Cesium carbonate → tert-Butyl 3-[3,5-dichlorophenyl)-1-[4-(methoxycarbonyl)benzyl]-1H-pyrazole-5-carboxylate

Participants

Reaction Steps

To a solution of the product from step D (6.8 g, 21.7 mmol) in 50 mL of N,N-dimethylformamide was added cesium carbonate (10.6 g, 32.6 mmol) and the resultant mixture stirred at ambient temperature for 15 min. Methyl 4-(bromo-methyl)benzoate (5.46 g, 23.9 mmol) was added and stirring continued for 3 h. The reaction mixture was diluted with ethyl acetate and the organic layer washed successively with six portions of water and one portion of brine then dried over magnesium sulfate and concentrated in vacuo. The residue was purified by flash column chromatography (SiO2, 5% ethyl acetate/hexanes) to give the title compound as a light tan solid. 1H NMR (500 MHz, CDCl3) δ; 8.03 (d, J=8.4 Hz, 2H); 7.75 (d, J=1.8 Hz, 2H); 7.35 (m, 3H); 7.12 (s, 1H); 5.88 (s, 2H); 3.94 (s, 3H); 1.57 (s, 9H).

Provenance & Evidence