42417-66-3Relevant articles and documents
Determination of the complete absolute configuration of petriellin A
Aurelio, Luigi,Brownlee, Robert T. C.,Dang, Jason,Hughes, Andrew B.,Polya, Gideon M.
, p. 407 - 414 (2008/02/04)
We report the full structural determination of the depsipeptide petriellin A. The absolute configuration of the amino acid residues, N-methyl isoleucine and N-methyl threonine, have been determined by a combination of HPLC and TLC comparison of synthetic Marfey's derivatives and Marfey's derivatives of the natural product hydrolysate. The configuration of the chiral centres in these two N-methylated residues was found to be the same as those of the common unmethylated l-amino acids. CSIRO 2006.
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
Hughes, Andrew B.,Sleebs, Brad E.
, p. 2611 - 2637 (2007/10/03)
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.
A simple and rapid protocol for N-methyl-α-amino acids
Reddy, G. Vidyasagar,Iyengar
, p. 299 - 300 (2007/10/03)
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.
The dolastatins. 19. Synthesis of dolaisoleuine
Pettit,Singh,Srirangam,Hogan-Pierson,Williams
, p. 1796 - 1800 (2007/10/02)
The synthesis of dolaisoleuine as its tert-butyl ester (Dil-OBu(t)), a β- methoxy-γ-amino acid component of dolastatin 10, has been achieved employing as key step an aldol condensation between N-(benzyloxycarbonyl)-N-methyl- (S,S)-isoleucinal and tert-butyl acetate followed by O-methylation. The overall six-step reaction sequence to Dil proved to be convenient for routine preparation of this new amino acid and its stereochemical assignment as (3R,4S,5S)-N,O-dimethylisostatine.
