INTERMEDIATE OF 19-NOR-VITAMIN D COMPOUND AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a new compound useful as the precursor of an intermediate (ring A synthon) used for a new method for synthesizing a 19-norvitamin D compound expected on a use as a medicine for treating malignant tumor. SOLUTION: A compound of formula I (X<1> and X<2> are each hydrogen or a hydroxy-protecting group; X<4> is hydroxy or a protected hydroxy), for example, (3R,4R,5R)ethyl[3,5-bis(tert-butyldimethylsilyloxy)-4-hydroxy]-cyclohe xylidene carboxylate. The compound of formula I is obtained by removing the 4-hydroxy of a quinic acid expressed by formula II (X<1> and X<2> are each a hydroxy- protecting group), for example, by a method comprising converting the hydroxyl group into a thiono-ester group and subsequently treating the product with a hydrogen radical source in the presence of a radical initiator, and subsequently condensing the obtained ketone of formula III.