97973-95-0

Upstream product

• 97973-84-7 N-(tert-butoxycarbonyl)-L-alanine isoxazolidide 
• 74-86-2 acetylene 
• 15761-38-3 L-N-Boc-Ala 
• 146553-06-2 tert-butyl {(S)-1-[methoxy(methyl)amino]-1-oxopropan-2-yl}carbamate 
• 4301-14-8 acetylenemagnesium bromide 
• 125814-30-4 BOC-L-alanine-NCA 

Downstream Products

• 1614240-23-1 methyl ((S,Z)-4-((tert-butoxycarbonyl)amino)-3-oxopent-1-en-1-yl)-L-tyrosinate 
• 1614240-24-2 methyl ((S,E)-4-((tert-butoxycarbonyl)amino)-3-oxopent-1-en-1-yl)-L-tyrosinate 
• 1614240-29-7 methyl ((S,Z)-4-((tert-butoxycarbonyl)amino)-3-oxopent-1-en-1-yl)-L-phenylalaninate 
• 1614240-30-0 methyl ((S,E)-4-((tert-butoxycarbonyl)amino)-3-oxopent-1-en-1-yl)-L-phenylalaninate 

Relevant academic research and scientific papers

Synthesis of enaminone-based vinylogous peptides

Vinylogous peptides 3 with a vinyl fragment inserted into the peptide C-N bond were prepared from ynones 6 and enaminones 7 that are easily available from Boc-protected α-amino acids 4. Coupling at the C terminus was achieved by 1,4-addition of amino esters 5 to the C≡C bond in 6 or by substitution of the NMe2 group in 7 to give N-terminal vinylogues 3a-p. Coupling at the N terminus of 3 and 7, in contrast, required temporary protection of the acidolytically labile enamino moiety. Thus, cyclization of 6 or 7 with hydroxylamine, removal of the Boc group with HBr-AcOH, acylation of free amine 10 with BocGlyOH (4a), and hydrogenolytic deprotection of the enamino moiety in the presence of GlyOMe (5a) led to tripeptides 3q-s with vinylogous amide as the central building block. Copyright

Cu(I)-catalyzed [3+2] cycloadditions of tert-butyl (S)-(3-oxopent-4-yn-2- yl)carbamate to 1-benzylidenepyrazole-3-one-derived azomethine imines

Parallel screening of suitable reaction conditions for Cu(I)-catalyzed [3+2] cycloadditions of (1Z,4R*,5R*)-4- benzoylamino-1-benzylidene-5-phenyl-3-oxopyrazolidin-1-ium-2-ide (1a) to methyl propiolate (2) has established that this reaction proceeds smoothly at room temperature in acetonitrile in the presence of CuI and Huenig's base. The optimized reaction conditions were then applied in regio- and stereo-selective 1,3-dipolar cycloadditions of racemic azomethine imines 1a-e to tert-butyl (S)-(3-oxopent-4-yn-2-yl)carbamate (6) leading to mixtures of diastereomeric non-racemic chromatographically separable cycloadducts 7a-d, 7′ a-d, 8e, and 8′e. The structures of the products were confirmed by NMR spectroscopy.

Diastereoselective synthesis of N-protected β-Amino-α-hydroxyacids (norstatines) from urethane N-carboxyanhydrides (UNCAs)

β-Amino-α-hydroxyacids (norstatines) are prepared from urethane N- protected carboxyanhydrides (UNCAs); the key step is the diastereoselective reduction of a keto-acetylenic compound, which lead is, with syn diastereoselectivity, to the corresponding prop

α-Amino Acids as Chiral Educts for Asymmetric Products. The Synthesis of α'-Amino-α,β-ynones

α-Amino acid isoxazolidides have been developed as educts for the preparation of optically pure α'-amino-α,β-ynones.The α-amino acids were first N-protected as their ethoxycarbonyl, tert-butoxycarbonyl, or phenylsulfonyl derivatives.The isoxazolidides then were formed by the simple, high yield acylation of isoxazolidine by in situ generated α-amino acid isobutyl carbonic anhydrides.Individual isoxazolidides of L-α-N-substituted alanine, phenylalanine, and methionine, when treated with lithium acetylide, lithium (trimethylsilyl)acetylide, or 1-hexynyllithium, gave high yields of the corresponding optically pure α,β-acetylenic ketones.