Picolinic acid

Picolinic acid is an organic compound with the formula C₅H₄N(CO₂H). It is a derivative of pyridine with a carboxylic acid (COOH) substituent at the 2-position. It is an isomer of nicotinic acid and isonicotinic acid, which have the carboxyl side chain at the 3- and 4-position, respectively. It is a white solid that is soluble in water.

Picolinic acid

Names
Preferred IUPAC name Pyridine-2-carboxylic acid
Other names Picolinic acid
Identifiers
CAS Number	98-98-6^Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:28747^Y
ChEMBL	ChEMBL72628^Y
ChemSpider	993^Y
ECHA InfoCard	100.002.472
PubChem CID	1018
UNII	QZV2W997JQ^Y
CompTox Dashboard (EPA)	DTXSID7031903
InChI InChI=1S/C6H5NO2/c8-6(9)5-3-1-2-4-7-5/h1-4H,(H,8,9)^Y Key: SIOXPEMLGUPBBT-UHFFFAOYSA-N^Y InChI=1/C6H5NO2/c8-6(9)5-3-1-2-4-7-5/h1-4H,(H,8,9) Key: SIOXPEMLGUPBBT-UHFFFAOYAC
SMILES c1ccnc(c1)C(=O)O
Properties
Chemical formula	C6H5NO2
Molar mass	123.111 g·mol^−1
Appearance	White to tan crystalline solid
Melting point	136 to 138 °C (277 to 280 °F; 409 to 411 K)
Solubility in water	Slightly soluble (0.41%) in water^[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is ^YN ?) Infobox references

In synthetic organic chemistry, has been used as a substrate in the Mitsunobu reaction and in the Hammick reaction.^[2]: 495ff

Coordination chemistry

Picolinic acid is a bidentate chelating agent of elements such as chromium, zinc, manganese, copper, iron, and molybdenum in the human body.^[3]: 72 Many of its complexes are charge-neutral and thus lipophilic. After its role in absorption was discovered, zinc picolinate dietary supplements became popular as they were shown to be an effective means of introducing zinc into the body.^[3]

Production

Picolinic acid is formed from 2-methylpyridine by oxidation, e.g. by means of potassium permanganate (KMnO₄).^[4][5]

 

Biosynthesis

Picolinic acid is a catabolite of the amino acid tryptophan through the kynurenine pathway.^[3][6] Its function is unclear, but it has been implicated in a variety of neuroprotective, immunological, and anti-proliferative effects. In addition, it is suggested to assist in the absorption of zinc(II) ions and other divalent or trivalent ions through the small intestine.^[7]

Picolinates

Salts of picolinic acid (picolinates) include:

• Chromium(III) picolinate
• Zinc picolinate

See also

• Dipicolinic acid

References

1. Lide, DR. "CRC Handbook of Chemistry and Physics, Internet Version 2005, http://hbcpnetbase.com, CRC Press, Boca Raton, Florida, 2005". {{cite journal}}: Cite journal requires |journal= (help)
2. Picolinic Acid chapter in Philip L. Fuchs. Handbook of Reagents for Organic Synthesis: Catalytic Oxidation Reagents. John Wiley & Sons, Jul 29, 2013 ISBN 9781118704820
3. Grant, RS; Coggan, SE; Smythe, GA (2009). "The physiological action of picolinic Acid in the human brain". International Journal of Tryptophan Research. 2: 71–9. doi:10.4137/ijtr.s2469. PMC 3195224. PMID 22084583.
4. Shimizu, Shinkichi; Watanabe, Nanao; Kataoka, Toshiaki; Shoji, Takayuki; Abe, Nobuyuki; Morishita, Sinji; Ichimura, Hisao (2007). "Pyridine and Pyridine Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a22_399.
5. Harold Hart (Autor), Leslie E. Craine (Autor), David J. Hart (Autor), Christopher M. Hadad (Autor); Nicole Kindler (Übersetzer): Organische Chemie, 3. Auflage, Wiley-VCH, Weinheim 2007, ISBN 978-3-527-31801-8, S. 494.
6. Tan, L.; et al. (December 2012). "The kynurenine pathway in neurodegenerative diseases: mechanistic and therapeutic considerations". J Neurol Sci. 323 (1–2): 1–8. doi:10.1016/j.jns.2012.08.005. PMID 22939820. S2CID 6061945.
7. Evans, Gary (1982). "The Role of Picolinic Acid in Metal Metabolism". Life Chemistry Reports. Harwood Academic Publishers. 1: 57–67. Retrieved 20 March 2015.