Synthesis and biological activity of 1α,2α,25-trihydroxyvitamin D3: active metabolite of 2α-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D3 by human CYP3A4.

ABSTRACT

Our previous studies revealed that recombinant human CYP3A4 converted 2α-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D3 (O2C3), which was a more potent binder to vitamin D receptor (VDR) than the natural hormone, 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3, 1), to 1α,2α,25-trihydroxyvitamin D3 (2). Here, we synthesized 2 using the Trost Pd-mediated coupling reaction between an A-ring precursor and a CD-ring bromoolefin and evaluated its preliminary biological activity. We found that metabolite 2 from O2C3 was still active as a VDR ligand while maintaining human VDR binding affinity (27.3% of 1α,25(OH)2D3) and HL-60 cell differentiation activity (62% of 1α,25(OH)2D3).