反应详情

温度

0 °C

1-Methyl-4-nitro-1H-pyrrole-2-carboxylic acid (Int. 15) (350 mg, 2.057 mmol) was dissolved in aqueous 1M sodium carbonate (15 ml, 15.00 mmol); 10% Pd/C (219 mg) was added, and the mixture was hydrogenated in a Parr apparatus at 40 psi for 2 hours. The catalyst was filtered off maintaining the mixture under nitrogen flow and the filtrate was collected in a cooled flask (ice bath). THF (20 ml) and benzenesulfonyl chloride (0.318 ml, 2.469 mmol) were added to the cooled solution and the resulting mixture was stirred at 0° C. for 0.5 hours and then at RT for 1 hour. The reaction mixture was extracted with Et2O and the organic layer was discarded. The aqueous layer was cautiously acidified by addition of solid KHSO4 to pH=3 and extracted twice with DCM. The combined organic layers were dried over Na2SO4 and the solvent was removed under vacuum to afford 1-methyl-4-(phenylsulfonamido)-1H-pyrrole-2-carboxylic acid (Int. 16) (540 mg, 1.927 mmol, MS/ESI+280.9 [MH]+), which was used without purification.

1. filtrationThe catalyst was filtered off
2. temperaturemaintaining the mixture under nitrogen flow
3. customthe filtrate was collected in a cooled flask (ice bath)
4. waitat RT for 1 hour
5. extractionThe reaction mixture was extracted with Et2O
6. additionThe aqueous layer was cautiously acidified by addition of solid KHSO4 to pH=3
7. extractionextracted twice with DCM
8. dry with materialThe combined organic layers were dried over Na2SO4
9. customthe solvent was removed under vacuum