Preparation of insect juvenile hormone (JH) antagonists and identification of JH receptors

4-[2-(叔丁基甲氧基)丁氧基]苯甲酸乙酯(ETB)是一种抗保幼激素(抗JH)药物，已被报道在幼虫表皮的靶组织中起部分JH拮抗剂的作用。通过修饰ETB的结构，我们发现[2-(6-甲基-3-吡啶氧基)丁氧基]苯甲酸乙酯(EMP)诱导家蚕幼虫性早熟变态，这是一种明显的JH缺乏症状。与ETB相反，EMP以剂量依赖的方式诱导性早熟变态。构效关系研究表明，苯环上的4-乙氧基羰基和6-甲基-3-吡啶基是活性所必需的。EMP的活性可以被JH激动剂美托品完全抵消，但不能被饲料中的20-羟基蜕皮酮所抵消，这表明EMP导致幼虫血淋巴中JH滴度的缺乏。为了鉴定可能与JH受体有关的电磁脉冲靶分子，电磁脉冲…制备了更多的辣根过氧化物酶偶联衍生物作为亲和配体。然而，在蛹和幼虫头囊的卵巢滤泡细胞中没有发现EMP的高亲和力结合部位。为了开发更有效的抗JH试剂，对EMP的乙基侧链进行了修饰。在所测试的化合物中，乙基4-[4-methyl-2-(6-methyl-3-pyridyloxy)pentyl-oxy]benzoate(1)对24小时龄3龄幼虫的效果最好。1R(+)-和1S(-)-对映体的早熟变态诱导活性无显著差异。由于苯甲酸类似物在局部应用和饮食给药中都没有显示出任何活性，因此乙氧基羰基本身就是活性的原因。化合物1处理3龄幼虫时，在4龄幼虫体内诱导出了最后一龄幼虫化蛹所必需的血淋巴JH酯酶。化合物1代表了一类结构新颖的抗JH试剂。较少

Ethyl 4-[2-(tert-butylcarbonyloxy)butyloxy]benzoate (ETB), an anti juvenile hormone (anti-JH) agent, has been reported to act as a partial JH antagonist at the target tissue of the larval epidermis. By modifying the structure of ETB, we have found that ethyl [2-(6-methyl-3-pyridyloxy)butyloxy]-benzoate (EMP) induced precocious metamorphosis in larvae of Bombyx mori, which is clearly recognized as a JH-deficiency symptom. In contrast to ETB, EMP induced precocious metamorphosis in a dose-dependent manner. The structure-activity relationship studies indicated that the 4-ethoxycarbonyl group on the benzene ring and the 6-methyl-3-pyridyl moiety were apparently essential for activity. The activity of EMP could be fully counteracted by methoprene, a JH agonist, but not by the dietary administration of 20-hydroxyecdysone, indicating that EMP causes a deficiency of JH titers in the larval hemolymph. In order to identify a target molecule of EMP, which might be related to a JH receptor, an EMP … More derivative coupled to horseradish peroxidase was prepared as an affinity ligand. However, high-affinity binding site for EMP was not found in the ovary follicular cell of the pupae and larval head capsules. To develop more potent anti-JH agent, the ethyl side chain of EMP was modified. Of the compounds tested, ethyl 4-[4-methyl-2-(6-methyl-3-pyridyloxy)pentyl-oxy]benzoate (1) was the most effective when applied to 24hr-old 3rd instar larvae. There was no significant different in precocious metamorphosis-inducing activity between 1R(+)- and 1S(-)-enantiomers. Since the benzoic acid analogs did not show any activity by both topical application and dietary administration, the ethoxycarbonyl group itself was responsible for activity. When 3rd instar larvae were treated with compound 1, hemolymph JH esterase, which is indispensable for the initiation of pupation in the last instar larvae, was induced during the 4th instar larvae. Compound 1 represents a structurally novel class of anti-JH agent. Less