Thionyl Chloride → 2,5-Dichlorobenzooxazole

Participants

Reaction Conditions

Reaction Steps

Subsequently, 5-chloro-2-mercaptobenzoxazole (3.1 g, 16.7 mmol) was dissolved in thionyl chloride (30 mL, 413 mmol). DMF (1.5 mL) was added and the reaction mixture was heated at 65° C. for 45 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 the excess SOCl2 (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 2,5-dichlorobenzoxazole, compound 19, as a red oil (3.2 g).

Provenance & Evidence