- 1,3,5-Trithianes and sulfur monochloride/sodium sulfide: an alternative route to 3,5-disubstituted 1,2,4-trithiolanes
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Treatment of substituted 1,3,5-trithianes with S2Cl2 and Na2S under mild conditions provides 3,5-disubstituted 1,2,4-trithiolanes, as mixture of diastereoisomers.
- Tanini, Damiano,Trapani, Francesca,Capperucci, Antonella
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p. 635 - 644
(2020/09/01)
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- Aroma compounds generated from thermal reaction of l-ascorbic acid with l-cysteine
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The reaction of l-ascorbic acid with l-cysteine in heated aqueous solution (141 ± 1 °C) at five different pH values (5.00, 6.00, 7.00, 8.00, or 9.00) for 2 h, resulted in the formation of a complex mixture of aroma volatiles. The volatile compounds generated were analysed by SPME-GC-MS. The results gave 43 aroma compounds. The reaction between l-ascorbic acid and l-cysteine led mainly to the formation of alicyclic sulphur compounds, thiophenes, thienothiophenes, thiophenones, thiazoles and pyrazines, most of which contain sulphur. Many of these volatiles had meaty flavour. The origin of many of the compounds was explained. The studies showed that thienothiophenes and thienones were formed mainly at acidic pH. In contrast, higher pH values could promote the production of thiophenes, thiazoles and pyrazines.
- Yu, Ai-Nong,Zhang, Ai-Dong
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experimental part
p. 1060 - 1065
(2011/12/02)
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- Evidence for heterolytic cleavage of C-S bonds in the photolysis of 1,3,5-trithianes
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The homolytic/heterolytic nature of photolytic C-S bond cleavage was studied in 1,3,5-trithianes. The mechanism of photolysis was refined from previous studies. First, evidence was presented for the existence of a precursor of the biradical-like transient (I) which itself was identified in previous studies. Second, the nature of I was further clarified through methanol-scavenging experiments where the results could be interpreted as lending credibility to the notion that I has significant bipolar character. Kinetic and spectral analyses of transient absorptions, following laser excitation of the trithianes, showed that I was reacting with methanol. Complementary steady-state photolytic quantum yields supported this finding, and additional, but unidentified, stable products from irradiations in methanol were seen in the HPLC. The formation of these products was interpreted as likely arising from a nucleophilic attack of methanol at the carbocationic end of the bipolar structure of I.
- Hug,Janeba-Bartoszewicz,Filipiak,Pedzinski,Kozubek,Marciniak
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p. 883 - 892
(2008/12/23)
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- A Novel Method for the Generation of Thial S-Sulfides from 2,4,6-Trisubstituted 5,6-Dihydro-1,3,5-dithiazines
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Treatment of 2,4,6-trisubstituted 5,6-dihydro-1,3,5-dithiazines with NCS or NBS afforded highly reactive thial S-sulfides, which underwent dimerization to give the corresponding 1,2,4,5-tetrathianes.The products were also selectively converted into naturally-occurring cyclic polysulfides, 1,2,4-trithiolanes and 1,2,3,5,6-pentathiepanes, by treatment with Ph3P, KCN, or Na2S4.
- Takikawa, Yuji,Makabe, Takahiro,Hirose, Naoyuki,Hiratsuka, Takamichi,Takoh, Ryuji,Shimada, Kazuaki
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p. 1517 - 1520
(2007/10/02)
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- Gas Phase Reactions, 24. The Thermal Generation of Thiocarbonyl Compounds
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Thiocarbonyl derivatives R1R2C=S with R1, R2 = H, CH3, C6H5 can be generated thermally in the gas phase from a variety of precursors.Especially advantageous are the cleavage of propene from allyl sulfides or, for their preparation in pure form, the pyrolysis of dithietane or trithiolane derivatives.Photoelectron spectroscopy proves to be well-suited for gas analysis in the flow tube used, for the optimization of the decomposition conditions, and via assignment of the observed ionization patterns for the characterization of the thioaldehydes and thioketones prepared.
- Bock, Hans,Hirabayashi, Takakuni,Mohmand, Shamsher
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p. 492 - 503
(2007/10/02)
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