Table 1. Noncyclic Boronic Acid Derivatives as Broad-Spectrum β-Lactamases Inhibitors.

^aEstimated K_i as per competitive inhibitor. Experiments were conducted as described in Materials and Methods (see Supporting Information). BAs, synthesized as pinacol esters, were assayed without previous deprotection since they spontaneously hydrolyzed to the free BA under assay conditions. All the experiments were performed in triplicate, and errors never exceeded 5%.

^bK_i data from Santucci et al.^24§Derivative was crystallized with the target protein and disclosed here for the first time.^&Previously disclosed binary complex.²⁵