It has recently been shown59 that a novel nitroreductase (NTR2) in Leishmania is responsible for the activation of nitroimidazooxazoles such as 4; therefore, differential nitroreductase binding may be a major factor behind the in vitro SARs for both VL and TB.57 Evaluation of a representative set of nine racemic compounds in the VL mouse model pinpointed phenylpyridines 71 and 93 as the most efficacious, with 93 being as impressive as 4 (50% inhibition at 1.56 mg/kg). The gene discussed is NTSR2; the disease is tuberculosis.