A round bottom flask was charged with 1-naphthalenesulfonyl chloride (20.0 g), Na2SO3 (33.36 g), NaHCO3 (22.24 g) and deionized water (350 mL). The mixture was stirred and heated to 65° C. under a nitrogen atmosphere for 2 hours, after which time the mixture was allowed to cool to room temperature and was then further cooled in a refrigerator. The cold mixture was acidified with concentrated H2SO4 which resulted in the formation of a precipitate. The mixture was extracted three times with 100 mL of ethyl acetate. The organic extracts were combined and the solvent was removed with a rotary evaporator to give a colorless solid that was then dissolved in 240 mL of 1:1 (v/v) methanol-deionized water in a beaker. The solution was titrated with a solution of 40% aqueous tetrabutylammonium hydroxide until the pH of the solution was 7.2. The solvent was removed with a rotary evaporator and the product was further dried in a vacuum oven at room temperature to afford 36.4 g of a yellow waxy solid.
