Copper‐Free Solid‐Phase Synthesis of Triazolo[1,5‐a][1,4]diazepin‐6‐ones.

Synthesis of triazolo[1,5‐a][1,4]diazepin‐6‐ones on solid support is reported in this article. Amino acids immobilized on Wang resin were nosylated and alkylated with propargyl alcohol, but‐2‐yn‐1‐ol or different 3‐phenylprop‐2‐yn‐1‐ols using Mitsunobu alkylation conditions. After denosylation, acylation with Fmoc‐azidoalanine yielded linear precursors that were thermally cyclized on resin to give immobilized triazolodiazepinones. After cleavage from the polymer support, the target compounds were obtained in high crude purities and good overall yields. Furthermore, the synthetic approach was applied to convenient solid‐phase synthesis of oligopeptide containing the triazolodiazepinone moiety as the peptidomimetic heterocyclic constraint. [ABSTRACT FROM AUTHOR]