2,5-Dihydroxyhydrocinnamic acid lactone 2669-94-5 2H-1-Benzopyran-2-one, 3,4-dihydro-6-hydroxy- 3,4-Dihydro-6-hydroxy-2H-1-benzopyran-2-one 3,4-Dihydro-6-hydroxycoumarin 6-Hydroxy-3,4-dihydrocoumarin EINECS 220-211-3 Hydrocoumarin, 6-hydroxy- NSC 169992