Title: Protocatechualdehyde
CAS Registry Number: 139-85-5
CAS Name: 3,4-Dihydroxybenzaldehyde
Synonyms: 3,4-dihydroxybenzenecarbonal; protocatechuic aldehyde; rancinamycin IV
Molecular Formula: C7H6O3
Molecular Weight: 138.12
Percent Composition: C 60.87%, H 4.38%, O 34.75%
Literature References: Prepn from catechol: Reimer, Tiemann,
Ber. 9, 1268 (1876); Tiemann, Koppe,
ibid. 14, 2015 (1881); from vanillin: Tiemann, Haarmann,
ibid. 7, 620 (1874); from veratric aldehyde: Dreyfus,
DE 193958;
Frdl. 9, 161 (1908-10); from piperonal: Hoering, Baum,
Ber. 41, 1914 (1908); Barger,
J. Chem. Soc. 93, 563 (1908); Buck, Zimmerman,
Org. Synth. coll. vol. II, 549 (1943).
Properties: Platelets from water or toluene. Dimorphic. Dec 153-154°. pK (25°) 7.55. Soly in water (g/100 ml): 5 (20°); 33 (99°); in ethanol: 79 (78°). Freely sol in ether.
pKa: pK (25°) 7.55