4-pyridone

Structural formula
General
Surname	4-pyridone
other names	4-pyridinol 4-hydroxypyridine 4-pyridinone Pyridin-4-one
Molecular formula	C 5 H 5 NO
Brief description	colorless solid
External identifiers / databases
CAS number 108-96-3 (4-pyridone) 626-64-2 (4-hydroxypyridine) EC number 203-633-2 ECHA InfoCard 100.003.304 PubChem 12290 Wikidata Q230024
properties
Molar mass	95.10 g mol −1
Physical state	firmly
Melting point	143-145 ° C
boiling point	230–235 ° C (16 hPa)
solubility	soluble in water
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 315-319-335 P: 261-305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

4-pyridone is an organic compound with the empirical formula C ₅ H ₅ NO. She belongs to the group of Pyridons .

presentation

Analogously to the isomeric 2-pyridone , 4-pyridone can be obtained by reacting 4-pyrone with ammonia .

properties

The keto form 4-pyridone is in chemical equilibrium with the tautomeric hydroxo form 4-hydroxypyridine . In solution , the equilibrium is almost entirely on the side of the ketone. The hydroxoform only represents a significant proportion in equilibrium in highly dilute solutions and in very non-polar solvents. In the gas phase, however, the hydroxoform is the dominant species.

The reaction behavior of 4-pyridone is determined by the keto form, which is why the designation 4-pyridinol should be avoided, as it implies a reactivity similar to phenol , which however does not occur. In solution, 4-pyridone has no classic aromatic properties. Thus, the isomeric has 3-hydroxypyridine a pyridintypischen pK _s value , while 4-pyridone a significantly lower basicity and having amidähnlich the oxygen protonated is.

4-Pyridone forms yellow-colored complexes with iron (III) chloride .

Occurrence and use

4-pyridone in free form does not occur naturally, but the basic structure occurs as a structural component in pyridosine , a hydrolysis product of milk . It also occurs in the natural substance mimopudine and the non- biogenic amino acid mimosine .

Structure of mimosine

The compound serves as a raw material for the synthesis of 4-chloropyridine and 3-hydroxy-4-pyridones. The latter are used as aluminum and iron binding drugs .

Individual evidence

1. ↑ ^{a b c d e f} Entry on pyridinoles. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.
2. ↑ ^{a b c} data sheet 4-pyridone at AlfaAesar, accessed on March 6, 2010 ( PDF )(JavaScript required) .
3. ↑ ^{a b} Data sheet 4-Hydroxypyridine from Sigma-Aldrich , accessed on October 22, 2016 ( PDF ).
4. ↑ External identifiers or database links for 4-hydroxypyridine : CAS number: 626-64-2, EC number: 210-958-3, ECHA InfoCard: 100.009.963 , Wikidata : Q24730939 .
5. ↑ ^{a b} J.A. Joules, K. Mills: Heterocyclic Chemistry 2000 , 4th Edition, Blackwell Science, Oxford, pp. 88-91; ISBN 0-632-05453-0 .