4: R'= H, R2= OH essential for enzymatic hydroxylation to la, 25-dihydroxyvitamin D,(3), which is thought to be the hormonal form of the vitamin. The introduction of the la-hydroxy substituent is an essential metabolic event for the action of vitamin D on b0ne. l la, 25- Dihydroxyvitamin D3 (3), together with the synthetic analogue la-hydroxyvitamin D3 (4), has been studied clinically in several disease states such as chronic renal failure, ...
![(2S,14S)-14-((E)-((1R,3aS,7aR)-7a-methyl-1-((R,Z)-6-methyl-6-((triethylsilyl)oxy)hept-3-en-2-yl)hexahydro-1H-inden-4(2H)-ylidene)methyl)-7,12-dioxo-1,2,3,4,5,7,12,14-octahydrophthalazino[2,3-b]phthalazin-2-yl acetate结构式](https://image.chemsrc.com/caspic/429/104875-13-0.png)
