By employing sanguinarine, a natural active quaternary isoquinoline alkaloid, as a model molecule, a series of structurally simple quaternary 2-aryl-3,4-dihydroisoquinolin-2-ium compounds were designed and synthesized and evaluated for in vitro acaricidal activity against P. cuniculi. A new approach towards the title compounds was developed with isochroman as starting material. The results showed that 22 of 24 tested compounds displayed the activity in varying degrees at 0.4 mg/mL. Fourteen compounds were significantly more effective than ivermectin, a standard acaricide, and 6-methoxy dihydrosanguinarine, a derivative of sanguinarine (p<0.05). And their comprehensive relative activity was 1.4 to 16.5 times than that of ivermectin and 1.5 to 18.8 times than that of 6-methoxy dihydrosanguinarine. The structure–activity relationship indicated that the introduction of a substituent to N-benzene ring, especially halogen atom and trifluoromethyl group, led to great improvement of the activity. The position of fluorine atom, methyl group and hydroxyl group made very significant effects on the activity. It was concluded that 2-aryl-3,4-dihydroisoquinolin-2-iums are very promising candidates for the development of new isoquinoline acaricidal agents.
通过使用天然活性季
铵类
异喹啉生物碱——
血根碱(sanguinarine)作为模型分子,设计合成了一系列结构简单的季
铵类2-芳基-
3,4-二氢异喹啉-2-
锗化合物,并评估了其对兔毛滴虫(P. cuniculi)的体外杀螨活性。开发了一种以
异喹啉为起始材料的新方法。结果显示,在24个测试化合物中,有22个在0.4 mg/mL浓度下显示出不同程度的活性。14个化合物的效果显著优于标准
杀螨剂伊维菌素(ivermectin)和
血根碱的衍
生物6-甲氧基二氢
血根碱(6-methoxy dihydrosanguinarine)(p<0.05)。它们的综合相对活性是伊维菌素的1.4到16.5倍,6-甲氧基二氢血根碱的1.5到18.8倍。结构-活性关系表明,在N-苯环上引入取代基,尤其是卤素原子和三氟甲基基团,会显著提高活性。氟原子、甲基和羟基的位置对活性也有非常显著的影响。结论是,2-芳基-3,4-二氢异喹啉-2-锗化合物是开发新型异喹啉
杀螨剂的有前景的候选者。