Methyl iodide → ethyl 5-methoxy-1H-pyrazole-3-carboxylate

5-Hydroxy-1H-pyrazole-3-carboxylic acid ethyl ester (300 mg, 1.92 mmol) was dissolved in anhydrous N,N-dimethylformamide (DMF) (35 ml) and cesium carbonate (626 mg, 1.92 mmol) was added. The resulting suspension was treated with iodomethane (120 μl, 273 mg, 1.92 mmol) and stirred for 12 h at room temperature. The reaction mixture was quenched with saturated potassium hydrogen sulfate solution and extracted with ethyl acetate (3×100 ml). The combined organic layers were washed with water (50 ml) and brine (50 ml). The extract was dried over sodium sulfate, evaporated and the crude product was purified by column chromatography on silica gel. Elution with ethyl acetate/n-heptane (1:3) yielded 124 mg (38%) of a white solid.

1. customThe reaction mixture was quenched with saturated potassium hydrogen sulfate solution
2. extractionextracted with ethyl acetate (3×100 ml)
3. washThe combined organic layers were washed with water (50 ml) and brine (50 ml)
4. dry with materialThe extract was dried over sodium sulfate
5. customevaporated
6. customthe crude product was purified by column chromatography on silica gel
7. washElution with ethyl acetate/n-heptane (1:3)

ORD record

ord-c81f16c948c749b3a200bd8f09761682

Source dataset

uspto-grants-2007_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07285569B2