Hydrochloric Acid → N-(3-chloro-4-hydroxynaphthalen-1-yl)thiophene-2-sulfonamide

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Reaction Steps

0.987 g N-(4-hydroxynaphthalen-1-yl)thiophene-2-sulfonamide (3) was suspended in 10 ml methanol, to which was added 3 ml hydrogen peroxide solution (35%). The mixture was stirred at r.t. for 2 h. Additional 3 ml hydrogen peroxide solution was added followed by 1 ml HCl solution (4 M in dioxane). The reaction was continued for another 2 h. The organic solvent was removed via rotavap and the residue was redissolved in ethyl acetate (100 ml). Washed with water (20 ml×3) and brine (20 ml×2), the organic phase was dried over Mg2SO4. The organic phase was filtered and concentrated. The crude product was separated via flash chromatography (Hex/EtOAc) affording 244 mg (22.2%) brown solid, m.p.: 113-115° C.

Provenance & Evidence