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81.
Two terthiophenes incorporating the synthon 3,4-(1,2-phenylenedioxy)thiophene (PheDOT) have been developed. Specifically, 2,5-bisthienyl-3,4-(1,2-phenylenedioxy)thiophene (BTh-PheDOT 1) and 2,5-bisethylenedioxythienyl-3,4-(1,2-phenylenedioxy)thiophene (BEDOT-PheDOT 2) were electropolymerized to form electroactive polymer films (P1 and P2) that switched between two highly colored states with the more electron-rich EDOT derivative P2 observed to switch at a lower potential. Additionally, both P1 and P2 displayed moderate to low optical bandgaps of 1.8 and 1.6 eV, respectively. Crystal structures of BTh-PheDOT showed the monomer to be nearly planar with π -stacking observable between monomers. These findings demonstrate the potential of PheDOT as an electroactive synthon for the formation of well-ordered systems. 相似文献
82.
A. A. Fadda S. B. Bondock A. M. Khalil Eman H. Tawfik 《Journal of heterocyclic chemistry》2013,50(4):838-843
The starting N‐(2‐pyridyl)‐6‐methyl‐4‐phenyl‐2‐thioxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carboxamide ( 4 ) was used as a key intermediate for the synthesis of new 1,2,3,4‐tetrahydropyrimidine‐2‐thione and their thiazolo[3,2‐a]pyrimidine, thiazino and benzothiazipen derivatives. The reaction of 4 with haloketones in ethanol catalyzed by base afforded the corresponding thiophenopyrimidine and pyrimidothiazipine derivatives 5 , 6 , 7 , 8 , 9 , 10 . Methylation and formylation of 4 led to the pyrimidine derivatives 15 and 16 , respectively. The preventative compounds were established on the basis of elemental and spectral data. 相似文献
83.
84.
Tarek A. Salama Saad S. Elmorsy Abdel‐Galel M. Khalil Margret M. Girges Abdel‐Aziz S. El‐Ahl 《合成通讯》2013,43(8):1313-1319
A combination of tetrachlorosilane and potassium cyanide (in situ trichlorosilyl cyanide) was found to work efficiently for hydrocyanation of ketones to afford the corresponding cyanohydrins in high yield under mild conditions. 相似文献
85.
An efficient one-step synthesis of 1,1-dipfienyl-1-silacyclopent-3-ene 1 is reported. 相似文献
86.
Eric Monflier Sbastien Tilloy Georges Fremy Yves Castanet Andr Mortreux 《Tetrahedron letters》1995,36(52):9481-9484
Solvent free biphasic hydroformylalion of various water-insoluble terminal olefins can be achieved in high yields and sclcctivitics by using a water-soluble rhodium/triphenylphosphine trisulfonate catalyst and per(2,6-di-o-mclhyl)-β-cyclodcxtrin as inverse phase transfer catalyst. The catalytic activities were up to ten times higher than those observed without pcr(2,6-di-o-methyl)-β-cyclodextrin. 相似文献
87.
Georges Langrand Michel Secchi Gérard Buono Jacques Barattil Christian Triantaphylides 《Tetrahedron letters》1985,26(15):1857-1860
The commercial preparation “lipase My” catalyses ester formation from an alcohol and a fatty acid in organic solvents. Preparative resolution of α-substituted cyclohexanols, including menthol, was achieved under these conditions. 相似文献
88.
Synthesis of the (R)- and (S)-Glycerol Acetonides. Determination of the Optical Purity The optical purity of (R)-glycerol acetonide ( 1 ) and (S)-glycerol acetonide ( 1 ′) has been determined with great accuracy by gas chromatography after derivatization. The optical purity of (S)-glycerol actonide prepared from D -mannitol was > 99.4% while for (R)-glycerol acetonide obtained from L -serine it was 95%. 相似文献
89.
Acid/base mobile phase modifiers affect enantioseparations in ways that are not yet understood for the lack of systematic studies, which makes the scale-up of preparative separations difficult to predict. Shifts of the selectivity of certain pairs of enantiomers upon exposure of the column to these modifiers is amply documented. Furthermore, once the modifier has been removed from the mobile phase, the improved selectivity remains, this phenomenon has been named the memory effect. We selected four enantiomeric pairs for a systematic study of this memory effect. The selectivity of 4-chlorophenylalanine ethyl ester (4CPEE) improves after a solution of ethanesulfonic acid (ESA) is percolated through the column. The selectivity of propranolol HCl and Tröger's base increases after a solution of diiospropylethylamine is percolated through the column. The selectivity of these three pairs of enantiomers is inversely affected by percolation of the opposite acid/base solution. Each of these four compounds reached an equilibrium concentration that maintained the separation of the enantiomeric pairs. In contrast, the selectivity of trans-stilbene oxide (TSO) is not affected by either acid/base modifier. Preparative separations can be used to detect changes in the active surface of the chiral polymer stationary phase by measuring the change in selectivity and resolution when modifiers are used. Preparative method development was carried out on analytical columns and scale-up to 1 cm ID columns were performed in this study. 相似文献
90.
Chardon E Puleo GL Dahm G Guichard G Bellemin-Laponnaz S 《Chemical communications (Cambridge, England)》2011,47(20):5864-5866
The synthesis of alkyne-substituted N-heterocyclic carbene complexes of Pd(II) and Pt(II) is reported. Catalyzed 1,3-dipolar cycloaddition with azides has been applied as a modular way of functionalisation of group 10 transition metal NHC complexes to generate potentially new metallodrugs. 相似文献