Chloral → (4S,5R)-5-methoxycarbonyl-4-phenyl-2-trichloromethyl-1,3-oxazolidine

HRID 1763

Reaction equation

HRID 1763 reaction equation
C(O[C:6]([NH:8][C@@H:9]([C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1)[C@@H:10]([OH:15])[C:11]([O:13][CH3:14])=[O:12])=O)(C)(C)C.O=C[C:24]([Cl:27])([Cl:26])[Cl:25].C1(C)C=CC(S([O-])(=O)=O)=CC=1.[NH+]1C=CC=CC=1>C1(C)C=CC=CC=1>[CH3:14][O:13][C:11]([C@@H:10]1[O:15][CH:6]([C:24]([Cl:27])([Cl:26])[Cl:25])[NH:8][C@H:9]1[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1)=[O:12]

Participants

5

Reactant 3

HCID 6407ChloralHCID 466102Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1)HCID 11140973Methyl (alphaR,betaS)-beta-(((1,1-dimethylethoxy)carbonyl)amino)-alpha-hydroxybenzenepropanoate

Product 1

HCID 57158288(4S,5R)-5-methoxycarbonyl-4-phenyl-2-trichloromethyl-1,3-oxazolidineYield 91%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
20 °C

Procedure

A solution of 3.0 g of methyl (2R,3S)-3-(tert-butoxycarbonylamino)-2-hydroxy-3-phenylpropionate, of 5 cm3 of chloral and of 0.05 g of pyridinium p-toluenesulphonate in 40 cm3 of anhydrous toluene is heated at reflux with distillation of the solvent. 15 cm3 of solvent are distilled and then 5 cm3 of chloral and 0.05 g of pyridinium p-toluenesulphonate are added. 20 cm3 of solvent are distilled and then 5 cm3 of chloral as well as 30 cm3 of anhydrous toluene are added. 25 cm3 of solvent are distilled and 5 cm3 of chloral and 35 cm3 of anhydrous toluene are added. 25 cm3 of solvent are distilled and then the solution is cooled to a temperature in the region of 20° C. The organic solution is washed with water (2 times 50 cm3), dried over sodium sulphate and concentrated to dryness under reduced pressure at approximately 50° C. The residue obtained is purified by liquid chromatography on silica gel, the eluent being an ethyl acetate/cyclohexane (1/3 by volume) mixture. There are thus obtained, with a yield of 91%, 3.0 g of (4S,5R)-5-methoxycarbonyl-4-phenyl-2-trichloromethyl-1,3-oxazolidine whose characteristics are the following:

Workup

  1. temperatureat reflux with distillation of the solvent
  2. distillation15 cm3 of solvent are distilled
  3. addition5 cm3 of chloral and 0.05 g of pyridinium p-toluenesulphonate are added
  4. distillation20 cm3 of solvent are distilled
  5. addition5 cm3 of chloral as well as 30 cm3 of anhydrous toluene are added
  6. distillation25 cm3 of solvent are distilled
  7. addition5 cm3 of chloral and 35 cm3 of anhydrous toluene are added
  8. distillation25 cm3 of solvent are distilled
  9. washThe organic solution is washed with water (2 times 50 cm3)
  10. dry with materialdried over sodium sulphate
  11. concentrationconcentrated to dryness under reduced pressure at approximately 50° C
  12. customThe residue obtained
  13. customis purified by liquid chromatography on silica gel

Sources & evidence

ORD record
ord-2efa0157f0794899ae4b9b6277f9cfd2
Source dataset
uspto-grants-1998_03
Patent number
US05726318

Linked notes

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