Hydrochloric Acid → HCID 178481857, compound

8.3 g (180.6 mmoles) of methylhydrazine and 5 ml of concentrated hydrochloric acid were added to a solution of 30.0 g (180.6 mmoles) of ethyl difluoroacetoacetate dissolved in 200 ml of ethanol. The mixture was refluxed for 2 days with heating, to give rise to a reaction. After the completion of the reaction, the reaction mixture was subjected to vacuum distillation to remove the most part of the solvent contained therein. The residue was poured into water. The mixture was allowed to have a pH of 4 using citric acid and extracted with ethyl acetate. The resulting organic layer was washed with water and an aqueous sodium chloride solution in this order and then dried over anhydrous magnesium sulfate. The resulting solution was subjected to vacuum distillation to remove the solvent contained therein. The residue was purified by silica gel column chromatography (developing solvent: hexane-ethyl acetate mixed solvent) to obtain 8.9 g (yield: 33.3) of 3-difluoromethyl-1-methyl-1H-pyrazol-5-ol.

1. temperatureThe mixture was refluxed for 2 days
2. temperaturewith heating
3. customto give rise
4. customto a reaction
5. customAfter the completion of the reaction
6. distillationthe reaction mixture was subjected to vacuum distillation
7. customto remove the most part of the solvent
8. additionThe residue was poured into water
9. extractionextracted with ethyl acetate
10. washThe resulting organic layer was washed with water
11. dry with materialan aqueous sodium chloride solution in this order and then dried over anhydrous magnesium sulfate
12. distillationThe resulting solution was subjected to vacuum distillation
13. customto remove the solvent
14. customThe residue was purified by silica gel column chromatography (developing solvent: hexane-ethyl acetate mixed solvent)

ORD record

ord-ff90e331f451457ca7e6e96788e4f924

Source dataset

uspto-grants-2007_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07238689B2