4-ethylguaiacol

Structural formula
General
Surname	4-ethylguaiacol
other names	p -ethylguaiacol; 4-ethyl-2-methoxyphenol ( IUPAC ); Homocresol; Guaiacylethane; 4-ETHYLGUAIACOL ( INCI ) ;
Molecular formula	C 9 H 12 O 2
External identifiers / databases
EC number	220-500-4
ECHA InfoCard	100.018.637
PubChem	62465
ChemSpider	56245
Wikidata	Q229953
properties
Molar mass	152.19 g mol −1
Physical state	firmly
Melting point	15 ° C
boiling point	234-236 ° C
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 315-319-335
	P: 261-305 + 351 + 338
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

4-Ethylguaiacol , also often abbreviated as 4-EG , is derived from guaiacol or 4-ethylphenol . This natural product is a phenolic compound with an attached ethyl group (–CH ₂ –CH ₃ ) and a methoxy group (–OCH ₃ ). As a flavoring substance , it plays a special role in wine .

In addition to 4-ethylphenol, 4-ethylguaiacol is produced in wine by the yeast Brettanomyces bruxellensis or B. anomalus . These phenols are often found in red wines. 4-Ethylguaiacol is perceived with a spicy or clove aroma, its odor threshold in wine is at least 33 µg / l. In and of themselves, these aromas give the wine a good note. 4-Ethylguaiacol occurs together with 4-ethylphenol, which is perceived as having a paint odor, smelling of horse sweat, phenolic or leathery (the odor threshold is 440 µg / l). Hence, the mix of these phenols often contributes to a wine flaw . The relationship between the two components influences the (individual) sensory perception of the wine.

4-Ethylguaiacol is produced biochemically from ferulic acid in a two-step process . The latter is first decarboxylated to a vinyl intermediate and then oxidized to 4-ethylguaiacol . The first reaction is catalyzed by Brettanomyces by a hydroxycinnamic acid decarboxylase, the second by a vinylphenol reductase.

Individual evidence

↑ Entry on 4-ETHYLGUAIACOL in the CosIng database of the EU Commission, accessed on March 21, 2020.
↑ ^a ^b ^c ^d Data sheet 4-Ethylguaiacol from Sigma-Aldrich , accessed on March 18, 2011 ( PDF ).
^ Jamie Goode: The Science of Wine: From Vine to Glass . Univ. of California Pr 2006; ISBN 978-0-520-24800-7 ; P. 210.
↑ Kenneth C. Fugelsang and Charles G. Edwards: Wine Microbiology: Practical Applications and Procedures . Springer, Berlin; 2nd edition 2006. ISBN 978-0-387-33341-0 ; P. 164.
↑ Riccardo Flamini and Pietro Traldi: Mass Spectrometry in Grape and Wine Chemistry . John Wiley & Sons; 2010. ISBN 978-0-470-39247-8 ; P. 146.
↑ Riccardo Flamini and Pietro Traldi: Mass Spectrometry in Grape and Wine Chemistry . John Wiley & Sons; 2010. ISBN 978-0-470-39247-8 ; P. 145.
↑ Brettanomyces Monitoring by Analysis of 4-ethylphenol and 4-ethylguaiacol at etslabs.com

[CosIng-1] Entry on 4-ETHYLGUAIACOL in the CosIng database of the EU Commission, accessed on March 21, 2020.

[Sigma-2] Data sheet 4-Ethylguaiacol from Sigma-Aldrich , accessed on March 18, 2011 ( PDF ).

[3] Jamie Goode: The Science of Wine: From Vine to Glass . Univ. of California Pr 2006; ISBN 978-0-520-24800-7 ; P. 210.

[4] Kenneth C. Fugelsang and Charles G. Edwards: Wine Microbiology: Practical Applications and Procedures . Springer, Berlin; 2nd edition 2006. ISBN 978-0-387-33341-0 ; P. 164.

[5] Riccardo Flamini and Pietro Traldi: Mass Spectrometry in Grape and Wine Chemistry . John Wiley & Sons; 2010. ISBN 978-0-470-39247-8 ; P. 146.

[6] Riccardo Flamini and Pietro Traldi: Mass Spectrometry in Grape and Wine Chemistry . John Wiley & Sons; 2010. ISBN 978-0-470-39247-8 ; P. 145.

[7] Brettanomyces Monitoring by Analysis of 4-ethylphenol and 4-ethylguaiacol at etslabs.com