- A closer insight into the mechanism operating in the trifluoroacetylation of pyrrole. New trifluoromethyl pyrroylmethane discovered
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A former studied reaction of acetylation of pyrrole was revisited and this allowed the identification of new compounds and the isolation and characterization of a very stable solid (2,2′,2″-(2,2,2-trifluoroethane-1,1,1-triyl)tris(1H-pyrrole)). All these m
- Peláez,Burgos Paci,Argüello
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- Meso-trifluoromethyl-substituted expanded porphyrins
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A series of meso-trifluoromethyl-substituted expanded porphyrins, including N-fused [24]pentaphyrin 3, [28]hexaphyrin 4, [32]heptaphyrin 5, [46]decaphyrin 6, and [56]dodecaphyrin 7, were synthesized by means of an acid-catalyzed one-pot condensation reaction of 2-(2,2,2-trifluoro-1-hydroxyethyl)pyrrole (1) as the first examples bearing meso-alkyl substituents. Besides these products, porphyrin 2 and two calix[5]phyrins 8 and 9 were also obtained. [28]Hexaphyrin 4 was quantitatively oxidized to [26]hexaphyrin 14 with MnO2. These expanded porphyrins have been characterized by mass spectrometry, 1H and 19F NMR spectroscopy, and UV/Vis spectroscopy. The single-crystal structures have been determined for 3, 4, 6, 7, and 14. The N-fused [24]pentaphyrin 3 displays a distorted structure containing a tricyclic fused moiety that is similar to those of mejo-aryl-substituted counterparts, whereas 8 and 9 are indicated to take roughly planar conformations with an inverted pyrrole opposite to the sp3-hybridized meso-carbon atom. Both [28]- and [26]hexaphyrins 4 and 14 have figure-of-eight structures. Solid-state structures of the decaphyrin 6 and dodecaphyrin 7 are remarkable, exhibiting a crescent conformation and an intramolecular two-pitch helical conformation, respectively.
- Shimizu, Soji,Aratani, Naoki,Osuka, Atsuhiro
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- Enhancements of Trifluoroacetic Acylated Five-membered Heterocyclic Compounds Using as Additives in Dye Sensitized Solar Cells
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In this study, five-membered heterocyclic compounds are trifluoroacetic acylated for the purpose of providing more long pairs to enhance electrolyte in dye sensitized solar cells (DSSCs). Four five-membered heterocyclic compounds will be trifluoroacetic acylated with trifluoroacetic anhydride by Friedel-Crafts acylation: furan, thiophene, pyrrole and N-methylpyrrole. The properties will be measured by cyclic voltage (CV), Fourier transform infrared spectroscopy (FTIR), solar simulator, and electrochemical impedance spectroscopy (EIS). We find out that furan and thiophene which we add in electrolyte as additives can increase short circuit current and photovoltaic efficiency, and furthermore, all the trifluoroacetic acylated heterocyclic compounds perform better photoelectric abilities than non-trifluoroacetic acylated one. The photovoltaic efficiency will be increased from 4.439% to 5.197% when 1wt% trifluoroacetic acylated thiophene is added in electrolyte as additives.
- Wang, Chung-Chun,Duann, Yeh-Fang
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p. 345 - 352
(2016/05/09)
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- Catalytic asymmetric hydrogenation of α-CF3- or β-CF3-Substituted acrylic acids using Rhodium(I) complexes with a combination of chiral and achiral ligands
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Only the mixture works! Acrylic acid derivatives with CF3 substituents in α or β position were efficiently hydrogenated in the presence of a RhI complex with a chiral secondary phosphine oxide (SPO; see scheme) and an achiral Ph3P as ligands. The corresponding propanoic acid derivatives were obtained with generally high conversion (>99 %) and high enantioselectivity (92->99 %). Copyright
- Dong, Kaiwu,Li, Yang,Wang, Zheng,Ding, Kuiling
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supporting information
p. 14191 - 14195
(2014/01/06)
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- Synthesis, spectra and photophysics of some free base tetrafluoroalkyl and tetrafluoroaryl porphyrins with potential applications in imaging.
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The synthesis, characterization and photophysical properties of two perfluoroalkyl (5,10,15,20-tetrakis-[trifluoromethyl]- and [heptafluoropropyl]-porphyrin) and two perfluoroaryl (5,10,15,20-tetrakis-[2,6-difluorophenyl]- and [pentafluorophenyl]-porphyri
- Grancho,Pereira,Miguel,Rocha, Gonsalves A M,Burrows
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p. 249 - 256
(2007/10/03)
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- A simple method for the preparation of aryl trifluoromethyl ketones
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4-Dimethylamino-1-trifluoroacetylpyridinium trifluoroacetate (2) is an effective, easy to handle and stable trifluoroacetylation agent. Aryl trifluormethyl ketones 4 are obtained in good yields by reaction of 2 with aromatic compounds 3 in the presence of aluminum chloride.
- Simchen, Gerhard,Schmidt, Andreas
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p. 1093 - 1094
(2007/10/03)
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- SYNTHESIS OF AROMATIC ALDEHYDES VIA 2-ARYL-N,N'-DIACYL-4-IMIDAZOLINES
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Diacylimidazolium ions yield adducts with aromatic compounds.Thus the N,N'-diacetylimidazolium ion and indole gives 1,3-diacetyl-2-(3-indolyl)-4-imidazoline.Less reactive substrates such as thiophene, anisole and 1,3-dimethylbenzene fail to react with this reagent but do form adducts (e.g. 1,3-bis-(trifluoroacetyl)-2-(2-thienyl)-4-imidazoline) with an imidazole/trifluoroacetic anhydride reagent.All of the adducts could be converted to the corresponding aldehyde under mild conditions.The synthetic scope of the new synthesis is similar to that of the Vilsmeier-Haack reaction.
- Bergman, Jan,Renstroem, Lars,Sjoeberg, Birger
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p. 2505 - 2512
(2007/10/02)
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- Products from N-Substituted Pyrroles and Trifluoroacetic Anhydride: Ratios and Conformations of Isomers
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A series of N-substituted pyrroles has been treated with trifluoroacetic anhydride.Small alkyl groups or aryl groups (as the N-substituents) lead exclusively, or almost exclusively, to the 2-trifluoroacetyl derivatives, bulky groups (notably 1-adamantyl) to the 3-derivatives, and those of intermediate size (such as i-propyl) to mixtures of isomers.N-Substituted 3-trifluoroacetylpyrroles exist in solution as mixtures of rotational isomers whereas the 2-isomers adopt a preferred conformation in which the nitrogen and oxygen atoms are in the syn orientation.
- Chadwick, Derek J.,Meakins, G. Denis,Rhodes, Caroline A.
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p. 878 - 886
(2007/10/02)
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- 4,5 Dihalopyrrol 2-yl di and tri halomethyl ketones
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4,5-Dihalopyrrol-2-yl di- and trihalomethyl ketones, prepared by reaction of pyrrole with a di- or trihaloacetyl halide or with a di- or trihaloacetic anhydride and halogenation of the resulting pyrrol-2-yl di- or trihalomethyl ketone, useful as antibacterial, herbicidal and insecticidal agents.
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