Synthesis and activity of novel benzoxazole derivatives of mannopeptimycin glycopeptide antibiotics

A series of benzoxazole derivatives of the mannopeptimycin glycopeptide antibiotics was synthesized via a novel benzoxazole formation reaction by treating aminophenol of mannopeptimycin-β with an aldehyde and DDQ in DMF. Some of these derivatives (e.g., 5b, 5d, 5m, and 7b) showed good activity against Gram-(+) bacteria when compared to the parent compound mannopeptimycin-β.