Acetic Acid → N-Benzhydryl-2,5-anhydro-2,5-imino-D-glucitol

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Reaction Steps

A suspension of 5-keto-D-fructose (Formula X, 50 g, 0.28 mol; obtained from Chemical Dynamics) in 400 mL of MeOH was treated with sodium cyanoborohydride (40 g, 0.476 mol). A slurry of benzhydrylamine (42.0 mL, 0.234 mol) in 120-mL of MEOH was treated with sufficient acetic acid to bring the pH to 6-7 and then added over a 0.5 h period to the 5-keto-D-fructose (Formula X) and sodium cyanoborohydride suspension. An additional portion of sodium cyanoborohydride (20 g. 0.235 mol) was added and the mixture was stirred at reflux for 6 h. The solvent was then removed, and the residue treated with 10% sodium carbonate (ca. 100 mi), and the product was extracted into chloroform. The chloroform layers were dried (MgSO4), filtered and concentrated to give a tacky yellow solid. This was purified on two Waters Prep 500 columns (CHCl3 /MeOH/NH4OH, 88:11:1) to give ca. 50 g of the target compound. Recrystallization from ethyl acetate gave 21.3 g (28%) of white needles, 152.5°-154.5° C. (corrected). Both 1H and 13C NMR in CDCl3 supported the assigned structure.

Provenance & Evidence