From Wikipedia, the free encyclopedia
Gentisic acid
[1]
Names
Preferred IUPAC name
2,5-Dihydroxybenzoic acid
Other names
DHB 5-Hydroxysalicylic acid Gentianic acid Carboxyhydroquinone 2,5-Dioxybenzoic Acid Hydroquinonecarboxylic acid
Identifiers
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard
100.007.017
KEGG
UNII
InChI=1S/C7H6O4/c8-4-1-2-6(9)5(3-4)7(10)11/h1-3,8-9H,(H,10,11)
Y Key: WXTMDXOMEHJXQO-UHFFFAOYSA-N
Y InChI=1/C7H6O4/c8-4-1-2-6(9)5(3-4)7(10)11/h1-3,8-9H,(H,10,11)
Key: WXTMDXOMEHJXQO-UHFFFAOYAO
Properties
C7 H6 O4
Molar mass
154.12 g/mol
Appearance
white to yellow powder
Melting point
204 °C (399 °F; 477 K)
[3]
Acidity (pK a )
2.97
[2]
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
Chemical compound
Gentisic acid is a
dihydroxybenzoic acid . It is a derivative of
benzoic acid and a minor (1%) product of the metabolic break down of
aspirin , excreted by the kidneys.
[4]
It is also found in the African tree
Alchornea cordifolia and in
wine .
[5]
Gentisic acid is produced by carboxylation of
hydroquinone .
[6]
C6 H4 (OH)2 + CO2 → C6 H3 (CO2 H)(OH)2
This conversion is an example of a
Kolbe–Schmitt reaction .
Alternatively the compound can be synthesized from
salicylic acid via
Elbs persulfate oxidation .
[7]
[8]
In the presence of the enzyme
gentisate 1,2-dioxygenase , gentisic acid reacts with
oxygen to give
maleylpyruvate :
2,5-dihydroxybenzoate + O2
⇌
{\displaystyle \rightleftharpoons }
maleylpyruvate
As a
hydroquinone , gentisic acid is readily oxidised and is used as an
antioxidant
excipient in some
pharmaceutical preparations.
In the laboratory, it is used as a sample matrix in
matrix-assisted laser desorption/ionization (MALDI)
mass spectrometry ,
[9] and has been shown to conveniently detect peptides incorporating the boronic acid moiety by MALDI.
[10]
^
Gentisic acid - Compound Summary ,
PubChem .
^ Haynes, p. 5.91
^ Haynes, p. 3.190
^ Levy, G; Tsuchiya, T (1972-08-31). "Salicylate accumulation kinetics in man". New England Journal of Medicine . 287 (9): 430–2.
doi :
10.1056/NEJM197208312870903 .
PMID
5044917 .
^ Tian, Rong-Rong; Pan, Qiu-Hong; Zhan, Ji-Cheng; Li, Jing-Ming; Wan, Si-Bao; Zhang, Qing-Hua; Huang, Wei-Dong (2009).
"Comparison of Phenolic Acids and Flavan-3-ols During Wine Fermentation of Grapes with Different Harvest Times" . Molecules . 14 (2): 827–838.
doi :
10.3390/molecules14020827 .
PMC
6253884 .
^ Hudnall, Phillip M. (2005) "Hydroquinone" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. Wiley-VCH, Weinheim.
doi :
10.1002/14356007.a13_499 .
^ Behrman, E.J. (1988).
Organic Reactions, Volume 35 . New York: John Wiley & Sons Inc. p. 440.
ISBN
978-0471832539 .
^ Schock, R. U. Jr.; Tabern, D. L. (1951). "The Persulfate Oxidation of Salicylic Acid. 2,3,5-Trihydroxybenzoic Acid". The Journal of Organic Chemistry . 16 (11): 1772–1775.
doi :
10.1021/jo50005a018 .
^ Strupat K, Karas M, Hillenkamp F (1991). "2,5-Dihidroxybenzoic acid: a new matrix for laser desorption-ionization mass spectrometry". Int. J. Mass Spectrom. Ion Process . 72 (111): 89–102.
Bibcode :
1991IJMSI.111...89S .
doi :
10.1016/0168-1176(91)85050-V .
^ Crumpton, J.; Zhang, W.; Santos, W. L. (2011).
"Facile Analysis and Sequencing of Linear and Branched Peptide Boronic Acids by MALDI Mass Spectrometry" . Analytical Chemistry . 83 (9): 3548–3554.
doi :
10.1021/ac2002565 .
PMC
3090651 .
PMID
21449540 .