(±)-2-(3,4-Carbonyldioxyphenyl)-2-(phthalimidooxy)acetic acid [(±)-1] was efficiently resolved into a pair of optically active forms by preferential crystallization. Successive preferential crystallization of (±)-1 was experimented at 15 °C under stirring in acetone, and (+)- and (−)-1 with optical purity of 68–85% were obtained. The racemization of (−)-1 proceeded smoothly in the presence of triethylamine to give (±)-1 which was reusable for the preferential crystallization procedure. A potent antipseudomonal cephalosporin M-14659 (2) was prepared from (+)-1.
(±)-2-(3,4-羧基二氧苯基)-2-(邻苯二甲酰胺氧基)
乙酸[(±)-1]通过优先结晶高效分离为一对光学活性形式。在15°C下搅拌的条件下,在
丙酮中对(±)-1进行了连续的优先结晶实验,得到了光学纯度为68–85%的(+)和(−)-1。(-)-1在
三乙胺的存在下平稳地进行了外消旋化反应,生成了可重复用于优先结晶过程的(±)-1。一种有效的抗伪单胞菌
头孢菌素M-14659(2)是从(+) -1制备而来的。