A compound (II) is reacted with a compound (III) or a reactive derivative at the carboxyl group thereof to obtain a compound (IV), which is reacted with a mixed acid anhydride of a compound (V) to prepare a compound (I). In recrystallization of the compound (I), temperature for the recrystallization and/or time for the crystal precipitation is controlled to selectively produce A-form crystals, B-form crystals and C-form crystals of the compound (I).
[Chemical formula 1]
化合物(II)与化合物(III)或其羧基的反应性衍
生物反应,得到化合物(IV),然后与化合物(V)的混合酸酐反应,制备化合物(I)。在化合物(I)的重结晶中,控制重结晶的温度和/或晶体沉淀的时间,以选择性地产生化合物(I)的A型晶体、B型晶体和C型晶体。[
化学式1]