Patent ID: 8754210

Claim:
A method for preparing an oxazolidinone derivative of formula (I) or a pharmaceutically acceptable salt thereof, comprising the steps of: introducing an amino protecting group to a cyclic amidrazone of formula (V) to obtain a compound of formula (VI); reducing the nitro group of the compound of formula (VI) to obtain a compound of formula (VII); subjecting the compound of formula (VII) to a reaction with 5-chloro-N-(((S)-oxiran-2-yl)methyl)thiophene-2-carboxamide to obtain a compound of formula (VIII) having a chlorothiophene group; conducting a carbonylation reaction of the compound of formula (VIII) using a phosgene equivalent to obtain an oxazolidinone of formula (IX); and removing the amino protecting group from the amidrazone ring of the oxazolidinone of formula (IX), wherein, R′ is hydrogen, C 1 -C 7 alkyl, C 3 -C 7 cycloalkyl, or C 4 -C 12 heteroaryl comprising 1 to 4 hetero atoms selected from the group consisting of oxygen, sulfur, and nitrogen; in which R′ may be optionally substituted with one or more substituents selected from the group consisting of C 1 -C 7 alkyl, C 1 -C 7 haloalkyl, C 1 -C 7 alkoxy, and halogen; and PG is formyl, (C 1 -C 7 alkyl)carbonyl, (C 1 -C 7 haloalkyl)carbonyl, (C 6 -C 12 aryl)carbonyl, (C 1 -C 7 alkoxy)carbonyl, (C 6 -C 12 aryl)(C 1 -C 7 alkoxy)carbonyl, or trityl.