反应详情

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]+).

1. customThe solvent was removed under vacuum
2. washthe organic phase was washed with brine
3. dry with materialdried over sodium sulfate
4. filtrationfiltered
5. customevaporated to dryness
6. customThe crude was purified by flash chromatography on silica gel cartridge (petroleum ether/EtOAc=8/2)