反应详情

A solution of 3-bromomethyl-5-chloro-1-methyl-4-nitropyrazole (5.0 g, 19.6 mmol) in methanol (50 ml) was treated with silver nitrate (5.75 g, 33.8 mmol) and the mixture heated under reflux for 2 hours. The cooled reaction mixture was filtered and the filtrate evaporated under vacuum. The residue was partitioned between ethyl acetate (100 ml) and water (50 ml) and the aqueous phase extracted with a further quantity of ethyl acetate (50 ml). The organic extracts were combined, dried (MgSO4) and evaporated under vacuum. Chromatography on silica gel, eluting with a 97:3 mixture of dichloromethane and methanol, gave the title pyrazole as a white solid (1.6 g, 40%), m.p. 59°-63° C. Found: C,34.65; H,3.83; N,20.05. C6H8ClN3O3 requires C,35.05; H,3.92; N,20.44%.

1. temperaturethe mixture heated
2. temperatureunder reflux for 2 hours
3. customThe cooled reaction mixture
4. filtrationwas filtered
5. customthe filtrate evaporated under vacuum
6. customThe residue was partitioned between ethyl acetate (100 ml) and water (50 ml)
7. extractionthe aqueous phase extracted with a further quantity of ethyl acetate (50 ml)
8. dry with materialdried (MgSO4)
9. customevaporated under vacuum
10. washChromatography on silica gel, eluting with a 97:3 mixture of dichloromethane and methanol