1,3-Isobenzofurandione, 3a,4,7,7a-tetrahydro-5-methyl- 3425-89-6 4-Cyclohexene-1,2-dicarboxylic anhydride, 4-methyl- 4-Methyl-.DELTA.4-tetrahydrophthalic anhydride 4-Methyl-.delta.-4-tetrahydrophthalic anhydride 4-Methyl-1,2,3,6-tetrahydrophthalic anhydride 4-Methyltetrahydrophthalic anhydride Isomethyltetrahydrophthalic anhydride NSC52669