is a naturally occurring organic compound
with the formula
). This colourless aromatic oil is derived from guaiacum
or wood creosote
. Samples darken upon exposure to air and light. Guaiacol is present in wood smoke
, resulting from the pyrolysis
Preparation and derivatives
Guaiacol is obtained directly from beechwood
tar. It is produced industrially from pyrocatechin by methylation with potash and potassium methyl sulfate, or from anisole
by nitration, reduction of the resulting ortho-nitroanisole to 2-aminoanisole, which is then diazotized and boiled with water. In the laboratory, it can be synthesized by the di-methylation
followed by selective mono-demethylation
- C6H4(OH)2 + 2 (CH3O)2SO2 → C6H4(OCH3)2 + 2 HO(CH3O)SO2
- C6H4(OCH3)2 + C2H5SNa → C6H4(OCH3)(OH)
Guaiacol carbonate is known as duotal, the phosphate as phosphatol, the phosphite as guaiaco-phosphal; phosphotal is a mixture of the phosphites of creosote phenols. The valerianic ester of guaiacol is known as geosote, the benzoic as benzosol, the salicylic as guaiacolsalol, while the glycerin ether appears as guaiamar.
Guaiacol is used medicinally as an expectorant
, and local anesthetic
. Guaiacol is also used in the preparation of eugenol
The related derivative, dimethoxybenzene or veratrol
, is also used in medicine.
Because of its natural color changing abilities, it is sometimes used as an indicator solution in various experiments involving enzymes.
- Merck Index, 13th Edition, 4568.