Sodium hydride → 1-(2-methoxyethyl)-3,5-dimethyl-1H-pyrazole-4-carboxylic acid

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Reaction Steps

Sodium hydride (60%, 120 mg, 3.0 mmol) was suspended in THF (2 ml) at 0 C. Ethyl 3,5-dimethyl-1H-pyrazole-4-carboxylate (168 mg, 1.0 mmol) dissolved in THF (2 mL) was added drop-wise. Stirring was maintained until the evolution of hydrogen stopped. 1-Bromo-2-methoxyethane (208 mg, 1.5 mmol) was added and the reaction was heated at reflux at 70 C for 48 hours. Reaction was quenched with water at 0 C, acidified to pH=1-2 with HCl (2M) and was extracted with EtOAc. The organic layer was washed with water, NH4Cl aq., and brine, and dried with Na2SO4, and concentrated. The residue was subjected to HPLC purification. White solid (67 mg, 0.34 mmol, 34%) was obtained after stripping of solvents and drying. ESI-MS m/z 199.4 (M+H).

Provenance & Evidence