Ethyl Acetate → Trifluoro-methanesulfonic acid 6-methyl-8-nitro-5-oxo-2,3-dihydro-5H-oxazolo[3,2-a]pyridin-7-yl ester

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Reaction Steps

Triflic anhydride (2.78 g, 9.9 mmol) was added dropwise to a stirred solution of 7-hydroxy-6-methyl-8-nitro-2,3-dihydro-oxazolo[3,2-a]pyridin-5-one (1.5 g, 7.0 mmol) and TEA (1.42 g, 14.060 mmol) in DCM (30 mL) at −78° C. over a period of 1 hour. The resulting mixture was stirred at room temperature for 5 hours. The reaction mixture was monitored by TLC (50% ethylacetate in hexane). The reaction mixture was partitioned between DCM and water. The organic layer was washed with water, brine solution, dried over Na2SO4 and concentrated. Purification by column chromatography on silica gel (50% ethylacetate in hexane) afforded 0.5 g of the product (20.6% yield).

Provenance & Evidence