Dimethyl Sulfoxide → 3-[3-(5-Chloro-1,3-dimethylpyrazole-4-sulfonyloxy)-5-methylphenoxy]propionaldehyde

Participants

Reaction Steps

To 227 mg (0.660 mmol) of 3-[3-(5-chloro-1,3-dimethyl-pyrazole-4-sulfonyloxy)-5-methylphenoxy]propanol, as prepared in the preceding step, in dichloromethane (2 mL) containing 61 μL (0.79 mmol) of anhydrous dimethyl sulfoxide and 275 μL (1.58 mmol) of N,N-diisopropylethylamine was added 124 mg (0.78 mmol) of sulfur trioxide pyridine complex. The reaction mixture was stirred at ambient temperature for 60 min and then purified by flash chromatography (dichloromethane then 20% ethyl acetate/dichloromethane) to give 75 mg of the title compound as an unstable oil. TLC clearly showed 3-(5-chloro-1,3-dimethylpyrazole-4-sulfonyloxy)-5-methylphenol as the major byproduct. 1H-NMR (300 MHz, CDCl3) δ 9.85 (t, 1H, J=1.5 Hz), 6.64 (s, 1H), 6.51-6.57 (m, 2H), 6.46 (t, 1H, J=2 Hz), 6.42 (t, 1H, J=2 Hz), 4.23 (t, 2H, J=6 Hz), 3.82 (s, 3H), 2.89 (td, 2H, J=1, 6 Hz), 2.29 (s, 3H), 2.26 (s, 3H).

Provenance & Evidence