- Preparation method of N-fluorenylmethoxycarbonyl-gamma-(S-triphenylmethyl-cysteamine)-L-glutamic acid
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The invention provides a preparation method of N-fluorenylmethoxycarbonyl-gamma-(S-triphenylmethyl-cysteamine)-L-glutamic acid. The preparation method mainly solves the technical problems of complexity, long period, high cost, and low yield of an original process, and comprises the following steps: (1) preparing N-fluorenylmethoxycarbonyl-L-glutamic acid; (2) preparing N-fluorenylmethoxycarbonyl-L-glutamic acid-1-benzyl ester; (3) preparing S-triphenylmethyl cysteamine; (4) preparing N-fluorenylmethoxycarbonyl-gamma-(S-triphenylmethyl-cysteamine)-L-glutamic acid-alpha-benzyl ester; and (5) preparing N-fluorenylmethoxycarbonyl-gamma-(S-triphenylmethyl-cysteamine)-L-glutamic acid. The method is rapid, high in yield and simple in separation and purification, and the used solvent is environment-friendly and is suitable for mass production.
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- Asymmetric michael addition of malonates to enones catalyzed by a primary Β-amino acid and its lithium salt
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Highly enantioselective Michael addition of malonates to enones was achieved using a mixed catalyst consisting of a primary Β-amino acid, O-TBDPS (S)-Β-homoserine, and its lithium salt. Various cyclic and acyclic enones were converted into 1,5-ketoesters in high yields (up to 92%) with high enantioselectivity (up to 97% ee) under mild reaction conditions. Details of synthesis of the catalyst, optimization of the reaction conditions for the Michael addition reaction, and a plausible reaction mechanism are described.
- Yoshida, Masanori,Narita, Mao,Hara, Shoji
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p. 8513 - 8517
(2011/12/03)
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- Glutamyl adenylate analogues are inhibitors of glutamyl-tRNA synthetase
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Glutamol adenylate 10 was a competitive inhibitor (K(i) = 3 μM) of glutamyl-tRNA synthetase from Escherichia coli. The N6-benzoyl adenine derivative 9 was also an inhibitor (K(i) ~ 60 μM). Replacement of adenine by other bases (purine, cytosine
- Desjardins, Michel,Garneau, Sylvie,Desgagnes, Julie,Lacoste, Lucille,Yang, Fu,Lapointe, Jacques,Chenevert, Robert
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- Selective removal of phenacyl ester group with a TBAF·xH2O-thiol system from amino acid derivatives containing benzyl or 4-nitrobenzyl ester
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A facile cleavage method of phenacyl ester bonds by combined use of tetrabutylammonium fluoride hydrate (TRAF·xH2O) and 1-octanethiol was established. Benzyl and 4-nitrobenzyl esters are almost stable toward this reagent.
- Ueki, Masaaki,Aoki, Hiroko,Katoh, Tsuyoshi
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p. 2783 - 2786
(2007/10/02)
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