Synthesis and Fungicidal Activities of Substituted Phenyl Hydrazono-3-Methyl-1, 2-Isoxazol-5-One Derivatives.

치환 Phenyl Hydrazono-3-Methyl-1, 2-Isoxazol-5-One 유도체의 합성과 살균활성

Fungicidal activity has been examined for a series of substituted phenylhydrazono-3-methyl-1,2-isoxazol-5-one against plant pathogenic fungi. 3-methyl isoxazol-5-one was obtained from ethyl acetoacetate and hydroxyl amine. Final products were prepared by aromatic diazo coupling with 3-methyl isoxazol-5-one. Fungicidal activities against Rhizoctonia solani, Colletotrichum gloeosporioides, Cladosporium cucumerinum, Pythium ultimum were tested and Pythium ultimum were tested and Pythium ultimum was selected for quantitative measurement of activity. Methyl, halogen, nitro derivatives possessed high fungicidal activity at p-, o-, p- position, respectively. Methyl, halogen derivatives were much more active than alkoxy, nitro derivatives and the order of activity of halogen derivatives was F > Cl > I. This result implied that the activity was related to the molecular volume of substitutents.

Hydrazone 결합을 지닌 화합물 중 농용으로 사용되는 것은 ferimzone, drazoxolon, metazoxolon 등으로 그 수가 매우 제한되어 있다. 본 연구에서는 hydrazone 결합 및 유사 결합구조인 formamidine, triazene 등의 toxophore로서 작용 여부를 규명하고자 하는 시도의 일환으로 일차적으로 hydrazone계 화합물 중 isoxazolone 유도체를 합성, 살균력을 검정하였다. Ethyl acetoacetate와 hydroxyl amine에서 합성된 isoxazolone에 aromatic diazonium coupling을 통하여 최종 산물을 얻었다. 합성된 16종 화합물들의 항균 활성을 Rhizoctonia solani, Colletotrichum gloeosporioides, Cladosporium cucumerinum, Pythium ultimum에 대하여 검정한 결과, 난균강에 속하는 Pythium ultimum에 강한 활성을 보였으며 이를 공시 균주로, $EC_{50}$을 계산하여 그 활성 정도를 비교하였다. p-methyl, o-fluoro, m-chloro 치환체가 강한 활성을 보였다.