反应详情

A stirred mixture of ethyl 2-(3-amino-4-hydroxyphenyl)propionate (8.4 g.), potassium ethylxanthate (6.33 g.), ethanol (38 ml.) and water (6.5 ml.) was heated under reflux for 4 hours. The solution was evaporated to half volume and diluted with water (65 ml.). The mixture was acidified with 2N-hydrochloric acid and extracted several times with ether. The ethereal solution was washed with water, then dried with anhydrous sodium sulphate, and evaporated to give ethyl 2-(2-thioxo-2,3-dihydrobenzoxazol-5-yl)propionate as an oil. Dry chlorine was passed into a solution of the thione (9 g.) in freshly dried and distilled chloroform (150 ml.) with stirring for 4 hours. The solution was then washed with water, N-sodium hydroxide solution, then water (3x). The dried (Na2SO4) organic solution was evaporated to yield ethyl 2-(2-chloro-5-benzoxazolyl)propionate as a brown oil which was shown to be a single compound by thin layer chromatography.

1. temperaturewas heated
2. temperatureunder reflux for 4 hours
3. customThe solution was evaporated to half volume
4. additiondiluted with water (65 ml.)
5. extractionextracted several times with ether
6. washThe ethereal solution was washed with water
7. dry with materialdried with anhydrous sodium sulphate
8. customevaporated