3,4-Dihydroxy-5-methoxybenzaldehyde 3934-87-0 4-08-00-02718 (Beilstein Handbook Reference) 5-Hydroxyvanillin 5-Methoxyprotocatechualdehyde BRN 1956546 Benzaldehyde, 3,4-dihydroxy-5-methoxy- EINECS 223-513-3 NSC 16679 Protocatechualdehyde, 5-methoxy- Protocatechualdehyde, 5-methoxy- (8CI)