Synthesis and evaluation of a 3-position diastereomer of 1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71)

Abstract A 3-position diastereomer of 1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D 3 (ED-71, 2 ), 3- epi -ED-71 ( 4 ), was synthesized by the convergent method coupling the A-ring fragment ( 5 ) with the C/D-ring fragment ( 6 ). As the results of preliminary in vitro biological evaluation of 3- epi -ED-71 ( 4 ), the inhibition of parathyroid hormone secretion in bovine parathyroid cells and binding affinity to human recombinant vitamin D receptor and to human vitamin D binding protein in comparison with ED-71 ( 2 ), 1α,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 , 1 ), and 3- epi -1,25(OH) 2 D 3 ( 3 ) are described.