- Lipase mediated preparation of the enantiomers of 3,3,3-trifluoro-2- methylpropanoic acid
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Both enantiomers of 3,3,3-trifluoro-2-methylpropanoic acid were prepared by a lipase mediated kinetic resolution of the racemate. The preparation of both enantiomers of 3,3,3-trifluoro-2-methylpropanoic acid by a lipase mediated kinetic resolution of the
- Beier, Petr,Z. Slawin, Alexandra M.,O'Hagan, David
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- Direct C(sp3)?H Trifluoromethylation of Unactivated Alkanes Enabled by Multifunctional Trifluoromethyl Copper Complexes
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A mild and operationally simple C(sp3)?H trifluoromethylation method was developed for unactivated alkanes by utilizing a bench-stable CuIII complex, bpyCu(CF3)3, as the initiator of the visible-light photoinduced reaction, the source of a trifluoromethyl radical as a hydrogen atom transfer reagent, and the source of a trifluoromethyl anion for functionalization. The reaction was initiated by the generation of reactive electrophilic carbon-centered CF3 radical through photoinduced homolytic cleavage of bpyCu(CF3)3, followed by hydrogen abstraction from an unactivated C(sp3)?H bond. Comprehensive mechanistic investigations based on a combination of experimental and computational methods suggested that C?CF3 bond formation was enabled by radical–polar crossover and ionic coupling between the resulting carbocation intermediate and the anionic CF3 source. The methylene-selective reaction can be applied to the direct, late-stage trifluoromethylation of natural products and bioactive molecules.
- Choi, Geunho,Lee, Geun Seok,Park, Beomsoon,Kim, Dongwook,Hong, Soon Hyeok
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supporting information
p. 5467 - 5474
(2021/01/20)
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- Low-Flammable Parahydrogen-Polarized MRI Contrast Agents
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Many MRI contrast agents formed with the parahydrogen-induced polarization (PHIP) technique exhibit biocompatible profiles. In the context of respiratory imaging with inhalable molecular contrast agents, the development of nonflammable contrast agents would nonetheless be highly beneficial for the biomedical translation of this sensitive, high-throughput and affordable hyperpolarization technique. To this end, we assess the hydrogenation kinetics, the polarization levels and the lifetimes of PHIP hyperpolarized products (acids, ethers and esters) at various degrees of fluorine substitution. The results highlight important trends as a function of molecular structure that are instrumental for the design of new, safe contrast agents for in vivo imaging applications of the PHIP technique, with an emphasis on the highly volatile group of ethers used as inhalable anesthetics.
- Ariyasingha, Nuwandi M.,Chekmenev, Eduard Y.,Chukanov, Nikita V.,Gelovani, Juri G.,Joalland, Baptiste,Koptyug, Igor V.,Kovtunov, Kirill V.,Nantogma, Shiraz,Salnikov, Oleg G.,Younes, Hassan R.
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p. 2774 - 2781
(2021/01/18)
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- 1,3,2-Diazaphospholenes Catalyze the Conjugate Reduction of Substituted Acrylic Acids
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The potent nucleophilicity and remarkably low basicity of 1,3,2-diazaphospholenes (DAPs) is exploited in a catalytic, metal-free 1,4-reduction of free α,β-unsaturated carboxylic acids. Notably, the reduction occurs without a prior deprotonation of the carboxylic acid moiety and hence does not consume an additional hydride equivalent. This highlights the excellent nucleophilic character and low basicity of DAP-hydrides. Functional groups such as Cbz group or alkyl halides which can be problematic with classical transition-metal catalysts are well tolerated in the DAP-catalyzed process. Moreover, the transformation is characterized by a low catalyst loading, mild reaction conditions at ambient temperature as well as fast reaction times and high yields. The proof-of-principle for a catalytic enantioselective version is described.
- Reed, John H.,Cramer, Nicolai
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p. 4262 - 4266
(2020/07/13)
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- PHENYL SUBSTITUTED PYRAZOLES AS MODULATORS OF RORgT
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The present invention comprises compounds of Formula I. wherein: R1, R3, R4, R5, R6, R7, R8, and Q are defined in the specification. The invention also comprises a method of treating or ameliorating a ROR-γ-t mediated syndrome, disorder or disease, including wherein the syndrome, disorder or disease is selected from the group consisting of rheumatoid arthritis, psoriatic arthritis, and psoriasis. The invention also comprises a method of modulating RORγt activity in a mammal by administration of a therapeutically effective amount of at least one compound of Formula I.
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Paragraph 0455
(2020/01/09)
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- ISOXAZOLIDINE DERIVED INHIBITORS OF RECEPTOR INTERACTING PROTEIN KINASE 1 (RIPK 1)
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The present disclosure relates generally to methods and compositions for preventing or arresting cell death and/or inflammation.
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Page/Page column 96
(2017/07/18)
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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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- Convenient synthesis of fluorinated alkanes and cycloalkanes by hydrogenation of perfluoroalkylalkenes under ultrasound irradiation
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Synthesis of several 1,4-disubstituted cyclohexanes, by hydrogenation of sterically hindered and electron poor perfluoroalkyl alkenes, was performed, at room temperature under hydrogen at atmospheric pressure. Hydrogenation was difficult to achieve without ultrasound whatever catalyst and pressure (from 1 to 120 bar) used. Coupling of ultrasonic irradiation with metallic catalysis dramatically increased the efficiency of hydrogenation of perfluoroalkyl alkenes.
- Carcenac,Tordeux,Wakselman,Diter
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p. 1347 - 1355
(2007/10/03)
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- Studies on the preparation of 2-(trifluoromethyl)acrylic acid and its esters from 3,3,3-trifluoropropene via hydrocarbonylation reactions
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The synthesis of methyl α-(trifluoromethyl)acrylate (MTFMA) has been carried out in three steps starting from commercially available 3,3,3,-trifluoropropene; this route involving the cobalt-catalyzed carbonylation of 2-bromo-3,3,3-trifluoropropene (2-Br-TFP) under very mild reaction conditions, gave only about 30% yield of the desired methyl ester. 2-(Trifluoromethyl)propanal, available in 90% yield by rhodium catalyzed hydroformylation of 3,3,3-trifluoropropene, proved to be an interesting starting product for the preparation of MTFMA: while the synthetic route involving the α-halogenation of 2-(trifluoromethyl)propanoic acid (TFMPA) failed to give any results, the reaction scheme based on the α-selenenylation of the above aldehyde followed by H2O2-oxidation afforded 68% yield of 2-(trifluoromethyl)acrylic acid (TFMAA).
- Botteghi, Carlo,Lando, Claudia,Matteoli, Ugo,Paganelli, Stefano,Menchi, Gloria
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- Preparation of optically active 2-(trifluoromethyl)alkan-1-ols by catalytic asymmetric hydrogenation
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The hydrogenation of (E)-2-(trifluoromethyl)alk-2-en-1-ols catalyzed by Ru-BINAP and Rh-BINAP has been carried out with good enantiomeric excess (71percent-83percent ee).Ru-BINAP-catalyzed hydrogenation converted 2-trifluoromethylacrylic acid to the corresponding saturated acid, the esterification and reduction of which gave optically active 2-(trifluoromethyl)propan-1-ol in 80percent ee.
- Iseki, Katsuhiko,Kuroki, Yoshichika,Nagai, Takabumi,Kobayashi, Yoshiro
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- 2-(2,2,2-Trifluoroethylidene)-1,3-dithianes. New Intermediates for the Preparation of CF3-Containing Compounds
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A simple and efficient synthesis of 2-(2,2,2-trifluoroethylidene)-1,3-dithianes is described.The title compounds are versatile intermediates for the preparation of trifluoromethyl derivatives.
- Solberg, Jan,Benneche, Tore,Undheim, Kjell
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- Regioselective Hydroesterification and Hydrocarboxylation of 3,3,3-Trifluoropropene and Pentafluorostyrene Catalyzed by Phosphine-Palladium Complex
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The hydroesterification and hydrocarboxylation of 3,3,3-trifluoropropene (TFP) and pentafluorostyrene (PFS) catalyzed by phosphine-palladium complexes were studied.It was found that the efficiency and the product distribution of the reaction depended markedly on the nature of nucleophile, i. e., water or alcohol, the structures of olefin and phosphine ligand, and other reaction variables such as solvent, temperature, and carbon monoxide pressure.Under optimal conditions either unbranched products or branched products were obtained in high yields with high regioselectivities.For example, 4,4,4-trifluorobutyric acid (5a) was obtained in 93percent yield with 99percent regioselectivity by using PdCl2(dppf)-SnCl2 as the catalyst in the hydrocarboxylation of TFP while ethyl 2-methyl-3,3,3-trifluoropropionate (2a) was obtained in 96percent yield with 79percent regioselectivity in the hydroesterification of TFP by using PdCl2(PPh3)2 as the catalyst.Similarly, 3-(pentafluorophenyl)propionic acid (5b) was obtained in 93percent yield with 99percent regioselectivity in the hydrocarboxylation of PFS catalyzed by PdCl2(dppf), and methyl 2-(pentafluorophenyl)propionate (2b) was obtained in 89percent yield with 95percent regioselectivity in the hydroesterification of PFS catalyzed by PdCl2(PPh3)2.Possible mechanisms of the present reactions are discussed.The hydrocarboxylations of TFP and PFS may involve (hydroxycarbonyl)palladium(II) intermediates while the hydroesterifications of TFP and PFS may proceed via alkylpalladium(II) and acylpalladium(II) intermediates.
- Fuchikami, Takamasa,Ohishi, Katsuyuki,Ojima, Iwao
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p. 3803 - 3807
(2007/10/02)
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