Acetic Anhydride → ethyl 2-(5-acetamido-3-phenyl-1H-pyrazol-1-yl)acetate

Participants

Reaction Steps

To a solution of ethyl 2-(5-amino-3-phenyl-pyrazol-1-yl)acetate (49 g, 0.17 mol) in pyridine (200 mL) was added acetic anhydride (17.4 g, 0.17 mol) dropwise at 0° C. under an atmosphere of nitrogen. The reaction mixture was stirred at room temperature for 16 h. The reaction mixture was concentrated in vacuo. The residue was diluted with CH2Cl2 and water. The layers were separated and the organic layer was washed with water and brine, dried (MgSO4) and concentrated in vacuo. CH2Cl2 was added to the residue and the solid was collected by filtration, yielding the title compound as a solid (22 g). The mother liquors were concentrated in vacuo and washed with cold CH2Cl2 to yield a second batch of 15 g.

Provenance & Evidence