2-Thiophenesulfonyl chloride → Methyl 5-methyl-4-[(2-thienylsulfonyl)amino]thiophene-2-carboxylate

Participants

Reaction Steps

To a mixture of methyl 4-amino-5-methylthiophene-2-carboxylate (20 g) and pyridine (100 mL) was added 2-thiophen-sulfonyl chloride (23.5 g) at 0° C., and the mixture was stirred at room temperature for 2 hr. The reaction mixture was concentrated, water was added, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated. The residue was subjected to silica gel column chromatography to give methyl 5-methyl-4-[(2-thienylsulfonyl)amino]thiophene-2-carboxylate (35.7 g, yield 96%) as pale-yellow crystals from a fraction eluted with ethyl acetate-hexane (1:3, volume ratio).

Provenance & Evidence