InChI=1/C10H8BrNO5/c1-15-9(14)5-3-10(17-12-5)2-4(11)6(13)7-8(10)16-7/h2,7-8H,3H2,1H methyl 4'-bromo-5'-oxo-4H-spiro[isoxazole-5,2'-[7]oxabicyclo[4.1.0]hept[3]ene]-3-carboxylate spiro[isoxazole-5(4H),2'-[7]oxabicyclo[4.1.0]hept[3]ene]-3-carboxylic acid, 4'-bromo-5'-oxo-, methyl ester