Azulen - С 10 Н 8 - bicyclo- [5.3.0] -deca-1,3,5,7,9-pentaene is a non-benzoic aromatic compound containing a condensed system of 5- and 7-membered rings. It is an isomer of naphthalene .
| Azulen | |
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| General | |
| Systematic name | Azulen |
| Chem. formula | C 10 H 8 |
| Physical properties | |
| Molar mass | 128.17 g / mol |
| Thermal properties | |
| T. melt. | 99 ° C |
| T. bale. | 242 ° C |
| Classification | |
| Reg. CAS number | 275-51-4 |
| PubChem | |
| Reg. EINECS number | |
| Smiles | |
| Inchi | |
| RTECS | CO4570000 |
| Chebi | |
| ChemSpider | |
Content
- 1 Discovery History
- 2 Being in nature
- 3 Physical properties
- 4 Chemical properties
- 5 Getting
- 6 Application
- 7 Physiological role
- 8 Notes
- 9 References
Discovery History
Azulene was first obtained in the 15th century as a blue coloring matter isolated from chamomile essential oil . Then he was not given any significance, and the substance was not identified. Secondarily, azulene was discovered in 1863 by French perfumer Septimus Piess in yarrow and wormwood . Then he got his name. The structure of azulene was discovered and its first synthesis was made by the Swiss organic chemist Leopold (Lavoslav) Ruzhichka in 1937 .
Being in nature
Derivatives of azulene are quite widely found in natural essential oils [1] :
- Chamazulen 1,4-dimethyl-7-ethylazolene: a component of essential oil from chamomile ( Matricaria chamomilla ) [syn. Matricaria recutita ] and yarrow ( Achillea millefolium ).
- Guaiazulene 1,4-dimethyl-7-isopropylazolene: part of the essential oil of some eucalyptus trees ; isolated from high-boiling fractions of the essential oil Eucalyptus globulus , guryun-balsam , reunion geranium , Geranium macrorrhizum and patchouli .
- Isoguiazulene 2,4-dimethyl-7-isopropylazolene. Found in essential oil of yarrow ( Achillea millefolium ).
Physical Properties
The crystalline substance is blue or blue-violet. Insoluble in water, soluble in hydrocarbons, diethyl ether , ethanol . It is distilled with steam [2] .
It is well soluble in sulfuric and phosphoric acid with the formation of salts (while its blue color disappears). It easily forms π-complexes with picric acid and trinitrobenzene .
The molecule has a dipole moment.
Chemical Properties
- When heated above 300 ° C, it isomerized to naphthalene .
- It is gradually oxidized by atmospheric oxygen , and under the action of KMnO 4 in an acidic environment it splits into a mixture of liquid and gaseous products.
- In electrophilic and radical substitution reactions, it behaves like highly active five-membered heterocycles.
Due to the high electron density on the 5-membered cycle, azulene has a relatively high chemical activity, easily reacting with electrophilic agents.
It is relatively easily nitrated with tetranitromethane in pyridine medium:
In the reactions of halogenation, acylation, azo coupling, etc., substitution goes to position 1 and then 3:
- In reactions with nucleophiles, azulene is less active, substitution goes to position 4, 8 and then to 6.
Getting
- From pyridinium salts [2] :
- By the reaction of 1,1-thiophenoxide with dimethylaminofulvene [3] :
Application
Azulene and, especially, its natural derivatives are widely used in perfumes and cosmetics : they are part of toothpastes, creams, shampoos and other body care products.
Physiological Role
Azulenes have anti-inflammatory, anti-allergenic and bacteriostatic activity, on which their use is based.
Notes
- ↑ AZULENES
- ↑ 1 2 Chemical Encyclopedia./ Azulene. // Editor-in-chief I. L. Knunyants. - M.: “Soviet Encyclopedia”, 1988. - T. 1.
- ↑ http://www.chemnet.ru/eng/teaching/nen/objects2/15_heterocycles_2_2006.pdf