反应详情

450 g of Sodium nitrite in 600 ml of water are added dropwise, at 0° over 3 hrs. to a solution of 1000 ml acetoacetic acid benzylester (benzylacetate) in 1000 ml of glacial acetic acid and the mixture stirred for 18 hrs. at room temperature. After the addition of 3000 ml of water the mixture is extracted three times with 1500 ml portions of dichloromethane. The combined extracts are washed twice with 500 ml portions of water. Potassium carbonate is added with thorough stirring until the aqueous phase is neutral. The organic phase is separated, dried with magnesium sulphate and the solvent removed in vacuum. The residue is taken up in 5000 ml of di-isopropyl ether, the insoluble material filtered off and the solution again evaporated to dryness. Trituration with petroleum ether and filtration yields the title product

1. customat room temperature
2. extractionis extracted three times with 1500 ml portions of dichloromethane
3. washThe combined extracts are washed twice with 500 ml portions of water
4. additionPotassium carbonate is added
5. customThe organic phase is separated
6. dry with materialdried with magnesium sulphate
7. customthe solvent removed in vacuum
8. filtrationthe insoluble material filtered off
9. customthe solution again evaporated to dryness
10. filtrationTrituration with petroleum ether and filtration