Benzaldehyde → alpha-L-mannopyranose

HRID 1706583

Reaction equation

HRID 1706583 reaction equation
C1(NN=[CH:9][C@@H:10]([C@@H:12]([C@H:14]([C@H:16]([CH2:18][OH:19])[OH:17])[OH:15])[OH:13])[OH:11])C=CC=CC=1.O.C(=[O:28])C1C=CC=CC=1.C(O)(=O)C1C=CC=CC=1>C(O)C>[OH:19][C@@H:18]1[O:11][C@@H:10]([CH2:9][OH:28])[C@H:12]([OH:13])[C@@H:14]([OH:15])[C@H:16]1[OH:17]

Participants

6

Reactant 4

HCID 240BenzaldehydeHCID 243Benzoic AcidHCID 962WaterHCID 86737045L-mannose phenylhydrazone

Product 1

HCID 6971016alpha-L-mannopyranose

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

The hydrazone (20 g.) was then refluxed for 3 hours with a solution containing water (200 ml.), ethanol (40 ml.), benzaldehyde (25 ml.) and benzoic acid (2.5 g.). The solution was cooled and then decanted from benzaldehyde phenylhydrazone, extracted three times with chloroform, decolorized with carbon and concentrated at reduced pressure. The resulting syrup was further evaporated with several portions of absolute ethanol to remove residual water and the resulting syrup (10 g.) was left to crystallize. The crystals were filtered with ethanol to give α-L-mannopyranose, m.p. 125°-126°, [α]D -26.9°→-14.4° (24 hr., c 2.0, water) compared to m.p. 128°-132°, [α]D -14.5° (equilibrium, c 3.4, water).

Workup

  1. temperatureThe solution was cooled
  2. customdecanted from benzaldehyde phenylhydrazone
  3. extractionextracted three times with chloroform
  4. concentrationconcentrated at reduced pressure
  5. customThe resulting syrup was further evaporated with several portions of absolute ethanol
  6. customto remove residual water
  7. waitthe resulting syrup (10 g.) was left
  8. customto crystallize
  9. filtrationThe crystals were filtered with ethanol

Sources & evidence

ORD record
ord-53d58275665e4f8ea062e31255bab0d8
Source dataset
uspto-grants-1980_06
Patent number
US04207413

Linked notes

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