Guaiacol or 2-methoxyphenol is a natural product found in guaiac resin and is formed by the oxidation of lignin. is the compound is colourless or yellow and it has a distinctive smell of smoke. Because of this it is commonly used as an aromatic agent in making coffee, whisky and is an important starting material in the synthesis of vanillin. It is used in medicine because of its antiseptic, expectorant and local anaesthetic properties. As most essential oils or correctly oleoresins, guaiac resin is a mixture of 10 to 200 volatile and lipophilic components, most of which are monoterpene and sesquiterpene hydrocarbons. EO are highly volatile, which allows them to be smelled in dilute forms.
The purpose of this thesis was the synthesis of lipophilic guaiacol derivatives and their olfactory evaluation. Our aim was to find derivatives that have a pleasant smell, which might be used in perfumes. Modifications were made on the free -OH group of guaiacol to synthesise esters and ethers. The reaction yielded mixtures of products, which we then cleaned by column chromatography to get the isolated synthesis products. We then analysed those with 1H NMR and IR spectroscopy to confirm 9 out of 10 reactions were successful.
Afterwards we made an olfactory evaluation of the synthesised products. Volunteers evaluated the pleasantness and intensity of the derivatives and listed their associations to the smells. They rated most of the smells as not pleasant, with only 3 derivatives out of 9 rated as pleasant. They associated 4 out of 9 samples with smoke and smoky smell, which means the derivatives retained the distinctive smell of guaiacol.
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