Structure-activity studies of divin: an inhibitor of bacterial cell division.

We describe the synthesis and SAR studies of divin-a small molecule that blocks bacterial division by perturbing the assembly of proteins at the site of cell septation. The bacteriostatic mechanism of action of divin is distinct from other reported inhibitors of bacterial cell division and provides an opportunity for assessing the therapeutic value of a new class of antimicrobial agents. We demonstrate a convenient synthetic route to divin and its analogs, and describe compounds with a 10-fold increase in solubility and a 4-fold improvement in potency. Divin analogs produce a phenotype that is identical to divin, suggesting that their biological activity comes from a similar mechanism of action. Our studies indicate that the 2-hydroxynaphthalenyl hydrazide portion of divin is essential for its activity and that alterations and substitution to the benzimidazole ring can increase its potency. The SAR study provides a critical opportunity to isolate drug resistant mutants and synthesize photoaffinity probes to determine the cellular target and biomolecular mechanism of divin.