Mandelic acid

Mandelic acid^[1]
Names
	IUPAC name 2-Hydroxy-2-phenylacetic acid
	Other names Mandelic acid; Phenylglycolic acid
Identifiers
CAS Number	90-64-2 ; 611-71-2 (R); 17199-29-0 (S);
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:35825 ;
ChEMBL	ChEMBL1609 ;
ChemSpider	1253 ;
ECHA InfoCard	100.001.825
EC Number	202-007-6;
PubChem CID	1292;
RTECS number	OO6300000;
UNII	NH496X0UJX ;
CompTox Dashboard (EPA)	DTXSID6023234 ;
	InChI InChI=1S/C8H8O3/c9-7(8(10)11)6-4-2-1-3-5-6/h1-5,7,9H,(H,10,11) Key: IWYDHOAUDWTVEP-UHFFFAOYSA-N ; InChI=1/C8H8O3/c9-7(8(10)11)6-4-2-1-3-5-6/h1-5,7,9H,(H,10,11) Key: IWYDHOAUDWTVEP-UHFFFAOYAD;
	SMILES O=C(O)C(O)c1ccccc1;
Properties
Chemical formula	C8H8O3
Molar mass	152.149 g·mol−1
Appearance	White crystalline powder
Density	1.30 g/cm3
Melting point	119 °C (246 °F; 392 K)
Boiling point	321.8 °C (611.2 °F; 595.0 K)
Solubility in water	15.87 g/100 mL
Solubility	soluble in diethyl ether, ethanol, isopropanol
Acidity (pKa)	3.41
Refractive index (nD)	1.5204
Thermochemistry
Std enthalpy of; formation (ΔfH⦵298)	0.1761 kJ/g
Hazards
Flash point	162.6 °C (324.7 °F; 435.8 K)
Related compounds
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Mandelic acid is an aromatic alpha hydroxy acid with the molecular formula C₆H₅CH(OH)CO₂H. It is a white crystalline solid that is soluble in water and polar organic solvents. It is a useful precursor to various drugs. Since the molecule is chiral, it exists in either of two enantiomers as well as the racemic mixture, known as paramandelic acid.

Isolation and synthesis

Mandelic acid was discovered while heating amygdalin, an extract of bitter almonds, with diluted hydrochloric acid. The name is derived from the German "Mandel" for "almond". Derivatives of mandelic acid are formed as a result of metabolism of adrenaline and noradrenaline by monoamine oxidase and catechol-O-methyl transferase.

Mandelic acid is usually prepared by the acid-catalysed hydrolysis of mandelonitrile,^[3] which is the cyanohydrin of benzaldehyde. Mandelonitrile can also be prepared by reacting benzaldehyde with sodium bisulfite to give the corresponding adduct, forming mandelonitrile with sodium cyanide, which is hydrolyzed:^[4]

Alternatively, it arises by base hydrolysis of phenylchloroacetic acid and dibromacetophenone.^[5] It also arises by heating phenylglyoxal with alkalis.

Uses

Mandelic acid has a long history of use in the medical community as an antibacterial, particularly in the treatment of urinary tract infections.^[6] It has also been used as an oral antibiotic, and as a component of 'chemical face peels', along with other alpha-hydroxy acids (AHAs).

The drugs cyclandelate and homatropine are esters of mandelic acid.

References

^ Merck Index, 11th Edition, 5599.
^ Bjerrum, J., et al. Stability Constants, Chemical Society, London, 1958.
^ Edwin Ritzer and Rudolf Sundermann “Hydroxycarboxylic Acids, Aromatic” in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a13_519
^ Corson, B. B.; Dodge, R. A.; Harris, S. A.; Yeaw, J. S. (1941). "Mandelic Acid". Organic Syntheses{{cite journal}}: CS1 maint: multiple names: authors list (link); Collected Volumes, vol. 1, p. 336.
^ J. G. Aston, J. D. Newkirk, D. M. Jenkins, and Julian Dorsky (1952). "Mandelic Acid". Organic Syntheses{{cite journal}}: CS1 maint: multiple names: authors list (link); Collected Volumes, vol. 3, p. 538.
^ Putten, P. L. (1979). "Mandelic acid and urinary tract infections". Antonie van Leeuwenhoek. 45 (4): 622. doi:10.1007/BF00403669.

This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press. {{cite encyclopedia}}: Missing or empty |title= (help)

[1] Merck Index, 11th Edition, 5599.

[2] Bjerrum, J., et al. Stability Constants, Chemical Society, London, 1958.

[3] Edwin Ritzer and Rudolf Sundermann “Hydroxycarboxylic Acids, Aromatic” in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a13_519

[4] Corson, B. B.; Dodge, R. A.; Harris, S. A.; Yeaw, J. S. (1941). "Mandelic Acid". Organic Syntheses{{cite journal}}: CS1 maint: multiple names: authors list (link); Collected Volumes, vol. 1, p. 336.

[5] J. G. Aston, J. D. Newkirk, D. M. Jenkins, and Julian Dorsky (1952). "Mandelic Acid". Organic Syntheses{{cite journal}}: CS1 maint: multiple names: authors list (link); Collected Volumes, vol. 3, p. 538.

[6] Putten, P. L. (1979). "Mandelic acid and urinary tract infections". Antonie van Leeuwenhoek. 45 (4): 622. doi:10.1007/BF00403669.

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