Reaction of Pyrrolobenzoxazinetriones with N,N′-Disubstituted Ureas. Synthesis of Substituted Spiro[imidazole-2,2′-pyrroles]

3-Aroylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones reacted with symmetrical N,N′-disubstituted ureas to give 1,3-disubstituted 9-aroyl-8-hydroxy-6-(2-hydroxyphenyl)-1,3,6-triazaspiro[4.4]non-8-ene-2,4,7-triones whose structure was confirmed by X-ray analysis. The resulting spiro heterocyclic systems contain a hydantoin fragment and are therefore interesting from the viewpoint of pharmaceutical chemistry.