Ethyl 2-amino-2-methylpropanoate hydrochloride → 3-(1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-5,5-dimethylimidazolidine-2,4-dione

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

1-((3,5-dimethylisoxazol-4-yl) methyl)-1H-pyrazole-4-carbonyl azide (Example 10-1a) (10 g, 41.0 mmol) is stirred under nitrogen in dry toluene (150 mL) along with molecular sieves at reflux until no emission of nitrogen was observed, which indicates complete conversion of 1-((3,5-dimethylisoxazol-4-yl) methyl)-1H-pyrazole-4-carbonyl azide into 4-((4-isocyanato-1H-pyrazol-1-yl)methyl)-3,5-dimethylisoxazole. The solution was cooled down to 50° C. and ethyl 2-amino-2-methylpropanoate hydrochloride (5.30 g, 41.0 mmol) was added in one portion. Stirring continued for 3 hours at 50° C. followed by reflux for 12 hours. The mixture was filtered over a pad of celite. The filtrate was concentrated on the rotovap and the residue was purified over silica gel using 25% ethyl acetate in hexanes. Yield 65% (8.00 g), white solid. 1H NMR (DMSO-d6, 400 MHz): □s, 6H), 2.15 (s, 3H), 2.41 (s, 3H), 5.18 (s, 2H), 7.78 (d, J=0.4 Hz, 1H), 8.16 (d, J=0.4 Hz, 1H), 8.59 (br s, 1H). MS 304 (MH+). This compound was shown to inhibit hT2R08 bitter receptor and had an IC50 of 2.27 μM.

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