2,3-Dimethylmaleic anhydride2,5-Dihydro-3,4-dimethylfuran-2,5-dione2,3-Dimethylmaleic anhydrideDimethylmaleic anhydride2,3-二甲基马来酸酐二甲基马来酸酐3,4-dimethyl-2,5-dihydrofuran-2,5-dioneDimethylmaleic anhydride2,3-二甲基马来酸 酐二甲基马来酸酐3,4-DiMethylfuran-2,5-dione3,4-Dimethyl-2,5-furandione