Synthesis of (24R)-11α-(4-carboxybutyryloxy)-24,25-dihydroxyvitamin D3: a novel haptenic derivative producing antibodies of high affinity for (24R)-24,25-dihydroxyvitamin D3

Abstract

The measurement of serum/plasma (24R)-24,25-dihydroxyvitamin D₃1a levels, which is one of the major metabolites of vitamin D₃1b, is important to clarify its physiological significance. To obtain highly specific antibodies to compound 1a which are useful for development of immunoassays, a novel haptenic derivative, (24R)-11α-(4-carboxybutyryloxy)-24,25-dihydroxyvitamin D₃2 was synthesized in 21 steps from a [17(20)Z]-ethylidene derivative 3 of 11α-hydroxydehydroepiandrosterone. The preparation of an immunogenic conjugate of the hapten 2 with bovine serum albumin and the properties of the resulting antibodies are also described briefly.