Combined strategy for phytotoxicity enhancement of benzoxazinones.
Fifteen new derivatives of D-DIBOA, including aromatic ring modifications and the addition of side chains in positions C-2 and N-4, were synthesized and their phytotoxicity, selectivity, and structure-activity relationships evaluated. The most active compounds among the derivatives at the C-2 position were 6-Cl-2-Et-D-DIBOA and 6-F-2-Et-D-DIBOA. Of the derivatives at N-4, the most active compounds were 6-Cl-4-Pr-D-DIBOA and 6-Cl-4-Val-D-DIBOA. These four compounds showed high levels of inhibition in root length at very low concentrations in all species. The most remarkable result is the 70% inhibition observed for the root length of cress at 100 nM caused by the latter two compounds. These results support our previous research and conclusions regarding the steric, electronic, and solubility requirements to achieve the maximum phytotoxic activity.
Macías
Francisco A
FA
Allelopathy Group, Department of Organic Chemistry, University of Cadiz, Avda Republica Saharaui, s/n 11510 Puerto Real, Cadiz, Spain. famacias@uca.es.
Chinchilla
Nuria
N
Arroyo
Elena
E
Molinillo
José M G
JM
Marín
David
D
Varela
Rosa M
RM
D048588:Benzoxazines / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity*; D010575:Pesticides / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity*; D063245:Plant Development; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D010944:Plants / Q000187:drug effects*; D013329:Structure-Activity Relationship
D048588:Benzoxazines; D010575:Pesticides; C104846:2,4-dihydroxy-1,4-benzoxazin-3-one