Sodium Hydroxide → 1,5-Naphthalenedisulfonic acid

Beteiligte Stoffe

Reaktionsschritte

A solution of 14.5 g of D-glucamine in 120 ml of water was covered with a solution of 11.4 g of naphthalene-1,5-disulfonyl chloride in 300 ml of ethyl acetate. 80 ml of a 1.0N sodium hydroxide solution were added dropwise to the vigorously stirred mixture during 4 hours. After stirring at room temperature for 20 hours the aqueous phase was separated, washed once with 100 ml of ethyl acetate and concentrated at 50° C. on a rotary evaporator. The viscous residue was evaporated azeotropically three times with 50 ml of toluene each time, subsequently taken up in a solution of 300 ml of pyridine and 100 ml of acetic anhydride and heated to reflux for 8 hours. The reaction mixture was again concentrated to dryness and partitioned between water and ethyl acetate. The organic phase was washed with water and sodium hydrogen carbonate solution, dried over magnesium sulfate and evaporated. The residue was chromatographed on silica gel in hexane/ethyl acetate as the eluent. 5.6 g of the purified product were dissolved in 100 ml of methanol and treated with 2 mg of sodium. After stirring for 16 hours. the insoluble precipitate was filtered off. This was dried at 50° C. in a high vacuum and gave naphthalene-1,5-disulfonic acid bis-D-glucit-1-ylamide, MS: m/z 615 ([M+H]+); 637 ([M+Na]+).

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