反应详情

A mixture of 3-(5-methyl-2-phenyl-4-oxazolyl)propionitrile (8.20 g), hydroxylammonium chloride (4.02 g), potassium carbonate (4.01 g) and 70% ethanol (100 mL) was heated under reflux for 24 hrs. The reaction mixture was concentrated and water was added to the residue. The obtained crystals were collected by filtration and washed with isopropyl ether. To a mixture of the obtained crystal, potassium carbonate (2.13 g) and acetone (50 mL) was added chloroacetyl chloride (3.48 g) under ice-cooling. The reaction mixture was stirred at room temperature for 15 hrs. Water was added to the reaction mixture, and the precipitated crystals were collected by filtration and washed with isopropyl ether. A mixture of the obtained crystals and xylene (150 mL) was subjected to azeotropic dehydration for 4 hrs. The reaction mixture was concentrated, and ethyl acetate was added to the residue. The organic layer was washed successively with water and saturated brine, dried over anhydrous magnesium sulfate, and concentrated. The obtained residue was subjected to silica gel column chromatography to give crystals (2.56 g, 23%) of 5-chloromethyl-3-[2-(5-methyl-2-phenyl-4-oxazolyl)ethyl]-1,2,4-oxadiazole from a fraction eluted with ethyl acetate-hexane (1:4, v/v). Recrystallization from ethyl acetate-hexane gave colorless prism crystals. melting point: 71-72° C.

1. temperaturewas heated
2. temperatureunder reflux for 24 hrs
3. concentrationThe reaction mixture was concentrated
4. additionwater was added to the residue
5. filtrationThe obtained crystals were collected by filtration
6. washwashed with isopropyl ether
7. additionTo a mixture of the obtained crystal, potassium carbonate (2.13 g) and acetone (50 mL)
8. additionwas added chloroacetyl chloride (3.48 g) under ice-
9. temperaturecooling
10. additionWater was added to the reaction mixture
11. filtrationthe precipitated crystals were collected by filtration
12. washwashed with isopropyl ether
13. additionA mixture of the obtained crystals and xylene (150 mL)
14. waitwas subjected to azeotropic dehydration for 4 hrs
15. concentrationThe reaction mixture was concentrated
16. additionethyl acetate was added to the residue
17. washThe organic layer was washed successively with water and saturated brine
18. dry with materialdried over anhydrous magnesium sulfate
19. concentrationconcentrated