PURPOSE: To obtain a compound useful as an intermediate for the synthesis of medicines, by esterifying and isomerizing one of the stereoisomers of hydroxycholesterol in the presence of a diazodicarboxylic acid and a phosphine.
CONSTITUTION: (A) A hydroxycholesterol of formula I: (R1 is acyl or a group forming an ether group with a hydroxyl group, etc.; R2 is H, hydroxyl, acyl, or a hydroxyl group protected by a group forming an ether group with a hydroxyl group) is reacted with (B) a diazodicarboxylic dialkyl ester of formula II: (R3 is alkyl group) in the presence of (C) a triarylphosphine, in (D) a solvent, e.g. an organic carboxylic acid, e.g. benzoic acid, and tetrahydrofuran at room temperature to isomerize and esterify the hydroxyl group linked to the asymmetric carbon atom at the 24-position. The acyl group is hydrolyzed to eliminate the hydroxyl-protecting group, if necessary.
FUJIMOTO YOSHINORI
TAKESHITA TOORU
IKEGAWA NOBUO
SHINGIJUTSU KAIHATSU JIGYODAN
TEIJIN IYAKU KK
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