申请人:Dynamit Nobel Aktiengesellschaft
公开号:US04198341A1
公开(公告)日:1980-04-15
A method of preparing certain dihalogen vinyl cyclopropane carboxylic acid esters of the formula ##STR1## wherein R is an alkyl moiety and X is chlorine or bromine by exposing a dihalogen vinyl dihydrofuran of the formula ##STR2## to light, e.g., ultraviolet light. Also disclosed is a method for preparing such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans by reaction of a .beta.-alkoxycrotonic acid ester or 3,3-bisalkoxybutyric acid ester with a 1,1,1-trihalogen-4-methyl-3- or -4-pentene-2-ol in the presence of an acid catalyst. Also disclosed is a method of converting such 2,4,4-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof uran by thermal rearrangement into 2,5,5-trimethyl-3-carbalkoxy-4-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans. Such 2,4,4- and 2,5,5-trimethyl-3-carbalkoxy-5-(.beta.,.beta.-dihalogenvinyl)-4,5-dihydrof urans are new.
一种制备某些二卤代乙烯基环丙烷羧酸酯的方法,其化学式为##STR1##其中R是烷基,X是氯或溴,方法是将二卤代乙烯基二氢呋喃的化学式##STR2##暴露于光线下,例如紫外线。还公开了一种制备这种2,4,4-三甲基-3-羧基烷氧基-5-(β,β-二卤代乙烯基)-4,5-二氢呋喃的方法,该方法是在酸催化剂存在下,将β-烷氧基巴豆酸酯或3,3-双烷氧基丁酸酯与1,1,1-三卤代-4-甲基-3或4-戊烯-2-醇反应。还公开了一种将这种2,4,4-三甲基-3-羧基烷氧基-5-(β,β-二卤代乙烯基)-4,5-二氢呋喃通过热重排反应转化为2,5,5-三甲基-3-羧基烷氧基-4-(β,β-二卤代乙烯基)-4,5-二氢呋喃的方法。这些2,4,4-和2,5,5-三甲基-3-羧基烷氧基-5-(β,β-二卤代乙烯基)-4,5-二氢呋喃是新的。