4-O-(2,5-dioxopyrrolidin-1-yl) 1-O-methyl butanedioate

4-Oxo-5-phenylpentansaeure-methylester

2,5-dioxo-2,3,4,5-tetrahydro-1H-benz[b]azepine-4-carboxylic acid methyl ester

methyl 4-(2-chloroethyl)amino-4-oxobutanoate

4-(thien-2-yl)-4-oxobutyric acid methyl ester