Trifluoroacetic anhydride → HCID 57552585, compound

Participants

Reaction Conditions

Reaction Steps

The 3-Methoxycarbonyloxy-5-methylsulfanyl-isothiazole-4-carboxylic acid methyl ester slurry was cooled to 0° C., and urea hydrogen peroxide addition compound (2.8 equiv, 12.8 g) was added. Trifluoroacetic acid anhydride (2.8 equiv, 19.2 mL, 28.4 g) was added dropwise over 20 minutes. The mixture stirred at 0° C. for 45 minutes, and quenched with sodium hydrogen sulfite (2.0 equiv, 10.0 g) in water (90 mL, 9 volumes) and stirred at 25° C. Most of the acetonitrile was removed under vacuum, then the aqueous residue was extracted once with 100 mL and once again with 50 mL dichloromethane to provide 5-Methanesulfonyl-3-methoxycarbonyloxy-isothiazole-4-carboxylic acid methyl ester.

Provenance & Evidence