(S)-(1,3-Dihydro-1,3-dioxo-2H-isoindol-2-yl)butanedioic acid 42406-53-1 Butanedioic acid, (1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-, (S)- N-Phthaloyl-L-aspartic acid