3-芳基-4,5-二氢异噁唑-5-甲酸环戊烷多氢菲酯类衍生物的合成与杀虫活性

为了寻找具有较高杀虫活性的胆固醇衍生物，将异噁唑啉片段引入母体胆固醇( 1 )的C-3位，制备了20个新的3-芳基-4,5-二氢异噁唑-5-甲酸环戊烷多氢菲酯类衍生物 Ia~It ，并经氢谱、红外光谱和高分辨质谱确证结构。化合物 Ie (R = 3-BrPh) 对小菜蛾Plutella xyllostella幼虫具有较好的杀虫活性，其48 h LC₅₀值为 0.940 mg/mL，是母体胆固醇 (LC₅₀ 值2.566 mg/mL) 的2.7倍；化合物 Ig (R = 3-FPh) 和 Ij (R = 4-CF₃Ph) 对苹果黄蚜Aphis citricola具有较好的杀虫活性，其48 h LD₅₀值为0.042与0.041 μg/头，是胆固醇 (LD₅₀ 值0.228 μg/头) 的5.4和5.6倍。初步构效关系表明，在苯环间位引入溴原子可提高对小菜蛾的杀虫活性；在苯环对位或间位引入氟原子、或者在对位引入三氟甲基可提高对苹果黄蚜的杀虫活性。

Synthesis and pesticidal activities of cyclopentanoperhydrophenanthrene 3-aryl-4,5-dihydroisoxazole-5-formate derivatives

In order to find cholesterol derivatives with high insecticidal activities, isoxazoline fragments were introduced into the C-3 position of cholesterol ( 1 ), and twenty novel cyclopentanoperhydrophenanthrene 3-aryl-4,5-dihydroisoxazole-5-formate derivatives ( Ia - It ) containing the isoxazoline fragment were prepared. Their structures were characterized by 1H NMR, IR and HRMS. Among them, compound Ie (R = 3-Br-Ph) exhibited good insecticidal activity against Plutella xyllostella with a LC₅₀ value of 0.940 mg/mL at 48 h, which was 2.7 times of that of 1 (LC₅₀: 2.566 mg/mL). Compounds Ig (R = 3-F-Ph) and Ij (R = 4-CF₃-Ph) showed the potent aphicidal activity against Aphis citricola with LD₅₀ values of 0.042 and 0.041 μg/nymph at 48 h, respectively, which were 5.4 and 5.6 times of that of 1 (LD₅₀: 0.228 μg/nymph). The preliminary study of structure-activity relationships (SARs) indicated that introduction of the bromine atom at the C-3 position of phenyl can improve the insecticidal activity against P. xyllostella; introduction of the fluorine atom at the C-3 or C-4 position of phenyl, or introduction of the CF₃ at the C-4 position of phenyl can improve the aphicidal activity against A. citricola.