Methanol → methyl 3-nitro-1H-pyrazole-5-carboxylate

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Reaction Steps

5-Nitro-3-pyrazol carboxylic acid (21.44 g, 136.5 mmol) is dissolved in dry methanol (200 mL). Then, thionyl chloride (9.9 mL, 136.5 mmol) is added slowly in a drop wise manner at RT. The reaction mixture is heated over night under reflux and under argon atmosphere. After cooling down, the solvent is evaporated under vacuum and the crude material is heated with boiling hexane (200 ml). After cooling down and removal of the hexane, the material is washed two times with 200 ml pentane. Then, the solvent is removed and the product is dried under vacuum to give 5-nitro-3-pyrazole-carboxylic acid methyl ester (22.35 g, 95.7%).

Provenance & Evidence