(5Z)-3,4,7,8-tetrahydrooxonine-2,9-dione 2,9-oxonindione, 3,4,7,8-tetrahydro-, (5Z)- InChI=1/C8H10O3/c9-7-5-3-1-2-4-6-8(10)11-7/h1-2H,3-6H2/b2-1