Toluene → Ethyl 2-chloro-5-sulfamoylthiophene-3-carboxylate

Participants

Reaction Steps

To a round bottom flask were added 5-chloro-4-carboxythiophene-2-sulfonamide (5.0 g, 20.7 mmole) along with toluene (25 mL), ethanol (20 ml), and conc. H2SO4 (25 drops). The reaction mixture was refluxed for 96 hours. The reaction mixture was cooled and the solvent was removed under vacuum. The residue was then poured onto ice and the pH adjusted to ~8.0 using 10% sodium carbonate. The basic aqueous layer was extracted with ethyl acetate and the organic layer was washed with water, brine, and dried (MgSO4). Solvent removal yielded 3.92 g (70%) of an off white solid which was used as is: mp =98°-99° C.

Provenance & Evidence