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  • N-Acylation  (2)
  • Biochemistry and Biotechnology  (1)
  • N-protected carboxyanhydrides (UNCAs)  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International journal of peptide research and therapeutics 4 (1997), S. 241-244 
    ISSN: 1573-3904
    Keywords: Urethane N-protected carboxyanhydrides (UNCAs) ; N-ProtectedN-acyl amino acids ; N-Acylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The reactivity of Grignard reagents with UNCAs (Urethane N-protected Carboxyanhydrides of Amino acids) is described. We observed that, depending on the method of addition of the organometallic compounds, the reaction proceeded differently: (i) when the UNCA was added to the Grignard reagent, we obtained a mixture of five different products which were all identified; and (ii) when the organometallic reagent was added to the UNCA, we also obtained a mixture of the same products but in different proportions, with the major component corresponding to the urethane N-protectedN-acyl amino acid derivative.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1075-2617
    Keywords: β-amino-alcohol ; statine ; UNCAs ; vicinal tricarbonyl compounds ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Urethane-protected N-carboxyanhydrides (UNCAs) are very reactives. They have been successfully used in peptide synthesis, in both solution and solid phase. We have demonstrated that UNCAs are interesting starting materials for the synthesis of various amino acid derivatives. Chemoselective reduction of UNCAs with sodium borohydride led the corresponding N-protected β amino alcohols. Reaction of UNCAs with Meldrum's acid, followed by cyclisation, yielded enantiomerially pure tetramic acid derivatives. Diastereoselective reduction of tetramic acid derivatives produced (4S,5S)-N-alkoxycarbonyl-4-hydroxy-5-alkylpyrrolidin-2-ones derived from amino acids, which after hydrolysis yielded statine and statine analogues. Tetramic acid derivatives could also be obtained by reaction of UNCAs with benzyl ethyl followed by hydrogenolytic deprotection and decarboxylation. UNCAs also reacted with phosphoranes to produce the ketophosphorane in excellent yields. Subsequent oxidation with oxone or with [bis(acetoxy)-iodol]-benzene produced vicinal tricarbonyl derivatives. These reactions usually proceeded smoothly and with high yields.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International journal of peptide research and therapeutics 4 (1997), S. 241-244 
    ISSN: 1573-3904
    Keywords: Urethane ; N-protected carboxyanhydrides (UNCAs) ; N-protected N-acyl amino acids ; N-Acylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The reactivity of Grignard reagents with UNCAs (UrethaneN-protected Carboxyanhydrides of Amino acids)is described. We observed that, depending on the method ofaddition of the organometallic compounds, the reactionproceeded differently:(i) when the UNCA was added to the Grignard reagent, weobtained a mixture of five different products whichwere all identified; and (ii) when the organometallic reagent was added to theUNCA, we also obtained a mixture of the same productsbut in different proportions, with the major componentcorresponding to the urethane N-protected N-acyl aminoacid derivative.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
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