2-Hydroxynicotinic acid
[CAS# 609-71-2]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Pyridine compound >> Pyridine derivative
• Name: 2-Hydroxynicotinic acid
• Synonyms: 2-Hydroxypyridine-3-carboxylic acid
• Molecular Formula: C₆H₅NO₃
• Molecular Weight: 139.11
• CAS Registry Number: 609-71-2
• EC Number: 210-198-2
• SMILES: C1=CNC(=O)C(=C1)C(=O)O

Properties

• Density: 1.5±0.1 g/cm³ Calc.^*
• Melting point: 258 - 261 °C (Expl.)
• Boiling point: 427.5±30.0 °C 760 mmHg (Calc.)^*
• Flash point: 212.4±24.6 °C (Calc.)^*
• Index of refraction: 1.626 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319
Eye irritation	Eye Irrit.	2A	H319

Discovery and Applications

2-Hydroxynicotinic acid, also known as picolinic acid or 2-pyridinecarboxylic acid with a hydroxyl substitution at the 2-position, is an organic compound characterized by a pyridine ring bearing both a hydroxyl group and a carboxylic acid functional group. Its molecular formula is C₆H₅NO₃. This compound is a hydroxylated derivative of nicotinic acid (vitamin B₃), distinguished by the presence of a hydroxyl group adjacent to the carboxyl group on the pyridine ring.

The compound was initially studied in the context of pyridine derivatives and their biological roles, with 2-hydroxynicotinic acid recognized for its metal-chelating properties due to the proximity of the hydroxyl and carboxyl groups enabling bidentate coordination. It is naturally occurring and also can be synthesized via chemical oxidation of nicotinic acid or through hydroxylation reactions on the pyridine ring.

2-Hydroxynicotinic acid has garnered attention for its chelating ability, which makes it useful in coordination chemistry for forming stable complexes with various metal ions including iron, copper, zinc, and others. These complexes have applications in catalysis, analytical chemistry, and environmental remediation, where metal ion sequestration is needed.

In biological systems, compounds structurally related to 2-hydroxynicotinic acid participate in metabolic pathways involving vitamin B₃ derivatives. While 2-hydroxynicotinic acid itself is not a vitamin, its structural features are important for understanding the reactivity and function of pyridine-based biomolecules.

The compound’s acidic nature and solubility in water and polar solvents facilitate its use in synthetic organic chemistry as an intermediate in the preparation of pharmaceuticals and agrochemicals. Its functional groups allow for further chemical modification, enabling the synthesis of derivatives with potential biological activities.

Analytically, 2-hydroxynicotinic acid is characterized by techniques such as nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and mass spectrometry (MS), which confirm its structure and purity. Ultraviolet-visible (UV-Vis) spectroscopy is used to study its electronic properties and interactions with metal ions.

In summary, 2-hydroxynicotinic acid is a hydroxylated pyridinecarboxylic acid known for its metal-chelating abilities and role as a chemical intermediate. It has significance in coordination chemistry, organic synthesis, and as a structural model for related biological compounds.