Reaktion #49995

Reaktionsgleichung

(3S,4S)-4-(1-hydroxymethylethenyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-1-di(p-anisyl)methyl-2-azetidinone

imidazole

t-butyldimethylchlorosilane

→

(3S,4S)-4-(1-t-butyldimethylsilyloxymethylethenyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-1-di(p-anisyl)methyl-2-azetidinone

Lösungsmittel

water

ethyl acetate

dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   ExtraktionThe aqueous layer was extracted with ethyl acetate (150 ml)
2. 2
   WaschenThe combined extracts were washed successively with 5% hydrochloric acid solution (80 ml×2) and brine (80 ml)
3. 3
   Trocknendried over anhydrous sodium sulfate
4. 4
   FiltrationAfter filtration
5. 5
   Einengenthe filtrate was concentrated in vacuo
6. 6
   Sonstigethe concentrate was crystallized from isopropanol

Vorschrift

A solution of (3S,4S)-4-(1-hydroxymethylethenyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-1-di(p-anisyl)methyl-2-azetidinone (20 g) and imidazole (5.6 g) in dry dimethylformamide (45 ml) was treated with t-butyldimethylchlorosilane (6.77 g) at room temperature for 2 hours. The reaction mixture was diluted with cold water (200 ml) and ethyl acetate (150 ml). The aqueous layer was extracted with ethyl acetate (150 ml). The combined extracts were washed successively with 5% hydrochloric acid solution (80 ml×2) and brine (80 ml), and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated in vacuo, and the concentrate was crystallized from isopropanol to give crystals of (3S,4S)-4-(1-t-butyldimethylsilyloxymethylethenyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-1-di(p-anisyl)methyl-2-azetidinone. m.p., 90°-92° C.

Quelle