845745-86-0

Upstream product

• 799766-53-3 (2R,3S)-3-Dibenzylamino-2-hydroxy-butyric acid methyl ester 
• 845745-84-8 C₁₉H₂₃NO₃ 

Relevant academic research and scientific papers

Stereoselective preparation of 3-amino-2-fluoro carboxylic acid derivatives, and their incorporation in tetrahydropyrimidin-4(1H)-ones, and in open-chain and cyclic β-peptides

The preparation of (2S,3S)- and (2R,3S)-2-fluoro and of (3S)-2,2-difluoro-3-amino carboxylic acid derivatives, 1-3, from alanine, valine, leucine, threonine, and β3h-alanine (Schemes 1 and 2, Table) is described. The stereochemical course of (diethylamino)sulfur trifluoride (DAST) reactions with N,N-dibenzyl-2-amino-3-hydroxy and 3-amino-2-hydroxy carboxylic acid esters is discussed (Fig. 1). The fluoro-β-amino acid residues have been incorporated into pyrimidinones (11-13; Fig. 2) and into cyclic β-tri- and β-tetrapeptides 17-19 and 21-23 (Scheme 3) with rigid skeletons, so that reliable structural data (bond lengths, bond angles, and Karplus parameters) can be obtained. β-Hexapeptides Boc[(2S)-β3hXaa(αF)]6OBn and Boc[β3hXaa(α,αF2)]6-OBn, 24-26, with the side chains of Ala, Val, and Leu, have been synthesized (Scheme 4), and their CD spectra (Fig. 3) are discussed. Most compounds and many intermediates are fully characterized by IR- and 1H-, 13C- and 19F-NMR spectroscopy, by MS spectrometry, and by elemental analyses, [α]D and melting-point values. Copyright

PROCESS FOR PRODUCING -FLUORO- -AMINO ACIDS

By reacting a β-hydroxy-α-amino acid with sulfuryl fluoride (SO2F2) in the presence of an organic base, it is possible to produce an α-fluoro-β-amino acid of the formula [2]. By using a C8-12 tertiary amine having two or more alkyl g

Synthesis and CD spectra of fluoro- and hydroxy-substituted β-peptides

β-Amino acids 1-3 with OH and F substituents in the α-position have been prepared (Scheme) from the natural (S)-α-amino acids alanine, valine, and leucine, and incorporated into β-hexa- and β-heptapeptides 4-12. The peptide syntheses were performed according to a conventional solution strategy (Boc/Bn protection) with fragment coupling. The new β-peptides with (series a) and without (series b) terminal protection were isolated in HPLC-pure form and characterized by NMR spectroscopy and MALDI mass spectrometry. The chemical properties as well as the patterns of the CD spectra (Figs. 3-5) depend upon constitution (OH, F, F2 substitution) and configuration (l or u) of the amino acid residues, upon the total number of OH and F substituents in the peptide chain, and upon the solvent used (H2O, MeOH, CF3CH2OH, (CF3)2CHOH). No reliable clues regarding the structures can be obtained from these CD spectra. Only a full NMR analysis will be able to answer the questions: a) with which known secondary structures (Figs. 1 and 2) of β-peptides are the OH and F derivatives compatible? b) Are new secondary structures enforced by the polar and/or H-bonding backbone substituents? Furthermore, the β-peptides described here will enable us to study changes in chemical, enzymatic, and metabolic stability, and in physiological properties caused by the heteroatoms.