Novel .gamma.-lactone derivatives are provided. These lactone derivatives, when reacted with hydrogen halide in alcohol, yield .gamma.-halogeno-.delta.-unsaturated carboxylic acid esters. This ring-opening process is useful for the purpose of increasing the yield of pyrethrin analogs which are of value as insecticides and agricultural chemicals. Thus, the .gamma.-lactone derivatives by-produced in the production process for dihalogenovinyl chrysanthemumates are caused to undergo ring-opening reaction to yield the corresponding .gamma.-halogeno-.delta.-unsaturated carboxylic acid esters which are important intermediates for said pyrethrin analogs.
提供了新型的.gamma.-内酯衍
生物。当这些内酯衍
生物在醇中与氢卤化物反应时,会生成.gamma.-卤代-.delta.-不饱和
羧酸酯。这种环开放反应对于增加拟
除虫菊酯类似物的产量非常有用,这些类似物在
杀虫剂和农业
化学品方面具有价值。因此,在二卤
乙烯菊酯生产过程中产生的.gamma.-内酯衍
生物会发生环开放反应,生成相应的.gamma.-卤代-.delta.-不饱和
羧酸酯,这些酯是所述拟
除虫菊酯类似物的重要中间体。