ethyl N-ethoxycarbonyliminocarbamate → tert-butyl 3-((3-(1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-2,4-dioxoimidazolidin-1-yl)methyl)benzylcarbamate

Participants

Reaction Steps

3-(1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)imidazolidine-2,4-dione (example 10-1) (070 mg, 0.254 mmol), tert-butyl 3-(hydroxymethyl)benzylcarbamate (0.254 mmol, 60 mg), diethyl azodicarboxylate (0.50 mmol, 86 mg), and P-tBu3 (125 mL, 0.50 mmol) were stirred in THF (1 mL) for 4 hours. The reaction was diluted with ethyl acetate (1.5 mL) and washed with saturated sodium bicarbonate solution (2×, 1.5 mL). The organic phase was collected and the mixture was concentrated under a stream of nitrogen. The crude product was purified by column chromatography on silica gel using ethyl acetate as the eluent. The pure fractions were combined and the solvents were removed on the rotovap to afford tert-butyl 3-((3-(1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-2,4-dioxoimidazolidin-1-yl)methyl)benzylcarbamate as a white solid (112 mg, 90%). 1H NMR (CDCl3, 400 MHz): δ 1.44 (s, 9H), 2.19 (s, 3H), 2.42 (s, 3H), 3.48 (bs, 1H), 3.84 (s, 2H), 4.31-4.30 (d, J=6 Hz, 1H), 4.60 (s, 2H), 4.87 (bs, 1H), 5.06 (s, 2H), 7.36-7.16 (m, 4H), 7.92 (s, 1 H), 8.08 (s, 1H). The title compound was shown to inhibit hT2R08 bitter receptor and had an IC50 of 0.90 μM.

Provenance & Evidence