56652-37-0Relevant academic research and scientific papers
A supramolecular microfluidic optical chemosensor
Rudzinski, Christina M.,Young, Albert M.,Nocera, Daniel G.
, p. 1723 - 1727 (2002)
A supramolecular microfluidic optical chemosensor (μFOC) has been fabricated. A serpentine channel has been patterned with a sol-gel film that incorporates a cyclodextrin supramolecule modified with a Tb3+ macrocycle. Bright emission from the T
How much does the hybridization of a carbon atom affect the transmission of the substituent effect on the chemical shift?
Jeong, Eun Jeong,Lee, In-Sook Han
, p. 295 - 299 (2015/03/03)
1H and 13C NMR spectra of aryl esters of propionic acid, acrylic acid, and propiolic acid were systematically examined to find out the substituent effect on the chemical shift. The values of the chemical shift of the carbonyl carbon showed an inverse correlation with the Hammett ?3 values, and the magnitude of the slope was the largest with the propiolates. The ?± carbons of acrylates and propiolates also showed an inverse correlation with much smaller values of the slopes than those of the carbonyl carbons; but those of the propionates showed absolutely no correlation. However, the ?2 carbons of acrylates and propiolates showed normal correlation with larger values of the slopes. The signs and the magnitudes of the slopes may be understood by the transmission of the substituent electronic effect through bonds as well as through space. The propiolyloxy group also showed a significantly large effect on the 13C chemical shift values of the benzene ring.
Reversal of regioselectivity and enhancement of rates of nitrile oxide cycloadditions through transient attachment of dipolarophiles to cyclodextrins
Barr, Lorna,Lincoln, Stephen F.,Easton, Christopher J.
, p. 8571 - 8580 (2007/10/03)
The reactions of nitrile oxides with monosubstituted dipolarophiles, such as propiolamide, typically afford proportionally 80% or more of the 3,5-disubstituted cycloadducts. By contrast, the reactions of 6 A-deoxy-6A-propynamido-β-cy
A Kinetic Study of the Hydrolysis of Aryl Esters by the pH-Stat Method
Marsh, Mary Rose,Gold, Victor,Hall, C. Dennis,Sghibartz, Christopher
, p. 1801 - 1814 (2007/10/02)
The rates of hydrolysis of a series of aryl acrylates and aryl acetates in water at 24 deg C have been monitored by the pH stat method.The second-order rate coefficients for base-induced reactions (kOH) determined by this method are consistent with literature values determined under buffered conditions and conform to the conventional BAC2 mechanism for ester hydrolysis.
Dehydrobromination of Some Substituted Phenyl 3-Bromopropionates and Phenyl 3-Bromothiolopropionates. Transmission of Activation Effects through Acyl Bonds
Gilbert, Arthur B.,Peters, Frances B.,Johnson, H. W.
, p. 2724 - 2728 (2007/10/02)
Thirteen aryl 3-bromopropionates and nine aryl 3-bromothiolopropionates were prepared and subjected to dehydrohalogenation with sodium 3,4-dinitrophenoxide in dry tetrahydrofuran at 34.25 deg C.The second-order rate constants for the sulfur esters were approximately 10 times those for the corresponding oxygen esters.Good Hammett plots with ρ's of +0.81+/-0.04 and 0.98+/-0.04 for the oxygen and sulfur series, respectively, were obtained by using ?n.Activation parameters were measured for two oxygen and two sulfur esters; in both bases, low (12-13 kcal/mol) activatio n enthalpies and moderately large negative (19-21 eu) activation entropies were found.At 34.25 deg C, 3'-nitrophenyl 3-bromopropionate dehydrohalogenated 14 times more rapidly than 3'-nitrophenyl 3-chloropropionate; phenyl 3-bromothiolopropionate dehydrohalogenated 11 times more rapidly than the phenyl 3-chlorothiolopropionate.The rate constant ratio for 4'-bromophenyl 3-bromopropionate vs. 4'-bromophenyl 3-bromopropionate-2-d was 1.84; the monodeuterated compound yielded olefinic product with 65percent D.H was abstracted preferentially from 4'-chlorophenyl 3-bromothiolopropionate partially deuterated in the 2-position, but no kinetic results were obtained.No evidence of reversibility was found with 2,4-dinitrophenol-d, and the addition of 2,4-dinitrophenol to kinetic mixtures had essentially no effect on the rate conatants.The results are interpreted to indicate an E2 process near the EL/E1cB borderline with the thiolo ester deviating somewhat more toward an E1cB-I process.
Control of the 'Extended' E1cB Mechanism of Acyl Group Transfer in Activated Esters of Acrylic Acids
Douglas, Kenneth T.,Williams, Andrew
, p. 131 - 134 (2007/10/02)
Aminolysis and alkaline hydrolysis of aryl propenoates are shown to proceed via a normal nucleophilic substitution mechanism.The 'extended' E1cB mechanism of hydrolysis involving attack of hydroxide ion at the β-carbon followed by expulsion of the phenolate ion from the resulting carbanion is shown not to occur with the parent propenoate.The 'extended' E1cB mechanism is taken by the hydrolysis of 2-cyano-3-(4-methoxyphenyl)propenoate esters due to the stabilising effect of the cyano-group on the intermediate carbanion.
