نتایج جستجو برای: tetrasubstituted imidazoles
تعداد نتایج: 4152 فیلتر نتایج به سال:
A general approach for the synthesis of bis(imidazolium) dichloride salts from imidazoles and dichloroalkanes is reported. Typical limitations this reaction formation methylene-bridge...
A FeCl3-catalyzed highly regioselective 1,2-addition/substitution sequence of 3-acetylcoumarins and indoles has been developed to afford highly hindered tetrasubstituted bis(indolyl)methanes bearing a biologically useful coumarin motif in 56-99% yields.
Iron-catalyzed alkylation of internal olefins, that is, α-oxo ketene dithioacetals, was successfully realized by using styrenes as the alkylating reagents. Highly functionalized tetrasubstituted olefins were prepared in moderate to high yields.
The regioselective, orthogonal functionalisation of 4,10-dichlorochrysene enables the synthesis of a variety of 2,8,4,10-"A2B2"-tetrasubstituted chrysenes. Such compounds exhibit broadened UV-vis absorption spectra, decreased band gap and higher HOMO levels compared to the parent chrysene.
New β-keto ester substituted stilbene derivatives have been synthesized and cyclized with selenium electrophiles in the presence of Lewis acids. This now allows access to 1,2,3,4-tetrasubstituted naphthalene derivatives as cyclization and rearrangement products.
[structure: see text]. Increased efficiency for ring-closing metathesis to form tetrasubstituted olefins using N-heterocyclic carbene ligated ruthenium catalysts was achieved by reducing the size of the substituents at the ortho positions of the N-bound aryl rings.
The three imidazole antimycotics clotrimazole, miconazole, and ketoconazole all inhibit the demethylation of lanosterol to ergosterol, resulting in inhibition of growth of Saccharomyces cerevisiae; this is a fungistatic action. At higher concentrations clotrimazole and miconazole are fungicidal, whereas ketoconazole is not. The fungicidal action reflects direct membrane damage by the imidazoles...
A short and efficient synthesis of 1,4-disubstituted imidazoles has been developed which provides the desired products with complete regioselectivity. This protocol allows preparation of compounds which are challenging to prepare by current literature methods in a regioselective fashion, a sterically and electronically diverse range of N-substituents being accessible. The sequence involves an u...
C3-Symmetric chiral trisimidazolines with m-chloroperbenzoic acid promoted the organocatalytic oxidation of N-sulfonyl ketimine. The present imidazoline catalysis produced oxaziridines bearing a tetrasubstituted carbon stereogenic center in high yields with up to 87% ee.
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