N-(2-Hydroxyethyl)succinimfde was formed with 80 X yield in the reaction of 2-oxarolidtnone with succinic anhydride at 210 C instead of polyesteramides obtained from N-substituted 2-oxazolidinones. The identification based on the crystal structure determination. Several patents concerning the use and synthesis of N-(2-hydroxyethyl)succinimide have been reported during the past twenty years. N-Hydroxyalkylimides are generally important for polyesteramide manufacture.l*2 N-(2-~dro~ethyl)succinfmide provides means for selective extraction of aromatic hydrocarbons.3-6 It has also been patented as another starting material for polyester and cellulose acetate textile dyes.7 N-(2-Hydroxyethyl)succinfmfde may be synthesized with good yields from succinic anhydride and ethanolamine,7'8 from succinic imide and ethylene carbonate.' and from succinfc imide and ethylene oxide.' In the present paper we report9 as far as we know, a new method to synthesize ~-(2-hydroxyethyl)succfnfmfde by the reaction of succfnfc anhydride with P-oxazolidfnone. The reaction product was identified by determining its crystal structure. RESULTS AN0 DISCUSSION 2-Oxarolidinone (1) and its derfvatfves are reactive 5-membered ring compounds. The reactions of succinic and phtalic anhydrides with N-substituted Z-oxazolidinones give in the presence of a few mole per cent of LiCl polyesteramides of molecular weights up to 3500 with high yields. lo The polymer yield corresponds to the CO2 evolution indicating an equal consumption of oxazolidinone and anhydrfde.l' 2-Oxazolidfnones may be regarded as ethylenefmfne derivatives due to their tendency to split off COP' Succfnic anhydride reacts similarly with ethyleneimine giving polyamide product In acetone at 0 OC l1 . However, as shown here, 2-oxazolidinone itself reacts with succinic anhydride in a different way. The reaction was conducted under optimum conditions for polyesteramide formation given by Burckhardt et &lo 2-Oxazolfdinone and succfnfc anhydride were heated with I mol.-% of LiCl at 210 'C in an oil thermostat while nitrogen gas was conducted through the smelt to remove CO2 liberated.12 The evolution of CO2 was followed by conducting the gases to a NaOH solution. Application of the method of Burckhardt et al, for the isolation of the expected polyesteramide (2) gave, however. no precipitate. Therefore, the following procedure was adapted: The cold reaction mixture, which was dark and viscous, was first treated with methanol (about 13 X remained unsoluble). After removal of the solvent the residue was further extracted with acetone (about 7 % remained unsoluble). Fractionation of the acetone extract gave a white product at 174-176 'C / 5 mn Hg with 80 X yield (mp. 59-60 'C after recrystallization from methanol). A molecular weight of 143 was obtained both osmometrically (benzene as a solvent) and ebulliometrfcally from methanol, HC-NH 2J \ W c=o -(NH -CH~ -CH~ -0 -co -CH~ -CH~ -co),c \o/ (2) In the acidic hydrolysis of this product (with 8-H HCl) succinic acid and ~noethanolamine hydrochloride (mp. 81-82 'C) were fsolated.13 Ethanolamine was liberated from the salt with alkali *Crystal structure