反应详情

1.5 ml of concentrated hydrochloric acid were carefully added to a solution of 2.33 g of O-(5-fluorobenzothiazol-2-ylmethyl)-4-nitrophenol [prepared as described in step (a) above] in 47 ml of ethanol with stirring at room temperature and then 3.63 g of stannous chloride were added in small portions to the resulting mixture. The reaction mixture was then stirred at room temperature for 30 minutes, at the end of which time 3 ml of concentrated hydrochloric acid were added and the mixture was stirred for a further 1.5 hours at room temperature. The reaction mixture was then heated to 50° C. and stirred at this temperature for 4 hours. The reaction mixture was then cooled in an ice-water bath and 10% aqueous sodium hydroxide solution was added to said solution to adjust the pH to 10. The resulting mixture was then extracted with ethyl acetate and the resulting extract was washed consecutively with water and a saturated aqueous sodium chloride solution and then dried over anhydrous sodium sulfate. The solvent was then removed under reduced pressure and the resulting residue was recrystallized from a mixed solvent of methylene chloride and hexane to give 1.54 g (yield 73%) of the title compound as a solid having a melting point of 125° to 128° C.

1. additionwere added
2. stirringthe mixture was stirred for a further 1.5 hours at room temperature
3. temperatureThe reaction mixture was then heated to 50° C.
4. stirringstirred at this temperature for 4 hours
5. temperatureThe reaction mixture was then cooled in an ice-water bath
6. extractionThe resulting mixture was then extracted with ethyl acetate
7. extractionthe resulting extract
8. washwas washed consecutively with water
9. dry with materiala saturated aqueous sodium chloride solution and then dried over anhydrous sodium sulfate
10. customThe solvent was then removed under reduced pressure
11. customthe resulting residue was recrystallized from a mixed solvent of methylene chloride and hexane