نتایج جستجو برای: β keto esters
تعداد نتایج: 209930 فیلتر نتایج به سال:
In this research, (Carboxy-3-oxopropylamino)-3-propylsilylcellulose (COPAPSC) as an organocatalyst, has been synthesized by grafting of succinic anhydride on the NH2-modified cellulose (cellulose functionalized with 3- aminopropyltriethoxysilane). The –CO2H group-functionalized cellulose (COPAPSC) is used as a catalyst for the synthesis of coumarin derivatives from the reaction of phenolic subs...
An efficient and simple one-pot approach for the synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives using antimony trichloride (SbCl3) as a mild catalyst by means of three-component Biginelli reaction between β-keto esters, aldehyde derivatives and urea/thiourea under thermal and solvent-free conditions with excellent yields and short reaction times is reported. This m...
The use of sonochemistry is described in the organocatalytic enamine-azide [3 + 2] cycloaddition between 1,3-diketones and aryl azidophenyl selenides. These sonochemically promoted reactions were found to be amenable to a range of 1,3-diketones or aryl azidophenyl selenides, providing an efficient access to new ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones in good to excellent yields and s...
Oxalic acid dihydrate as a green, mild and efficient catalyst for the one-pot three-component Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives from the reaction between β-keto esters (methyl or ethyl acetoacetate), aromatic aldehyde (benzaldehye derivatives) and urea or thiourea under thermal and solvent-free conditions with excellent yields and short reaction time is st...
A series of peracylated glycosamine-derived thioureas have been synthesized and their behavior as bifunctional organocatalysts has been tested in the enantioselective nucleophilic addition of formaldehyde tert-butyl hydrazone to aliphatic α-keto esters for the synthesis of tertiary azomethyl alcohols. Using the 1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-β-d-glucosamine derived 3,5-bis-(trifluoromet...
1,2-Diamine derivatives are valuable building blocks to heterocyclic compounds and important precursors of biologically relevant compounds. In this respect, amino acid-derived β-keto esters are a suitable starting point for the synthesis of β,γ-diamino ester derivatives through a two-step reductive amination procedure with either simple amines or α-amino esters. AcOH and NaBH(3)CN are the addit...
Abstract A highly diastereo‐ and enantioselective Mannich reaction of α ‐acetoxy‐ β ‐keto esters with isatin imine was developed. The quinine thiourea organocatalyst smoothly promoted the asymmetric to furnish various 3‐substituted‐3‐aminooxindole derivatives bearing two adjacent tetra‐substituted stereocenters in up 93 % yield, 98 ee >20 : 1 dr . transition state structure absolute configur...
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