نتایج جستجو برای: ring opening
تعداد نتایج: 167807 فیلتر نتایج به سال:
maleic anhydride (man) copolymers with methyl methacrylate(mma), ethyl methacrylate(ema), methyl acrylate(ma), ethyl acrylate (ea) and buthyl acrylate (ba) ( in a 1:1 mole ratio) were synthesized by free radical polymerizations method under vacuum -azobis(isobutironitrile)(aibn) as an initiator of reaction at 701c. the copolymer compositions were determined using related 1h nmr spectra techni...
This study represents a highly efficient and regioselective ring-opening of epoxides with acetic anhydride in the presence of NaOAc<span style="font-size: 10.0pt; font-family: 'Times ...
Key words Sc(OTf)3 - aziridine carboxylates ring opening tryptophan derivatives
for the first time nakayama introduced qf-ring. in 1967 carl. faith and elbert a. walker showed that r is qf-ring if and only if each injective right r-module is projective if and only if each injective left r-modules is projective. in 1987 s.k.jain and s.r.lopez-permouth proved that every ring homomorphic images of r has the property that each cyclic s-module is essentialy embeddable in dire...
A rational approach towards the borylative ring-opening of vinylepoxides and vinylaziridines, by the in situ formed MeO(-)→bis(pinacolato)diboron adduct, has been developed. The enhanced nucleophilic character of the Bpin (sp(2)) moiety from the reagent favours the SN2' conjugated B addition with the concomitant opening of the epoxide and aziridine rings. The reaction proceeds with total chemos...
Ring Opening Polymerization In article 2200359, Sonja Herres-Pawlis, Andreas Jupke, and co-workers show that the transition of new non-toxic catalysts for lactide ring opening polymerization from lab scale to industry is a highly complex process. Hence, promising end up in valley death between these scales. Model-based analysis can bridge this gap, giving an in-depth understanding pave way subs...
In this paper, the ring-opening reaction of 2,5-dioctyldithieno[2,3-b:3',2'-d]thiophene with aryllithium in THF at low temperature to generate 2'-arylthio-3,3'-bithiophene-2-carbaldehydes is studied. Nine examples are explored and all the products are characterized by (1)H NMR, (13)C NMR and HRMS. The relative relationship between the structures of aryl groups and the efficiency of ring-opening...
A recently reported protolytic gating effect on the ring closing reaction of an oligo(phenylene ethynylene) (OPE) embedded difurylperfluorocyclopentene (S) with a dimethylaminophenyl chain link in each of the side arms, was quantitatively analyzed in detail. The reaction system (So, SoH(+), SoH2(2+), Sc, ScH(+), ScH2(2+)) comprising three protolytic forms in both open and closed configuration, ...
A highly diastereoselective and efficient synthesis of P-stereogenic bulky alkyl and aryl aminophosphines that relies on ring opening of tert-butyl-oxazaphospholidine 2 is described. Ring opening with several organometallic reagents takes place with inversion of configuration at the phosphorus center as it has been demonstrated by X-ray analysis of two ring-opened intermediates. The unprecedent...
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