反应详情

温度

130 °C

Methyl 2-[2-(5-bromo-1-methyl-1H-pyrazol-4-yl)-2-oxoethyl]-2-formylhydrazine carboxylate (1.20 g, 3.76 mmol) was mixed with ammonium acetate (1.16 g, 15.0 mmol), formamide (4 mL) and acetonitrile (5 mL). The reaction was heated to 130° C., and the acetonitrile was allowed to boil off for 10 minutes. Heating was continued for an additional 4 hours. After addition of water, the crude mixture was extracted eight times with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo; purification via silica gel chromatography (Gradient: 0% to 100% [10% methanol in ethyl acetate] in heptane) afforded the product as a pinkish solid. Yield: 800 mg, 2.67 mmol, 19% over two steps. LCMS m/z 299.8 (M+1). 1H NMR (400 MHz, CD3OD) δ 3.80 (br s, 3H), 3.90 (s, 3H), 7.52 (d, J=1.3 Hz, 1H), 7.77 (d, J=1.3 Hz, 1H), 7.85 (s, 1H).

1. temperatureHeating
2. waitwas continued for an additional 4 hours
3. extractionthe crude mixture was extracted eight times with ethyl acetate
4. dry with materialThe combined organic layers were dried over sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. custompurification via silica gel chromatography (Gradient: 0% to 100% [10% methanol in ethyl acetate] in heptane)