2-pyridone

Structural formula
General
Surname	2-pyridone
other names	2-pyridinol 2-oxopyridine 2-hydroxypyridine 2-pyridinone Pyridin-2-one
Molecular formula	C 5 H 5 NO
Brief description	beige crystals with a musty odor
External identifiers / databases
CAS number 142-08-5 EC number 205-520-3 ECHA InfoCard 100.005.019 PubChem 8871 Wikidata Q209474
properties
Molar mass	95.10 g mol −1
Physical state	firmly
density	1.39 g cm −3
Melting point	104-107 ° C
boiling point	279-281 ° C
solubility	in water: 450 g l −1
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 301 P: 309 + 310
Toxicological data	124 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

2-pyridone is a chemical compound from the group of nitrogen-containing heterocycles . Its structure is derived from that of pyridine . 2-Pyridone belongs to the group of lactams , but is in a tautomeric equilibrium with its lactime form 2-hydroxypyridine ( lactam-lactime tautomerism ).

Extraction and presentation

2-pyridone can be obtained by reacting 2-pyrone with ammonia , but there are also other synthesis options, e.g. B. known from pyridine or by Guareschi-Thorpe reaction .

properties

At room temperature, 2-pyridone is a solid which is in equilibrium with its tautomeric form (2-hydroxypyridine).

The position of the equilibrium depends on the polarity of the solvent . In polar solvents such as water, the equilibrium is almost entirely on the side of the 2-pyridone, while in non-polar solvents the 2-hydroxypyridine is preferred. In the gas phase , the compound is predominantly in the lactim form.

2-pyridone forms dimers by linking two molecules via relatively strong hydrogen bonds .

The dimeric structure is also present in the crystal. The dimer has a similar structure to the adenine - thymine base pair found in DNA .

use

2-Pyridone is used as an intermediate, catalyst or ligand in the manufacture of drugs such as ciclopirox , levetiracetam and amphenidone .

See also

• Ricinine
• Piroctone olamine
• 4-pyridone

Individual evidence

1. ↑ ^{a b c d e f g} Data sheet 2-hydroxypyridine (PDF) from Merck , accessed on March 20, 2011.
2. ↑ Entry on 2-pyridone at ChemBlink , accessed on February 25, 2011.
3. ↑ ^{a b} A. Held, BB Champagne, DW Pratt: Inertial axis reorientation in the S ₁ <–– S ₀ electronic transition of 2-pyridone. A rotational Duschinsky effect. Structural and dynamic consequences , in: J. Chem. Phys. , 1991 , 95 (12) , pp. 8732-8744; doi : 10.1063 / 1.461209 .