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 acids starting 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)
描述了从丙氨酸开始完全保护α-甲基化α-氨基酸的新途径(参见方案)。这些经由恶唑烷酮(2 S,4 R)-和(2 R,4 S)-2的碱催化打开而获得的衍生物可以直接用于肽合成中。Z保护的α-甲基天冬氨酸β-(叔丁基)酯(O 4-(叔丁基)2-甲基天冬氨酸(R)或(S)-4a),α-甲基谷氨酸的两种对映体的合成酸γ-(叔丁基)酯(ø 5 - (叔丁基)氢2- methylglutamate([R )-或(小号) -图4b),以及Ñ ε -二-Boc保护α甲基赖氨酸(Ñ 6,Ñ 6 -双[(叔-butyloxy )羰基] -2-甲基赖氨酸([R )-或(小号) -图4c)中充分详细地描述。