihydroxyvitamin D3 derivatives (1a) and (1b) labeled with 125I-Bolton-Hunter reagent [N-succinimidyl 3-(4-hydroxy-3-iodo[125I]phenyl)propionate] (1), which is known as a protein-labeling reagent, as tracers for radioimmunoassay (RIA). The radiospecific activities of these tracers (1a) and (1b) were calculated as 2,200 Ci/mmol (81.4 TBq/mmol).