Minor constituents of essential oils and aromatic extracts. Oximes derived from natural flavor and fragrance raw materials – Sensory evaluation, spectral and gas chromatographic characteristics

Abstract

A small library of 57 low molecular weight oximes was prepared from fragrant aldehydes and ketones, and their olfactory profiles were determined. The most substantive and interesting in terms of the sensory impressions were (+)-isomenthone oxime (fresh, musty, green) and cyclocitral oxime (earthy with patchouli, moss and leather notes). The linear retention indices (LRI) were determined for DB-1, DB-5 and DB-WAX columns, and E/Z isomers of 22 out of 57 compounds were resolved on the DB-5 column. Attempts were made to resolve enantiomers of the chosen oximes on chiral GC columns. The best results were obtained by using a Cyclosil B column, on which the enantiomers of camphor, menthone, piperitone and carvone oximes were fully resolved. NMR and MS spectra were acquired to characterize the synthesized library. Gas chromatography–olfactometry was used to assess odoriferous properties of both isomers of oximes. In most cases both isomers possessed similar profile and intensity.