D-(-)-Fructose → HCID 129629243, compound

Participants

Reaction Steps

Typical procedure from fructose: 18.0 g (100 mmol) of D-(−)-fructose was treated at 0° C. with freshly distilled benzyl amine (3-8 equiv.). The reaction mixture was allowed to warm to room temperature and was then heated at 40° C. for 20 h. The TLC (dichloromethane:methanol:ammonium hydroxide 2:1:1) showed the disappearance of the starting material. The excess of benzyl amine was removed by repeated washings with petroleum ether according to the following method: 150-500 mL of petroleum ether was added into the reaction mixture and subsequently cooled to between −25 and −20° C. (dry ice-alcohol bath) until the carbohydrate-rich phase was frozen. The organic layer was then decanted, and the procedure was repeated 4-5 times. The obtained crude fructosyl amine was diluted with methanol (200-300 mL) and treated with glacial acetic acid (15-20 mL) at room temperature for 2-4 h. TLC (dichloromethane:methanol:ammonium hydroxide 20:4:0.5) showed consumption of the ketosylamine and the formation of N-benzyl-2-amino-2-deoxy-D-mannose together with N-benzyl-2-amino-2-deoxy-D-glucose in a ratio of 2:8-4:6 as the main products. The solvent was evaporated under reduced pressure and the residue purified by column chromatography (dichloromethane:methanol:ammonium hydroxide 20:4:0.5) to give N-benzyl-2-amino-2-deoxy-D-mannose as an amorphous solid (4.1-8.6 g).

Provenance & Evidence