Cesium carbonate → Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid [2-bromo-4-(5-chloro-2-difluoromethoxy-phenyl)-thiazol-5-yl]-amide

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Reaction Steps

To a solution of pyrazolo[1,5-a]pyrimidine-3-carboxylic acid [2-bromo-4-(5-chloro-2-hydroxy-phenyl)-thiazol-5-yl]-amide (1.1 g, 2.4 mmol) in DMF (20 mL) and water (2 mL) was added cesium carbonate (1.1 g, 3.4 mmol) and then sodium chlorodifluoroacetate (839 mg, 5.5 mmol). The mixture was stirred at 100° C. for 16 hours before further cesium carbonate (2.2 g, 6.8 mmol) and sodium chlorodifluoroacetate (1.7 g, 11 mmol) was added and stirring continued at 100° C. for 6 hours. The mixture was allowed to cool to room temperature and partitioned between ethyl acetate and water and the phases separated. The organic layer was washed with brine. The combined aqueous layer was extracted with ethyl acetate once and the combined organic layer dried (Na2SO4), filtered and evaporated. The resultant residue was purified by flash chromatography on silica eluting with 50% ethyl acetate in cyclohexane to give the title compound as a yellow solid (710 mg, 59%). LCMS (Method 3) [M+H]+=500.1, RT=3.97 min. 1H NMR (400 MHz, DMSO-d6) δ: 10.84 (s, 1H), 9.42 (dd, 1H, J=1.6, 6.9 Hz), 8.79 (s, 1H), 8.66 (dd, 1H, J=1.6, 4.3 Hz), 7.76 (d, 1H, J=2.8 Hz), 7.51 (d, 1H, J=8.8 Hz), 7.36 (dd, 1H, J=4.2, 7.0 Hz), 7.22 (t, 1H, J=73.1 Hz).

Provenance & Evidence