反应详情

To a solution of 4-chloro-2-formylphenylboronic acid (200 mg, 1.09 mmol) in DMF (10 mL) are added pyrazole (88 mg, 1.3 mmol), Cu(OAc)2 (295 mg, 1.6 mmol), pyridine (171 mg, 2.2 mmol) and molecular sieve (200 mg) at room temperature. The mixture is stirred for 48 hours with open cap. The mixture is filtered through a short pad of diatomaceous earth (2 g) rinsing with MeOH (10 mL). The combined filtrate is extracted with H2O (15 mL) and EtOAc (3×10 mL). The combined organic layer is dried with MgSO4 and filtered. The filtrate is concentrated and the residue is purified by silica gel flash column chromatography eluting with 10% EtOAc in heptane to afford 5-chloro-2-pyrazol-1-yl-benzaldehyde (50 mg, 22%) as a white solid.

1. filtrationThe mixture is filtered through a short pad of diatomaceous earth (2 g)
2. washrinsing with MeOH (10 mL)
3. extractionThe combined filtrate is extracted with H2O (15 mL) and EtOAc (3×10 mL)
4. dry with materialThe combined organic layer is dried with MgSO4
5. filtrationfiltered
6. concentrationThe filtrate is concentrated
7. customthe residue is purified by silica gel flash column chromatography
8. washeluting with 10% EtOAc in heptane