Study of the N-methylcarbamylsuccinamic Acid Synthesis

A successful condensation of maleic anhydride with urea or monosubstituted ureas has been reported in literature [1]. The reactions took place in two steps obtaining first maleuric acids which cyclize to N-carbamylmaleimides (scheme 1). The reactions were performed in glacial acetic acid at 50-60°C in 12 h to obtain the maleuric acids, while the cyclization is accomplished by heating to 90-95°C in acetic anhydride.