- Direct evidence of edge-to-face CH/π interaction for PAR-1 thrombin receptor activation
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Heptapeptide SFLLRNP is a receptor–tethered ligand of protease-activated receptor 1 (PAR-1), and its Phe at position 2 is essential for the aggregation of human platelets. To validate the structural elements of the Phe-phenyl group in receptor activation, we have synthesized a complete set of S/Phe/LLRNP peptides comprising different series of fluorophenylalanine isomers (Fn)Phe, where n = 1, 2, 3, and 5. Phe-2-phenyl was strongly suggested to be involved in the edge-to-face CH/π interaction with the receptor aromatic group. In the present study, to prove this receptor interaction definitively, we synthesized another series of peptide analogs containing (F4)Phe-isomers, with the phenyl group of each isomer possessing only one hydrogen atom at the ortho, meta, or para position. When the peptides were assayed for their platelet aggregation activity, S/(2,3,4,6-F4)Phe/LLRNP and S/(2,3,4,5-F4)Phe/LLRNP exhibited noticeable activity (34% and 6% intensities of the native peptide, respectively), whereas S/(2,3,5,6-F4)Phe/LLRNP was completely inactive. The results indicated that, at the ortho and meta positions but not at the para position, benzene-hydrogen atoms are required for the CH/π interaction to activate the receptor. The results provided a decisive evidence of the molecular recognition property of Phe, the phenyl benzene-hydrogen atom of which participates directly in the interaction with the receptor aromatic π plane.
- Asai, Daisuke,Inoue, Naoko,Sugiyama, Makiko,Fujita, Tsugumi,Matsuyama, Yutaka,Liu, Xiaohui,Matsushima, Ayami,Nose, Takeru,Costa, Tommaso,Shimohigashi, Yasuyuki
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- Preparation method of tetrafluorobenzene methanol
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Belonging to the technical field of organic synthesis, the invention discloses a preparation method of tetrafluorobenzene methanol. The method includes: reacting tetrafluorobenzoic acid with thionyl chloride to produce tetrafluorobenzoyl chloride, then taking tetrafluorobenzoyl chloride as the raw material, and conducting reduction in water with sodium borohydride activated by an ether solvent toobtain tetrafluorobenzene methanol. According to the invention, the ether solvent and sodium borohydride are subjected to complexing to activate sodium borohydride, water is adopted as the solvent forreduction, the reaction yield is high, the reductant sodium borohydride can complete the reaction at a catalytic amount, and the reaction process is greener and more environmentally friendly.
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Paragraph 0047; 0049-0051
(2019/02/13)
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- Preparation and Physicochemical Properties of [6]Helicenes Fluorinated at Terminal Rings
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The first racemization-stable helicene derivatives fluorinated at terminal rings, 1,2,3,4-tetrafluoro[6]helicene (6) and 1,2,3,4,13,14,15,16-octafluoro[6]helicene (15), were synthesized via the Wittig reaction followed by oxidative photocyclization in an
- Církva, Vladimír,Jakubík, Pavel,Stra?ák, Tomá?,Hrbá?, Jan,Sykora, Jan,Císa?ová, Ivana,Vacek, Jan,?ádny, Jaroslav,Storch, Jan
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- Photochemical Aromatization of 8-Chloro-1,2,3,4,8-pentafluoro-bicyclo[2.2.2]octa-2,5-dien-7-ones
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8-Chloro-1,2,3,4,8-pentafluorobicyclo[2.2.2]octa-2,5-dien-7-ones containing alkyl or aryl substituents at the double bond or fused benzene ring undergo photochemical isomerization in chloroform to yield 1,2,3,4-tetrafluoroaromatic compounds as the major p
- Bogachev,Kobrina
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p. 681 - 683
(2007/10/03)
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- Photosubstitution reactions on aromatic and heteroaromatic rings evidence for addition and substitution mechanism
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Irradiation of a cyclohexane solution of hexafluorobenzene in the presence of benzophenone resulted in both, substitution and addition products. Similar photoreaction has been observed by irradiation of hexafluorobenzene in some alcohols in the presence of benzophenone. The reaction of pentafluorobenzene with methanol or cyclohexane resulted in the substitution of a 2-or 4-fluoro atom, while the reaction of pentafluoroanisole resulted in the formation of o-, m- and p-isomers. Irradiation of a cyclohexane solution or of an alcohol solution of octafluoronaphthalene yielded 1- and 2-substituted products. On the other hand, the photosubstitution of fluorine atom in pentafluoropyridine took place exclusively at the position four, thus forming 4-cyclohexyl or 4-(1-hydroxyalkyl) substituted products.
- Sket, Boris,Zupan, Marko,Zupancic, Natasa,Pahor, Barbara
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p. 5029 - 5042
(2007/10/02)
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- SYNTHESIS OF AN AMINOISOXAZOLIDINE SUBSTITUTED QUINOLONE ACID
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New heterocycle aminoisoxazolidine 7 and tetrafluorobenzoic acid are synthesized for the synthesis of a quinolone antibacterial agent.The synthesis of a chiral aminoisoxazolidine substituted quinolone acid, U-82662A, is described.
- Kim, Kyoung Soon
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