Chlorosulfonic acid → 5-(5-Ethyl-2-methyl-6-oxo-1,6-dihydropyridin-3-yl)thiophene-2-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

Phosphorus pentachloride (4.67 g, 22.4 mmol) is placed in a three neck round bottom flask and cooled to 0° C. Chlorosulfonic acid (6.53 g, 56.0 mmol) is added slowly. The reaction is stirred until the fuming action stops and the reaction mixture becomes clear. Then a solution of 3-ethyl-6-methyl-5-(thiophen-2-yl)-1H-pyridin-2-one (4.92 g, 22.4 mmol) of the above reaction in chloroform (35 mL) is added dropwise, and stirring at 0° C. is maintained for 5 min, then at room temperature. After 30 min, the reaction is poured into ice water (200 mL) and extracted with dichloromethane. The organic layer is washed with water, dried (sodium sulfate), filtered and concentrated and the residue is triturated with hepatane-30% ethyl acetate to afford the title compound (6.88 g, 97% yield) as a yellow solid. MS: m/e=318 (M+H). 1H-NMR (D6-DMSO, δ ppm) 13.2 (br s, 1H); 7.25 (s, 1H); 7.05 (d, 1H, J=3.2 Hz); 6.82 (d, 1H, J=3.2 Hz); 2.39 (q, 2H, J=7.4 Hz); 2.27 (s, 3H); 1.10 (t, 3H, J=7.4 Hz).

Provenance & Evidence