| 摘要 |
PROBLEM TO BE SOLVED: To enable the esterification of exclusively the desired hydroxyl group without protecting other hydroxyl groups by reacting mometasone with furoyl chloride in an inert solvent in the presence of a specific amine. SOLUTION: The objective mometasone 17-(2-furoate) can be produced by reacting mometasone with 2-furoyl chloride in an inert solvent (preferably a non-polar water-immiscible solvent, especially preferably dichloromethane) in the presence of a t-amine (preferably triethylamine). The amounts of 2-furoyl chloride and triethylamine are preferably 2.5-4 equivalent and 3-6 equivalent based on 1 (mol) equivalent of mometasone, respectively. The reaction is preferably carried out at 0-25 deg.C. Preferably, the product produced by the above reaction is treated with an aqueous solution of hydrochloric acid to remove an enol-type furoate formed at the 3- and 20-site of mometasone furoate.
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