To a mixture of 2-(5-oxo-2-thioxoimidazolidin-1-yl)-3-phenylpropanoic acid (0.053 g, 0.199 mmol) and 5-(4-bromophenyl)thiophene-2-carbaldehyde (0.050 g, 0.199 mmol) in acetic acid 5 mL is added β-alanine (1.8 mg, 0.020 mmol) and heat to 170° C. for 30 min under microwave irradiation. The resulting reaction mixture is cooled down and the solvent is removed. The pure product (0.060 g, 0.120 mmol, red solid) is obtained by column chromatography using MeOH/DCM, 2-7% ration solvent system. 1H-NMR (CD3OD/300 MHz): 7.83 (dm, J=9.0 Hz, 2H), 7.44 (dm, J=9.3 Hz, 2H), 7.17 (m, 5H), 7.03 (s, 2H), 6.47 (s, 1H), 5.64 (d, J=8.7 Hz, 1H), 3.69 (m, 1H), 3.49 (m, 1H). MS (ES−, m/z): 495.2 (M−, 80.0).
