Heteroatom - containing benzo cyclopentane - oxazolidinone

PROBLEM TO BE SOLVED: To obtain the subject compound having lower toxicity and esp. wider bactericidal action on Gram-positive coccus, Mycobacteria, Corynebacteria, Haemophilus, Haemophilus and/or Bacillus influenzae and anaerobes. SOLUTION: This compound, or its salt, its tautomer or its isomer is expressed by formula I {wherein, R 1 is an azide, OH or NR 2 R 3 (wherein, R 2 and R 3 are each H, a 1-6C cycloalkyl, or the like); A is expressed by formula H [wherein, G, L and M are each H, carboxy, a halogen, or the like; R 12 is H, a 3-6C cycloalkyl(carbonyl), or the like; D is O or S; E is O, S or NH]}, e.g. (5S)-3-(2-methylthio-3-methyl-benzothiazol-6-yl)-5-(acetylaminomethyl)- oxazolidin-2-one iodide of formula III. The compound is obtained e.g. by reacting a compound of the formula: A-N=C=O with lithium bromide/(C 4 H 9 ) 3 PO and epoxides of formula IV (wherein, Q is a 1-6C acyloxy) in an inactive solvent and optionally in the presence of a base, and, if needed, by treatment comprising the hydrolysis of the ester of the resultant product. COPYRIGHT: (C)1996,JPO