反应详情

A mixture of 2-(2-chlorostyryl)-5-methyl-4-oxazolecarboxylic acid (4.8 g) and thionyl chloride (24 ml) was refluxed with stirring for an hour. The thionyl chloride was distilled off and the crystalline residue (acid chloride) was washed with isopropyl ether and dissolved in dimethoxyethane (20 ml). The solution was added dropwise to a suspension of sodium borohydride (1.4 g) in dimethoxyethane (30 ml) with ice-cooling and stirring. The reaction was allowed to proceed under ice-cooling for 30 minutes and the reaction mixture was adjusted to pH 2 with 2N hydrochloric acid and refluxed for 30 minutes. The solvent was then distilled off and the residue was neutralized with aqueous sodium hydrogen carbonate and extracted with ethyl acetate. The ethyl acetate layer was washed with water and dried over anhydrous magnesium sulfate. The solvent was distilled off and the resulting crystalline precipitate was collected by filtration and washed with isopropyl ether to give 2-(2-chlorostyryl)-4-hydroxymethyl-5-methyloxazole; yield 3.9 g (85.9%). Recrystallization from ethanol gave colorless needles melting at 122°-123° C.

1. temperaturewas refluxed
2. distillationThe thionyl chloride was distilled off
3. washthe crystalline residue (acid chloride) was washed with isopropyl ether
4. dissolutiondissolved in dimethoxyethane (20 ml)
5. additionThe solution was added dropwise to a suspension of sodium borohydride (1.4 g) in dimethoxyethane (30 ml) with ice-
6. temperaturecooling
7. stirringstirring
8. temperaturecooling for 30 minutes
9. temperaturerefluxed for 30 minutes
10. distillationThe solvent was then distilled off
11. extractionextracted with ethyl acetate
12. washThe ethyl acetate layer was washed with water
13. dry with materialdried over anhydrous magnesium sulfate
14. distillationThe solvent was distilled off
15. filtrationthe resulting crystalline precipitate was collected by filtration
16. washwashed with isopropyl ether