Optisch aktive 3‐Amino‐2<i>H</i>‐azirine als Bausteine für enantiomerenreine α,α‐disubstituierte α‐Aminosäuren: Synthese des α‐Methylphenylalanin‐Synthons and Einbau in Modell‐Peptide

Abstract

Optically Active 3‐Amino‐2 H ‐azirines as Synthons for Enantiomerically Pure αα‐Disubstituted α‐Amino Acids: Synthesis of the α‐Methylphenylalanine Synthons and Some Model Peptides The synthesis of a novel 2‐benzyl‐2‐methyl‐3‐amino‐2 H ‐azirine derivative with a chiral amino group is described. Chromatographic separation of the diastereoisomer mixture yielded the pure diastereoisomers 9a and 9b ( Scheme 4 ) which are the D ‐ and L ‐2‐methylphenylalanine ((α‐Me)Phe) synthons, respectively. The reaction of 9a and 9b with thiobenzoic acid and with Z‐leucine yielded the monothiodiamides 10a and 10b ( Scheme 5 ) and the dipeptide derivatives 11a and 11b ( Scheme 6 ), respectively. Methanolysis of 11b yielded 12b . The absolute configuration of 10a was established by X‐ray crystallography. The absolute configuration of (α‐Me)Phe in 12b has been deduced from the known configuration of L ‐leucine.