Structure-activity relationship (SAR) studies of benzoxazinones, their degradation products, and analogues. Phytotoxicity on problematic weeds Avena fatua L. and Lolium rigidum Gaud.
Avena fatua L. (wild oat) and Lolium rigidum Gaud. (rigid ryegrass) are highly problematic weeds affecting a wide variety of cereal crops worldwide. The fact that both of these weeds have developed resistance to several herbicide groups made them optimal candidates as target organisms for ongoing research about the potential application of allelochemicals and analogue compounds as natural herbicide models. Benzoxazinones, a family of natural allelochemicals present in corn, wheat, and rye, including 2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one and 2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one, together with some degradation products, found in crop soils as well as in other systems, and some synthetic analogues of them were tested on wild oat and rigid ryegrass seeds; the results were statistically treated, and some structure-activity relationships, useful in further development of natural herbicide models, were elucidated. The most active compounds were the synthetic benzoxazinone 2-acetoxy-(2H)-1,4-benzoxazin-3(4H)-one and the degradation product 2-aminophenoxazin-3-one, with highly significant inhibition on the development of both weeds. The ecological role of these compounds is discussed by considering both degradability and phytotoxicity. The bioactivity of aminophenoxazines has been correlated by their aqueous solubility-lipophilicity predicted by means of computational methods.
Grupo de Alelopatía, Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, C/República Saharaui s/n, 11510 Puerto Real, Spain. famacias@uca.es
Francisco A
FA
Macías
David
D
Marín
Alberto
A
Oliveros-Bastidas
Diego
D
Castellano
Ana M
AM
Simonet
José M G
JM
Molinillo
D048588:Benzoxazines; D008129:Lolium / Q000187:drug effects*; D008782:Methylurea Compounds / Q000494:pharmacology*; D010078:Oxazines / Q000737:chemistry* / Q000494:pharmacology*; D010675:Pheromones / Q000737:chemistry / Q000494:pharmacology; D006109:Poaceae / Q000187:drug effects*; D013329:Structure-Activity Relationship
D048588:Benzoxazines; D008782:Methylurea Compounds; D010078:Oxazines; D010675:Pheromones; C034222:methoxuron; C104846:2,4-dihydroxy-1,4-benzoxazin-3-one; C050733:2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one