Five-membered 2,3-dioxo heterocycles: LXI. Reaction of 3-aroyl-1H-pyrrolo2,1-c1,4benzoxazine-1,2,4-triones with α-enamino esters. Crystalline and molecular structure of methyl 11-benzoyl-2-o-hydroxyphenyl-3,4,10-trioxo-6,9-diphenyl-7-oxa-2,9-diazatricyclo6.2.1.01,5undec-5-ene-8-carboxylate

3-Aroyl-1H-pyrrolo2,1-c1,4benzoxazine-1,2,4-triones react with methyl 4-aryl-2-arylamino-4-oxobut-2-enoate to give substituted methyl 7-aryl-4,9-bis(aroyl)-3-hydroxy-1-(2-hydroxyphenyl)-2,6-dioxo-1,7-diazaspiro4.4nona-3,8-diene-8-carboxylates which undergo thermal cyclization to methyl 9-aroyl-4,7-diaryl-1-(2-hydroxyphenyl)-2,3,8-trioxo-2,3,7,8-tetrahydro-1H,6H-6,8a-methanopyrrolo2,3-e1,3oxazepine-6-carboxylates. The crystalline and molecular structures of methyl 9-benzoyl-1-(2-hydroxyphenyl)-2,3,8-trioxo-4,7-diphenyl-2,3,7,8-tetrahydro-1H,6H-6,8a-methanopyrrolo2,3-e1,3oxazepine-6-carboxylate was studied by X-ray analysis.