The highly enantioselective Friedel–Crafts alkylation of furan and thiophene derivatives with trifluoropyruvate, which have never provided the high level of asymmetric induction and yield until now, was achieved by using dicationic palladium complexes as Lewis acid catalysts. Moreover, glyoxyla...
A series of simple α-oxo acids (RCOCOOH, R = H, CH3, CH3CH2, CF3) were deprotonated by negative electrospray ionisation and subjected to collision-induced dissociation and mass spectrometric analysis. Decarboxylation is the major process, observed for all four carboxylates. In addition, glyoxyl...
The highly stereoselective trifluoropyruvate-ene reaction with steroidal 1,1-disubstituted Δ20(22)-side chain olefin was achieved by the dicationic BINAP-Pd complex as an effective chiral Lewis acid catalyst to give the Δ20(21)-steroidal ene-product in high yield and enantioselectivity. The en...
An efficient asymmetric carbonyl-ene reaction of trifluoropyruvate catalyzed by chiral Pd(II)/(S)-SunPhos complex was developed. A series of optically active homoallylic alcohols containing a CF3 group were obtained with high yields and excellent ee under mild conditions. Particularly, the react...
A straightforward synthesis of enantiopure (S)- and (R)-α-Tfm-pyroglutamic acid is reported. The strategy is based on the use of a chiral CF3-hydroxymorpholinone intermediate conveniently obtained from ethyl trifluoropyruvate-based chiral CF3-oxazolidines (Fox). The key step is an oxidative cyc...
A facile synthesis of 3-hydroxy-3-(trifluoromethyl)-1H-pyrrol-2(3H)-ones based on trifluoroacetic acid-catalyzed condensation–cyclization reactions of β-enamino esters and ethyl trifluoropyruvate is described. These reactions afford a series of α-trifluoromethylated γ-lactam compounds in goo...
By using the chain to chain mode of cyclization the title glutathione analogue (4), containing the 11-membered disulfide ring replacing the native -Cys-Gly fragment, has been synthesized and characterized together with its reduced dithiol form γ-Glu-Cys-Asp-Cys (5). The activity of (4) with γ...
Protein-based hydrogels that possess tunable properties have long been a challenge in tissue engineering. Keratin is a group of natural proteins derived from skin and skin appendant, and features a rich content of cysteine residue which exists in the form of disulfide bonds. Inspired by this, in...
SummaryDisulfide formation in the mitochondrial intermembrane space (IMS) is an essential process. It is catalyzed by the disulfide relay machinery, which couples substrate import and oxidation. The machinery relies on the oxidoreductase and chaperone CHCHD4-Mia40. Here, we report on the driving...
Chitosan, a natural biopolymer, is used as a multifunctional agent for modification of wool either through chemical crosslinking or physical coating. For the first time, wool fabric has been modified with chitosan through disulfide bond breaking and reforming reactions. The chitosan was thiolate...
AimsAn increase in reactive oxygen species leads to formation of covalent bonds between sulfur atoms, thus thiol/disulfide homeostasis shifts towards the disulfide direction and oxidative damage occurs. We aimed to determine thiol/disulfide homeostasis in children with T1DM.
Mouse selenoprotein W (SELENOW) is a small protein containing a selenocysteine (Sec, U) and four cysteine (Cys, C) residues. The Sec residue in SELENOW is located within the conserved CXXU motif corresponding to the CXXC redox motif of thioredoxin (Trx). It is known that glutathione (GSH) binds ...
Cell adhesion to extracellular matrix, mediated by integrin receptors, is crucial for cell survival. Receptor-ligand interaction involves conformational changes in the integrin by a mechanism not fully elucidated. In addition to several direct evidence that there is disulfide re-arrangement of i...
The paper presents the results of investigations of reactive extraction of acetic and propionic acids from aqueous solutions using supercritical carbon dioxide (scCO2) and tri-n-octylamine (TOA). The experimental results of reactive extraction were compared with those of physical extraction. The...
A series of polyamides and poly(amide–imide)s were prepared by the direct poly-condensation of 2,2-bis(4-aminophenoxy) benzonitrile [4-APBN] with aromatic dicarboxylic acids and bis(carboxyphthalimide)s in N-methyl-2-pyrrolidone [NMP] with triphenyl phosphite and pyridine as condensing agents. ...
In an effort to develop structure–property understanding of fluoro-polymer/inorganic clay nanocomposite (i.e., Ceramer) technology, two series of fluoro-poly(ether amic acid) (6F-PEAA)/organosoluble Montmorillonite (MMT) clay nanocomposite formulations containing varying percentage of diamine m...
A new-type tetraimide-dicarboxylic acid (I) was synthesized starting from the ring-opening addition of p-aminobenzoic acid, 4,4′-oxydiphthalic anhydride, and 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS) at a 2:2:1 molar ratio in N-methyl-2-pyrrolidone (NMP), followed by cyclodehydration to t...
Thermo-chemically stable ultrafiltration (UF) membranes based on soluble copoly (bis[4-(3-aminophenoxy)-phenyl]sulfone/3,3′,4,4′-benzophenonetetracarboxyl/pyromellite) imides(CPIs) were prepared by conventional phase inversion and the factors determining their permeation characteristics were s...
The novel diamine containing methyl-substituted arylene sulfone ether, 3,3′5,5′-tetramethylbis[4-(4-aminophenoxy)phenyl]sulfone (TBAPS), was used as a monomer with various aromatic tetracarboxylic dianhydrides to synthesize polyimides via a conventional two-stage procedure that included ring-o...
A new symmetric aromatic diamine containing diphenylsilarylene and oxyphenyl units was synthesized and characterized. This diamine was used further for preparing poly(amide)s (O-PAs) when reacted with dicarboxylic acids containing diphenylsilarylene groups. Additionally, a poly(amide) without th...
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