نتایج جستجو برای: sulfones
تعداد نتایج: 1199 فیلتر نتایج به سال:
Dibenzothiophenes (DBTs) bearing alkyl substitutions adjacent to the sulfur atom, such as 4,6-diethyldibenzothiophene (4,6-DEDBT), are referred to as sterically hindered with regard to access to the sulfur moiety. By using enrichment cultures with 4,6-DEDBT as the sole sulfur source, bacterial isolates which selectively remove sulfur from sterically hindered DBTs were obtained. The isolates wer...
[reaction: see text] The R(1) substituents at C(2) of the haloallylic sulfones 1 play a pivotal role in controlling the diastereoselectivity of the indium-mediated addition reaction to benzaldehyde to produce the homoallylic alcohols 3. The R(1) Me group of 1 prefers the chair form in the In-coordinated six-membered cyclic transition state to give anti-3a, and the R(1) Ph group of 1 favors the ...
By 1926, two French physicians working in Indochina, R. Pons and L. Chastel, have suggested to treat leprosy by subcutaneous injections of bacillus Calmette-Guerin. This treatment appeared efficient since the lepromatous lesions quickly regressed and the Hansen bacillus disappeared from the nasal mucus. These results were quickly confirmed by other authors. They were all more appreciated than, ...
The conversion of SO2 into arylsulfones under metal-free conditions was achieved for the first time by reacting SO2 with (hetero)arylsilanes and alkylhalides in the presence of a fluoride source. The mechanism of this transformation was elucidated based on DFT calculations, which highlight the influence of SO2 in promoting C-Si bond cleavage.
A method for measuring the ligand concentration in heterogeneous materials like chromatography media is described. In this method, (13)C single pulse excitation magic angle spinning NMR experiment with broadband (1)H decoupling is used to determine the peak integrals for a butyl ligand in the spectrum of a dried chromatography medium. Within a carefully controlled protocol, those integrals comp...
The title compound, C(16)H(20)N(2)O(4)S, exhibits a V-shape structure with a dihedral angle of 77.5 (11)° formed by the two benzenel rings. The mol-ecular packing is stabilized by intra-molecular and inter-molecular hydrogen bonds as well as π-π [3.738 (3) Å] and C-H⋯π inter-actions.
Bacterial β-lactamase enzymes are in large part responsible for the decreased ability of β-lactam antibiotics to combat infections. The inability to overcome β-lactamase mediated resistance spurred the development of inhibitors with penems and penam sulfones being amongst the most potent and broad spectrum mechanism-based inactivators. These inhibitors form covalent, "suicide-type" inhibitory i...
A green, efficient and selective approach for the oxidation of sulfides to sulfoxides and sulfones with UHP at room temperature is reported. The reaction is performed in the presence of vanadia catalyst supported on mesocellular silica foam (MCF) with a V content ranging from 2% to 10% as heterogeneous and reusable catalyst. The structural and textural characterization of this catalyst were don...
Cinchona alkaloid-derived organocatalysts are widely employed in various asymmetric transformations, yielding products with high enantiopurity. In this respect, a bifunctional quinine-derived sulfonamide organocatalyst was developed to catalyze the sulfa-Michael reaction of naphthalene-1-thiol trans -chalcone derivatives. The target adducts were obtained up 96% ee under mild conditions and low ...
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