Synthesis and Utilization of Chiral α-Methylated α-Amino Acids with a Carboxyalkyl Side Chain in the Design of Novel Grb2-SH2 Peptide Inhibitors Free of Phosphotyrosine
alpha-aminoadipic acid (Adi) in position Y + 1. The enantiopure l(or D)-(alpha-Me)Aa bearing various chain length carboxylalkyl side chain was conveniently synthesized by an optimized oxazolidinone methodology. The incorporation of (S)-(alpha-Me)Aa into the non-pTyr-containing peptide framework with a 5-amino acid sequence binding motif of X (-2)-Leu-(3'-substituted-Tyr) (0)-X (+1)-Asn really improved the
We describe an original asymmetric synthesis of (S)-α-methylDOPA proceeding by the concept of memory of chirality, the only source of chirality being the starting d-alanine. The initial chirality of the amino acid is temporarily transferred to a dynamic axial chirality of a tertiaryaromatic amide. The (S)-α-methylDOPA hydrochloride is obtained after four steps with 98% ee.
Versatile Stereoselective Synthesis of Completely Protected Trifunctional ?-Methylated ?-Amino Acids Starting from Alanine
作者:Eva Altmann、Kurt Nebel、Manfred Mutter
DOI:10.1002/hlca.19910740414
日期:1991.6.19
α-amino acidsstarting from alanine is described (see Scheme). These derivatives, which are obtained via base-catalyzed opening of the oxazolidinones (2S,4R)- and (2R,4S)-2, can be directly employed in peptide synthesis. The synthesis of both enantiomers of Z-protected α-methylaspartic acid β-(tert-butyl)ester (O4-(tert-butyl) hydrogen 2-methylaspartates (R) or (S)-4a), α-methyl-glutamic acid γ-(tert-butyl)
Stereoselectivity in Reactions of Metal Complexes. Part X. Kinetics and stereoselectivity of the inner-sphere electron-transfer reaction between [Co(bamap)H2O]+ (bamap = 2,6-bis(3-carboxy-1,2-dimethyl-2-azapropyl)pyridine) and optically active iron(II) complexes
The kinetics of the electron-transfer reaction between racemic or opticallyactive [Co(bamap)H2O]+ and opticallyactive Fe2+ complexes of the three new pentadentate ligands bamap, alamp, and valmp has been investigated. All the reacting species show C2 symmetry. With respect to aquo-Fe2+, the reaction rate for the Fe2+ complexes is enhanced by a factor of 104 to 105, and the observed kΔΛ/kΛΛ ratio