... 1,4-pyrone, CAS: 501-30-4) is whiteor off-white crystal, 3). Kojic acid, (5-hydroxy-2-hydroxymethyl-1,4-pyrone, CAS: 501-30-4) ... : (1) Cosmetics: Kojic acid, (5-hydroxy-2-hydroxymethyl-1,4-pyrone, CAS: 501-30-4) is used for macula-removing and whitening ... headache and toothache, etc.).(4) Agriculture: Kojic acid, (5-hydroxy-2-hydroxymethyl-1,4-pyrone, CAS: 501-30-4) is used in producing biological ...