Trifluoroacetic acid → (R)-5-(5-bromo-2-fluoro-phenyl)-2,2,5-trimethyl-1,1-dioxo-1lambda6-thiomorpholin-3-one

Participants

Reaction Conditions

Reaction Steps

A mixture of (R)-5-(5-bromo-2-fluoro-phenyl)-5-methyl-1,1-dioxo-1λ6-thio morpholin-3-one (2.1 g, 4.08 mmol, Eq: 1.00) and trifluoroacetic acid (46.5 g, 31.5 ml, 408 mmol, Eq: 100) was stirred at 23° C. After 1 hour trifluoromethanesulfonic acid (1.23 g, 725 μl, 8.16 mmol, Eq: 2.0) was added and stirring continued for 2 hours. Poured into 1 M Na2CO3-sol. and extracted twice with ethyl acetate. The combined organic layers were dried over Na2SO4, filtered and evaporated. The residue was chromatographed on 70 g silica gel with heptane/ethyl acetate 1:1 to give (R)-5-(5-bromo-2-fluoro-phenyl)-2,2,5-trimethyl-1,1-dioxo-1λ6-thio morpholin-3-one (1.4 g, 3.84 mmol, 94.2% yield) as an off-white solid. MS (ISP): m/z=364.0 [M+H]+ and 366.3 [M+2+H]+.

Provenance & Evidence