Synthesis of 4-Aminobutanoic Acid Maleimide

Example 56

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To a solution of maleic anhydride (268 g, 2.73 mol) in acetic acid (1 L) was added 4-aminobutanoic acid (285 g, 2.76 mol). After stirring at r.t. for 30 min, the reaction was refluxed for 1.5 h, cooled to r.t. and evaporated under vacuum to give a residue, which was taken up in EA, washed with water and brine, and dried over anhydrous Na₂SO₄, filtered and concentrated. The crude product was crystallized from EtOAc and PE to give a white solid (400 g, 80% yield). ¹H NMR (500 MHz, CDCl₃) δ 6.71 (s, 2H), 3.60 (t, J=6.7 Hz, 2H), 2.38 (t, J=7.3 Hz, 2H), 2.00-1.84 (m, 2H).