Synthesis and Assignment of Novel (125I)-Labeled 1.ALPHA.,25-Dihydroxyvitamin D3 Derivatives.

This paper describes the synthesis and structural assignment of novel 125I-l α, 25-dihydroxyvitamin D3 derivatives (1a) and (lb) 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 (lb) were calculated as 2, 200 Ci/mmol (81.4TBq/mmol).