Syntheses of 2-hydroxy-4,7-dimethoxy-2H-1,4-benzoxazin-3(4H)-one: A precursor of a bioactive electrophile from Gramineae

2-Hydroxy-4,7-dimethoxy-2H-1,4-benzoxazin-3(4H)-one (8), the hitherto undescribed free hemiacetalic aglycone of a benzoxazinoid acetal glucoside naturally occurring in wheat, has been synthesized following two pathways, independently. This cyclic hydroxamic acid methyl ester proved to be very unstable when in solution. This gives rise to the assumption that HDIBOA naturally released from its acetal glucoside is by methoxide elimination a precursor to form a multi-centered electrophile that was recently reported to be the bioactive principle of the benzoxazinoid lead. (C) 1997, Elsevier Science Ltd.