Dichloromethane ethylacetate → HCID 59579884, compound

Participants

Reaction Steps

A solution of sodium nitrite (1.0 g, 15.1 mmol) in 5.0 mL of water is added dropwise to a solution of ethyl 3-amino-1-pyrimidin-2-yl-1H-pyrazole-4-carboxylate (2.7 g, 11.6 mmol) in 18 mL of conc. HCl at −5° C. with stirring. After 1 h at 0° C., the reaction mixture is added dropwise to a suspension of copper (I) chloride (1.8 g, 18.6 mmol) in 18 mL of CHCl3 at RT. After 1 h at RT, water (40 mL) and CHCl3 (40 mL) are added, and the layers are separated. The organic layer is washed once more with water (40 mL), dried (Na2SO4), filtered, and evaporated in vacuo to give a greenish/yellow solid. TLC analysis (70% EtOAc/CH2Cl2) of this crude solid reveals 2 products, which are separated by column chromatography (10% EtOAc/CH2Cl2) to afford ethyl 3-chloro-1-pyrimidin-2-yl-1H-pyrazole-4-carboxylate (Rf≈0.7) as a white solid. The minor, more polar compound ethyl 5-chloro-1-pyrimidin-2-yl-1H-pyrazole-4-carboxylate, Rf≈0.5) is also isolated as a white solid.

Provenance & Evidence