Sulfuric Acid → L-mannose phenylhydrazone

Participants

Reaction Steps

1-Deoxy-1-nitro-L-mannitol (20 g.) was dissolved in 2 N sodium hydroxide (60 ml.), and the solution was immediately added dropwise to a stirred solution of sulfuric acid (30 ml.) in water (36 ml.) at room temperature. Some cooling (ice bath) was used to keep the reaction mixture at 22°±5°. The solution was then diluted to 400 ml. with water, just neutralized with solid sodium hydrogen carbonate, and a solution of phenylhydrazine (12 ml.) in glacial acetic acid (28 ml.) added. The mixture was stirred overnight at 5° and then filtered, and the L-mannose phenylhydrazone was washed with cold water, ethanol, and ether. Recrystallization from ethanol gave pure L-mannose phenylhydrazone, m.p. 198°-199°, [α]D -33.5° (c 2.5, pyridine) compared with m.p. 199°-200°, [α]D +34° for the D-isomer, p. 240).

Provenance & Evidence