Diethyl Carbonate → (4R,5S)-(+)-4-Methyl-5-phenyl-2-oxazolidinone

HRID 1769560Notes

Reaction equation

HRID 1769560 reaction equation
[CH3:1][C@@H:2]([NH2:11])[C@@H:3]([OH:10])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.[C:12](=O)(OCC)[O:13]CC.C(=O)([O-])[O-].[K+].[K+]>C(O)C>[CH3:1][C@@H:2]1[C@H:3]([C:4]2[CH:5]=[CH:6][CH:7]=[CH:8][CH:9]=2)[O:10][C:12](=[O:13])[NH:11]1

Participants

5

Reactant 3

HCID 7766Diethyl CarbonateHCID 11430Potassium CarbonateHCID 26934(1S,2R)-2-amino-1-phenylpropan-1-ol

Product 1

HCID 2733812(4R,5S)-(+)-4-Methyl-5-phenyl-2-oxazolidinoneYield 101.8%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Conditions

Temperature
160 °C

Procedure

A round bottom flask, equipped with a distillation apparatus, is charged with (1S,2R) -norephedrine (18.16 g, 99.1 mmol), diethyl carbonate (27.6 mL, 228 mmol), and potassium carbonate (28.9 g, 209 mmol), and heated at 160° C. (oil bath temperature). The distillation head temperature remained at ca 80° C. when ethanol is collected in the collection flask, which is cooled in an ice bath. When the head temperature drops to 60° C. (ca 5 hours), the oil bath is removed and the mixture is cooled to room temperature. The mixture is diluted in dichloromethane and washed with water (2X) and dried (magnesium sulfate). Concentration in vacuo affords an off-white solid (17.88 g), which is recrystallized in hexane-ethyl acetate 1:1.5, to afford the title compound as white crystals, 15.2 g; mp 120°-121° C., [α]D =171.4° (2.042% in chloroform).

Workup

  1. customA round bottom flask, equipped with a distillation apparatus
  2. customremained at ca 80° C.
  3. customis collected in the collection flask, which
  4. temperatureis cooled in an ice bath
  5. customdrops to 60° C.
  6. custom(ca 5 hours)
  7. customthe oil bath is removed
  8. temperaturethe mixture is cooled to room temperature
  9. additionThe mixture is diluted in dichloromethane
  10. washwashed with water (2X)
  11. dry with materialdried (magnesium sulfate)
  12. concentrationConcentration in vacuo

Sources & evidence

ORD record
ord-824b4c40eb114a5490a0eb370e0592d8
Source dataset
uspto-grants-1995_01
Patent number
US05380925

Reaction notes

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