Isopropyl Isothiocyanate → N-(3-Amino-5-chloro-2-thienylsulfonyl)-N'-isopropylthiourea

Participants

Reaction Steps

Potassium tert-butoxide (0.49 g, 4.4 mmol) was added to a solution of 3-amino-5-chlorothiophene-2-sulfonamide hydrochloride (0.5 g, 2.0 mmol) in dry N,N-dimethylformamide (5 ml) with stirring on an ice bath. After 5 min, isopropyl isothiocyanate (0.26 ml, 2.4 mmol) was added dropwise to the resulting suspension, and the mixture was stirred for 30 min at 0° C. The cooling bath was removed, and stirring was continued at room temperature for 30 min. The solvent was evaporated at <50° C., and the residue was taken up in 25 ml of water, treated with decolorising charcoal, and filtered. Acidification of the filtrate with acetic acid to pH 3-4 and filtration afforded 0.50 g (80%) the title compound; mp 142.0°-142.5° C. decomp., 1H-NMR (DMSO-d6): δ 1.12 (d, 6H), 4.25 (m, 1H), 6.48 (br s, 2H), 6.65 (s, 1H), 8.02 (d, 1H), 11.2 (br s, 1H).

Provenance & Evidence