Reaktion #62560

Reaktionsgleichung

NaOH

chloroformic acid allyl ester

(3S,4S)-1-(p-methoxybenzyl)-3-[(1R)-1-hydroxyethyl)-4-tert.-butoxycarbonyl-2-azetidinone

chloroformic acid allyl ester

→

title compound

(3S,4S)-1-(p-methoxybenzyl)-3-[(1R)-1-allyloxycarbonyloxyethyl]-4-tert.-butoxycarbonyl-2-azetidinone

Lösungsmittel

methylene chloride

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe aqueous phase is separated off
2. 2
   Waschenthe organic layer is washed in succession with 5% aqueous citric acid and 8% aqueous NaHCO3 solution
3. 3
   Sonstigedried
4. 4
   Einengenconcentrated by evaporation
5. 5
   SonstigeAfter purifying by chromatography

Vorschrift

At 0°, 24 ml of 1N NaOH, 820 mg of tetrabutylammonium bisulphate and 1 ml of chloroformic acid allyl ester are added to a solution of 2 g of (3S,4S)-1-(p-methoxybenzyl)-3-[(1R)-1-hydroxyethyl)-4-tert.-butoxycarbonyl-2-azetidinone in 24 ml of methylene chloride and the whole is stirred vigorously. After a reaction time of 20 and 40 minutes, further portions (each of 1 ml) of chloroformic acid allyl ester are added. The reaction mixture is diluted with methylene chloride, the aqueous phase is separated off and the organic layer is washed in succession with 5% aqueous citric acid and 8% aqueous NaHCO3 solution and then dried and concentrated by evaporation. After purifying by chromatography, the pure, amorphous title compound is obtained.

Quelle