N-((4aS*,5R*,7aS*)-7a-(2,4-Difluorophenyl)-5-methyl-4a,5,7,7a-tetrahydro-4H-furo[3,4-d][1,3]thiazin-2-yl)benzamide (95 mg, 0.24 mmol) was dissolved in TFA (218 μL, 2.93 mmol) and sulfuric acid (78.2 μl, 1.47 mmol). NBS (39 mg, 0.22 mmol) was added and the reaction was stirred at 60° C. for 1 hour. The reaction mixture was cooled to room temperature, neutralized with 2N NaOH and extracted with EtOAc (×3). The combined organics were dried and concentrated in vacuo. The residue was purified by column chromatography, eluting with 0-30% EtOAc in n-hexane to give the desired compound. (78 mg). 1H NMR (400 MHz, CDCl3) δ ppm: 8.05-8.10 (m, 2H), 7.52-7.62 (m, 2H), 7.44-7.51 (m, 2H), 6.95-7.04 (m, 1H), 4.46-4.53 (m, 2H), 3.95 (dd, J=2.45, 9.41 Hz, 1H), 3.17 (dd, J=3.42, 13.45 Hz, 1H), 2.77-2.83 (m, 1H), 2.70-2.77 (m, 1H), 1.37-1.46 (m, 3H).
