1-(2-Methoxyethyl)-1H-pyrazole-4-carboxylic acid synthesis

Yield:874196-94-8 600 mg

Reaction Conditions:

with water;lithium hydroxide in tetrahydrofuran at 20; for 3 h;

Steps:

1.b b. I -(2-methoxyethyl)-I H-pyrazole-4-carboxyl ic acid

To a solution of ethyl 1-(2-methoxyethyl)-1 H-pyrazole-4-carboxylate (1.50 g, crude) in tetrahydrofuran (10 ml) was added aq. LiOH (20 ml, 32 mmol, 1.6 M) at room temperature. The resulting mixture was stirred for 3 h at room temperature. When the reaction was done, it was quenched with H20 (10 ml). The resulting mixture wasextracted with dichloromethane (100 ml x 3) and the organic phases were combined, washed with brine and dried over anhydrous Na2SO4. The solvent was removed under reduced pressure and the residue was purified by flash chromatography eluting with MeOH in DCM (0% to 70% gradient) to yield 1-(2- methoxyethyl)-1 H-pyrazole-4-carboxylic acid as a white solid (600 mg, 52% for 2 steps). MS: m/z= 171.2 [M+H].

References:

WO2019/25099,2019,A1 Location in patent:Page/Page column 141; 142