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Thioacids derived from N-protected amino or dipeptide and tripeptide acids undergo facile N-acylation with aromatic amines to afford N-protected amino or peptide aryl amides in good to excellent yields and enantiopurities. The method also furnishes difficult-to-prepare N-Fmoc amino acid 4-nitroanilides in good yields. This simple oxidative Nα-acylation of thioacids with aromatic amines proceeds in the presence of iodine, 1-hydroxybenzotriazole and N,N-diisopropylethylamine at room temperature in tetrahydrofuran. [ABSTRACT FROM AUTHOR]

A facile one-pot procedure for the synthesis of urea-linked peptidomimetics and neoglycopeptides under Curtius rearrangement conditions employing Deoxo-Fluor and TMSN3 is described. The method is efficient and circumvents the isolation of acyl azide and isocyanate intermediates. The rearrangement of the in situ generated acyl azide via the acyl fluoride was carried out under ultrasonication followed by amine capture to insert a urea bond. The protocol worked well with all the common N-urethane-protected amino acids and also with a sugar-6-acid. [ABSTRACT FROM AUTHOR]