Abstract: The present invention relates to novel cephalosporin derivatives represented by Chemical Formula 1. Wherein, X, Y, L, R1, and R2 are as same as defined in the description of the invention. The present invention also relates to pharmaceutical antibiotic compositions comprising a novel celphalosporin derivative represented by Chemical Formula 1, a prodrug thereof, a hydrate thereof, a solvate thereof, an isomer thereof, or a pharmaceutically acceptable salt thereof as an effective ingredient. Compounds of the present invention are effective ingredients for the broad spectrum of antibiotic resistance, exhibit low toxicity, particularly in Gram-negative bacteria, which can be useful with strong antimicrobial activity.

Abstract: Disclosed is a novel oxazolidinone derivative, particularly a novel oxazolidinone compound with a cyclic amidoxime or cyclic amidrazone group. Also disclosed is a pharmaceutical antibiotic composition including a novel oxazolidinone derivative, in vivo hydrolysable ester thereof, in vivo hydrolysable phosphate ester thereof, an isomer thereof or a pharmaceutically acceptable salt thereof as an effective ingredient. Because the novel oxazolidinone derivative, in vivo hydrolysable ester thereof, in vivo hydrolysable phosphate ester thereof, an isomer thereof or a pharmaceutically acceptable salt thereof exhibits a wide antibacterial spectrum against resistant bacteria, a low toxicity, and a strong antibacterial activity against Gram-positive and Gram-negative bacteria, it can be usefully used as an antibiotic.