New Structure Activity Relationship Insight into the Role of the C‐3 Extension on Rifamycin Antimycobacterial Activity

Herein, the antimycobacterial screening of a series of rifamycin analogues, modified at their C-3 extension, is reported. Overall, these compounds display potent activity against a wild-type Mtb strain assayed in three different growth media. Several promising C-3 extensions are identified through this screen, with compounds featuring rigid tertiary alicyclic hydrazones displaying superior activity to amino compounds. In addition, a general correlative trend between logP and biological activity is observed. This study adds to the growing literature surrounding structure activity relationship pertaining the important C-3 extension of rifamycin, which in addition to a poorly understood role in target engagement, has utility for modulating physicochemical properties, a key condition in antimycobacterial drug discovery.