反应详情

At 10° to 20° C add 77 g of phosphorus oxychloride dropwise to 183 g of dimethylformamide. Stir for 30 minutes at room temperature and, at a temperature not exceeding 40° C, add thereto 55.7 g of 5-nitro-2-acetylfuran-phenylhydrazone. Stir under nitrogen for 1 hour at this temperature and then for 2.5 hours at 50° C. Pour the resulting solution (containing 4-pyrazolylmethylenedimethylammonium salt) onto 2.5 kg of ice and water. Heat for 2 hours at 40° C before vacuum filtering at 20° to 30° C. Wash the residue well with water to obtain a 98% yield of 3-(5-nitro-2-furyl)-1-phenylpyrazole-4-carboxaldehyde [m.p. 208° to 209° C (from dimethylformamide/water)].

1. customexceeding 40° C
2. additionadd
3. stirringStir under nitrogen for 1 hour at this temperature
4. waitfor 2.5 hours at 50° C
5. additionPour
6. temperatureHeat for 2 hours at 40° C before vacuum
7. filtrationfiltering at 20° to 30° C
8. washWash the residue well with water