نتایج جستجو برای: aryl
تعداد نتایج: 14792 فیلتر نتایج به سال:
The total syntheses of the Lythracea alkaloids (+)-vertine and (+)-lythrine are described. Enantioenriched pelletierine is used as a chiral building block and engaged into a two step pelletierine condensation leading to two quinolizidin-2-one diastereomers in a 8 : 1 ratio. The major product is used in the synthesis of (+)-vertine via aryl-aryl coupling and ring closing metathesis to provide a ...
Trans- and cis-2-aryl-3-(2-cyanoethyl)aziridines, prepared via alkylation of the corresponding 2-aryl-3-(tosyloxymethyl)aziridines with the sodium salt of trimethylsilylacetonitrile, were transformed into variable mixtures of 4-[aryl(alkylamino)methyl]butyrolactones and 5-[aryl(hydroxy)methyl]pyrrolidin-2-ones via KOH-mediated hydrolysis of the cyano group, followed by ring expansion. In additi...
The non-enzymatic acylative kinetic resolution of challenging aryl-alkenyl (sp2 vs. sp2 ) substituted secondary alcohols is described, with effective enantiodiscrimination achieved using the isothiourea organocatalyst HyperBTM (1 mol %) and isobutyric anhydride. The kinetic resolution of a wide range of aryl-alkenyl substituted alcohols has been evaluated, with either electron-rich or naphthyl ...
A bimetallic system of Pd/CuF2, catalytic in Pd and stoichiometric in Cu, is very efficient and selective for the coupling of fairly hindered aryl silanes with aryl, anisyl, phenylaldehyde, p-cyanophenyl, p-nitrophenyl, or pyridyl iodides of conventional size. The reaction involves the activation of the silane by Cu(II), followed by disproportionation and transmetalation from the Cu(I)(aryl) to...
Structural analyses of the protein-tyrosine phosphatase 1B (PTP1B) active site and inhibitor complexes have aided in optimization of a peptide inhibitor containing the novel (S)-isothiazolidinone (IZD) phosphonate mimetic. Potency and permeability were simultaneously improved by replacing the polar peptidic backbone of the inhibitor with nonpeptidic moieties. The C-terminal primary amide was re...
Chemical modification is an important technique to modulate the chemical and optical properties of graphene quantum dots (GQDs). In this paper, we report a versatile diazonium chemistry method to graft aryl groups including phenyl, 4-carboxyphenyl, 4-sulfophenyl and 5-sulfonaphthyl to GQDs via Gomberg-Bachmann reaction. The aryl-modified GQDs are nanocrystals with lateral dimensions in the rang...
Some 5-aryl-2-mercapto-1,3,4-oxadiazole (I) reacted with maleic anhydride, maleic acid and p-benzoquinone affording 2-(5-aryl-1,3,4-oxadiazol-2-ylthio)succinic anhydrides (II), 2-(5-aryl-1,3,4-oxadiazol-2-ylthio)succinic acids (III) and 2-(2,5-dihydroxyphenylthio)-5-aryl-l,3,4-oxadiazoles (IV), respectively. Treatment of 2-methylthio-5-phenyl-l,3-oxadiazole (V) with amines gives 2-[(alkyl or ar...
Although the past 15 years have witnessed the development of sterically bulky and electron-rich alkylphosphine ligands for palladium-catalyzed cross-couplings with aryl chlorides, examples of palladium catalysts based on either triarylphosphine or bidentate phosphine ligands for efficient room temperature cross-coupling reactions with unactivated aryl chlorides are rare. Herein we report a pall...
Some N¬-acyl-N'-aryl thiourea derivatives 4(a-f) have been prepared by the reaction of acyl halides ammonium thiocyanate and aryl amines. The structures of synthesized compounds have been characterized by IR, 1HNMR spectral studies. The synthesized compounds 5(a-f) have been screened for antibacterial activity. The effect of the structure of the investigated compounds on the antibacterial activ...
The expeditious synthesis of 2-aryl-benzothia/(oxa)zoles was carried out by the condensation of 2-aminothiophenol/2-aminophenol and diverse aryl aldehydes in presence of Acacia concinna as a biocatalyst under microwave irradiation. The catalytic process is associated with excellent yields, greener reaction conditions and the environmentally friendly microwave technique which are the st...
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