2,6-Diacetylpyridine
[CAS# 1129-30-2]

Identification

• Classification: Flavors and spices >> Synthetic spice >> Lactone and oxygen-containing heterocyclic compound >> Thiazole, thiophene and pyridine
• Name: 2,6-Diacetylpyridine
• Synonyms: 1-(6-acetylpyridin-2-yl)ethanone
• Molecular Formula: C₉H₉NO₂
• Molecular Weight: 163.17
• CAS Registry Number: 1129-30-2
• EC Number: 214-442-9
• SMILES: CC(=O)C1=NC(=CC=C1)C(=O)C

Properties

• Density: 1.1±0.1 g/cm³ Calc.^*
• Melting point: 79 - 82 °C (Expl.)
• Boiling point: 287.2±25.0 °C 760 mmHg (Calc.)^*
• Flash point: 131.9±29.6 °C (Calc.)^*
• Index of refraction: 1.521 (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
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovery and Applications

2,6-Diacetylpyridine is an organic compound with the molecular formula C9H9NO2. Structurally, it features a pyridine ring substituted at the 2 and 6 positions with acetyl groups. This symmetrical substitution pattern imparts distinct reactivity to the molecule, especially in coordination and condensation chemistry.

The compound has been known and studied since the early 20th century, primarily in the context of ligand development. It serves as a valuable building block in the synthesis of Schiff bases and macrocyclic ligands due to the presence of two reactive carbonyl groups positioned to allow chelation when condensed with diamines. These ligands are commonly used to coordinate metal centers in organometallic and coordination chemistry, facilitating the formation of stable metal complexes with applications in catalysis, magnetism, and materials science.

In synthetic chemistry, 2,6-diacetylpyridine has been employed in the preparation of polydentate ligands such as bis(imino)pyridines. These ligands have received considerable attention for their role in homogeneous catalysis, especially in olefin polymerization and hydrofunctionalization reactions. The central pyridine nitrogen and flanking imine groups enable robust binding to transition metals such as iron, cobalt, and nickel, often resulting in complexes with well-defined electronic and geometric structures.

The compound is typically synthesized through Friedel–Crafts acetylation of pyridine derivatives under controlled conditions, although more refined routes involving acylation using acyl chlorides or ketene intermediates have also been reported. It is generally stable under ambient conditions and is soluble in many polar organic solvents.

Beyond catalysis, 2,6-diacetylpyridine and its derivatives have been explored for their biological relevance, including antimicrobial and anti-inflammatory activity, largely through their function as precursors to more complex bioactive molecules. The compound continues to be of interest for the development of functional materials, coordination polymers, and supramolecular assemblies due to its defined geometry and versatile reactivity.

References

1960. Neue Reaktionen zum Nachweis und zur quantitativen photometrischen Bestimmung kleiner Nickelgehalte. Fresenius' Zeitschrift für analytische Chemie, 174(3).
DOI: 10.1007/bf00562325

1975. Preparation and crystal structure of bis(protonated 2,6-diacetylpyridine bis(phenylhydrazone)) uranyl tetrachloride, CH3CN. Journal of Crystal and Molecular Structure, 5(1).
DOI: 10.1007/bf01202547

2021. Synthesis, Crystal Structure and DNA-Binding Study of a New Zinc(II) Complex Based on 2,6-Bis(imino)pyridyl Ligand. Journal of Chemical Crystallography, 51(4).
DOI: 10.1007/s10870-021-00887-0