134958-24-0 3,4-Premercapturic acid 3-S-Premercapturic acid L-Cysteine, N-acetyl-S-(3-bromo-6-hydroxy-2,4-cyclohexadien-1-yl)- N-Acetyl-S-(2-hydroxy-5-bromocyclohexa-3,5-dienyl)cysteine