- Iridium-Catalyzed Asymmetric Hydrogenation of N-Alkyl α-Aryl Furan-Containing Imines: an Efficient Route to Unnatural N-Alkyl Arylalanines and Related Derivatives
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High throughput experimentation (HTE) has enabled the rapid identification of ligand/precatalyst combinations that facilitate highly enantioselective hydrogenations of prochiral N-alkyl α-aryl ketimines containing a furyl moiety. The chiral amines obtained have proven to be modular precursors in the synthesis of unnatural mono N-alkylated arylalanines and related derivatives. (Figure presented.).
- Mazuela, Javier,Antonsson, Thomas,Knerr, Laurent,Marsden, Stephen P.,Munday, Rachel H.,Johansson, Magnus J.
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supporting information
p. 578 - 584
(2018/12/11)
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- Compounds which inhibit leukocyte adhesion mediated by VLA-4
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Disclosed are compounds which bind VLA-4. Certain of these compounds also inhibit leukocyte adhesion and, in particular, leukocyte adhesion mediated by VLA-4. Such compounds are useful in the treatment of inflammatory diseases in a mammalian patient, e.g.
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- A simple and rapid protocol for N-methyl-α-amino acids
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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.
- Reddy, G. Vidyasagar,Iyengar
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p. 299 - 300
(2007/10/03)
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- AN ALTERNATIVE ROUTE TO Nα-METHYLAMINO ACID DERIVATIVES: SYNTHESIS AND CONFORMATION OF SOME Nα-acetyl-Nα-METHYLAMINO ACID METHYLAMIDES
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The methylation of tert-butyl- or isopropyl esters of Nα-4-toluenesulfonyl-amino acids by dimethylsulfate in aqueous alkaline solution in the presence of a detergent gives the corresponding Nα-methylderivatives.Using this synthetic route the Nα-acetylderivatives of MeAla, MeLeu, MeOrn and MePhe methylamides have been prepared and the solution conformation of these dipeptide units has been investigated. 1H and 13C NMR spectra show that, while in dimethylsulfoxide the tertiary amide group is mostly in cis-conformation, in protic solvents the equilibrium is shifted towards trans-conformation.Circular dichroism spectra reveal some specific features (e.g. high band intensities in protic solvents) which cannot be explained solely on the basis of the increased rigidity caused by the Nα-methyl group.We tried to explain these effects supposing that the tertiary amide group is deviated from the planar arrangement (due to the interaction between the methyl groups, a substituent on Cα and solvent molecule attached to the oxygen atom) and contributes to the observed circular dichroism as the inherently chiral chromophore.
- Hlavacek, Jan,Fric, Ivo,Budesinsky, Milos,Blaha, Karel
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p. 2473 - 2494
(2007/10/02)
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