Reaktion #564643

Reaktionsgleichung

anisole

(3S,4S)-3-[(1R)-1-t-Butyldimethylsilyloxyethyl]-4-[(1R)-1-p-chlorophenylthiocarbonylethyl]-1-t-butoxy- carbonylmethyl-2-azetidinone

water

sodium bicarbonate

→

(3S,4S)-3-[(1R)-1-hydroxyethyl]-4-[(1R)- 1-p-chlorophenylthiocarbonylethyl]-1-(1-carboxymethyl)-2-azetidinone

Lösungsmittel

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe aqueous layer was separated
2. 2
   Extraktionextracted with ethyl acetate
3. 3
   TrocknenThe extract was dried over anhydrous sodium sulfate
4. 4
   Einengenconcentrated under reduced pressure
5. 5
   workup.ADDITIONEthyl acetate (1 ml) was added to the residue
6. 6
   workup.ADDITIONAfter dropwise addition of toluene (5 ml)
7. 7
   workup.STIRRINGthe resultant mixture was stirred for 30 minutes
8. 8
   Temperaturto cool to room temperature
9. 9
   FiltrationThe precipitated crystals were collected by filtration
10. 10
    Sonstigedried

Vorschrift

(3S,4S)-3-[(1R)-1-t-Butyldimethylsilyloxyethyl]-4-[(1R)-1-p-chlorophenylthiocarbonylethyl]-1-t-butoxy- carbonylmethyl-2-azetidinone (1.0 g) was dissolved in dry methylene chloride (10 ml), and anisole (497 mg) and boron trifluoride-diethyl ether complex (1.04 g) were added thereto, followed by stirring at 38° to 42° C. for 3 hours. The organic layer was shaken with water and aqueous sodium bicarbonate. The aqueous layer was separated, adjusted to pH 1 with concentrated hydrochloric acid and extracted with ethyl acetate. The extract was dried over anhydrous sodium sulfate and concentrated under reduced pressure. Ethyl acetate (1 ml) was added to the residue, and the resultant mixture was warmed at 50° C. After dropwise addition of toluene (5 ml), the resultant mixture was stirred for 30 minutes and allowed to cool to room temperature. The precipitated crystals were collected by filtration and dried to give (3S,4S)-3-[(1R)-1-hydroxyethyl]-4-[(1R)- 1-p-chlorophenylthiocarbonylethyl]-1-(1-carboxymethyl)-2-azetidinone. m.p., 81°-83° C.

Quelle