Arocalciferols: synthesis and biological evaluation of aromatic side-chain analogues of 1 alpha,25-dihydroxyvitamin D3(1a).

Aromatic side-chain analogues (arocalciferols 6-9) of the steroid hormone 1 alpha,25-dihydroxyvitamin D3 (1) were synthesized and biologically evaluated. The analogues were prepared by coupling the vitamin D A-ring enyne 14 with the appropriate enol triflate of a modified CD steroid fragment of the type 22. The resulting dienyne 23 was then transformed in three steps to the vitamin D analogues 6-9. Biological evaluation of these analogues have provided information concerning side-chain topographical effects on in vivo and in vitro activity.