反应详情

A mixture of 3-nitrobenzaldehyde (18.67 g), 2,3-butanedione-2-oxime (12.50 g) and 4N hydrogenchloride-ethyl acetate (400 mL) was stirred at room temperature for 16 hrs. The reaction mixture was concentrated. A mixture of the residue, tetrahydrofuran (400 mL) and thionyl chloride (13.6 mL) was heated under reflux for 2 hrs. The reaction mixture was concentrated and ethyl acetate was added to the residue. The ethyl acetate layer was washed successively with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous magnesium sulfate and concentrated. The residue was subjected to silica gel column chromatography and the crude product obtained from a fraction eluted with ethyl acetate-hexane (1:4-1:3, v/v) was washed with diethyl ether-hexane to give 4-chloromethyl-5-methyl-2-(3-nitrophenyl)-1,3-oxazole as colorless crystals (2.67 g, yield 8.6%). Recrystallization from ethyl acetate-hexane gave colorless prism crystals. melting point: 111-113° C.

1. concentrationThe reaction mixture was concentrated
2. additionA mixture of the residue, tetrahydrofuran (400 mL) and thionyl chloride (13.6 mL)
3. temperaturewas heated
4. temperatureunder reflux for 2 hrs
5. concentrationThe reaction mixture was concentrated
6. additionethyl acetate was added to the residue
7. washThe ethyl acetate layer was washed successively with saturated aqueous sodium hydrogen carbonate solution and saturated brine
8. dry with materialdried over anhydrous magnesium sulfate
9. concentrationconcentrated
10. customthe crude product obtained from a fraction
11. washeluted with ethyl acetate-hexane (1:4-1:3
12. washv/v) was washed with diethyl ether-hexane