SYNTHESIS OF NOVEL VITAMIN-D ANALOGS

Structural modifications of the side-chain of vitamin D lead potential ly to analogs in which a separation is effected between calcemic activ ity and cellular differentiation. Vitamin D analogs are used clinicall y for diseases involving cell proliferation. We have discovered an imp ortant lead compound, namely, 24- (R)-ethyl-1 alpha-hydroxyvitamin D-3 (5d) also called 1 alpha-ydroxyvitamin D-5, which is active as an ant i-cancer agent. The renal metabolism of 5d results in hydroxylation at C-26 (C-27), to yield 9 or 10. Synthesis of this metabolite is presen ted.