... , CAS: 501-30-4) is whiteor off-white crystal, 3). Kojic acid, (5-hydroxy-2-hydroxymethyl-1,4-pyrone, CAS: 501-30-4) is ... acid, (5-hydroxy-2-hydroxymethyl-1,4-pyrone, CAS: 501-30-4) is the mateial for making maltol and cthyl maltol.(3) Medicine: Kojic acid ... , (5-hydroxy-2-hydroxymethyl-1,4-pyrone, CAS: 501-30-4 ...