production of vitamin d2 and vitamin d3 or active vitamin d2 and active vitamin d3 or its derivatives.

摘要

Vitamin D2 and Vitamin D3 derivs of formula (I) (where R is H or Me; R3 is H or a hydroxyl-protecting gp; X and Y are H, 0H or a derivatised 0H; broken line is a single bond or (if R=H) a double bond); are produced from the 7,8-dihydroxy derivs of formula (II) (where R1 and R2 are H or a hydroxyl-protecting gp) by reductive elimination via the cyclic orthoester or thiocarbonate on the 7,8-hydroxyl gps, or by elimination using a reductive metal such as Ti.