Amino Triazolo Diazepines (Ata) as Constrained Histidine Mimics

Two synthetic routes for the synthesis of amino-triazolodiazepine (Ata) scaffolds are presented. The scope of both of these proceeding through key intra- and intermolecular Huisgen cycloaddition reactions is discussed. The replacement of the His-Pro dipeptide segment in angiotensin IV by the dipeptide mimetic Ata-Gly and subsequent biological evaluation in two inhibitory enzyme assays validated the use of the Ata moiety as a His mimic given the equipotency of both peptidic analogs.