Benzofuran-2-acetic esters as a new class of natural-like herbicides

BACKGROUND: In recent decades, the use of synthetic herbicides has been increasing, mainly in emerging countries. However,their intensive and indiscriminate application is a major cause of environmental pollution and human health injury. Therefore,there is an increasing need to develop new herbicides with safer toxicological and environmental profiles. A promising strategyis to synthesize new molecules containing the core of natural products as a template for the production of ‘bio-inspired’ or‘natural-like’ herbicides.RESULTS: The potential herbicidal activity of some benzofuran-2-acetic esters was assessedin vitroonArabidopsis thaliana,a model species. All five molecules (M1-M5) showed significant phytotoxic activity, reducing both shoot and root system atlow concentrations. In particular, methyl 2-(5-methoxybenzofuran-2-yl)hexanoate (M3) exhibited the highest phytotoxicitydisplayed against two crops and weeds, monocots (Zea maysL. andE. crus-galli) and dicots (Lactuca sativaL. andAmaranthusretroflexusL.). The M3 activity was also compared with glyphosate, a common herbicide, showing a lower but similar activity.Moreover, the results evidenced that M3 was more effective in post-emergency.CONCLUSION: Readily synthesizable benzofuran-2-acetic esters possessing the benzofuran ring as ‘bio-inspired’ core, showsignificant herbicidal activity making them very efficient even at low concentrations. They can be sprayed in liquid form, and theaddition of adjuvants can improve penetration through the leaf cuticle. These results confirm the importance of these moleculesas models for the development of new natural-like herbicides.© 2019 Society of Chemical Industry