Abstract：
Ethyl 5-cyano-1,6-dihydro-2-methyl-4-(2\'-thienyl)-6-thioxonicotinate (A) was synthesized and reacted with ethyl chloroacetate in the presence of sodium acetate or sodium carbonate to give ethyl 5-cyano-6-((2-ethoxy-2-oxoethyl)thio)-2-methyl-4-(2\'-thienyl)nicotinate (1a) or its isomeric thieno[2,3-b]pyridine 2a. 3-Aminothieno[2,3-b]pyridine-2-carboxamide 2b was also synthesized by the reaction of A with 2-chloroacetamide. The reaction of 1a with hydrazine hydrate in boiling ethanol gave acethydrazide 3. Heating ester 1a with hydrazine hydrate under neat conditions afforded 3-amino-1H-pyrazolo[3,4-b]pyridine 10. Compounds 2b, 3, and 10 were used as precursors for synthesizing other new thieno[2,3-b]pyridines and pyrazolo[3,4-b]pyridines containing mainly the ethyl nicotinate scaffold. Structures of all new compounds were confirmed by elemental and spectral analyses. Most of the obtained compounds were evaluated for their insecticidal activity toward the nymphs and adults of Aphis gossypii (Glover,1887). Some compounds such as 4, 9b, and 9c showed promising results. The effect of some sublethal concentrations, less than LC50, of compounds 4, 9b, and 9c on the examined Aphis was subjected to a further study. The results demonstrated that exposure of A. gossypii nymphs to sublethal concentrations of compounds 4, 9b, and 9c had noticeable effects on their biological parameters, i.e., nymphal instar duration, generation time, and adult longevity. The highest concentration C1 of all three compounds increased the nymphal instar duration and generation time and decreased adult longevity and vice versa.
摘要：
合成5-氰基-1,6-二氢-2-甲基-4-（2'-噻吩基）-6-硫代烟酸乙酯（A），并在乙酸钠或碳酸钠存在下与氯乙酸乙酯反应，得到5-氰基-6-（（（2-乙氧基-2-氧代乙基）硫基）-2-甲基-4-（2'-噻吩基）吡啶（1a）。3-氨基噻吩并[2,3-b]吡啶-2-甲酰胺2b也通过A与2-氯乙酰胺的反应合成。1a与水合肼在沸腾的乙醇中的反应得到乙酰肼3。在纯条件下将酯1a与水合肼加热,得到3-氨基-1H-吡唑并[3,4-b]吡啶10。化合物2b,3和10用作合成主要含有烟酸乙酯支架的其他新的噻吩并[2,3-b]吡啶和吡唑并[3,4-b]吡啶的前体。通过元素和光谱分析证实了所有新化合物的结构。评估了大多数获得的化合物对若虫和成虫的杀虫活性（格洛弗，1887).一些化合物如4，9b，和9c显示了有希望的结果。一些亚致死浓度的影响，低于LC50，化合物4，9b，和9c对检查的Aphis进行了进一步研究。结果表明，棉铃虫若虫暴露于亚致死浓度的化合物4，9b，9c对它们的生物学参数有明显的影响，即，若虫龄,生成时间,和成人长寿。所有三种化合物的最高浓度C1增加了若虫的龄期和世代时间，并降低了成虫的寿命，反之亦然。
