The subject of the invention is process the preparation of travoprost of formula (I) characterized by that the free acid of formula (II) is a.) activated with 2-chloro-1,3-dimethylimidazolinium chloride (DMC) and the resulting activated carboxylic acid intermediate is reacted with isopropyl alcohol, or b.) reacted with alkyl haloformate and the resulting mixed anhydride is reacted with isopropyl alcohol, or c.) activated with a straight or branched C1-8 dialkyl dicarbonate and reacted with isopropanol in the presence of water-free magnesium salt.本發明係關於製備式(I)的曲伏前列素(travoprost)之方法,其特徵是式(II)之自由態酸是a.)用2-氯-13-二甲基氯化咪唑啉鎓(DMC)活化並將所得經活化的羧酸中間物與異丙醇反應,或b.)與鹵甲酸烷基酯反應並將所得的混合酐與異丙醇反應,或c.)用直鏈或支鏈的二碳酸C1-8二烷基酯活化,並在無水鎂鹽存在下與異丙醇反應。
