In the title Schiff base, C14H13NO4, which adopts the phenol-imine tautomeric form, the dihedral angle between the planes of the benzene and heterocyclic (r.m.s. deviation = 0.037 Å) rings is 53.31 (11)°. An intra-molecular O-H⋯N hydrogen bond closes an S(6) ring. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds to generate C(11) chains propagating in the [010] direction. A weak C-H⋯O link is also observed, leading to the formation of R (5) 5(32) rings extending parallel to the (101) plane.
Keywords: crystal structure; hydrogen bonding; hydroxy Schiff base; phenol–imine tautomer; proton-transfer processes; pyran-2-one.