| 摘要 |
<p>A process for preparing N-substituted-oxazolidine-2,4-diones comprising (a) contacting carbon dioxide and a primary amine or ammonia in the presence of an aprotic organic solvent and an organic, nitrogenous base to produce the corresponding ammonium carbamate salt, and (b) reacting the ammonium carbamate salt with an α-substituted carboxylic acid ester having the formula X-CHR1CO2R2 to produce the corresponding N-substituted-oxazolidine-2,4-dione. A second embodiment comprises recovering the ammonium carbamate salt of Step (a) prior to reacting the ammonium carbamate salt with the α-substituted carboxylic acid ester in the presence of an aprotic organic solvent and an organic, nitrogenous base. A third embodiment comprises reacting the N-substituted-oxazolidine-2,4-dione with a nucleophile selected from the group consisting of aliphatic or alicyclic primary amines, alcohols and thiols, wherein the reaction is conducted in the presence of a Lewis acid catalyst when the nucleophile is an aliphatic or alicyclic alcohol.</p> |
