Piperidine

Structural formula
General
Surname	Piperidine
other names	Hexahydropyridine Pentamethyleneimine Azinane Azacyclohexane
Molecular formula	C 5 H 11 N
Brief description	colorless liquid with an ammonia-like odor
External identifiers / databases
CAS number 110-89-4 EC number 203-813-0 ECHA InfoCard 100.003.467 PubChem 8082 Wikidata Q410234
properties
Molar mass	85,15 g · mol -1
Physical state	liquid
density	0.86 g cm −3
Melting point	−10 ° C
boiling point	106 ° C
Vapor pressure	33 h Pa (20 ° C)
solubility	miscible with water soluble in ethanol, diethyl ether, benzene, chloroform
Refractive index	1.4530 (20 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 225-302-331-311-314-412 P: 210-261-280-303 + 361 + 353-305 + 351 + 338-370 + 378
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Piperidine (systematic name according to the Hantzsch-Widman system : Azinan ) is a colorless liquid that smells of spermidine (semen-like). According to its chemical structure, it is a ring-shaped secondary amine .

history

Piperidine was first isolated from pepper in 1819 by the Danish chemist Hans Christian Ørsted . In 1894 Albert Ladenburg and Scholz succeeded in the first full synthesis of piperidine.

Occurrence

Piperidine is a structural component of the piperidine alkaloids , which include the piperine of black pepper ( Piper nigrum ) or the coniin of the spotted hemlock ( Conium maculatum ). But piperidine also occurs endogenously in mammalian organisms . Von Euler discovered in 1944 that it is a normal component of human urine. In 1960, the Honegger team detected piperidine in the brain. When tritiated piperidine was administered, the highest concentrations were found in the caudate nucleus of the basal ganglia . Abood then suspected that piperidine was an endogenous psychotropic substance that had a regulating effect on behavior.

Extraction and presentation

By catalytic hydrogenation of pyridine (1) , piperidine (2) is obtained quantitatively:

The electrochemical reduction of pyridine also gives piperidine.

properties

Piperidine is a base ( pK _s of Piperidiniumions = 11.12). It forms complexes with heavy metal salts .

Piperidine forms flammable vapor-air mixtures. With a flash point of 4 ° C, the substance is considered highly flammable. The explosion range is between 1.3 vol.% As the lower explosion limit (LEL) and 10.3 vol.% As the upper explosion limit (UEL).

Pharmacological Aspects

Piperidine appears to be an endogenous substance with a regulatory effect in the CNS. It is particularly interesting that piperidine can antagonize the central and psychotomimetic effects of piperidyl benzilates such as JB-336 in animals and humans. Prior administration of piperidine blocked the effect of JB-336. From these findings it was concluded that piperidine may also be suitable as a psychotropic drug for the treatment of mental health problems. In 1962 the effects of piperidine were examined in clinical studies. Larger amounts of piperidine administered (in the form of piperidine salts) had a calming effect on anxiety and tension states as well as a certain antipsychotic effect. The effective quantities are in the range of 0.3–3 g (divided into 3–4 individual servings). In experiments in which 1-3 g of piperidine hydrochloride were administered daily, no significant side effects and no changes in blood and liver values ​​occurred. At extremely high doses, mild nicotinic effects and non-curar-like muscle relaxation were observed in animals. Piperidine is currently not used in human or veterinary medicine.

use

Piperidine is used as a solvent , an intermediate product in the synthesis of pharmaceuticals , pesticides and fragrances , as a hardener for epoxy resins , as a catalyst for condensation reactions , as a rubber auxiliary and as a reagent for aldehydes , gold , cerium , magnesium or zirconium .

Since piperidine can be used to manufacture the non-marketable narcotic phencyclidine , it is listed in the annexes to the Basic Substance Monitoring Act. Trade, import / export and manufacture of 500 g or more are notifiable.

Sterically hindered piperidine derivatives (usually 2,2,6,6-tetramethylpiperidine derivatives) are used as technically and economically important light stabilizers for plastics and also as HALS-compounds referred to (by English H indered A mine L ight S tabilizers ).

Individual evidence

1. ↑ ^{a b c d e f g h i j} Entry on piperidine in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
2. ↑ Entry on piperidine. In: Römpp Online . Georg Thieme Verlag, accessed on June 13, 2014.
3. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-436.
4. ↑ Entry on piperidines in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ^ Latscha et al .: Chemistry for biologists , Springer Verlag, 2nd edition
6. ↑ US by Euler; Piperidine as a Normal Pressor Constituent of Human Urine. , Acta Physiol. Scand. 1944, 8, 380.
7. ↑ US by Euler; The occurrence and determination of piperidine in human and animal urine. , Acta Pharmacol. Toxicol. 1945, 1, 29.
8. ^ CG Honegger, R. Honegger, Volatile Amines in Brain. , Nature 1960, 185, 530.
9. ↑ LG Abood, F. Rinaldi, Virginia Eagleton distribution of piperidines in the Brain and Its Possible Significance in behavior. , Nature 1961, 191, 201.
10. ↑ ^{a b} D.C. Tasher, LG Abood, FA Gibbs, E. Gibbs, J., Introduction of a new type of psychotropic drug: cyclopentimine. , J. Neuropsychiat. 1960, 1, 266.
11. ↑ LG Abood, piperidines: Psycho-Chemotherapeutik , US Patent 3,035,977 (1962).