138052-34-3Relevant academic research and scientific papers
New Amino Acids for the Topographical Control of Peptide Conformation: Synthesis of All the Isomers of α,β-Dimethylphenylalanine and α,β-Dimethyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic Acid of High Optical Purity
Kazmierski, Wieslaw M.,Urbanczyk-Lipkowska, Zofia,Hruby, Victor J.
, p. 1789 - 1795 (2007/10/02)
The synthesis of all four diastereomers of α,β-dimethylphenylalanine (4) as well as those of α,β-dimethyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (5 and 6) have been accomplished in high yield and high optical purity.Molecular mechanics calculations on the Nα-acetyl and N-methylcarboxamide derivatives of (3R,4R)-6 and (3R,4S)-5 indicate large and moderate energy stabilization for the gauche(-) but not the gauche(+) side-chain conformers of (3R,4S)-5 and (3R,4R)-6, respectively.By symmetry rules, the same holds for (3S,4R)-5 and (3S,4S)-6, respectively.Thus, these amino acids are potential building blocks for the topographical design of peptides (Kazmierski et al., J.Am.Chem.Soc. 1991, 113, 2275-2283) by providing acylated 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid derivatives in which a gauche(-) and not a gauche(+) side-chain conformation is energetically more stable for the L amino acid.Synthetic details and implications of these new amino acids for peptide and protein design are discussed.
Addition of Chiral Glycine, Methionine, and Vinylglycine enolate Derivatives to Aldehydes and Ketones in the Preparation of Enantiomerically Pure α-Amino-β-hydroxy Acids
Seebach, Dieter,Juaristi, Eusebio,Miller, David D.,Schickli, Christof,Weber, Theodor
, p. 237 - 261 (2007/10/02)
Chiral enolates of imidazolidinones and oxazolidinones from the title amino acids react with carbonyl compounds to afford the corresponding alcohols in excellent yields (see Scheme 5).Furthermore, the addition to aldehydes proceeds with high diastereoselectivity to give, after acid hydrolysis, threo-α-amino-β-hydroxy acids of high enantiomeric purity.Some of the threo-α-amino-β-hydroxy acids prepared in this work are the proteinogenic (S)-threonine (26), the naturally occuring (S)-3-phenylserine (28), and (S)-3-hydroxyleucine (27) as well as the unnatural (S)-4,4,4-rtifluorothreonine (30) and (S)-3-(4-pyridyl)serine (31).The N-methylamide of (2S,3R,4R,6E)-3-hydroxy-4-methyl-2-(methylamino)-6-octenoic acid (32), the uniqe amino acid in the immunosuppressive cyclosporine, was prepared by the new method.This report presents also information suggesting that both steric and stereoelectronic effects are responsible for the good stereoselectivities observed.
