Process for the preparation of 4-methyleneoxazolidine-2,5-diones

摘要

4-Methyleneoxazolidine-2,5-diones of the general formula <IMAGE> in which the substituents R<1> and R<2> have certain meanings, are prepared by reacting 2-azidocarboxylic acids of the general formula <IMAGE> with phosgene or diphosgene in an inert solvent at a temperature between 0 and 150@C in the presence of a perrhenate. The compounds of the general formula (I) are useful starting compounds for the preparation of 2-amino-2,3-dehydrocarboxylic acids and dehydrooligopeptides.