申请人:ZENECA LIMITED
公开号:EP0832873A1
公开(公告)日:1998-04-01
A process for the preparation of a lower alkyl ester of 3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)- 2,2-dimethylcyclopropane carboxylic acid where lower alkyl means alkyl of up to four carbon atoms which comprises the steps of (a) reacting a compound of formula:
CF3-CXCl-CH(OH)-CH=C(CH3)2 (I)
wherein X is chloro or bromo, with a tri-lower-alkyl orthoacetate containing up to four carbon atoms in each alkyl group in the presence of at least a catalytic amount of an active clay at an elevated temperature for a sufficient time to obtain a compound of formula:
CF3-CXCl-CH=CH-C(CH3)2-CH2CO2R (III)
wherein R is an alkyl group containing up to four carbon atoms, and (b) treating said compound of formula (III) with at least one molar equivalent of a base to obtain said alkyl ester of 3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropane carboxylic acid.
一种制备 3-(2-氯-3,3,3-三氟丙烯-1-基)-2,2-二甲基环丙烷羧酸的低级烷基酯的工艺,其中低级烷基指碳原子数不超过四个的烷基,该工艺包括以下步骤:(a)使式:
CF3-CXCl-CH(OH)-CH=C(CH3)2 (I)
其中 X 为氯或溴,与每个烷基中含有最多四个碳原子的三低烷基原乙酸酯在至少催 化量的活性白土存在下,在高温下反应足够长的时间,以获得式化合物:
CF3-CXCl-CH=CH-C(CH3)2-CH2CO2R (III)
其中 R 是含有最多四个碳原子的烷基,以及 (b) 用至少一个摩尔当量的碱处理所述式 (III) 化合物,以获得所述 3-(2-氯-3,3,3-三氟丙烯-1-基)-2,2-二甲基环丙烷羧酸烷基酯。