Reacción #422698

Ecuación de reacción

Trifluoroacetic acid anhydride

3-Methoxycarbonyloxy-5-methylsulfanyl-isothiazole-4-carboxylic acid methyl ester

urea hydrogen peroxide

sodium hydrogen sulfite

→

5-Methanesulfonyl-3-methoxycarbonyloxy-isothiazole-4-carboxylic acid methyl ester

Disolventes

water

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added
2. 2
   workup.STIRRINGstirred at 25° C
3. 3
   OtroMost of the acetonitrile was removed under vacuum
4. 4
   Extracciónthe aqueous residue was extracted once with 100 mL and once again with 50 mL dichloromethane

Procedimiento

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.

Fuente