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对氯苯氧异丁酸,[α-(4-氯苯氧基)-α-甲基丙酸],是合成降血脂药安妥明及类似物的主要中间体。文献报道对氯苯氧异丁酸的合成是在无水条件下,以固体氢氧化钠为催化剂,将对氯苯酚与丙酮、氯仿缩合而得,收率约50～75％。因固体氢氧化钠在丙酮中溶解度小,需长时间搅拌才能溶解。若用浓氢氧化钠溶液代替,则催化能力降低,并会引起氯仿水解。鉴于上述缺点,我们根据文献的提示,改用相转移催化法合成。以氯化三乙基苄基铵(TEBA)为相转移催化剂,使对氯苯酚与丙酮和氯仿之间的反应在50％氢氧化钠溶液中进行。反应历程可能是氯仿在TEBA和苛性
Para-chlorophenoxyisobutyric acid, [α- (4-chlorophenoxy) -α-methylpropionic acid], is a major intermediate in the synthesis of hypolipidemic agents such as clofibrate and its analogues. Reported in the literature of chlorophenoxy isobutyric acid synthesis is in anhydrous conditions, solid sodium hydroxide as catalyst, the p-chlorophenol and acetone, chloroform derived from condensation, the yield of about 50 to 75%. Due to the low solubility of solid sodium hydroxide in acetone, stirring takes a long time to dissolve. If replaced with concentrated sodium hydroxide solution, the catalytic ability to reduce, and will lead to chloroform hydrolysis. In view of the above shortcomings, according to the tips of the literature, we use phase transfer catalysis instead. The reaction between p-chlorophenol and acetone and chloroform was carried out in 50% sodium hydroxide solution using triethylbenzylammonium chloride (TEBA) as the phase transfer catalyst. The reaction may be chloroform in TEBA and caustic