| abstract |
A process for preparing novel spiro-oxazolidinediones of the general formula (I) or pharmaceutically acceptable salts thereof, wherein X is oxygen or sulfur, R is hydrogen, alkyl, benzyl or monosubstituted benzyl by reacting an appropriately substituted 4-hydroxy-4-carboximidate derivative with Phosgene in the presence of a base, such as triaethylamine, in an inert organic solvent, such as ether, or with an alkyl haloformate, or with a 1,1'-carbonylimidazole. The spiro-oxazolidinediones are readily isolated from the reaction medium with conventional measures. Pharmaceutically acceptable salts can be readily prepared from compounds of formula (I) wherein R is hydrogen by conventional methods. The novel spiro-oxazolidinediones are useful for the treatment of certain chronic complications caused by diabetes mellitus, such as diabetic cataracts and neuropathy. |