Synthesis and Olfactory Characteristics of Hydroxyether Derivatives of Methyl Eugenol

Methyl eugenol is a naturally occurring substance found in the essential oils of several plant species. It is a cheap and abundant material with a rather limited interest as perfuming ingredient. This research investigated the structure-odour relationship of methyl eugenol and its derivatives, focusing on the chemical transformation of the double bond to hydroxyether derivatives in a controlled manner. Two derivatives 2-(4-ethyl-3 - methoxybenzyl)oxirane (68.8% yield) and 1-(3,4-dimethoxyphenyl)-3-ethoxypropan-2-ol (63.58% yield), were synthesized from methyl eugenol. This research found that the odour characteristic of 2-(4-ethyl-3-methoxybenzyl)oxirane [floral, fresh, slight lime and sweet]compounds, is clearly different from the odours of the 1-(3,4-dimethoxyphenyl)-3- ethoxypropan-2-ol [Glue-like, pungent, and Caramel-like]. It is evident from our observations that double bond substitution and functional alteration of the methyl eugenol modifies the perceived odour of methyl eugenol derivative. Thus, structural modification overall led to an increase in odour potency.