PROBLEM TO BE SOLVED: To provide a method for crystallizing a vitamin D derivative represented by formula (I), the method being carried out more economically and in a shorter time than the conventional technique.SOLUTION: A crude vitamin D derivative represented by formula (I) is dissolved, at room temperature, in a carboxylic acid (acetic acid or propionic acid) at a proportion of 1 g of the former to 10-50 ml of the latter, and then an adequate poor solvent (hydrocarbon or water) is added to deposit the crystal of the vitamin D derivative. Then, the deposited crystal is filtrated and dried to gain the crystal of the vitamin D derivative which is high in purity. The method gains the objective crystal at a shorter time and at a higher yield than the conventional method.COPYRIGHT: (C)2012,JPO&INPIT【課題】 従来技術より短時間で、しかも経済的に実施することができる、式(I)で表されるビタミンD誘導体の結晶化方法の提供。【解決手段】式(I)で示されるビタミンD誘導体の粗体を、粗体1gに対して10~50mlのカルボン酸(酢酸またはプロピオン酸)に室温で溶解し、さらに適当な貧溶媒(炭化水素または水)を加え、ビタミンD誘導体の結晶を析出させる。次に析出した結晶をろ過し、乾燥することにより、ビタミンD誘導体の高純度結晶を得る。従来の方法に比べて短期間でしかも高収率で目的の結晶を取得することができる。【選択図】 なし
