Boron trifluoride → (3S,4S)-1-carboxymethyl-4-[(1R)-1-(p-chlorophenylthiocarbonyl)ethyl]-3-[(1R)-1-hydroxyethyl]-2-azetidinone

HRID 1033458Notes

Reaction equation

HRID 1033458 reaction equation
[Si]([O:8][C@@H:9]([C@@H:11]1[C@@H:14]([C@H:15]([C:17]([C:19]2[CH:24]=[CH:23][C:22]([Cl:25])=[CH:21][CH:20]=2)=[S:18])[CH3:16])[N:13]([CH2:26][C:27]([O:29]C(C)(C)C)=[O:28])[C:12]1=[O:34])[CH3:10])(C(C)(C)C)(C)C.B(F)(F)F>C(Cl)Cl>[OH:8][C@@H:9]([C@@H:11]1[C@@H:14]([C@H:15]([C:17]([C:19]2[CH:20]=[CH:21][C:22]([Cl:25])=[CH:23][CH:24]=2)=[S:18])[CH3:16])[N:13]([CH2:26][C:27]([OH:29])=[O:28])[C:12]1=[O:34])[CH3:10]

Participants

4

Reactant 2

HCID 6356Boron trifluorideHCID 57265013HCID 57265013, compound

Product 1

HCID 18636525(3S,4S)-1-carboxymethyl-4-[(1R)-1-(p-chlorophenylthiocarbonyl)ethyl]-3-[(1R)-1-hydroxyethyl]-2-azetidinone

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of (3S,4S)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-[(1R)-1-p-chlorophenylthiocarbonylethyl]-1-(t-butyloxycarbonylmethyl)azetidin-2-one (200 mg) in dry methylene chloride (1.5 ml), there was added BF3 --ET2O complex (263 mg), followed by stirring at room temperature for 1 hour. After evaporation of the solvent, the residue was dissolved in methanol (0.5 ml), diluted with brine and extracted with ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate and evaporated to give (3S,4S)-3-[(1R)-1-hydroxyethyl]-4-[(1R)-1-p-chlorophenylthiocarbonylethyl]-1-(carboxymethyl)azetidin-2-one as a crude product. The crude product, t-butyldimethylsilyl chloride (246 mg) and imidazole (151 mg) were dissolved in dry dimethylformamide (2.5 ml) and allowed to stand at room temperature overnight. The reaction mixture was poured into cold brine, adjusted with 1M potassium hydrogensulfate to pH and extracted with diethyl ether three times. The organic layer was washed with brine two times, dried over sodium sulfate and evaporated. The residue was purified by silica gel chromatography to give (3S,4S)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-[(1R)-1-p-chlorophenylthiocarbonylethyl]-1-(carboxymethyl)azetidin-2-one.

Workup

  1. customAfter evaporation of the solvent
  2. dissolutionthe residue was dissolved in methanol (0.5 ml)
  3. additiondiluted with brine
  4. extractionextracted with ethyl acetate
  5. washThe organic layer was washed with brine
  6. dry with materialdried over sodium sulfate
  7. customevaporated

Sources & evidence

ORD record
ord-089e7eb759844a2f90c032eee8c53074
Source dataset
uspto-grants-1994_05
Patent number
US05310897

Reaction notes

Loading…