Production method of racemic or opticaly active 5-substituted oxazolidi-2,4-diones

Hypoglycemic 5-chromanyl, 2,3-dihydro-5-benzo[b]furanyl, 5-pyridyl, 5-quinolyl, 5-pyrrolyl, 5-indolyl, 5-thiazolyl, 5-oxazolyl, 5-isothiazolyl and 5-isoxazolyl oxazolidine-2,4-diones and the pharmaceutically acceptable salts thereof; certain 3-acylated derivatives thereof; a method of treating hyperglycemic animals therewith; and intermediates useful in the preparation of said compounds.