SYNTHESIS OF NOVEL 1,3-OXAZINO[6,5-B]INDOLE-2,4-(3H,9H)-DIONE AND 2H-1,3,5-OXADIAZINO[3,2-A]INDOLE-2,4-(3H)-DIONE FROM OXINDOLES

Two novel tricyclic ring systems were designed as serine protease inhibitors and synthesized from oxindoles; the first series, 1,3-oxazino[6,5-b]indole-2,4-(3H,9H)-diones, were prepared from 2,3-dihydro-2-oxo-(1H)-indole-3-carboxamides and phosgene in tetrahydrofuran with triethylamine. The second, a 2H-1,3,5-oxadiazino[3,2-a]indole-2,4-(3H)-dione was made using a similar cyclization on 2,3-dihydro-2-oxo-N-phenyl-(1H)-indole-1-carboxamide