反应详情

To a solution of ethyl 3-methyl-1H-pyrazole-4-carbaldehyde (6.4 g, 58.0 mmol) in 60 mL of anhydrous N,N-dimethylformamide were added potassium carbonate (10.8 g, 77.8 mmol) and 2,4-dichloropyrimidine (8.64 g, 58.0 mmol) at room temperature. The resulting suspension was stirred for 14 hours at room temperature with monitoring a reaction with LC-MS or thin layer chromatography (TLC). The reaction mixture was diluted with ethyl acetate and washed with brine (×2). The collected organic layer was dried over anhydrous sodium sulfate and then concentrated in vacuo. The resulting residue was purified by silica gel chromatography using a mixture of heptanes and ethyl acetate to afford the desired intermediate 2 as a white solid (5.47 g, 42%); MS (ESI) m/z 223 [M+H]+, 1H NMR (300 MHz, CDCl3) δ 10.06 (s, 1H), 9.04 (s, 1H), 8.70 (d, 1H, J=5.4 Hz), 7.87 (1H, d, J=5.4 Hz), 2.59 (s, 3H).

1. customa reaction with LC-MS or thin layer chromatography (TLC)
2. washwashed with brine (×2)
3. dry with materialThe collected organic layer was dried over anhydrous sodium sulfate
4. concentrationconcentrated in vacuo
5. customThe resulting residue was purified by silica gel chromatography
6. additiona mixture of heptanes and ethyl acetate