Search results for "Ethyl acrylate"
showing 10 items of 32 documents
Reactivity of [1,2,3]Triazolo[1,5-a]pyridines as 1,3-dipoles
2016
Abstract We have studied the reactions between [1,2,3]Triazolo[1,5- a ]pyridines 1a,b,c and electron-deficient ethylenes in different conditions. Compounds 1a and 1b react with ethyl propiolate, and dimethyl acetylene dicarboxylate giving a new class of biaryl compounds pyridyl pyrazoles, and with ethyl acrylate giving pyridyl cyclopropanes. Compound 1c did not give any product in the studied conditions. A proposal of mechanism of these reactions is done in which the triazolopyridines act as 1,3-dipoles giving 1,3-dipolar cycloadditions.
Reactions of the hydrofluoroborate salts of open-chain analogues of Reissert compounds with some α,β-ethylenic esters
1999
The reaction of the hydrofluoroborate salt of an open-chain analogue of a Reissert compound with some α,β-ethylenic esters does not give a [4 + 2] cycloadduct, as previously described in the case of ethyl acrylate. The reaction starts with a 1,3-dipolar cycloaddition of a munchnone imine 5c, d. The [3 + 2] cycloadducts 13 evolve via a rearrangement–condensation sequence to give a substituted 2-pyridone derivative 18 or 19. The proposed mechanism has been verified by the isolation and structural X-ray analysis of some compounds of the reaction sequence.
Cycloaddition reactions of 3-vinylthiophen
1987
Abstract Cycloaddition reactions between 3-vinylthiophen and the dienophiles maleic anhydride, methyl acrylate, dimethyl acetylene - dicarboxylate, and methyl propiolate give products including methyl benzo[b]thiophen-7-carboxylate (11) and its dihydroderivative (10), the 6,7-dicarboxylic acid (3), its dimethyl ester (7) and dihydroester (6); the naphtho[a,b]dithiophen (14), and the novel ethano bridged benzo[b]thiophen (15).
Response of human chondrocytes to a non-uniform distribution of hydrophilic domains on poly (ethyl acrylate-co-hydroxyethyl methacrylate) copolymers.
2005
A series of polymer and copolymer networks with varying hydrophilicity and distribution of the hydrophilic groups was synthesized and biologically tested with monolayer culture of human chondrocytes in vitro. Cell viability (MTT), proliferation (BrdU incorporation) and aggrecan expression (PG ELISA) were quantified at 7 and 14 days from seeding. Both assays (MTT and BrdU) showed complementary results that are consistent with positive cellular adhesion on the material. When human chondrocytes were cultured on polymer substrates in which the hydrophilic groups were homogeneously distributed, hydrophobic substrates showed higher values in all the biological parameters analysed. Adhesion, proli…
A molecular electron density theory (MEDT) study of the role of halogens (X2= F2, Cl2, Br2and I2) on the aza-Michael-addition reactions
2020
Using the Molecular Electron Density Theory (MEDT), a set of uncatalyzed and X2 molecule-catalyzed (X2 = F2, Cl2, Br2, or I2) aza Michael addition reactions (aza-MARs) between pyrrolidine (PYR) and methyl acrylate (MA) have been studied in the gas phase and in dichloromethane (DCM) medium from the kinetics and molecular mechanism aspects. Analysis of the conceptual DFT reactivity indices indicates that the coordination of the X2 molecules to the oxygen of the MA's carbonyl group increases both the softness and the electrophilic character of MA, thus explaining the catalytic role of the X2 molecules. The nucleophilic attack of the nitrogen of PYR on the MA's β conjugated carbon is the rate-d…
A convenient chemo-enzymatic synthesis and 18F-labelling of both enantiomers of trans-1-toluenesulfonyloxymethyl-2-fluoromethyl-cyclopropane
2008
The present report is concerned with a stereoselective, reliable route to trans-1,2-disubstituted cyclopropanes and in particular to (S,S)-1-tosyloxymethyl-2-fluoromethyl-cyclopropane (1) and (R,R)-1-tosyloxymethyl-2-fluoromethyl-cyclopropane (ent-1) as conformationally restricted, terminally fluorinated C4-building blocks for medicinal chemistry. The enzymatic kinetic resolution based synthesis of 1 and ent-1 utilises inexpensive, commercially available starting materials. It is based on enantiomeric resolution of rac-cyclopropane carboxylic esters using esterase from Streptomyces diastatochromogenes. Both enantiomers of 1 were prepared selectively in high overall yield over nine steps, st…
Mono- and Bidentate Phosphine Ligands in the Palladium-Catalyzed Methyl Acrylate Dimerization
2003
The influence of several phosphine ligands on the activity, selectivity and stability of the catalytic system Pd(acac)2, ligand, [HOEt2][BF4] was studied in the dimerization of methyl acrylate (MA). It was found that the catalyst's activity increased with increasing the basicity of the monodentate ligands used, whereas bulky phosphines lowered the linearity of the dimers and the reaction rates. With chelating P N-, P P-, and P As-ligands the Pd-catalyst could be efficiently stabilized during the reaction. The use of 1-dibutylphosphino-2-dimethylaminoethane as ammonium tetrafluoroborate salt allowed the highest overall activity.
Stereoselective 1,3-Dipolar Cycloadditions of a Chiral Nitrone Derived from Erythrulose. An Experimental and DFT Theoretical Study
2000
We have investigated several 1,3-dipolar cycloadditions of a chiral nitrone prepared from L-erythrulose. While cycloadditions to carbon-carbon multiple bonds of dipolarophiles such as ethyl acrylate, ethyl propiolate, or dimethyl acetylenedicarboxylate were poorly stereoselective, reaction with acrylonitrile provided predominantly one diastereomeric adduct. Furthermore, the regioselectivity exhibited by the two structurally similar dipolarophiles ethyl acrylate and ethyl propiolate was found to be opposite. The molecular mechanisms of these cycloadditions have thus been investigated by means of density functional theory (DFT) methods with the B3LYP functional and the 6-31G and 6-31+G basis …
Cycloaddition reactions of 2-vinylthiophen
1985
Abstract Cycloaddition reactions between 2-vinylthiophen and the dienophiles maleic anhydride, dimethyl acetylenedicarboxylate,' methyl propiolate, and methyl acrylate, are reported. Products include simple benzo[b]thiophen carboxylates (6, 13, 17) and reduced derivatives (3, 4, 18). The acetylenic dienophiles also gave a dihydrobenzthienyl-acrylate (16) or -fumarate (11), and the dithienylcyclohexene esters (7) and (14).
DFT exploration of [3 + 2] cycloaddition reaction of 1H-phosphorinium-3-olate and 1-methylphosphorinium-3-olate with methyl methacrylate
2018
A Molecular Electron Density Theory (MEDT) study of the regio- and stereoselectivity of the [3 + 2] cycloaddition (32CA) reaction of 1H-phosphorinium-3-olate and 1-methylphosphorinium-3-olate with methyl methacrylate was carried out using the B3LYP/6-31G(d) method. In order to test the method dependence for the most favorable reaction path leading to the 1H-substituted 6-exo cycloadduct (CA) various functionals using higher basis sets were taken into consideration in the gas phase. An analysis of the energetic parameters indicates that the reaction path leading to 6-exo CA are kinetically as well as thermodynamically favored in the gas phase, THF and ethanol. The calculated energetic parame…