671233-63-9

Upstream product

• 70-34-8 2,4-Dinitrofluorobenzene 
• 671233-62-8 (S)-β²-homomethionine 
• 637337-73-6 (S)-2-({[(benzyloxy)carbonyl]amino}methyl)-4-(methylsulfanyl)butanoic acid 
• 671233-57-1 (S)-2-{[(methoxycarbonyl)amino]methyl}-4-(methylsulfanyl)butanoic acid 
• 671233-56-0 (R)-4-isopropyl-3-((S)-2-{[(methoxycarbonyl)amino]methyl}-4-(methylsulfanyl)-1-oxobutyl)-4-isopropyl-5,5-diphenyloxazolidin-2-one 

Relevant academic research and scientific papers

Preparation of (S,S)-Fmoc-β2hIle-OH, (S)-Fmoc-β 2hMet-OH, and (S)-Fmoc-β2hTyr(tBu)-OH for Solid-Phase Syntheses of β2- and β2/β 3-Peptides

The preparation of three new N-Fmoc-protected (Fmoc=[(9H-fluoren-9-yl)methoxy]carbonyl) β2-homoamino acids with proteinogenic side chains (from Ile, Tyr, and Met) is described, the key step being a diastereoselective amidomethylation of the corresponding Ti-enolates of 3-acyl-4-isopropyl-5,5-diphenyloxazolidin-2-ones with CbzNHCH2OMe/TiCl4 (Cbz=(benzyloxy)carbonyl) in yields of 60-70% and with diastereoselectivities of > 90%. Removal of the chiral auxiliary with LiOH or NaOH gives the N-Cbz-protected β-amino acids, which were subjected to an N-Cbz/N-Fmoc (Fmoc=[(9H-fluoren-9-yl)methoxy]carbonyl) protective-group exchange. The method is suitable for large-scale preparation of Fmoc-β2hXaa-OH for solid-phase syntheses of β-peptides. The Fmoc-amino acids and all compounds leading to them have been fully characterized by melting points, optical rotations, IR, 1H- and 13C-NMR, and mass spectra, as well as by elemental analyses.