In laboratory i tried to synthesise 4-((2-hydroxyethyl)amino)-4-oxobutanoic acid using succinic anhydride and monoethanolamine.

I tried out two different conditions :

1. Acetone, ice bath, monoethanolamone is a bit in excess, stirring for 2 h

2. THF, 1:1 raw materials, room temperature, stirring for 24 h.

I obtained the same spectra in DMSO :

1H NMR (500 MHz, DMSO) δ 3.49 (t, J=5.4 Hz), 2.76 (t, J=5.4 Hz), 2.23 (s).

Are there some different conditions, for example, using catalyst?