A mixture of 1-(4-bromophenyl)-3,3-dimethoxycyclobutanamine (0.66 g, 2.306 mmol), ethyl 1,3-dioxoisoindoline-2-carboxylate (0.56 g, 2.55 mmol) and triethylamine (1.3 ml, 9.33 mmol) in CHCl3 (15 ml) was heated at 70° C. for 16 h. The reaction mixture was concentrated to as dry as possible. Methanol (˜5 ml) was added. The solution was concentrated to dryness. Methanol (˜5 ml) was added again and the resulted solid was collected by filtration to afford product as a white solid (0.39 g). 1H NMR (500 MHz, CDCl3): 7.70 (dd, 2H), 7.60 (dd, 2H), 7.44 (dd, 2H), 7.37 (dd, 2H), 3.18 (m, 4H), 3.10 (s, 3H), 3.02 (s, 3H).
