关键词: α-蒎烯, 桃金娘烯醛, 噻唑-腙, 合成, 抑菌活性

Abstract: [Objective] Myrtenal can be derived by selective oxidation of α-pinene, which is renewable and abundant in China.Myrtenal has been found to exhibit various biological activities. The compounds containing thiazole orhydrazone moieties have been found to show a wide range of biological activities, and have been widely used as blocks for designing bioactive molecules. Therefore,a series of novel myrtenal-based thiazole-hydrazone bioactive compounds can be synthesized by incorporating both thiazole and hydrazone active blocks into the myrtenal skeleton with an attempt to provide a new pathway for the modification and high-value utilization of α-pinene which is a natural and preponderant forest resource in China.[Method] Myrtenal was prepared by the selectively allylic oxidation of α-pinene. Then, myrtenal-based thiosemicarbazone was prepared by the condensation reaction of myrtenal with thiosemicarbazide, followed by the reaction of myrtenal-based thiosemicarbazone with a series of substituted α-bromoacetophenones to yield sixteen myrtenal-based thiazole-hydrazone compounds 4a-4p which have not been reported in the literature. The molecular structures of the target compounds were confirmed by FT-IR,¹H-NMR,¹³C-NMR, and ESI-MS, and antifungal activity of the target products was evaluated by agar dilution method.[Result] Sixteen novel myrtenal-based thiazole-hydrazone target compounds were synthesized.At 50 mg·L^-1, the antifungal activity test showed that all the target compounds exhibited to certain degree antifungal activity against Rhizoctonia solani,Fusarium oxysporum f. sp. cucumerinum,Cercospora arachidicola,Helminthosporium maydis, Physalospora piricola,Colleetotrichum lagenarium,Alternaria solani, and Gibberella zeae. In total, the target compounds displayed the best antifungal activity against P.piricola,and there were twelve compounds with an inhibition rate of more than 60%, in particular, compound 4n (R=4-NO₂)presented the best inhibition rate of 90.6% (A-class activity level).[Conclusion] A series of novel myrtenal-based thiazole-hydrazone compounds were synthesized. These compounds exhibited to certain degree antifungal activity, and among them compound 4n (R=4-NO₂) was a leading compound worthy of deep research.

Key words: α-pinene, myrtenal, thiazole-hydrazone, synthesis, antifungal activity