Α-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
CAS Number	80-56-8 unspecified Y 7785-70-8 (+)-α-Pinene Y 7785-26-4 (−)-α-Pinene Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:36740 unspecified N CHEBI:28660 (−)-α-Pinene N CHEBI:28261 (+)-α-Pinene N
ChemSpider	389795 Y
ECHA InfoCard	100.001.175
KEGG	C06308 Y
PubChem	440968
RTECS number	DT7000000 (unspec. isomer)
UNII	JPF3YI7O34 Y
InChI 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 Y Key: GRWFGVWFFZKLTI-IUCAKERBSA-N Y 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
SMILES C\1=C(\[C@@H]2C[C@H](C/1)C2(C)C)C
Properties
Chemical formula	C10H16
Molar mass	136.24 g·mol−1
Appearance	Clear colorless liquid
Density	0.858 g/mL (liquid at 20 °C)
Melting point	−64 °C (−83 °F; 209 K)
Boiling point	155 °C (311 °F; 428 K)
Solubility in water	Very low
Solubility in acetic acid	miscible
Solubility in ethanol	miscible
Solubility in acetone	miscible
Chiral rotation ([α]D)	−50.7° (1S,5S-Pinene)
Hazards
Main hazards	flammable
R-phrases	R10 R20/21/22 R36/37/38 R43 R51
S-phrases	S16 S26 S36 S37 S60 S61
NFPA 704	2 1 0
Flash point	33 °C (91 °F; 306 K)
Related compounds
Related alkene	β-Pinene, Camphene, 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  (what is YN ?)
Infobox references

α-Pinene is an organic compound of the terpene class, one of two isomers of pinene. It is an alkene and it contains a reactive four-membered ring. It is found in the oils of many species of many coniferous trees, notably the pine. It is also found in the essential oil of rosemary (Rosmarinus officinalis) and Satureja myrtifolia (also known as "Zoufa" in some regions.) Both enantiomers are known in nature; (1S,5S)- or (−)-α-pinene is more common in European pines, whereas the (1R,5R)- or (+)-α-isomer is more common in North America. The racemic mixture is present in some oils such as eucalyptus oil and orange peel oil.

The four-membered ring in α-pinene 1 makes it a reactive hydrocarbon, prone to skeletal rearrangements such as the Wagner-Meerwein rearrangement. For example, attempts to perform hydration or hydrogen halide addition with the alkene functionality typically lead to rearranged products. With concentrated sulfuric acid and ethanol the major products are terpineol 2 and its ethyl ether 3, while glacial acetic acid gives the corresponding acetate ester 4. With dilute acids, terpin hydrate 5 becomes the major product.