3-(1-(1-methylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-2,5-dioxoimidazolidin-4-yl)acetic acid (example 10-44) (100 mg, 0.3 mmol), aniline (33 mg, 0.36 mmol), Pybop (187 mg, 0.36 mmol) and triethyl amine (0.05 mL, 0.36 mmol) were mixed in DMF (1 mL). The reaction stirred at 65° C. for 4 hours. The reaction was allowed to cool to room temperature and then diluted with ethyl acetate (2 mL). The organic phase was washed with saturated sodium bicarbonate solution (2×, 2 mL) and then with saturated NaCl solution (1 ml). The organic phase was extracted, dried over anhydrous Na2SO4, and filtered. The crude product was re-suspended in MeOH (1 mL) and purified by reversed phase HPLC (5-95% acetonitrile in H2O; 16 minute gradient). The pure fractions were combined and solvent was removed on the rotovap to afford 2-(1-(1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-2,5-dioxoimidazolidin-4-yl)-N-phenylacetamide as a white solid (50%). 1H NMR (CDCl3, 400 MHz): δ 2.18 (s, 3H), 2.40 (s, 3H), 2.72 (m, 1H), 3.14-3.13 (d, 1H, J=4 Hz), 4.54-4.51 (d, J=8 Hz 1H), 5.04 (s, 2H), 6.53 (bs, 1H), 7.15-7.13 (m, 1H), 7.33-7.22 (m, 2H), 7.47-7.45 (d, J=8 Hz, 2H), 7.78 (bs, 1H), 7.09 (s, 1H), 8.05 (s, 1H). The title compound was shown to inhibit hT2R08 bitter receptor and had an IC50 of 0.75 μM.
