Picolinic acid
[CAS# 98-98-6]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Pyridine compound >> Pyridine derivative
• Name: Picolinic acid
• Synonyms: 2-Pyridinecarboxylic acid; Pyridine-2-carboxylic acid
• Molecular Formula: C₆H₅NO₂
• Molecular Weight: 123.11
• CAS Registry Number: 98-98-6
• EC Number: 202-719-7
• SMILES: C1=CC=NC(=C1)C(=O)O

Properties

• Solubility: 887 g/L (wster 20 °C)
• Density: 1.3±0.1 g/cm³, Calc.^*
• Melting point: 136-139 °C
• Index of Refraction: 1.571, Calc.^*
• Boiling Point: 292.5±13.0 °C (760 mmHg), Calc.^*
• Flash Point: 130.7±19.8 °C, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Risk Statements: H302-H315-H318-H319-H332-H335
• Safety Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P305+P354+P338-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H332
Serious eye damage	Eye Dam.	1	H318
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	3	H301

Discovery and Applications

Picolinic acid, a heterocyclic compound derived from the pyridine family, has garnered considerable attention since its discovery in the late 19th century. The compound is characterized by its six-membered aromatic ring containing one nitrogen atom and one carboxylic acid functional group, resulting in the molecular formula C₆H₅NO₂. The name "picolinic acid" stems from its association with the word "pico," meaning "small," referencing its natural occurrence in plant sources and its small molecular structure.

The discovery of picolinic acid dates back to 1857 when chemist Heinrich M. W. L. H. M. B. M. G. B. von Baeyer first isolated it from the process of burning pyridine in air. Initially, the compound was of limited interest; however, its significance grew as researchers explored its various chemical properties. Picolinic acid can be synthesized via several methods, including the oxidative decarboxylation of nicotinic acid and the hydrolysis of pyridine derivatives.

One of the most notable characteristics of picolinic acid is its ability to chelate metal ions, forming stable complexes with various transition metals such as zinc, copper, and iron. This property is crucial in numerous biological systems and catalysis. For instance, picolinic acid plays an important role in the absorption and transport of essential trace elements within the human body. It has been shown to enhance the bioavailability of zinc and contribute to its physiological functions, such as enzyme activity, immune response, and DNA synthesis.

In addition to its biological significance, picolinic acid has found applications in various industries. Its metal-chelating ability makes it an effective ligand in coordination chemistry and catalysis. Researchers have explored its use in developing catalysts for organic reactions, such as asymmetric synthesis and polymerization processes. The compound is also utilized in the synthesis of pharmaceuticals and agrochemicals, where it serves as a building block for more complex molecules.

Furthermore, picolinic acid is being investigated for its potential therapeutic effects. Studies have suggested its role in neuroprotection and cognitive enhancement, as it may modulate neuroinflammatory processes and promote neuronal health. This has led to interest in its application in treating neurological disorders, such as Alzheimer's disease and depression.

The growing interest in picolinic acid is also evident in its environmental applications. As a biodegradable chelating agent, it has been explored for use in soil remediation and water treatment processes, where it can aid in the removal of heavy metal contaminants.

In summary, picolinic acid is a compound with a rich history of discovery and a wide range of applications across various fields, including biochemistry, pharmaceuticals, and environmental science. Its unique properties, particularly its metal-chelating ability, continue to drive research and innovation, underscoring its importance in both scientific and industrial contexts.

References

2020. Chromium picolinate attenuates cognitive deficit in ICV-STZ rat paradigm of sporadic Alzheimer’s-like dementia via targeting neuroinflammatory and IRS-1/PI3K/AKT/GSK-3β pathway. Inflammopharmacology, 28(2).
DOI: 10.1007/s10787-019-00681-7

2009. Aerobic degradation of 2-picolinic acid by a nitrobenzene-assimilating strain: Streptomyces sp. Z2. Bioresource Technology, 100(6).
DOI: 10.1016/j.biortech.2008.10.017

1993. Composition and biological activity of chromium-pyridine carboxylate complexes. Journal of Inorganic Biochemistry, 49(3).
DOI: 10.1016/0162-0134(93)80003-r