- 373 - ABSTRUCTProvided is a novel compound which is useful as a pharmaceutical composition by inhibiting an LpxC activity, thereby exhibiting potent antimicrobial activity against gram-negative bacteria including Pseudomonas aeruginosa and its drug resistant bacteria. Provided is a hydroxamic acid derivative represented by the following general formula [1] or a pharmaceutically acceptable salt thereof:[Chemical formula 1]431R—N 02 11.N%2OHw LA 1