1,9a-epoxy-1,2,3,4,4a,4b,5,8,8a,9a-decahydro-2-methyl-4-nitro-5,8-methano-9H-fluoren-9-one

The six-membered ring of the title compound, C15H17NO4, adopts a half-chair conformation, and the methyl and nitro groups are attached equatorially to it. The five-membered ring fused to it is in a fattened envelope conformat ion. In the norbornene ring system, the six-membered ring adopts a fairly s ymmetrical boat conformation and the two five-membered rings formed by the bridging C atom adopt envelope conformations. The mean plane through the fu sed five-membered ring forms dihedral angles of 31.14(5) and 84.28(7)degree s with the mean planes of the adjacent six-membered rings.