Modified benzoxazinones in the system Oryza sativa-Echinochloa crus-galli: an approach to the development of biorational herbicide models.

The utility of benzoxazinones and some of their synthetic derivatives in the search for new leads for herbicide model development has been explored. The work described focuses on obtaining derivatives that present selectivity in the system Oryza sativa- Echinochloa crus-galli. To achieve this goal the influence of lipophilicity in this system has been studied by preparing 14 ester derivatives at the N-4 position of D-DIBOA along with other compounds with different functionalization and chain lengths at position C-2. These compounds have been tested in the aforementioned system, and the dose-response profiles have been compared. The most active compound was 2-ethyl-4-hydroxy-(2H)-1,4-benzoxazin-3(4H)-one, which presented higher selectivity than the specific herbicide Cotanil-35. These results confirm the potential of D-DIBOA as a lead herbicide for the control of Echinochloa spp. in rice crops.