Sulfur Dioxide → N-tert-Butyl-5-sulfamoylthiophene-2-sulfonamide

Participants

Reaction Conditions

Reaction Steps

To a solution of the product from Step A (1.5 g, 6.85 mmol) in THF (10 mL) cooled to -60° C. was added n-butyllithium in hexane (2.5M, 6.0 mL, 15.1 mmol). The mixture was stirred for 15 min at -60° C. and for 30 min at -10° C. Sulfur dioxide gas was passed through the surface of the mixture for 10 min. The cooling bath was removed and the mixture was stirred for an additional 1 h. The volatiles were evaporated and the residue was dissolved in water (30 mL) and sodium acetate trihydrate (5.59 g, 41.1 mmol) was added. The mixture was cooled in an ice-water bath and hydroxylamine-O-sulfonic acid (2.71 g, 23.9 mmol) was added. The cooling bath was removed and the mixture was stirred for 2 h. The suspension was extracted with ethylacetate (3×50 mL) and the combined extracts were washed with 5% sodium bicarbonate solution, brine and dried over molecular sieves. The solvent was evaporated and the residue was chromatographed on silica eluting with 40% ethylacetatehexane, to yield 1.25 g (61%) of a liquid which solidified on standing: mp 116°-120° C.

Provenance & Evidence