67680-10-8Relevant academic research and scientific papers
T BuOK-triggered bond formation reactions
Xu, Yulong,Shi, Xiaonan,Wu, Lipeng
, p. 24025 - 24029 (2019/08/13)
Recently, inexpensive and readily available tBuOK has seen widespread use in transition-metal-free reactions. Herein, we report the use of tBuOK for S-S, S-Se, NN and CN bond formations, which significantly extends the scope of tBuOK in chemical synthesis. Compared with traditional methods, we have realized mild and general methods for disulfide, azobenzenes imine etc. synthesis.
Thiol peroxidase activity of diaryl ditellurides as determined by a 1H NMR method
Engman, Lars,Stern, David,Cotgreave, Ian A.,Andersson, Carl M.
, p. 9737 - 9743 (2007/10/02)
A 1H NMR method was developed for the assessment of the glutathione peroxidase-like activity of synthetic compounds. In this assay, thiols (N-acetylcysteine, tert-butyl mercaptan and 1-octyl mercaptan) were oxidized to the corresponding disulfides in CD3OD or CD3OD/D2O in the presence of hydrogen peroxide and the catalyst to be evaluated. The time required to reduce the thiol concentration with 50%, t50, was determined as a measure of the thiol peroxidase activity of the catalyst. Several diaryl ditellurides were efficient catalysts when present in low concentrations (0.3 mol %), whereas compounds with well-documented glutathione peroxidase-like activity in other assays were inactive (Ebselen, diaryl diselenides). The glutathione peroxidase-like activity of diaryl ditellurides was also assessed by using the classical coupled reductase assay. A mechanistic study showed that diaryl ditellurides, in the presence of hydrogen peroxide and a thiol, were rapidly converted to tellurosulfides. These species were stable enough to be isolated in some cases. The tellurosulfides reacted very slowly with added thiol, but in the presence of thiol/hydrogen peroxide the thiol was rapidly converted to its corresponding disulfide. On the basis of these observations, a mechanism involving a tellurinic acid thiol ester was proposed for the thiol peroxidase reaction of ditellurides. In contrast to tellurosulfides, selenosulfides, obtained either from diphenyl diselenide/hydrogen peroxide/1-octyl mercaptan or from Ebselen and 1-octyl mercaptan, were found to react very slowly with thiols in the presence of hydrogen peroxide.
Reactivity of Nucleophiles toward and the Site of Nucleophilic Attack on Bis(alkylthio) Selenides
Kice, John L.,Slebocka-Tilk, Henryka
, p. 7123 - 7130 (2007/10/02)
Bis(alkylthio)selenides, RSSeSR (1), a class of compounds that occupy a key role as intermediates in the incorporation of inorganic selenium into biological systems, react quite readily with nucleophilic reagents.In principle, such reactions could take place at either sulfur (eq 3a) or at selenium (eq 3b).In the present work the reaction of a series of 1 having R groups of varying steric dimensions (n-Bu, i-Pr, t-Bu) with a group of common nucleophiles (thiolate, cyanide, and sulfite ions, phenyllithium, piperidine) has been examined.The results show that when R = t-Bu, reaction with the nucleophile at selenium occurs considerably faster than reaction at sulfur, but that when R is an n-alkyl group (n-Bu), reaction at sulfur is considerably faster than reaction at selenium.With R = i-Pr, the rates of reaction at the two sites are comparable.For reaction at sulfur, the retardation in rate accompanying a change in R from n-Bu to i-Pr to t-Bu parallels closely the decrease in rate with the same change in R that has been observed in other nucleophilic substitution at dicoordinate sulfur.As might be expected, an increase in steric dimensions of R has a considerably smaller effect on the rate of mechanism at selenium.Comparison of the rate of reaction of n-BuS- with n-BuSSeSBu-n and n-BuSSBu-n shows that bis(n-alkylthio) selenides can be expected generally to be more than several orders of magnitude more reactive toward nucleophiles than the corresponding disulfide.
