Triacetic acid lactone (TAL; 4-hydroxy-6-methyl-2-pyrone) is an organic compound derived enzymatically from glucose. It is a light yellow solid that is soluble in organic solvents. Triacetic acid lactone (TAL; 4-hydroxy-6-methyl-2-pyrone) is an organic compound derived enzymatically from glucose. It is a light yellow solid that is soluble in organic solvents. Triacetic acid lactone consists of two main tautomers.