Method of purifying carbazole ester precursors of 6-chloro-alpha-methyl-carbazole-2-acetic acid
申请人:Pfizer Products Inc.
公开号:EP0965586A1
公开(公告)日:1999-12-22
A process of purifying a (6-chloro-2-carbazolyl)methyl-malonic acid di(C1 -C6 alkyl) ester of Formula (I):
wherein Ra and Rb must be the same and are selected from the group consisting of C1 -C6 alkyl; comprises phase separating one or more impurities from said carbazole ester at least once wherein the solvent used to carry out said phase separation is acetic acid. In a preferred embodiment said acetic acid is glacial acetic acid which is maintained at a temperature of from about 30° to about 110° C and said carbazole ester is obtained in a purity of at least 99. 90% by weight, so that the amount of impurities present therein is 0.10% or less by weight. In a more preferred embodiment of said process, said temperature is from about 50° to about 70° C, and said phase separation is carried out only once.
一种提纯式(I)的(6-氯-2-咔唑基)甲基丙二酸二(C1-C6 烷基)酯的工艺:
其中 Ra 和 Rb 必须相同,且选自 C1 -C6 烷基组成的组;包括从所述咔唑酯中至少相分离一次一种或多种杂质,其中用于进行所述相分离的溶剂为乙酸。在一个优选的实施方案中,所述乙酸是冰醋酸,其温度保持在约 30° 至约 110° C,获得的所述咔唑酯的纯度至少为 99.90%(按重量计),因此其中存在的杂质量为 0.10%或更少(按重量计)。在所述工艺的一个更优选的实施方案中,所述温度为约 50° 至约 70°C,且所述相分离仅进行一次。