A series of 1, 4-bis (alkoxycarbonyl) azetidin-2-ones, designed as potential suicide-inhibitors of serine proteases, has been synthesized and evaluated against porcine pancreatic elastase (PPE). The most active compound (Ki∼ 10μM; reversible inhibitor) was equipped with phenethyloxycarbonyl and benzyloxycarbonyl side-chains at positions N1 and C4, respectively, with the (S)-configuration. 1H NMR spectroscopic analysis of the reaction ...