- Structure-odor correlations in homologous series of alkanethiols and attempts to predict odor thresholds by 3d-qsar studies
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Homologous series of alkane-1-thiols, alkane-2-thiols, alkane-3-thiols, 2-methylalkane-1-thiols, 2-methylalkane-3-thiols, 2-methylalkane-2-thiols, and alkane-1,??-dithiols were synthesized to study the influence of structural changes on odor qualities and odor thresholds. In particular, the odor thresholds were strongly influenced by steric effects: In all homologous series a minimum was observed for thiols with five to seven carbon atoms, whereas increasing the chain length led to an exponential increase in the odor threshold. Tertiary alkanethiols revealed clearly lower odor thresholds than found for primary or secondary thiols, whereas neither a second mercapto group in the molecule nor an additional methyl substitution lowered the threshold. To investigate the impact of the SH group, odor thresholds and odor qualities of thiols were compared to those of the corresponding alcohols and (methylthio)alkanes. Replacement of the SH group by an OH group as well as S-methylation of the thiols significantly increased the odor thresholds. By using comparative molecular field analysis, a 3D quantitative structure-activity relationship model was created, which was able to simulate the odor thresholds of alkanethiols in good agreement with the experimental results. NMR and mass spectrometric data for 46 sulfur-containing compounds are additionally supplied.
- Polster, Johannes,Schieberle, Peter
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p. 1419 - 1432
(2015/03/05)
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- Linear Ladder-Type π-Conjugated Polymers Composed of Fused Thiophene Ring Systems
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The study of a linear ladder-type π-conjugated polymers of carbon-sulfur (C2S) analogue of polyacene was presented. The synthesis of ladder-type polymer was achieved via the intramolecular condensation process that resulted in the formation of fused, cross-conjugated thiophene rings. The geometrical relaxation process and various energetic and structural aspects of the convergence behavior of the polaronic and bipolaronic defects on the long chains were also studied. The energetic aspects of doping behavior suggested the possession of polaron as the prevailing charged species by the ladder-type polymer.
- Oyaizu, Kenichi,Iwasaki, Tomokazu,Tsukahara, Yoshiaki,Tsuchida, Eishun
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p. 1257 - 1270
(2007/10/03)
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- Direct synthesis of thiols from halides and epoxides using hydrosulfide exchange resin in methanol
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Various thiols are prepared directly from the corresponding alkyl halides and epoxides using hydrosulfide exchange resin in methanol in the presence of equimolar amounts of triethylammonium chloride at room temperature. The reaction not only proceeds with unique chemoselectivity, but also gives better yields of thiols than most commonly used indirect methods and has an additional advantage of a simple workup.
- Choi,Yoon
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p. 373 - 375
(2007/10/02)
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- Synthesis of thiols via palladium catalyzed methanolysis of thioacetates with borohydride exchange resin
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Various thiols are prepared quantitatively from the corresponding thioacetates via Pd catalyzed methanolysis with borohydride exchange resin under a mild and neutral conditions. One-pot synthesis of thiols from alkyl halides through the formation of alkyl thioacetates using thioacetate exchange resin followed by methanolysis is also described.
- Choi,Yoon
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p. 2655 - 2663
(2007/10/02)
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