Reaktion #49998

Reaktionsgleichung

sulfuric acid

water

(3S,4S)-4-(1-(R)-hydroxymethylethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone

Jones reagent

→

(3S,4S)-4-(1-(R)-carboxyethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone

Lösungsmittel

acetone

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe reaction mixture was quenched with isopropanol (0.5 ml) at 10°-20° C. for 15 minutes
2. 2
   workup.ADDITIONdiluted with ethyl acetate (122 ml)
3. 3
   Waschenwashed with water (135 ml)
4. 4
   SonstigeThe aqueous layer was separated from the organic layer
5. 5
   Extraktionextracted with ethyl acetate (61 ml)
6. 6
   Extraktionextracted with 5% aqueous sodium bicarbonate solution (30 ml)
7. 7
   WaschenThe extract was washed with dichloromethane (60 ml)
8. 8
   Temperaturcooling
9. 9
   ExtraktionThe acidic solution was extracted twice with dichloromethane (60 ml)
10. 10
    WaschenThe extracts were washed with brine
11. 11
    Trocknendried over anhydrous sodium sulfate
12. 12
    FiltrationAfter filtration
13. 13
    Einengenthe filtrate was concentrated in vacuo

Vorschrift

A solution of (3S,4S)-4-(1-(R)-hydroxymethylethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone (6.1 g) in acetone (60 ml) was treated with the Jones reagent, prepared from chromium trioxide (2.78 g), 98% sulfuric acid (4.4 g) and water (8.1 ml), at 10°-20° C. for 1 hour. The reaction mixture was quenched with isopropanol (0.5 ml) at 10°-20° C. for 15 minutes, diluted with ethyl acetate (122 ml) and washed with water (135 ml). The aqueous layer was separated from the organic layer and extracted with ethyl acetate (61 ml). The ethyl acetate extracts and the organic layer were combined together and extracted with 5% aqueous sodium bicarbonate solution (30 ml). The extract was washed with dichloromethane (60 ml) and acidified with 10% hydrochloric acid solution (20 ml) with ice-cooling. The acidic solution was extracted twice with dichloromethane (60 ml). The extracts were washed with brine and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated in vacuo to give (3S,4S)-4-(1-(R)-carboxyethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone.

Quelle