Elena Arroyo, Nuria Chinchilla, Ceferino Carrera, José M.G. Molinillo and Francisco A. Macías*
Allelopathy Group, Department of Organic Chemistry, Institute of Biomolecules (INBIO), Campus de Excelencia Internacional Agroalimentario (ceiA3), University of Cádiz, Avda. República Saharaui, s/n, 11510 Puerto Real, Cádiz, Spain.
Benzoxazinones and their degradation products are naturally occurring allelochemicals that are present in wheat, corn, rye, other members of the Gramineae, and some non-Gramineae species. 2,4-Dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA) is the major hydroxamic acid in Secale cereal L. This compound is unstable in solution and soils and is transformed into 2-benzoxazolinone (BOA) and other degradation products. Further degradation of this compound yields the tricyclic structures 2-amino-3H-phenoxazin-3-one (APO). The synthesis of a wide variety of compounds with an aminophenoxazine skeleton has been studied extensively, mainly due to their pharmaceutical interest rather than for their agronomical use. In this sense, we have prepared a new generation of chemicals that includes eighteen derivatives with the aminophenoxazine skeleton with the aim of improving their phytotoxicity. These compounds were tested in a wheat coleoptile bioassay and with selected standard target species (STS) in the search for the optimal levels for phytotoxicity.
Keywords: Allelochemicals, Aminophenoxazines, Benzoxazinoids, 2-Benzoxazolinone, SAR.
RECEIVED: June 17, 2014
ACCEPTED: June 29, 2014