氟虫腈磺酰胺类衍生物的合成及对柞蚕饰腹寄蝇的防治效果试验

Synthesis of Fipronil Sulfanilamide Derivatives and Their Control Effect on Blepharipa tibialis Chao

柞蚕饰腹寄蝇(Blepharipa tibialis Chao)是严重危害柞蚕的寄生性害虫,因长期使用单一防治药剂已导致防效下降,需要寻求新型药剂有效控制其危害。以苯基吡唑类杀虫剂氟虫腈为母体化合物,分别合成了5种氟虫腈磺酰胺类衍生物(FSD),采用熔点测试、红外光谱(IR)和核磁谱(1H-NMR)确认结构后,经反相高效液相色谱测定FSD的色谱容量因子(log K)作为疏水性参数,其取值范围为0.169~0.778,低于氟虫腈(4.271),表明5种FSD化合物的亲水性强于氟虫腈。FSD对柞蚕4龄幼虫的毒性试验表明,其5%致死浓度(LC5)均>1 300 mg/L。在此基础上以被柞蚕饰腹寄蝇寄生的柞蚕5龄幼虫为试虫测试FSD的防治效果:质量浓度为500 mg/L的5种FSD药液处理组的防效均<70%,并随着药液浓度增加防效略有增加,其中编号为1的FSD化合物质量浓度为1 000 mg/L时的防效达到80%以上;用5种FSD化合物100~1000 mg/L药液处理后,柞蚕的结茧率经归一化处理均达到96%以上。综上试验结果认为,FSD由于具有磺酰胺键而提高了氟虫腈的亲水性,对柞蚕的毒性较氟虫腈原药大幅降低,但需要对FSD结构进行改进设计,筛选出对柞蚕饰腹寄蝇防治效果更明显的药剂。

Blepharipa tibialis Chao is a kind of parasitic pest which causes serious damage to tussah silkworm. Long- term use of one single control agent has led to decrease of control effect against this pest. Thus, it is urgent to seek new agents for effective control of B. tibialis Chao. Using phenylpyrazole pesticides fipronil as parent compound, five fipronil sulfonamide derivatives （FSDs） were synthesized and their structures were confirmed by melting point test, infrared spectrometry （IR） and nuclear magnetic resonance spectroscopy （1 H-NMR）. The chromatographic capacity factor （log K） of FSDs determined by reversed-phase HPLC was taken as hydrophobic parameter. The log K of FSDs rangedfrom 0.169 to 0.778, which are al fipronil （4. 271 ）, suggesting that the FSDs is better than that of fipron lower than that of hydrophilicity of five The toxicity test of FSDs to the 4th instar Antheraea pemyi larvae showed that the 5% lethal concentration （LCs） is higher than 1 300 mg/L. On basis of this toxicity test, B. tibialis Chao parasitized 5th-instar tussah silkworm larvae were used to evaluate control effect of FSDs. When the 5 FSD drugs at 500 mg/L concentration were used, their control effectwere all 〈70%. The control effect increased slightly with the increase of drug concentration~ among which compound No. 1 at 1 000 mg/L concentration had a control effect 〉80%. The normalized cocooning rate of tussah silkworm reached 〉 96% from treatments with the five FSDs at 100-1 000 mg/L concentrations. In conclusion, hydrophilicity of FSDs is im- proved owing to existence of a sulfonamide bond. Thus, their toxicity to tussah silkworm is greatly reduced in comparison with FiproniI.However, further work is required to modify FSD structures and to screen drugs with better control effect against B. tibialis Chao.