Acetic Anhydride → (2R,3R,4S)-6-acetylamino-3,4-dihydro-3-hydroxy-2-dimethoxymethyl-2-methyl-4-(2-thioxobenzoxazol-3-yl)-2H-1-benzopyran

Participants

Reaction Steps

100 mg (0.25 mmol) of the compound obtained in Example 17 was dissolved in 2 ml of dichloromethane, to which 23 μl (0.25 mmol) of acetic anhydride, 52 μl (0.37 mmol) of triethylamine and 9.1 mg (0.07 mmol) of 4-dimethylaminopyridine were added in that order. The reaction was stirred for 3 hours at room temperature, 10 ml of saturated NaHCO3 solution was added and extraction was performed with 40 ml of dichloromethane. The extract was washed with brine and dried over anhydrous MgSO4, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=2:1), to give 96 mg (yield: 86%) of the target compound.

Provenance & Evidence