Disclosed are novel oxazolidinone derivatives with cyclic amidoxime or cyclic amidrazone group, pharmaceutically acceptable salts thereof, methods for preparing the same and pharmaceutical compositions containing the same. The crude product composition contains from 0. The interferometer introduces a path length difference between at least a segment of the transmitted and reflected portions that recombine to form an output beam having an intensity that varies as a function of wavelength of the input beam.