Design and synthesis of novel n-butyphthalide derivatives as promising botanical fungicides.

Zhongfu Luo,Lei Tang,Judi Fan,Yong Li,Yu Deng,Wei Xue,Lingling Fan,Bilan Luo,Qing Lan

doi:10.1515/znc-2020-0192

Abstract

In order to obtain novel botanical fungicides, three series of novel 6-substituted n-butyphthalide derivatives have been designed and synthesized via nucleophilic addition, reduction, nitrification, amination, sulfonation, Sandmeyer and Suzuki reaction. The mycelium growth rate method was used to evaluate the inhibition activity against eight phytopathogenic fungi in vitro. Preliminary bioassay tests showed that compounds 6f, 6n, 6p, 6r and 7a exhibited better activity for some fungi at 50μg/mL than the positive drug hymexazol and lead compound n-butyphthalide (NBP). The preliminary structure-activity relationships indicated that the antifungal activity is significantly affected by the substituents on the benzene ring.

Highlights

Plant disease is a natural disaster caused by plant pathogenic fungi, which tremendously influence the yield and quality of grain, vegetables and fruits, and some pathogenic fungi can produce carcinogenic, neurotoxic or teratogenic secondary metabolites
Compound 4 was subjected to standard Sandmeyer reactions to give the 6-bromobutylphthalide (5)
The target compounds 6a–s were prepared by suzuki reaction of compound 5, and compounds 7a–f and 8a–c were synthesized by sulfonylation and acylation reaction of compound 4 (Scheme 2)

Summary

Introduction

Plant disease is a natural disaster caused by plant pathogenic fungi, which tremendously influence the yield and quality of grain, vegetables and fruits, and some pathogenic fungi can produce carcinogenic, neurotoxic or teratogenic secondary metabolites

Results and discussion

Conclusion

General information

The general procedures for synthesis of compounds 7a–f and 8a–d

Biological assay