نتایج جستجو برای: tetrasubstituted imidazoles
تعداد نتایج: 4152 فیلتر نتایج به سال:
The enantioselective intramolecular oxyamination of unsaturated alkoxyamines using a hybrid catalytic system consisting Cp*RhIII/chiral disulfonate/CuOAc is described. Tetrahydrofuran derivatives with tetrasubstituted chiral center were obtained under the optimized conditions in 91:9–97:3 er. use sterically hindered disulfonate and Cu additive was essential for high enantioselectivity.
The preparation of two meso-imidazolylporphyrins was achieved in good yield by Ullmann coupling between a meso-bromotriarylporphyrin and imidazoles. Subsequent alkylation afforded the corresponding imidazolium functionalized porphyrins as direct precursors of the carbene. The complexation of these azolium salts with palladium led to trans-anti bis-porphyrin carbenic complexes.
Catalytic amounts of Co(Sal(tBu,tBu))Cl and organosilane irreversibly isomerize terminal alkenes by one position. The same catalysts effect cycloisomerization of dienes and retrocycloisomerization of strained rings. Strong Lewis bases like amines and imidazoles, and labile functionalities like epoxides, are tolerated.
The Diels-Alder cycloadducts of 4-vinylimidazoles and N-phenylmaleimide are shown to undergo facile intermolecular ene reactions. Overall the reaction of three simple molecules (a diene, a dienophile and an enophile) in a two-step process gives 4,5,6,7-tetrahydro-1H-benzo[d]imidazoles with high yields, high atom economy and diastereocontrol of up to 5 new stereocentres.
A series of ethylene bis-imidazoles was synthesized via a novel microwave-mediated synthesis. Biological testing on eight isozymes of carbonic anhydrase (CA) present in the human brain revealed compounds with nanomolar potency against CA VA and CA VII, also displaying excellent selectivity against other CA isozymes present in this organ.
A scalable method for the preparation of 4,5-disubstituted thiazoles and imidazoles as distinct regioisomeric products using a modular flow microreactor has been devised. The process makes use of microfluidic reaction chips and packed immobilized-reagent columns to effect bifurcation of the reaction pathway.
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