94400-15-4Relevant articles and documents
A facile and efficient anti-selective four-component direct aldol addition via chemoselective thioester enolate formation
Zhou, Guoqiang,Yost, Julianne M.,Sauer, Scott J.,Coltart, Don M.
, p. 4663 - 4665 (2007)
(Chemical Equation Presented) A facile and efficient four-component anti-selective direct aldol addition of thioester enolates has been developed that is fully compatible with enolizable aldehydes and able to be conducted using untreated reagent-grade CH
Tandem type polymerization. Synthesis and characterization of ordered poly(amide-thioether) from 2,6-dichlorophenyl methacrylate, 4,4′-thiobis(benznenethiol), and 4,4′-oxydianiline
Tsuchiya, Kousuke,Shibasaki, Yuji,Ueda, Mitsuru
, p. 1815 - 1818 (2007/10/03)
Ordered poly(amide-thioether) (17) was prepared by tandem type polymerization of 2,4-dichlorophenyl acrylate (11), 4,4′-thiobis(benznenthiol) (12), and 4,4′-oxydianiline (16). The polymerization was carried out by mixing all monomers in the presence of catalytic amounts of triethylamine (TEA) and 1-hydroxybenzotriazole (HOBt) in 1-methyl-2-pyrrolidinone (NMP) at 20 °C for 2 h and then 80 °C for 2 days, yielding polymer 17 with a number-average molecular weight (Mn) of 25 000. Authentic ordered poly(amide-thioether) (18) was prepared to verify the structure of polymer 17. The microstructure of polymers obtained was investigated by 1H and 13C NMR spectroscopy, and it has been found the polymer obtained has the expected ordered structure. Furthermore, model reactions were studied in detail to demonstrate the feasibility of ordered polymer formation.
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.
