Design, synthesis and herbicidal evaluation of novel uracil derivatives containing an isoxazoline moiety

• Published in: Pest management science Vol. 76; no. 10; pp. 3395 - 3402
• Main Authors: Yang, Jichun, Guan, Aiying, Wu, Qiao, Cui, Dongliang, Liu, Changling
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.10.2020; Wiley Subscription Services, Inc
• Subjects: Bioassays; Glyphosate; glyphosate‐resistant weeds; herbicidal activities; Herbicides; intermediate derivatization method (IDM); isoxazoline; Mass spectra; NMR; Nuclear magnetic resonance; Protoporphyrinogen oxidase; structure–activity relationship; Uracil; Weeds
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.5970

BACKGROUND Glyphosate is the most widely used and successful herbicide discovered to date, but its utility is now threatened by the occurrence of several glyphosate‐resistant weed species. Saflufenacil is a relatively new herbicide developed by BASF in 2010. It is a highly effective selective herbicide showing excellent control on broadleaf weeds (more than 90 species), significantly superior to other protoporphyrinogen oxidase (PPO) inhibitor herbicides at the level of weeds controlled. It is also effective against glyphosate‐resistant Conyza canadensis if used in combination with glyphosate. A series of novel uracil‐based PPO inhibitors containing an isoxazoline moiety were designed via the intermediate derivatization method, synthesized using a key saflufenacil raw material as starting material and evaluated for herbicidal activity. RESULTS The target compounds were characterized by 1H NMR and high‐resolution electrospray mass spectra. Bioassays indicated that some title compounds can control efficiently and effectively both broadleaf weeds and grassy weeds at low doses, especially the glyphosate‐resistant weeds C. canadensis and Eleusine indica. CONCLUSION This work provides a basis for further studies of 9b for control of a wider range of weeds, particularly for glyphosate‐resistant weeds. A series of uracil derivatives containing an isoxazoline moiety were designed and synthesized via the intermediate derivatization method. Compound 9b was the optimal structure with excellent herbicidal post‐emergence activity and broad herbicidal spectrum against both broadleaf weeds and grass weeds at 7.5 g ha−1 in the greenhouse, and also offered significant synergism with glyphosate on resistant weeds. © 2020 Society of Chemical Industry