7-位N取代的香豆素类衍生物的合成、光谱性能及生物活性

以2-甲基-3-硝基苯酚为原料,通过Duff反应、Perkin反应、还原反应和缩合反应等反应合成了6个7-位N取代的香豆素类衍生物,其结构经~1HNMR、~(13)CNMR和HRMS确证。在对香豆素衍生物的光谱性能研究中,发现8-甲基-7-氨基香豆素(7)具有很强的蓝色荧光,进而研究了不同溶剂、不同金属离子和不同pH值对其紫外光谱和荧光光谱变化的影响。结果表明,增强溶剂极性,会使化合物7的紫外光谱明显的红移;当pH值在2.5和11.5左右时,化合物7的荧光急剧减弱;但其荧光不受金属离子的影响。采用菌丝生长速率法测试了目标化合物对草莓炭疽、马铃薯晚疫、猕猴桃褐斑和草莓灰霉这4种常见植物病原真菌的抑菌活性,结果显示部分化合物对植物病原真菌的抑制效果高于对照蛇床子素,并且这些化合物的细胞毒性很低。上述结果表明,7-位N取代的香豆素类衍生物作为抗真菌的植物源农药具有一定的研究价值。

Synthesis, spectral properties and biological activity of 7-N-substituted coumarin derivatives

Six kinds of 7-position N-substituted coumarin derivatives were synthesized from 2-methyl-3- nitrophenol via Duff reaction, Perkin reaction, reduction reaction and condensation reaction. Their structures were confirmed by ¹H NMR, ¹³C NMR and HRMS. In the study of the spectral properties of coumarin derivatives, we found that 7-amino-8-methylcoumarin (7) had strong blue fluorescence properties. The effects of different solvents, different metal ions and different pH values on the changes of UV and fluorescence spectra were then investigated. The results showed that increasing the polarity of the solvent caused a significant red shift in the UV spectrum of compound 7. When the pH value was around 2.5 and 11.5, the fluorescence of the compound 7 was sharply attenuated, but the fluorescence was not affected by the metal ions. We firstly tested the antifungal activities of these compounds on four common pathogenic fungi, such as Colletotrichum fragariae, Phytophthora infestans, Actinidia chinensis brown spot and Botrytis cinerea Persoon, by mycelial growth rate method. The results showed that the inhibitory effects of some compounds on phytopathogenic fungi were significantly higher than that of osthole. Meanwhile, the compounds had weak toxicity. The above results show the research value of 7-position N-substituted coumarin derivatives as antifungal plant pesticide.