Structure-activity studies in floral odorants.

This paper reviews the results of our research on the relationships between chemical structure and floral odour, with particular reference to the characteristic note of muguet. Our investigation was aimed at the design and synthesis of substitutes for hydroxycitronellal and other compounds of similar odour, currently employed in perfumery and cosmetics. In order to approach this problem in a systematic way, we have synthesised a great number of tetrahydropyranyl and tetrahydrofuranyl derivatives, as well as other cyclic compounds, that could help modelling the interactions between odorant and receptor proteins, and define the role of each molecular parameter in eliciting the characteristic olfactory note. The compounds exhibiting the best olfactory notes have been used in a conformational analysis, by means of NMR in two different solvents and molecular modelling. A seletion of the odorants synthesised has been also employed in ligand-binding studies, using odorant-binding-proteins purified from nasal mucosa of the bovine and the pig.