Synthetic studies of vitamin D analogues. XIV. Synthesis and calcium regulating activity of vitamin D3 analogues bearing a hydroxyalkoxy group at the 2 beta-position.

Four vitamin D3 analogues (7a, 7b, 7c and 7d) bearing a hydroxyalkoxy group at the 2 beta-position were synthesized from the alpha-epoxide (5). The C-3 analogue (7b) showed the highest potency for elevating plasma calcium levels in rats. Furthermore, the 25-hydroxylated C-3 analogue (ED-71) (3), prepared from the 25-hydroxylated alpha-epoxide (9), significantly increased plasma calcium to levels much higher than those in rats administered 1 alpha,25-(OH)2-D3 (1).