Methanesulfonyl chloride → Tert-butyl 5-(methylsulfonamido)thiophene-2-carboxylate

Participants

Reaction Steps

To a solution of tert-butyl 5-aminothiophene-2-carboxylate (Int. 55) (1.481 g, 7.43 mmol) in pyridine (50 ml) cooled to 0° C., methanesulfonyl chloride (0.695 ml, 8.92 mmol) was added drop-wise. The reaction was warmed to RT and stirred for 3 days. The solvent was removed under vacuum, and the residue was portioned between EtOAc and 1N HCl; the organic phase was washed with brine, dried over sodium sulfate, filtered and evaporated to dryness. The crude was purified by flash chromatography on silica gel cartridge (petroleum ether/EtOAc=8/2) to afford tert-butyl 5-(methylsulfonamido)-thiophene-2-carboxylate (Int. 56) (773 mg, 2.79 mmol, MS/ESI+299.9 [MNa]+) and tert-butyl 5-(N-(methylsulfonyl)-methylsulfonamido)thiophene-2-carboxylate (Int. 57) (420 mg, 1.182 mmol, MS/ESI+ not detectable [MH]+).

Provenance & Evidence