4-Hydroxybenzoic acid

Source: Wikipedia, the free encyclopedia.
(Redirected from
P-hydroxybenzoic acid
)
4-Hydroxybenzoic acid
Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name
4-Hydroxybenzoic acid
Other names
p-Hydroxybenzoic acid
para-Hydroxybenzoic acid
PHBA
4-hydroxybenzoate
Identifiers
3D model (
JSmol
)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.002.550 Edit this at Wikidata
EC Number
  • 202-804-9
IUPHAR/BPS
KEGG
UNII
  • InChI=1S/C7H6O3/c8-6-3-1-5(2-4-6)7(9)10/h1-4,8H,(H,9,10) checkY
    Key: FJKROLUGYXJWQN-UHFFFAOYSA-N checkY
  • InChI=1/C7H6O3/c8-6-3-1-5(2-4-6)7(9)10/h1-4,8H,(H,9,10)
    Key: FJKROLUGYXJWQN-UHFFFAOYAQ
  • O=C(O)c1ccc(O)cc1
  • c1cc(ccc1C(=O)O)O
Properties
C7H6O3
Molar mass 138.122 g·mol−1
Appearance White crystalline
Odor Odorless
Density 1.46 g/cm3
Melting point 214.5 °C (418.1 °F; 487.6 K)
Boiling point N/A, decomposes[1]
0.5 g/100 mL
Solubility
log P 1.58
Acidity (pKa) 4.54
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Irritant
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
0
0
250 °C (482 °F; 523 K)
Lethal dose or concentration (LD, LC):
2200 mg/kg (oral, mouse)
Safety data sheet (SDS) HMDB
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

4-Hydroxybenzoic acid, also known as p-hydroxybenzoic acid (PHBA), is a

3-hydroxybenzoic acid
.

Natural occurrences

It is found in plants of the genus Vitex such as V. agnus-castus or V. negundo, and in Hypericum perforatum (St John's wort). It is also found in Spongiochloris spongiosa, a freshwater green alga.

The compound is also found in

medicinal mushroom
with the longest record of use.

Cryptanaerobacter phenolicus is a bacterium species that produces benzoate from phenol via 4-hydroxybenzoate.[2]

Occurrences in food

4-Hydroxybenzoic acid can be found naturally in coconut.[3] It is one of the main catechins metabolites found in humans after consumption of green tea infusions.[4] It is also found in wine,[5] in vanilla, in Macrotyloma uniflorum (horse gram), carob[6] and in Phyllanthus acidus (Otaheite gooseberry).

cloudy olive oil[citation needed] and in the edible mushroom Russula virescens (green-cracking russula).[citation needed
]

Related compounds

p-Hydroxybenzoic acid glucoside can be found in mycorrhizal and non-mycorrhizal roots of Norway spruces (Picea abies).[8]

glucosides associated with a delphinidin
.

Agnuside is the ester of aucubin and p-hydroxybenzoic acid.[9]

Biosynthesis

ubiquinone biosynthesis in Escherichia coli
and other Gram-negative bacteria.

Benzoate 4-monooxygenase is an enzyme that utilizes benzoate, NADPH, H+ and O2 to produce 4-hydroxybenzoate, NADP+ and H2O. This enzyme can be found in Aspergillus niger.

4-Hydroxybenzoate also arises from tyrosine.[10]

Metabolism

As an intermediate

The enzyme 4-methoxybenzoate monooxygenase (O-demethylating) transforms 4-methoxybenzoate, an electron acceptor AH2 and O2 into 4-hydroxybenzoate, formaldehyde, the reduction product A and H2O. This enzyme participates in 2,4-dichlorobenzoate degradation in Pseudomonas putida.

The enzyme

4-hydroxybenzaldehyde, NAD+ and H2O to produce 4-hydroxybenzoate, NADH and H+. This enzyme participates in toluene and xylene degradation in bacteria such as Pseudomonas mendocina. It is also found in carrots (Daucus carota
).

The enzyme that 2,4'-dihydroxyacetophenone dioxygenase transforms 2,4'-dihydroxyacetophenone and O2 into 4-hydroxybenzoate and formate. This enzyme participates in bisphenol A degradation. It can be found in Alcaligenes species.

The enzyme 4-chlorobenzoate dehalogenase uses 4-chlorobenzoate and H2O to produce 4-hydroxybenzoate and chloride. It can be found in Pseudomonas species.

The enzyme

4-hydroxybenzoyl-CoA and H2O to produce 4-hydroxybenzoate and CoA. This enzyme participates in 2,4-dichlorobenzoate degradation. It can be found in Pseudomonas
species.

The enzyme

ubiquinone
biosynthesis.

The enzyme

4-hydroxybenzoate geranyltransferase utilizes geranyl diphosphate and 4-hydroxybenzoate to produce 3-geranyl-4-hydroxybenzoate and diphosphate. Biosynthetically, alkannin is produced in plants from the intermediates 4-hydroxybenzoic acid and geranyl pyrophosphate. This enzyme is involved in shikonin biosynthesis. It can be found in Lithospermum erythrorhizon
.

The enzyme

3-hydroxybenzoate and CoA to produce AMP, diphosphate and 3-hydroxybenzoyl-CoA. The enzyme works equally well with 4-hydroxybenzoate. It can be found in Thauera aromatica
.

Biodegradation

The enzyme 4-hydroxybenzoate 1-hydroxylase transforms 4-hydroxybenzoate, NAD(P)H, 2 H+ and O2 into hydroquinone, NAD(P)+, H2O and CO2. This enzyme participates in 2,4-dichlorobenzoate degradation. It can be found in Candida parapsilosis.

The enzyme

protocatechuate, NADP+ and H2O. This enzyme participates in benzoate degradation via hydroxylation and 2,4-dichlorobenzoate degradation. It can be found in Pseudomonas putida and Pseudomonas fluorescens
.

The enzyme 4-hydroxybenzoate 3-monooxygenase (NAD(P)H) utilizes 4-hydroxybenzoate, NADH, NADPH, H+ and O2 to produce 3,4-dihydroxybenzoate (protocatechuic acid), NAD+, NADP+ and H2O. This enzyme participates in benzoate degradation via hydroxylation and 2,4-dichlorobenzoate degradation. It can be found in Corynebacterium cyclohexanicum and in Pseudomonas sp.

The enzyme 4-hydroxybenzoate decarboxylase uses 4-hydroxybenzoate to produce phenol and CO2. This enzyme participates in benzoate degradation via coenzyme A (CoA) ligation. It can be found in Klebsiella aerogenes (Aerobacter aerogenes).

The enzyme

4-hydroxybenzoyl-CoA. This enzyme participates in benzoate degradation via CoA ligation. It can be found in Rhodopseudomonas palustris
.

Coniochaeta hoffmannii is a plant pathogen that commonly inhabits fertile soil. It is known to metabolize aromatic compounds of low molecular weight, such as p-hydroxybenzoic acid.

Glycosylation

The enzyme

UDP-glucose and 4-hydroxybenzoate into UDP and 4-(beta-D-glucosyloxy)benzoate. It can be found in the pollen of Pinus densiflora
.

Chemistry

The Hammett equation describes a linear free-energy relationship relating reaction rates and equilibrium constants for many reactions involving benzoic acid derivatives with meta- and para-substituents.

Chemical production

4-Hydroxybenzoic acid is produced commercially from potassium

Kolbe-Schmitt reaction.[11] It can also be produced in the laboratory by heating potassium salicylate with potassium carbonate to 240 °C, followed by treating with acid.[12]

Chemical reactions

4-Hydroxybenzoic acid has about one tenth the acidity of benzoic acid, having an acid dissociation constant Ka = 3.3×10−5 M at 19 °C.[citation needed] Its acid dissociation follows this equation:

HOC6H4CO2H ⇌ HOC6H4CO−2 + H+

Chemical use

liquid crystal polymer. Chemically it is an aromatic polyester produced by the polycondensation of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acid. The fiber has been shown to exhibit strong radiation shielding used by Bigelow Aerospace and produced by StemRad.[13]

4,4′-Dihydroxybenzophenone is generally prepared by the rearrangement of p-hydroxyphenylbenzoate. Alternatively, p-hydroxybenzoic acid can be converted to p-acetoxybenzoyl chloride. This acid chloride reacts with phenol to give, after deacetylation, 4,4′-dihydroxybenzophenone.

Examples of drugs made from PHBA include nifuroxazide, orthocaine, ormeloxifene and proxymetacaine.

Bioactivity and safety

4-Hydroxybenzoic acid is a popular antioxidant in part because of its low toxicity. The LD50 is 2200 mg/kg in mice (oral).[14]

4-Hydroxybenzoic acid has

binding affinity for the receptor.[16][18][19] It is about 0.2% to 1% as potent as an estrogen as estradiol.[18]

See also

References

  1. ^ "4-Hydroxybenzoic acid" (PDF). International Programme on Chemical Safety (IPCS). Archived from the original (PDF) on 24 September 2015. Retrieved 10 January 2015.
  2. PMID 15653882
    .
  3. PMID 15900879
    .
  4. S2CID 37684286
    .
  5. PMID 19255542
    .
  6. PMID 27834921
    .
  7. PMID 18522407
    .
  8. S2CID 43504838
    .
  9. doi:10.1002/1099-1565(200009/10)11:5<327::AID-PCA523>3.0.CO;2-0
    .
  10. PMID 27060254
    .
  11. doi:10.1002/14356007.a13_519
  12. ^ Buehler, C. A.; Cate, W. E. (1943). "p-Hydroxybenzoic acid". Organic Syntheses; Collected Volumes, vol. 2, p. 341.
  13. ^ Charles Fishman, Dan Winters (2016-04-11). "This Expandable Structure Could Become the Future of Living in Space". Smithsonian Magazine. Retrieved 2020-12-07.
  14. ^ Lewis, R. J., ed. (1996). Sax's Dangerous Properties of Industrial Materials. Vol. 1–3 (9th ed.). New York, NY: Van Nostrand Reinhold. p. 2897.
  15. ^
    ISBN 978-1-118-89115-5
    .
  16. ^
    S2CID 12342018
    .
  17. ^
    ISBN 978-1-60980-462-6
    .
  18. ^
    PMID 9417843
    .
  19. ISBN 978-92-64-07885-7
    .

External links

4-Hydroxybenzoic acid at Phenol-Explorer.eu

Retrieved from "https://en.wikipedia.org/w/index.php?title=4-Hydroxybenzoic_acid&oldid=1219071236"