69907-67-1

953817-12-4

69907-67-1

Step B: Maleamic acid (36.8 g, 144 mmol) and sodium acetate (13.6 g, 165 mmol) prepared in Step A were dissolved in acetic anhydride (368 mL), and the mixture was transferred to a sealed glass reaction vessel and heated to react for 3 hours at 120 °C. Upon completion of the reaction, the cooled black slurry reaction mixture was slowly poured into water (3 L), stirred thoroughly and extracted with dichloromethane. The organic layers were combined, dried with anhydrous sodium sulfate, filtered through a sintered glass funnel, and the filtrate was evaporated to dryness and dried under high vacuum to afford the target product trans-4-(maleimidomethyl)cyclohexanecarboxylic acid as a yellow solid (7.00 g, 20% yield). The product was characterized by 1H NMR (300 MHz, CDCl3): δ 6.73 (s, 2H), 3.40 (d, 2H, J = 7 Hz), 2.28 (m, 1H), 2.06 (m, 2H), 1.75 (m, 3H), 1.42 (m, 2H), 1.03 (m, 2H).