Reaction of Ferulic Acid with Nitrite:  Formation of 7-Hydroxy-6-methoxy-1,2(4H)-benzoxazin-4-one

Ferulic acid was reacted with nitrite under acidic conditions to give complex mixtures of products. Chromatographic purification afforded products that were characterized by 1 H- and 13 C-NMR spectral analyses. The major fluorescent product was identified as 7-hydroxy-6-methoxy-1,2(4 H )-benzoxazin-4-one along with 3-methoxy-4-hydroxybenzaldehyde (vanillin) and 2-methoxy-4,6-dinitrophenol. The structure of the unusual benzoxazinone was confirmed by its chemical degradation in base to methyl-2,4-dihydroxy-5-methoxybenzoic acid.