反应详情

A mixture of crude 2-ethoxymethylene-1-(2-nitro-4-trifluoromethylphenyl)butan-1,3-dione (13.25 g) and hydroxylamine hydrochloride (3.7 g) in ethanol (80 ml) was stirred for 5 hours. The solution was evaporated almost to dryness and the resultant solution was diluted with ethyl acetate (100 ml). The solution was washed with water (3×40 ml), dried (anhydrous sodium sulphate) and filtered. The filtrate was evaporated to dryness. The residue was triturated with a mixture of ether and petroleum spirit (bp 60°-80° C.) (1:1) and the resultant buff solid was filtered off. The solid was dissolved in dichloromethane (100 ml) and filtered through silica. The silica was washed with dichloromethane (100 ml) and the combined filtrates were evaporated to dryness to give 4-(2-nitro-4-trifluoromethylbenzoyl)-5-methylisoxazole (Compound 1, 4.5 g) as an off-white solid mp 85°-86° C.

1. customThe solution was evaporated almost to dryness
2. additionthe resultant solution was diluted with ethyl acetate (100 ml)
3. washThe solution was washed with water (3×40 ml)
4. dry with materialdried (anhydrous sodium sulphate)
5. filtrationfiltered
6. customThe filtrate was evaporated to dryness
7. customThe residue was triturated with a mixture of ether and petroleum spirit (bp 60°-80° C.) (1:1)
8. filtrationthe resultant buff solid was filtered off
9. dissolutionThe solid was dissolved in dichloromethane (100 ml)
10. filtrationfiltered through silica
11. washThe silica was washed with dichloromethane (100 ml)
12. customthe combined filtrates were evaporated to dryness