نتایج جستجو برای: amino functionalized chitosanm
تعداد نتایج: 227274 فیلتر نتایج به سال:
Single-entity electrochemistry measurements were used to compare the electrocatalysis of oxygen reduction reaction (ORR) by means multiwalled carbon nanotubes (MWCNTs) or amino-functionalized (MWCNTs-NH2). All evidence showed that an electroactive surface functionality played most important role in catalysis process, not nitrogen content.
The unprecedented application of unmodified aldehydes as nucleophilic donors in direct catalytic asymmetric Mannich-type reactions is disclosed in a full account. Our efforts in broadening the applicability of chiral pyrrolidine-based catalysts in direct asymmetric Mannich-type reactions led to the highly diastereo- and enantioselective and concise synthesis of functionalized alpha- and beta-am...
Herein is presented a strategy for the enantioseparation of amino acids enantiomers using β-CD functionalized Fe(3)O(4) nanospheres, in which β-CD provides the ability to chirally discriminate amino acids enantiomers, while the Fe(3)O(4) nanoparticles serve as magnetic separators.
A novel axially chiral spiro-phosphine-catalyzed highly regio-, diastereo- and enantioselective [3+2] cycloaddition of alkylidene azlactones with various allenic esters has been developed, affording the corresponding functionalized spirocyclic products in moderate to excellent yields under mild conditions. These spirocyclic products as masked amino acids can be easily transformed into aspartic ...
A rapid and simple procedure was devised for the synthesis of multifunctionalized cyclic β-amino esters and γ-amino alcohols via the 1,3-dipolar cycloaddition of nitrile oxides to β-aminocyclopentenecarboxylates. The opening of the isoxazoline reductive ring to the corresponding highly functionalized 2-aminocyclopentanecarboxylates occurred stereoselectively with good yields.
one-pot multicomponent reaction between isatin, barbituric acid, and 6-amino-1,3-dimethyl uracil was investigated in the presence of sulfonic acid functionalized nanoporous silica (sba-pr-so3h) and resulted in the formation of spirooxindole dipyrimidines. spirooxindole unit is found in many natural products and biologically active molecules and 1,4-dihydropyridines are an important class of com...
A study exploring the chemical behavior of some dihydroxylated β-amino ester stereo- and regioisomers, derived from unsaturated cyclic β-amino acids is described. The nucleophilic fluorinations involving hydroxy-fluorine exchange of some highly functionalized alicyclic diol derivatives have been carried out in view of selective fluorination, investigating substrate dependence, neighboring group...
A range of novel 4-amino-6-arylpyrimidines has been prepared under mild conditions by an electrochemical reductive cross-coupling between 4-amino-6-chloro-pyrimidines and functionalized aryl halides. The process, which employs a sacrificial iron anode in conjunction with a nickel(II) catalyst, allows the formation of coupling products in moderate to high yields.
The synthesis of novel chiral coumarins functionalized with proteinogenic amino acid side chains via N-protected γ-amino-β-keto esters and their incorporation into the cell permeable HIV-1 TAT peptide through the modified solid phase peptide synthesis are described.
A Simple and efficient method for synthesis of tetrahydropyrimido[4,5-b]quinoline derivatives via three component reaction of aromatic aldehydes, dimedone and 6-amino uracil derivatives using a catalytic amount of sulfonic acid functionalized nanoporous silica (SBA-15-Pr-SO3H) is described. The advantages of this method are easy and clean work-up, high yield, mild reaction c...
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