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
摘要:
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.
AbstractThe authors describe a new general synthesis of cis‐β‐ethylene aldehydes: the alkylation of 1‐methoxy‐1‐buten‐3‐yne to 1‐methoxy‐1‐alken‐3‐ynes followed by addition of methanol produces 1,1‐dimethoxy‐3‐alkynes. The catalytical reduction of these compounds to 1,1‐dimethoxy‐3‐alkenes followed by mild acidic hydrolysis yields cis‐β‐ethylene aldehydes.
A Mild Chemo-Enzymatic Oxidation–Hydrocyanation Protocol
作者:Danielle J. Vugts、Lars Veum、Kanar al-Mafraji、Renske Lemmens、Rob F. Schmitz、Frans J. J. de Kanter、Marinus B. Groen、Ulf Hanefeld、Romano V. A. Orru
DOI:10.1002/ejoc.200500905
日期:2006.4
Oxidation–hydrocyanation of γ,δ-unsaturated alcohols using (immobilised) TEMPO/PhI(OAc)2 in combination with HbHNL proceeds smoothly. After (in situ) protection, the resulting cyanohydrin derivatives were obtained in good overall yields and high ee’s. A mild TEMPO-catalysed oxidation protocol is described that yields β,γ-unsaturated aldehydes without isomerisation of the double bond and that is compatible
(Z)-3-Unsaturated volatile acids, alcohols, and aldehydes are commonly found in foods and other natural sources, playing a vital role in the attractiveness of foods but also as compounds with chemocommunicative function in entomology. However, a systematic investigation of their smell properties, especially regarding humans, has not been carried out until today. To close this gap, the odor thresholds