spiro[2-cyclopropene-1,9'-fluorene]-2,3-dimethyldicarboxylate

methyl 2H-phenanthro[9,10-c]pyrazole-3-carboxylate

dimethyl 3H-phenanthro[9,10-c]pyrazole-3,3-dicarboxylate

dimethyl 2H-phenanthro[9,10-c]pyrazole-1,3-dicarboxylate

dimethyl 9bH-cyclopenteno[1,2,3-l,m]fluorene-1,2-dicarboxylate