化合物分了结构对于口服剧毒性的一些影响是值得注意的,例如吡嗪类化合物的 LD_(50)范围为体重每千克456～1910mg,引入甲基的数目和位置对毒性有影响,如果用乙基代替甲基则毒性影响小一些,邻位甲基则大大增强毒性。噻唑类和噻唑啉类无论有没有取代基,毒性都比较小,它们的毒性表现在与硫胺素焦磷酸盐争夺酶而使酶失去活性。呋喃硫酯与它的母体2,5-二甲基-3-呋喃硫醇有类似的毒性而且毒性略轻,从这些数据可以看 For example, the LD50 of pyrazines ranges from 456 to 1910 mg / kg body weight. The number and location of methyl groups introduced have an impact on the toxicity. If the Ethyl instead of methyl is less toxic, ortho methyl greatly enhances toxicity. Thiazoles and thiazolines, with or without substituents, are less toxic and their toxicity is shown to compete with thiamin pyrophosphate for enzyme inactivation. Furanyl thioester is similar in toxicity and less toxic to its parent 2,5-dimethyl-3-furanylthiol as can be seen from these data