Synthesis and Biological Evaluation of Norcantharidin Derivatives Possessing an Aromatic Amine Moiety as Antifungal Agents

Molecules

Yang Wang²  Wenbo Sun¹  Shunqing Zha²  Huan Wang¹  Yalin Zhang¹ 

[1]Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, Northwest A & F University, Yangling 712100, China

[2]State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A & F University, Yangling 712100, China

关键词: cantharidin;    natural product;    structural modification;    arylamine;    fungicidal activity;   

DOI  :  10.3390/molecules201219782

来源: mdpi

【 摘 要 】

Based on the structure of naturally produced cantharidin, different arylamine groups were linked to the norcantharidin scaffold to provide thirty six compounds. Their structures were confirmed by melting point, ¹H-NMR, ¹³C-NMR and HRMS-ESI studies. These synthetic compounds were tested as fungistatic agents against eight phytopathogenic fungi using the mycelium growth rate method. Of these thirty six derivatives, seven displayed stronger antifungal activity than did norcantharidin, seven showed higher activity than did cantharidin and three exhibited more significant activity than that of thiabendazole. In particular, 3-(3′-chloro-phenyl)carbamoyl norcantharidate II-8 showed the most significant fungicidal activity against Sclerotinia fructigena and S. sclerotiorum, with IC₅₀ values of 0.88 and 0.97 μg/mL, respectively. The preliminary structure-activity relationship data of these compounds revealed that: (1) the benzene ring is critical for the improvement of the spectrum of antifungal activity (3-phenylcarbamoyl norcantharidate II-1 vs norcantharidin and cantharidin); (2) among the three sites, including the C-2′, C-3′ and C-4′ positions of the phenyl ring, the presence of a halogen atom at the C-3′position of the benzene ring caused the most significant increase in antifungal activity; (3) compounds with strongly electron-drawing or electron-donating groups substitutions were found to have a poor antifungal activity; and (4) compared with fluorine, bromine and iodine, chlorine substituted at the C-3′ position of the benzene ring most greatly promoted fungistatic activity. Thus, compound II-8 has emerged as new lead structure for the development of new fungicides.

【 授权许可】

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