17223-96-0Relevant articles and documents
Micellar Effects on the Reaction of (Arylsulfonyl)alkyl Arenesulfonates with Hydroxide Ion. 2. The Absence of Substrate Orientational Effects in a Series of Sulfonates of Different Hydrophobicities
Witte, Frank M.,Engberts, Jan B. F. N.
, p. 4130 - 4134 (1985)
Second-order rate constants for nucleophilic attack of hydroxide ion at the sulfonate sulfur atom of a series of sulfonates R1SO2CH2OSO2R2 (1a-g) in the presence of CTAB micelles (at 50 deg C) have been analyzed in terms of the pseudophase ion-exchange (PPIE) model.It is shown that the catalysis by the micelles is caused by the increased reactant concentrations in the micellar reaction volume.Large variations in the hydrophobicities of the substituents R1 and R2 (alkylaryl, alkyl) had only a minor influence on the rate constant for reaction in the micellar pseudophase (km).The same conclusion holds if the rate constants km are corrected for the different propensities of the sulfonates to respond to changes in the polarity of the reaction medium as expressed in the dielectric constant.Therefore there is no evidence that the depth of penetration and/or the orientation of the sulfonates 1a-g bound to the cetyltrimethylammonium bromide micelles is significantly affected by the hydrophobicities of R1 and R2.These findings are reconcilable with recent views cincerning the morphology of micelles.
Synthesis of 1,5-Ring-Fused Imidazoles from Cyclic Imines and TosMIC – Identification of in situ Generated N-Methyleneformamide as a Catalyst in the van Leusen Imidazole Synthesis
Mayer, Peter,Rudy, Heinrich-Karl A.,Wanner, Klaus T.
, (2020)
Imidazoles fused with a cyclic system in 1,5-position were synthesized via the van Leusen imidazole synthesis employing saturated aliphatic tricycles including an imine function in the base catalyzed cycloaddition reaction with p-toluenesulfonyl-methyl isocyanide (TosMIC). Thereby, N-(tosylmethyl)formamide, a decomposition product of TosMIC, was found to act as a promoter of this reaction leading to considerably reduced reaction times and improved yields. Mechanistic studies revealed that N-(tosylmethyl)formamide is transformed into N-methyleneformamide acting as a catalyst in this reaction under the applied basic conditions. Being a Michael acceptor, the employed imines add to this compound, thus being transformed into iminium ions. The so formed intermediates facilitate the first step of the van Leusen imidazole synthesis, which is the addition of deprotonated TosMIC to the iminium subunit. N-methyleneformamide is finally reformed during the overall reaction and can thus be considered as an organocatalyst of the studied cycloaddition reaction.
Copper-Mediated Selenazolidine Deprotection Enables One-Pot Chemical Synthesis of Challenging Proteins
Zhao, Zhenguang,Metanis, Norman
, p. 14610 - 14614 (2019)
While chemical protein synthesis has granted access to challenging proteins, the synthesis of longer proteins is often limited by low abundance or non-strategic placement of cysteine residues, which are essential for native chemical ligations, as well as multiple purification and isolation steps. We describe the one-pot total synthesis of human thiosulfate:glutathione sulfurtransferase (TSTD1). WT-TSTD1 was synthesized in a C-to-N synthetic approach involving multiple NCL reactions, CuII-mediated deprotection of selenazolidine (Sez), and chemoselective deselenization. The seleno-analog Se-TSTD1, in which the active site Cys is replaced with selenocysteine, was also synthesized with a kinetically controlled ligation with an N-to-C synthetic approach. The catalytic activity of the two proteins indicated that Se-TSTD1 possessed only four-fold lower activity than WT-TSTD1, thus suggesting that selenoproteins can have physiologically comparable sulfutransferase activity to their cysteine counterparts.
Cobalt-Catalyzed Redox-Neutral Sulfonylative Coupling from (Hetero)aryl Boronic Acids, Ammonium Salts and Potassium Metabisulfite
Zhang, Yingying,Zhu, Haibo,Fan, Qiangwen,Yang, Liu,Xie, Zongbo,Le, Zhang-Gao
, (2022/01/08)
An efficient cobalt-catalyzed redox-neutral sulfonylative coupling to afford (hetero)aryl alkyl sulfones from boronic acids, ammonium salts and potassium metabisulfite has been realized. Commercially available and air-stable CoCl2, in combination with phenanthroline ligand, is sufficient to achieve rapid and high-yielding conversion of the reactants into the corresponding sulfones. This practical transformation proceeds smoothly through C?N bond cleavage under redox-neutral catalytic conditions and shows broad functional-group tolerance. Other carbon based electrophiles, including diaryliodonium salts, heteroaryl halides, and carbonates were compatible. Further transformation of aryl alkyl sulfones then allows conversion into olefins, alkenyl sulfones and halogenated sulfones, respectively, in a one-pot process.
Se-Phenyl Areneselenosulfonates: Their Facile Formation and Striking Chemistry
Gancarz, Roman A.,Kice, John L.
, p. 4899 - 4906 (2007/10/02)
Benzeneseleninic acid reacts rapidly at 0 deg C with aromatic sulfinic acids according to the stoichiometry of eq 3 to form Se-phenyl arenesulfonates, PhSeSO2Ar (2), in high yield.In contrast to thiosulfonates, PhSSO2Ar, areneselenosulfonates are extremely photosensitive and undergo quite rapid photodecomposition.The principal products of this photodecomposition are the sulfonic anhydride, ArSO2OSO2Ar, and diphenyl diselenide.In the presence of added alkenes the facile photodissociation of 2 can be used to initiate a free-radical chain reaction that results in the addition of 2 to the alkene to form β-phenylseleno sulfones in good yield.The β-phenylseleno sulfones can be converted to synthetically useful α,β-unsaturated sulfones by oxidation of the β-phenylseleno group to the corresponding selenoxide and subsequent elimination of PhSeOH.Photoaddition of 2 to 2,5-norbornadiene to 5-(phenylseleno)-exo-3-nortricyclyl aryl sulfone as the almost exclusive product, while photoaddition to 1,5-cyclooctadiene gives a mixture of approximately equal amounts of the 1,2-adduct, 5-(phenylseleno)-6-arenesulfonyl-1-cyclooctene, and the product of transannular addition, 6-(phenylseleno)-exo-2-arenesulfonyl-cis-bicyclooctane.Besides their extraordinary ease of photodissociation, compounds 2 also react extremely readily with nucleophiles: Nu- + PhSeSO2Ar -> PhSeNu + ArSO2-.Kinetic studies show that the reactivity of PhSeSO2Ar with cyanide ion in such a reaction is 70000 times larger than the reactivity of the corresponding thiosulfonate, PhSSO2Ar.
