Influence of the Chemical Structure on Odor Qualities and Odor Thresholds in Homologous Series of Alka-1,5-dien-3-ones, Alk-1-en-3-ones, Alka-1,5-dien-3-ols, and Alk-1-en-3-ols

Odor qualities and odor thresholds
in air in homologous series
of synthesized alk-1-en-3-ols and alka-1,5-dien-3-ols and their corresponding
ketones were evaluated by gas chromatography–olfactometry.
In the series of the alk-1-en-3-ols and alk-1-en-3-ones the odor quality
changed successively from pungent for the compounds with five carbon
atoms via metallic, vegetable-like for the six- and seven-carbon odorants
to mushroom-like for the compounds with eight and nine carbon atoms.
With further increase in chain length the mushroom-like impression
decreased and changed to citrus-like, soapy, or herb-like. In both
series, two odor threshold minima were found for the six-carbon and
also for the eight- and nine-carbon odorants, respectively. In contrast
to this, the odor qualities in the series of the (Z)- and (E)-alka-1,5-dien-3-ols and their corresponding
ketones did not change significantly with geranium-like, metallic
odors and an increasing mushroom-like odor note with increasing chain
length. The lowest thresholds were found for the eight- and nine-carbon
(Z)-compounds, respectively.