反应详情

Subsequently, the 5-methyl-2-mercaptobenzoxazole (6.2 g, 38 mmol) was dissolved in thionyl chloride (36.9 mL) and 2.79 mL of DMF was added. The reaction mixture was then stirred at r.t. for 30 min. The solvent was removed under reduced pressure and to the residue was added toluene (2×60 mL) followed by evaporation each time to remove excess SOCl2 via an azetrope. The resultant crude product was dissolved in ethyl acetate (100 mL), washed with water (100 mL) and dried over Na2SO4. Evaporation of ethyl acetate gave crude 22 which was purified by silica-gel column chromatography (eluent: petroleum ether) to provide pure 2-chloro-5-methylbenzoxazole, compound 22, (3.5 g, 58%).

1. customThe solvent was removed under reduced pressure and to the residue
2. additionwas added toluene (2×60 mL)
3. customfollowed by evaporation each time
4. customto remove excess SOCl2 via an azetrope
5. dissolutionThe resultant crude product was dissolved in ethyl acetate (100 mL)
6. washwashed with water (100 mL)
7. dry with materialdried over Na2SO4
8. customEvaporation of ethyl acetate
9. customgave crude 22 which
10. customwas purified by silica-gel column chromatography (eluent: petroleum ether)