- [F-18]-labeled L-glutamic acid, [F-18]-labeled L-glutamine, derivatives thereof and use thereof and processes for their preparation
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The compounds and the synthesis of [F-18]-labeled L-glutamic acid, [F-18]-labeled L-glutamate, their derivatives as set forth in formula (I) and their uses are described.
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Page/Page column 37; 38
(2016/08/03)
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- [F-18]-LABELED L-GLUTAMIC ACID, [F-18]-LABELED L-GLUTAMINE, DERIVATIVES THEREOF AND USE THEREOF AND PROCESSES FOR THEIR PREPARATION
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The compounds and the synthesis of [F-18]-labeled L-glutamic acid, [F-18]-labeled L-glutamate, their derivatives as set forth in formula (I) and their uses are described.
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Paragraph 0890
(2016/12/01)
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- [F-18]-LABELED L-GLUTAMIC ACID, [F-18]-LABELED L-GLUTAMINE, DERIVATIVES THEREOF AND USE THEREOF AND PROCESSES FOR THEIR PREPARATION
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The compounds and the synthesis of [F-18]-labeled L-glutamic acid, [F-18]-labeled L-glutamate, their derivatives as set forth in formula (I) and their uses are described.
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- Electrophilic fluorination of pyroglutamic acid derivatives: Application of substrate-dependent reactivity and diastereoselectivity to the synthesis of optically active 4-fluoroglutamic acids
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Electrophilic fluorination of enantiomerically pure 2-pyrrolidinones (4) derived from (L)-glutamic acid has been investigated as a method for the synthesis of single stereoisomers of 4-fluorinated glutamic acids. Reaction of the lactam enolate derived from 9 with NFSi results in a completely diastereoselective monofluorination reaction to yield the monocyclic trans-substituted α-fluoro lactam product 21. Unfortunately, a decreased kinetic acidity in 21 and other structurally related monofluorinated products renders them resistant to a second fluorination. In contrast, the bicyclic lactam 12 is readily difluorinated under the standard conditions described to yield the α,α-difluoro lactam 24. The difference in reactivity between the two types of related lactams is attributed mainly to the presence or lack of a steric interaction between the base used for deprotonation and the protecting group present in the pyrrolidinone substrates. This conclusion was reached based on analysis of the X-ray crystal structure of 21, molecular modeling, and experimental evidence. The key intermediates 21 and 24 are converted to (2S,4R)-4-fluoroglutamic acid and (2S)-4,4-difluoroglutamic acid, respectively.
- Konas,Coward
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p. 8831 - 8842
(2007/10/03)
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- Practical synthesis of L-erythro- and L-threo-4-fluoroglutamic acids using aminoacylase
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Enantiomerically pure L-erythro- and L-threo-4-fluoroglutamic acids 1a and 1b were conveniently prepared. The key steps in this synthesis relied upon separation of diastereomers of N-chloroacetyl-4-fluoroglutamic acid 5-methyl ester 7 by recrystallization and enzymatic resolution of enantiomers of the resulting 7(a+c) and 7(b+d) by aminoacylase. Protection of the γ-carboxyl group as a methyl ester was found to be crucial for this enzymatic reaction.
- Kokuryo, Yoshitsugu,Nakatani, Takuji,Kobayashi, Kobee,Tamura, Yoshinori,Kawada, Kenji,Ohtani, Mitsuaki
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p. 3545 - 3551
(2007/10/03)
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- Stereospecific syntheses of all four stereoisomers of 4-fluoroglutamic acid
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(+)-L-threo-4-fluoroglutamic acid . (-)-D-threo-4-Fluoroglutamic acid was prepared analogously from trans-4-hydroxy-D-proline, obtained from its diastereomer by inversion of configuration at carbon 4 of the pyrrolidine ring using the diethyl azodicarboxylate-triphenylphosphine procedure. cis-4-Hydroxy-L-proline, necessary for the synthesis of (+)-L-erythro-4-fluoroglutamic acid , was prepared from trans-4-hydroxy-L-proline by benzyloxycarbonylation at the nitrogen, oxidation of the 1-benzyloxycarbonyl-trans-4-hydroxy-L-proline to 1-benzyloxycarbonyl-4-oxo-L-proline, its reduction to 1-benzyloxycarbonyl-cis-4-hydroxy-L-proline and deprotection of the latter at the nitrogen. (-)-cis-4-Fluoro-L-proline and (+)-trans-4-fluoro-D-proline were isolated after the hydrolysis of incompletely oxidized methyl 1-acetyl-cis-4-fluoro-L-prolinate and methyl 1-acetyl-trans-4-fluoro-D-prolinate, respectively.
- Hudlicky, M.
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p. 193 - 210
(2007/10/02)
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- Resolution of γ-Methyl and γ-Fluoroglutamic Acids. Lack of Stereospecificity of Leucine Aminopeptidase with L-Leucyl-L-erythro-γ-substituted Glutamates
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The hydrolysis of L-leucyl-γ-substituted D,L-glutamates by leucine aminopeptidase, from porcine kidney, is stereospecific with threo-γ-methyl and threo-γ-fluoroglutamate containing dipeptides whereas there is a lack of stereospecificity with erythro-isomers.The optical purities of L-threo- and L-erythro-glutamate isomers thus obtained have been monitored by gas chromatography, high pressure liquid chromatography, or nuclear magnetic resonance.The optical rotations of optically pure L-isomers have been measured and the discrepancies with former publications are discussed.
- Bory, Sonia,Dubois, Joelle,Gaudry, Michel,Marquet, Andree,Lacombe, Liliane,Weinstein, Shulamith
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p. 475 - 480
(2007/10/02)
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