Phosphoric Acid → Diacetone-D-glucose

Participants

Reaction Steps

To a suspension of 100 grams of anhydrous D-glucose in one liter of anhydrous acetone is added 80 grams of anhydrous zinc chloride and 5 grams of 85% phosphoric acid. The mixture is stirred for 30 hours at room temperature and then neutralized with a 50% NaOH solution. The insoluble materials are removed by filtration and washed with acetone. The combined filtrates are evaporated under reduced pressure to heavy syrup and the residual syrup is diluted with 500 ml. of chloroform. The chloroform solution is extracted three times with water and concentrated in vacuo to give crude 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose. The crude product is purified by crystallization from a chloroform and hexane mixture to give 77 grams (91% yield based on the D-glucose consumed) of a pure product having a melting point of 105°-109° C.

Provenance & Evidence