- A novel synthesis of N-but-3-enyl-α- and β-amino acids
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N-But-3-enyl-α- and β-amino acids can be prepared by cleaving 1,3-oxazolidin-5-ones and 1,3-oxazinan-6-ones in the presence of allylsilanes and boron trifluoride etherate at room temperature in good to excellent yields. Georg Thieme Verlag Stuttgart.
- Van Nguyen,Brownlee, Robert T. C.,Hughes, Andrew B.
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experimental part
p. 1991 - 1998
(2010/03/24)
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- Effective methods for the synthesis of N-methyl β-amino acids from all twenty common α-amino acids using 1,3-oxazolidin-5-ones and 1,3-oxazinan-6-ones
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N-Methyl β-amino acids are generally required for application in the synthesis of potentially bioactive modified peptides and other oligomers. Previous work highlighted the reductive cleavage of 1,3-oxazolidin-5-ones to synthesise N-methyl α-amino acids. Starting from α-amino acids, two approaches were used to prepare the corresponding N-methyl β-amino acids. First, α-amino acids were converted to N-methyl α-amino acids by the so-called '1,3-oxazolidin-5-one strategy', and these were then homologated by the Arndt-Eistert procedure to afford N-protected N-methyl β-amino acids derived from the 20 common α-amino acids. These compounds were prepared in yields of 23-57% (relative to N-methyl α-amino acid). In a second approach, twelve N-protected α-amino acids could be directly homologated by the Arndt-Eistert procedure, and the resulting β-amino acids were converted to the 1,3-oxazinan-6-ones in 30-45% yield. Finally, reductive cleavage afforded the desired N-methyl β-amino acids in 41-63% yield. One sterically congested β-amino acid, 3-methyl-3-aminobutanoic acid, did give a high yield (95%) of the 1,3-oxazinan-6-one (65), and subsequent reductive cleavage gave the corresponding AIBN-derived N-methyl β-amino acid 61 in 71% yield (Scheme 2). Thus, our protocols allow the ready preparation of all N-methyl β-amino acids derived from the 20 proteinogenic α-amino acids.
- Hughes, Andrew B.,Sleebs, Brad E.
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p. 2611 - 2637
(2007/10/03)
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- Microwave accelerated efficient synthesis of N-fluorenylmethoxycarbonyl/t-butoxycarbonyl/benzyloxycarbonyl-5- oxazolidinones
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The synthesis of N-protected 5-oxazolidinones using amino acids, paraformaldehyde and p-toluene sulfonic acid in a minimum amount of toluene accelerated by microwave irradiation for 3 min in high yield is described.
- Tantry, Subramanyam J.,Kantharaju,Suresh Babu, Vommina V.
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p. 9461 - 9462
(2007/10/03)
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- A novel, one-pot preparation of N-methyl-α-amino acid dipeptides from oxazolidinones and amino acids
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A new synthetic method has been developed to prepare N-methyl dipeptides in one-pot directly from oxazolidinones. Treatment of oxazolidinone 1 with an amino ester yields an intermediate N-hydroxymethyl dipeptide 3, which is treated with TFAA and triethyls
- Dorow,Gingrich, Diane E.
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p. 467 - 470
(2007/10/03)
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- Selective reductions of oxazolidinones: New protocol for diastereoselective synthesis of vicinal amino alcohols
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Selective reductions of oxazolidinones using sodium borohydride and their application to the diastereoselective synthesis of vicinal amino alcohols are described.
- Reddy, G. Vidyasagar,Rao, G. Venkat,Iyengar
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p. 2653 - 2656
(2007/10/03)
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- A simple and rapid protocol for N-methyl-α-amino acids
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A two step strategy for optically pure N-Protected-N-methyl-α-amino acids starting from N-protected-α-amino acids via reductive cleavage of oxazolidinones using NaCNBH3/TMSCl is described.
- Reddy, G. Vidyasagar,Iyengar
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p. 299 - 300
(2007/10/03)
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- A practical approach for the optically pure N-Methyl-α- amino acids
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A new practical synthesis of N-Methyl-α-amino acids by racemization free methodology has been developed. The method involves the reductive cleavage of N-protected oxazotidinones using hydrogen in the presence of Pd/C to give the title compounds in quantitative yields.
- Reddy, G. Vidyasagar,Rao, G. Venkat,Iyengar
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p. 1985 - 1986
(2007/10/03)
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