| 摘要 |
<p>NEW MATERIAL:The compound of formula I [R1 is H or (protected) OH; R2 is H or protecting group; R3 is OH; R4 is H or OH, or R3 and R4 may together form a bond; the dotted line between the 7- and 8-C atoms represents the arbi trary existence of a double bond]. EXAMPLE:26,27-F6-3beta-(2-tetrahydropyranyloxy)cholesta-5,24-diene. USE:Intermediate for pharmaceuticals, especially vitamin D compounds. PREPARATION:The compound of formula I (R3 and R4 together form a bond) can be produced by (1) reacting the 24-halogenosteroid derivative of formula II (X is halogen) with triphenyl phosphine, (2) treating the resultant phosphonium slat with a base and, (3) reacting the produc with hexafluoroacetone.</p> |
