Chemistry:Anisole
| |||
| |||
| Names | |||
|---|---|---|---|
| Preferred IUPAC name
Anisole[1] | |||
| Systematic IUPAC name
Methoxybenzene[1] | |||
| Other names
Methyl phenyl ether[1]
Phenoxymethane | |||
| Identifiers | |||
3D model (JSmol)
|
|||
| 506892 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| EC Number |
| ||
| 2964 | |||
| KEGG | |||
PubChem CID
|
|||
| RTECS number |
| ||
| UNII | |||
| UN number | 2222 | ||
| |||
| |||
| Properties | |||
| C7H8O | |||
| Molar mass | 108.140 g·mol−1 | ||
| Appearance | Colorless liquid | ||
| Density | 0.995 g/cm3 | ||
| Melting point | −37 °C (−35 °F; 236 K) | ||
| Boiling point | 154 °C (309 °F; 427 K) | ||
| Solubility | Insoluble | ||
| −72.79×10−6 cm3/mol | |||
| Hazards | |||
| GHS pictograms |  
| ||
| GHS Signal word | Warning | ||
| H226, H315, H319 | |||
| P210, P233, P240, P241, P242, P243, P264, P280, P302+352, P303+361+353, P305+351+338, P321, P332+313, P337+313, P362, P370+378, P403+235, P501 | |||
| NFPA 704 (fire diamond) | |||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose)
|
3700 mg/kg (rat, oral) | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
 verify (what is   ?)
| |||
| Infobox references | |||
Anisole, or methoxybenzene, is an organic compound with the formula CH
3OC
6H
5. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound is mainly made synthetically and is a precursor to other synthetic compounds. Structurally, it is an ether (–O–) with a methyl (–CH
3) and phenyl (–C
6H
5) group attached. Anisole is a standard reagent of both practical and pedagogical value.[2]
It can be prepared by the Williamson ether synthesis; sodium phenoxide is reacted with a methyl halide to yield anisole.
Reactivity
Anisole undergoes electrophilic aromatic substitution reaction at a faster speed than benzene, which in turn reacts more quickly than nitrobenzene. The methoxy group is an ortho/para directing group, which means that electrophilic substitution preferentially occurs at these three sites. The enhanced nucleophilicity of anisole vs. benzene reflects the influence of the methoxy group, which renders the ring more electron-rich. The methoxy group strongly affects the pi cloud of the ring as a mesomeric electron donor, more so than as an inductive electron withdrawing group despite the electronegativity of the oxygen. Stated more quantitatively, the Hammett constant for para-substitution of anisole is –0.27.
Illustrative of its nucleophilicity, anisole reacts with acetic anhydride to give 4-methoxyacetophenone:
Unlike most acetophenones, but reflecting the influence of the methoxy group, methoxyacetophenone undergoes a second acetylation. Many related reactions have been demonstrated. For example, phosphorus pentasulfide (P
4S
10) converts anisole to Lawesson's reagent, [(CH
3OC
6H
4)PS
2]
2.[3]
Also indicating an electron-rich ring, anisole readily forms π-complexes with metal carbonyls, e.g. Cr(η6−anisole)(CO)
3.[4]
The ether linkage is highly stable, but the methyl group can be removed with strong acids, such as hydroiodic acid or boron trichloride:[5]:{{{1}}}
Birch reduction of anisole gives 1-methoxycyclohexa-1,4-diene.[6]
Preparation
Anisole is prepared by methylation of sodium phenoxide with dimethyl sulfate or methyl chloride:[7][5]
- 2 C
6H
5O−
Na+
+ (CH
3O)
2SO
2 → 2 C
6H
5OCH
3 + Na
2SO
4
Applications
Anisole is a precursor to perfumes, insect pheromones, and pharmaceuticals.[5] For example, synthetic anethole is prepared from anisole.
Safety
Anisole is relatively nontoxic with an -1">50 of 3700 mg/kg in rats.[8] Its main hazard is its flammability.[8]
Popular culture
In the board game Scrabble, the word "anisole" is the 39th-most-likely word (out of over 25,000 possibilities) for a "bingo"/"bonus", i.e. the deployment of all seven letters in one's own hand simultaneously.[9]
See also
- Anethole
- Bromoanisole
- Butylated hydroxyanisole
- Ether
- Ethyl phenyl ether
- Phenol
- 2,4,6-Trichloroanisole (cork taint)
References
- ↑ 1.0 1.1 1.2 Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 702–703. doi:10.1039/9781849733069-00648. ISBN 978-0-85404-182-4. "Anisole, C
6H
5–O–CH
3, is the only name in the class of ethers which is retained both as a preferred IUPAC name and for use in general nomenclature. For preferred IUPAC names, no substitution is allowed; for general nomenclature substitution is allowed on the ring and on the side chain under certain conditions (see P-34.1.1.4)." - ↑ Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, ISBN 978-0-471-72091-1, https://books.google.com/books?id=JDR-nZpojeEC&printsec=frontcover
- ↑ I. Thomsen; K. Clausen; S. Scheibye; S.-O. Lawesson (1984). "Thiation with 2,4-Bis(4-Methoxyphenyl)-1,3,2,4-Dithiadiphosphetane 2,4-Disulfide: N-Methylthiopyrrolidone". Organic Syntheses 62: 158. doi:10.15227/orgsyn.062.0158.
- ↑ E. Peter Kündig (2004). "Synthesis of Transition Metal η6-Arene Complexes". Topics Organomet Chem.. Topics in Organometallic Chemistry 7: 3–20. doi:10.1007/b94489. ISBN 978-3-540-01604-5.
- ↑ 5.0 5.1 5.2 Helmut Fiege; Heinz-Werner Voges; Toshikazu Hamamoto; Sumio Umemura; Tadao Iwata; Hisaya Miki; Yasuhiro Fujita; Hans-Josef Buysch et al.. "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_313.
- ↑ A. J. Birch and K. B. Chamberlain (1977). "Tricarbonyl[(2,3,4,5-η)-2,4-Cyclohexadien-1-one]Iron and Tricarbonyl[(1,2,3,4,5-η)-2-Methoxy-2,4-Cyclohexadien-1-yl]Iron(1+) Hexafluorophosphate(1−) from Anisole". Organic Syntheses 57: 107. doi:10.15227/orgsyn.057.0107.
- ↑ G. S. Hiers and F. D. Hager (1929). "Anisole". Organic Syntheses 9: 12. doi:10.15227/orgsyn.009.0012.
- ↑ 8.0 8.1 MSDS
- ↑ "Fun with analytics: Probabilities and Scrabble" (in en-us). https://www.illumine8.com/blog/fun-with-analytics-probabilities-and-scrabble.
External links
- International Chemical Safety Card 1014
- Pherobase pheromone database entry
 |  |
