1,9a-(iminomethano)-9aH-benzo[1,3]cycloprop[1,2-a]indene-5,10(9H)-dione, 11-acetyl-4a,4b,5a,6-tetrahydro- 11-acetyl-4a,4b,6,9-tetrahydro-1,9a-(epiminomethano)benzo[1,3]cyclopropa[1,2-a]indene-5,10(5aH)-dione InChI=1/C17H15NO3/c1-9(19)18-12-7-4-6-10-13-14(20)11-5-2-3-8-16(11,15(18)21)17(10,12)13/h2-4,6-7,10-11,13H,5,8H2,1H