REACTION OF 5-SUBSTITUTED-2-AMINO-2-OXAZOLINES WITH ETHOXYCARBONYL ISOCYANATE - A ROUTE TO AHYDRO-4H-OXAZOLO[3,2-A]-1,3,5-TRIAZINE-2,4-DIONES

The reaction of 2-amino-2-oxazolines with ethoxycarbonyl isocyanate wa s investigated in order to access to fused 1,3,5-triazine-2,4-diones w ith a potential 5-HT2 antagonist activity. The reaction leads to ahydr o-4H-oxazolo[3,2-a]-1,3,5-triazine-2,4-diones and to 1-carbethoxy-3-(2 -iminooxazolidine)ureas. During the carbamoylation the regioselectivit y seems to be related to the strong nucleophilic character of the endo nitrogen atom of 2-amino-2-oxazolines. The structures of two compound s were studied by X-ray crystallography. N-Substituted compounds have been prepared by alkylation of the methyl-4H-oxazolo[3,2-a]-1,3,5-tria zine-2,4-dione.