Synthesis of (E) Stilbenes from 2, 4, 5-Trimethoxybenzyltriphenyl phosphonium Ylide and their Fungicidal Activity

Plants use multiple defense mechanisms in order to prevent entering of phytopathogenic microorganisms. In many plant species one of the most efficient responses to combat attacking microbes is the rapid synthesis of antimicrobial low molecular weight phytoalexins, for example, stilbenes produced by several plants may be a useful lead structure for the chemical synthesis of antimicrobials. In this study, a series of novel 2, 4, 5-trimethoxy stilbene derivatives have been synthesized via the Wittig reaction. The starting material 2, 4, 5- trimethoxy benzaldehyde (asaronaldehyde) was obtained from β-asarone of sweet flag oil. The key intermediate 2, 4, 5-trimethoxybenzyltriphenyl phosphonium chloride was prepared for the first time from the corresponding benzyl chloride. All the trans-stilbenes were characterized by HRMS, 1H and 13C NMR spectral analysis and tested in vitro for their fungicidal activity against two plant pathogenic fungi viz., Phytophthora capsici and Sclerotium rolfsii.