Synthesis and Olfactory Characterization of New Fragrant Materials through Chemical Modification of Methyleugenol Molecular Framework by Introducing Ester Functional Groups

Abstract

There is a continuing search for materials having desirable fragrance properties. Such materials are sought either to replace costly natural materials or to provide new fragrances or perfume types, which have not heretofore been available. Hence, the objective of this paper is the synthesis and olfactory characterization of new fragrant materials through chemical modification of methyleugenol (ME) molecular framework by introducing Ester functional groups using appropriate standard procedures. ME is a common phenylpropanoid found in many plant species, particularly in spices and medicinal plants. It is used as a flavouring agent in food and as a fragrance in cosmetics. In this research, methyleugenol was modified to obtain esters. The transformations involve the opening of 2-(4-ethyl-3-methoxybenzyl) oxirane (epoxide ring) to yield 3-(3,4-dimethoxyphenyl)propane-1,2-diol (Dihydroxy). 1-(3,4-dimethoxyphenyl)-3-hydroxypropan-2-yl acetate (53.33% yield) derivatives, was synthesized from the Dihydroxy. The results showed that the odour characteristic of 3-(3,4-dimethoxyphenyl)propane-1,2-diol [floral, pungent, Caramel and sweet] compounds, is clearly different from the odours of the 1-(3,4-dimethoxyphenyl)-3-hydroxypropan-2-yl acetate [fresh, pungent,  lime-like, sweet]. Our findings show that double bond substitution and functional alterations to methyl eugenol modify the perceived odour of methyl eugenol derivatives. Thus, overall structural alteration increased odour potency.