The molecule is a dicarboxylic acid comprising 2-hydroxy-2H-pyran having two carboxy groups located at the 4- and 6-positions. It is a dicarboxylic acid, a member of pyrans and a lactol. It is a conjugate acid of a 4-carboxy-2-hydroxymuconate semialdehyde hemiacetal(2-).
2-hydroxy-2H-pyran-4,6-dicarboxylic acid