α-Pinene

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Alpha-Pinene
)
α-Pinene
(+)-α-pinene
(−)-α-pinene
Names
IUPAC name
(1S,5S)-2,6,6-Trimethylbicyclo[3.1.1]hept-2-ene ((−)-α-Pinene)
Identifiers
3D model (
JSmol
)
ChEBI
ChemSpider
ECHA InfoCard
 100.029.161 Edit this at Wikidata
EC Number
  • (−): 232-077-3
KEGG
RTECS number
  • DT7000000 (unspec. isomer)
UNII
UN number 2368
  • InChI=1S/C10H16/c1-7-4-5-8-6-9(7)10(8,2)3/h4,8-9H,5-6H2,1-3H3/t8-,9-/m0/s1 checkY
    Key: GRWFGVWFFZKLTI-IUCAKERBSA-N checkY
  • InChI=1/C10H16/c1-7-4-5-8-6-9(7)10(8,2)3/h4,8-9H,5-6H2,1-3H3/t8-,9-/m0/s1
    Key: GRWFGVWFFZKLTI-IUCAKERBBG
  • C\1=C(\[C@@H]2C[C@H](C/1)C2(C)C)C
Properties
C10H16
Molar mass 136.238 g·mol−1
Appearance Clear colorless liquid
Density 0.858 g/mL (liquid at 20 °C)
Melting point −62.80 °C; −81.04 °F; 210.35 K[1]
Boiling point 155 °C (311 °F; 428 K)[1]
Very low
Solubility Insoluble in chloroform, diethyl ether
Solubility in acetic acid Miscible
Solubility in ethanol Miscible
Solubility in acetone Miscible
Vapor pressure 0.5 kPa
−50.7° (1S,5S-Pinene)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Flammable
GHS labelling:
GHS02: FlammableGHS07: Exclamation markGHS08: Health hazard
Danger
H226, H302, H304, H315, H317, H410
P210, P233, P240, P241, P242, P243, P261, P264, P270, P272, P273, P280, P301+P310, P301+P312, P302+P352, P303+P361+P353, P321, P330, P331, P332+P313, P333+P313, P362, P363, P370+P378, P391, P403+P235, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
3
0
Flash point 33 °C (91 °F; 306 K)
255 °C (491 °F; 528 K)
Explosive limits
 0.8% v/v (lower)
6% v/v (upper)
Lethal dose or concentration (LD, LC):
300-2000 mg/kg (rat, oral)
> 5 g/kg (rabbit, dermal)
625 ppm/min (rat)
Safety data sheet (SDS) Fisher Scientific
Related compounds
Related alkene
3-carene, limonene
Related compounds
 borneol, camphor, terpineol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

α-Pinene is an

orange peel oil
.

Reactivity

Some general reactions of α-pinene

Commercially important derivatives of alpha-pinene are linalool, geraniol, nerol, a-terpineol, and camphene.[5]

α-Pinene 1 is reactive owing to the presence of the four-membered ring adjacent to the alkene. The compound is prone to skeletal rearrangements such as the

terpin hydrate
5 becomes the major product.

With one

dipentene hydrochloride) is the major product along with some 6b. Nitrosyl chloride followed by base leads to the oxime 8 which can be reduced to "pinylamine" 9. Both 8 and 9 are stable compounds containing an intact four-membered ring, and these compounds helped greatly in identifying this important component of the pinene skeleton.[7]

Under aerobic oxidation conditions, the main oxidation products are pinene oxide, verbenyl hydroperoxide, verbenol and verbenone.[8]

Atmospheric role

Monoterpenes, of which α-pinene is one of the principal species, are emitted in substantial amounts by vegetation, and these emissions are affected by temperature and light intensity. In the atmosphere α-pinene undergoes reactions with ozone, the hydroxyl radical or the NO3 radical,[9][full citation needed] leading to low-volatility species which partly condense on existing aerosols, thereby generating secondary organic aerosols. This has been shown in numerous laboratory experiments for the mono- and sesquiterpenes.[10][11] Products of α-pinene which have been identified explicitly are pinonaldehyde, norpinonaldehyde, pinic acid, pinonic acid and pinalic acid.[citation needed]

Properties and usage

α-Pinene is highly

PGE1,[12] and is likely antimicrobial.[13] It exhibits activity as an acetylcholinesterase inhibitor, aiding memory.[12] Like borneol, verbenol and pinocarveol (−)-α-pinene is a positive modulator of GABAA receptors. It acts at the benzodiazepine binding site.[14]

α-Pinene forms the biosynthetic base for

HU-308.[12]

α-Pinene is one of the many

marijuana.[16] It is widely theorized by scientists and cannabis experts alike that these terpenes and terpenoids contribute significantly to the unique "character" or "personality" of each marijuana strain's unique effects.[17] α-Pinene in particular is thought to reduce the memory deficits commonly reported as a side-effect of THC consumption.[citation needed] It likely demonstrates this activity due to its action as an acetylcholinesterase inhibitor, a class of compounds which are known to aid memory and increase alertness.[18][additional citation(s) needed
]

α-Pinene also contributes significantly to many of the varied, distinct, and unique odor profiles of the multitude of marijuana strains, varieties and

cultivars.[19]

References

  1. ^ a b "α-Pinene". Archived from the original on 2018-01-30. Retrieved 2018-01-29.
  2. ^ Simonsen, J. L. (1957). The Terpenes. Vol. 2 (2nd ed.). Cambridge: Cambridge University Press. pp. 105–191.
  3. ^ PDR for Herbal Medicine. Montvale, NJ: Medical Economics Company. p. 1100.
  4. S2CID 95564601. Archived
    from the original on 2016-08-04.
  5. ISBN 0471238961
    .
  6. ^ Richter, G.H. (1952). Textbook of Organic Chemistry (3rd ed.). New York, NY: John Wiley & Sons. pp. 663–668.
  7. doi:10.1002/hlca.19210040161
    .
  8. ^ Neuenschwander, U. (2010). "Mechanism of the Aerobic Oxidation of α-Pinene". ChemSusChem (in German). 3 (1): 75–84.
    PMID 20017184
    .
  9. ^ IUPAC Subcommittee on Gas Kinetic Data Evaluation
  10. doi:10.1021/es950943+
    .
  11. PMID 22869714
    .
  12. ^
    PMID 21749363
    .
  13. PMID 19969046
    .
  14. PMID 27573669
    .
  15. S2CID 19504014
    .
  16. PMID 6991645
    .
  17. PMID 28861479
    .
  18. PMID 28096851
    .
  19. ^ Mediavilla, V.; Steinemann, S. (1997). "Essential oil of Cannabis sativa L. strains". Journal of the International Hemp Association. 4: 80–82.
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