| abstract |
NEW MATERIAL: A compound represented by formula I (wherein K is O, ethylenedioxy; R 1 , R 2 are each H, an acyl) or by formula II. n EXAMPLE: 1α-25-Dihydroxy-24-epivitamin D 2 wherein K is ethylene-dioxy. n USE: A precursor of 1α,25-dihydroxylated compounds of the vitamin D 2 series such as 1α,25-dihydroxyvitamin D 2 and (24R)-epimer thereof, etc. n PREPARATION: A vitamin D-ketal derivative of formula III (wherein R is H, tosyl) is subjected to solvolysis in an alcoholic medium to form a novel compound of formula IV (wherein Z is CH 3 ) and this compound is added to a CH 2 Cl 2 solution containing anhydrous pyridine of SeO 2 and t-BuOOH to obtain a compound of formula V wherein R 1 is H. This compound is acetylated with pyridine and an acetic anhydride solution to form a compound of formula V wherein R 1 is an acyl, which is then reacted with p-toluenesulfonic acid in a dioxane/H 2 O mixed solution to obtain a compound of formula I wherein K is ethylenedioxy. n COPYRIGHT: (C)1990,JPO |