نتایج جستجو برای: amination
تعداد نتایج: 1883 فیلتر نتایج به سال:
Poly(hexafluoropropylene-co-tetrafluoroethylene) (FEP) was successfully radiationgrafted with vinylbenzyl chloride (VBC). Subsequently amination with trimethylamine followed by ion exchange with aqueous hydroxide yielded alkaline anion-exchange membranes (AAEMs). Experimental parameters were established for maximising the degree of grafting (d.o.g.); the optimum treatment duration for maximum a...
Key words photpcatalysis - metal-organic layer cobalt catalyst dehydrogenative amination
Deoxyribozymes are particular DNA sequences that have catalytic ability, analogous to protein enzymes as functional amino acid sequences. The discovery of natural RNA enzymes (ribozymes) spurred the search for artificial deoxyribozymes, which are identified by in vitro selection. Most deoxyribozyme-catalyzed reactions involve phosphodiester bond cleavage or ligation, although other reactions su...
The Pd-catalyzed amination of unprotected benzo-fused heterocycles is reported, which allows for greater flexibility and efficiency in the modification of this important class of molecules. The generality of these simple and efficient procedures is demonstrated through the synthesis of a wide variety of structural types.
Iridium-catalysed allylic substitutions with anionic N-nucleophiles were achieved with regioselectivity of up to 49:1 and enantiomeric excess of up to 98%.
Evidence for the production in viva from pyridoxine of compounds with increased activity for certain lactic acid bacteria (1) and for the production of similar compounds by amination or oxidation procedures in vitro (2, 3) has been reported. Only a limited number of structures for the compounds resulting from amination or oxidation appeared possible; synthesis (4, 5) of certain of these resulte...
The nickel-catalyzed amination of aryl O-sulfamates and chlorides using the green solvent 2-methyl-THF is reported. This methodology employs the commercially available and air-stable precatalyst NiCl2(DME), is broad in scope, and provides access to aryl amines in synthetically useful yields. The utility of this methodology is underscored by examples of gram-scale couplings conducted with cataly...
Compared to their C1-symmetric counterparts, planar chiral C2-symmetric metallocenyl P,N-ligands are efficient chiral ligands for Pd-catalyzed asymmetric allylic aminations, providing a number of amination products with high enantioselectivities. A non-C2-symmetric ferrocenyl P,N-ligand (a by-product obtained during the synthesis of the above C2-symmetric species) was also found to be an effici...
Individual diastereomeric phosphoramidites and mixtures of diastereomeric phosphoramidites were evaluated in the iridium-catalyzed amination of allylic carbonates. The original process was conducted with a phosphoramidite ligand containing a resolved 2,2-dihydroxy-1,1-binaphthyl (BINOL) group and a diastereomerically and enantiomerically pure bis(phenethyl)amino group. Evaluation of the structu...
Organocatalytic asymmetric alpha-oxidation and amination reactions of carbonyl compounds are highly useful synthetic methodologies, especially in generating chiral building blocks that previously have not been easily accessible by traditional methods. The concept is relatively new and therefore the list of new catalysts, oxidizing and aminating reagents, as well as new substrates, are expanding...
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