Sodium Pyrosulfite → Benzenesulfonamide

Participants

Reaction Steps

4-[2-Methylthio-4-phenyl-5-oxazolyl]benzenesulfonamide (Example 50) (0.5 g, 1.44 mmol), ethanol (100 mL), water (50 mL), and Oxone® (potassium peroxymonosulfate, 0.88 g, 1.44 mmol) were stirred at room temperature for 16.0 hours. Sodium metabisulfite (5 g) and water (50 mL) were added and the resulting mixture stirred for 0.25 hours before the addition of ethyl acetate (200 mL). The organic layer was separated and washed with brine and water, dried over MgSO4 and concentrated. The residue was purified by flash chromatography eluting with ethyl acetate:hexanes (1:3). The first material collected was concentrated and recrystallized to yield 4-[2 -methylsulfonyl)-4-phenyl-5-oxzolyk]benzenesulfonamide as a white solid (0.3 g, 55%): mp 186-188° C. 1H NMR (DMSO-d6) 300 MHz δ 7.92 (d, J=8.5 Hz, 2H) 7.81 (d, J=8.5 Hz, 2H) 7.6 (m, 2H) 7.48 (m, 5H) 3.3 (s, 3H). Anal. Calc'd. for C16H14N2O5S2 : C, 50.78; H, 3.73; N, 7.40. Found: C, 50.79; H, 3.72; N, 7.38. The second material collected was concentrated and recrystallized to yield 4-[2-methylsulfinyl)-4-phenyl-5-oxazolyl]benzenesulfonamide as a white solid (0.16 g, 31%): mp 174-176° C. 1H NMR (DMSO-d6) 300 MHz δ 7.9 (d, J=8.5 Hz, 2H) 7.8 (d, J=8.5 Hz, 2H) 7.6 (m, 2H) 7.48 (m, 5H) 3.2 (s, 3H). Anal. Calc'd. for C16H14N2O4S2 : C, 53.03; H, 3.89; N, 7.73. Found: C, 53.08; H, 3.85; N, 7.66.

Provenance & Evidence