Reaktion #87490

Reaktionsgleichung

(1S,2S,3S,4R,5S)-5-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-1-hydroxymethyl-6,8-dioxa-bicyclo[3.2.1]octane-2,3,4-triol

acetyl chloride

methanol

→

product

Ausbeute 87.0%

Acetic acid (1R,2S,3S,4R,5S)-5-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-2,3,4-trihydroxy-6,8-dioxa-bicyclo[3.2.1]oct-1-ylmethyl ester

Ausbeute 87.0%

Lösungsmittel

collidine

Reaktionsbedingungen

Aufarbeitung

1. 1
   EinengenThe crude mixture was concentrated under reduced pressure
2. 2
   SonstigeThe crude material was purified by flash chromatography over silica gel using the biotage
3. 3
   Wascheneluting with a gradient of 0 to 15% methanol in dichloromethane

Vorschrift

To a vigorously stirred solution of (1S,2S,3S,4R,5S)-5-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-1-hydroxymethyl-6,8-dioxa-bicyclo[3.2.1]octane-2,3,4-triol (1A, 0.481 g, 1.1 mmol) in collidine (2.5 mL) cooled to −35 degrees Celsius was added drop-wise over 10 minutes acetyl chloride (0.149 mL, 2.1 mmol). After 1 hour, methanol (0.5 mL) was added and the reaction mixture was allowed to warm to room temperature. The crude mixture was concentrated under reduced pressure and codistilled three times with toluene. The crude material was purified by flash chromatography over silica gel using the biotage automated chromatography unit (50 g silica gel column) and eluting with a gradient of 0 to 15% methanol in dichloromethane. 456 mg (87% yield) of product obtained as a white solid.

Quelle