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 recreates 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