Synthesis of Chiral TFA-Protected ?-Amino Aryl-Ketone Derivatives with Friedel-Crafts Acylation of ?-Amino Acid N-Hydroxysuccinimide Ester.

ABSTRACT: Chiral N-protected ?-amino aryl-ketones are one of the useful precursors used in the synthesis of various biologically active compounds and can be constructed via Friedel-Crafts acylation of N-protected ?-amino acids. One of the drawbacks of this reaction is the utilization of toxic, corrosive and moisture-sensitive acylating reagents. In peptide construction via amide bond formation, N-hydroxysuccinimide ester (OSu), which has high storage stability, can react rapidly with amino components and produces fewer side reactions, including racemization. This study reports the first synthesis and utilization of N-trifluoroacetyl (TFA)-protected ?-amino acid-OSu as a potential acyl donor for Friedel-Crafts acylation into various arenes. The TFA-protected isoleucine derivative and its diastereomer TFA-protected allo-isoleucine derivative were investigated to check the retention of ?-proton chirality in the Friedel-Crafts reaction. Further utilization of OSu in other branched-chain and unbranched-chain amino acids results in an adequate yield of TFA-protected ?-amino aryl-ketone without loss of optical purity.

SUBMITTER: Tachrim ZP 

PROVIDER: S-EPMC6151496 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature