反应详情

温度

30 °C

Add 3 ml of 65% nitric acid dropwise to 11 ml of acetic anhydride at room temperature. Then add 1 drop of concentrated sulfuric acid thereto before stirring for 30 minutes and then incorporating therein 1.5 g of 3-(2-furyl)-1H-pyrazole-4-carboxaldehyde. Stir the resulting admixture for 45 minutes at room temperature before adding 4.8 g of sodium acetate. Heat for 1 hour at 30° C and then for 2 hours at 40° C. Pour the thus-produced solution on ice, neutralize it with concentrated ammonia solution and extract the neutralized solution several times with chloroform. Concentrate by evaporation in vacuum and then chromatograph over a silica gel column with chloroform/ethanol (9:1) to obtain 3-(5-nitro-2-furyl)-1H-pyrazole-4-carboxaldehyde [m.p. 187° to 187.5° C].

1. stirringStir the resulting admixture for 45 minutes at room temperature
2. waitfor 2 hours at 40° C
3. additionPour the thus-produced solution on ice
4. extractionextract the neutralized solution several times with chloroform
5. concentrationConcentrate by evaporation in vacuum