40789-98-8Relevant articles and documents
Effect of pH on the maillard reaction of [C]xylose, cystein, and thiamin
Cerny, Christoph,Briffod, Matthieu
scheme or table, p. 1552 - 1556 (2009/10/01)
The influence of different pH values, ranging from 4.0 to 7.0, on the formation of sulfur volatiles in the Maillard reaction was studied using a model system with [13C5]xylose, cysteine, and thiamin. The use of 13C-labeled xylose allowed, by analysis of the mass spectra, volatiles that incorporated xylose carbons in the molecule from other carbon sources to be discerned. For 2-furaldehyde and 2-furfurylthiol, which were favored at low pH, the labeling experiments clearly indicated that xylose was the exclusive carbon source. On the other hand, xylose was virtually not involved in the formation of 3-mercapto-2-butanone, 4,5-dihydro-2-methyl-3- furanthiol, and 5-(2-hydroxyethyl)-4-methylthiazole, which apparently stemmed from thiamin degradation. Both xylose and thiamin seemed to significantly contribute to the formation of 2-methyl-3-furanthiol, 3-mercapto-2-pentanone, and 2-mercapto-3-pentanone, and therefore different formation pathways must exist for each of these molecules. In general, the pH determined strongly which volatiles were formed, and to what extent. However, the relative contribution of xylose to the C-skeleton of a particular compound changed only slightly within the investigated pH range, when both xylose and thiamin were involved in the formation.
Process research on the synthesis of silthiofam: A novel fungicide for wheat
Phillips, Gary,Fevig, Thomas L.,Lau, Patrick H.,Klemm, George H.,Mao, Michael K.,Ma, Chun,Gloeckner, James A.,Clark, Art S.
, p. 357 - 366 (2013/09/06)
The development of an efficient, low-cost synthesis of the novel wheat fungicide silthiofam (1) is described. Improvements to the original Discovery route allowed 300 kg of material to be prepared in two, overlapping pilot-plant campaigns. Thereafter, efforts were focused on further optimizing the pilot-plant route, and on devising alternate, lower cost routes to silthiofam. One potential new route involved a cydoaddition reaction between 3-mereapto-2-butanone and N-(2-propenyl)-3-trimethylsilyl-propynamide. The cyclic product could be directly dehydrated to silthiofam, however the overall yield was modest, raw material costs were high, and there were purification problems. The route ultimately selected for development proceeds in 6 chemical steps and about 60% yield from the inexpensive precursors 3-chloro-2-butanone and methyl 3-methoxyacrylate. Key features of the route are a novel thiophene-3-carboxylate synthesis involving cycloaddition of 3-mercapto-2-butanone with the acrylate followed by acid catalyzed aromatization, the room temperature formation and silylation of a thiophene-3-carboxylate dianion, and conversion of the resulting carboxylic acid into silthiofam with negligible loss of the silyl group. The process involves isolation of just two intermediates, only one of which is purified, and uses only three organic solvents, all of which are recycled. It can be run safely on large scale to give highpurity silthiofam.
A general and mild synthesis of thioesters and thiols from halides
Zheng, Tu-Cai,Burkart, Maureen,Richardson, David E.
, p. 603 - 606 (2007/10/03)
The conversion of a wide variety of halides to thioesters by reaction with potassium thiocetate under mild conditions is described, and the generality of the method is demonstrated.
Evaluation of the Key Odorants in a Thermally Treated Solution of Ribose and Cysteine by Aroma Extract Dilution Techniques
Hofmann, Thomas,Schieberle, Peter
, p. 2187 - 2194 (2007/10/02)
Application of the aroma extract dilution analysis on a solvent extract isolated from a thermally treated solution (145 deg C; 20 min) of cysteine/ribose led to the identification of 2-furfurylthiol, 3-mercapto-2-pentanone, 2-methyl-3-furanthiol, 5-acetyl-2,3-dihydro-1,4-thiazine, 3-mercapto-2-butanone, and bis(2-methyl-3-furyl) disulfide showing the highest flavor dilution factors among the 29 odor-active volatiles.HRGC/olfactometry of decreasing headspace volumes established especially 2-furfurylthiol and 2-methyl-3-furanthiol as important odorants and revealed 2-thenyl mercaptan and ethyl mercaptan as further key contributors to the overall roasty, meatlike, sulfury odor of the model mixture. 5-acetyl-2,3-dihydro-1,4-thiazine, identified for the first time among the volatiles of Maillard model reactions or foods, exhibited an intense roasty, popcorn-like odor at the low odor threshold of 0.06 ng/L of air, which was of the same order of magnitude as those reported in the literature for the roasty-smelling odorants 2-acetyl-1-pyrroline and 2-acetyl-2-thiazoline.Keywords: Aroma extract dilution analysis; nonenzymatic browning; Maillard reaction; ribose; cysteine; flavor; 5-acetyl-2,3-dihydro-1,4-thiazine
Some Novel Meatlike Aroma Compounds from the Reactions of Alkanediones with Hydrogen Sulfide and Furanthiols
Mottram, Donald S.,Madruga, Marta S.,Whitfield, Frank B.
, p. 189 - 193 (2007/10/02)
The products of reactions of hydrogen sulfide with 2,3-butanedione and with 2,3-pentanedione in dilute ethanolic solution were analyzed by GC-MS and GC-odor port analysis.Components were also collected from the GC column and analyzed by 1H NMR.Mercaptoketones were formed which readily oxidized to the corresponding disulfides with traces of mono- and trisulfides.When 2-methyl-3-furanthiol or 2-furylmethanethiol was added to the reaction mixtures, a series of disulfides containing alkanone, 2-methyl-3-furyl and 2-furanmethyl moieties were formed.Some of these compounds have been found recently in the volatiles of cooked meat and in meatlike model systems.GC-odor port evaluation of the components of the reaction systems showed that disulfides containing the 2-methyl-3-furyl group had meaty aromas, whereas those without this group were sulfurous or onion-like in character.Keywords: Aroma; meat; mercaptoketones; disulfides
2-Mercaptoaldehyde dimers and 2,5-dihydrothiophenes from 1,3-oxathiolan-5-ones
McIntosh, John M.,Siddiqui, Maqbool A.
, p. 1872 - 1875 (2007/10/02)
Representative 1,3-oxathiolan-5-ones (6), prepared from 2-mercaptoacids, have been reduced to 2-mercaptoaldehydes 1 with diisobutylaluminum hydride.The aldehydes 1, which appear to exist in several dimeric forms, react with vinyltriphenylphosphonium bromide to give 2,5-dihydrothiophenes.
