Water → 3-[7-fluoro-4-propargyl-2H-1,4-benzoxazin-3(4H)-on-6-yl]-5-isopropylidene-1,3-oxazolidin-2,4-dione

Participants

Reaction Steps

To a solution of 7-fluoro-6-(1-methoxycarbonyl-2-methyl-2-propenyloxycarbonylamino)-4-propargyl-2H-1,4-benzoxazin-3(4H)-one (10 g) in toluene (100 g), sodium methoxide was added in an amount of 0.05 equivalent to one equivalent of the benzoxazine. The resulting mixture was refluxed for 3 hours, cooled to room temperature, combined with water and extracted with ethyl acetate. The organic layer was washed with water three times, dried over magnesium sulfate and concentrated. The residue was purified by silica gel column chromatography using a mixture of hexane and ethyl acetate as the eluent to give Compound No. 9 (6.1 g). m.p., 194°-198° C.

Provenance & Evidence