Reaktion #5935

Reaktionsgleichung

(R)-2-(4-Chlorophenyl)-4-[(S)-N-(2-naphthalenesulfonyl)prolyl]-3,4-dihydro-2H-1,4-benzothiazine

potassium hydroxide

→

(R)-(+)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine

Ausbeute 58.7%

Lösungsmittel

ethanol water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture is refluxed for 30 minutes
2. 2
   Extraktionthe mixture is extracted with ethyl acetate
3. 3
   WaschenThe ethyl acetate layer is washed with water and saline
4. 4
   Trocknendried over sodium sulfate
5. 5
   workup.DISTILLATIONdistilled
6. 6
   Sonstigeto remove the solvent
7. 7
   SonstigeThe residue is purified by silica gel column chromatography (CHCl3)
8. 8
   Sonstigerecrystallized from ethyl acetate-hexane twice

Vorschrift

(R)-2-(4-Chlorophenyl)-4-[(S)-N-(2-naphthalenesulfonyl)prolyl]-3,4-dihydro-2H-1,4-benzothiazine (9.40 g, 0.017 mole) is suspended in ethanol-water (10:1, 188 ml), and thereto is added 86 % potassium hydroxide (11.2 g, 0.172 mole), and the mixture is refluxed for 30 minutes. The reaction mixture is poured into ice water and the mixture is extracted with ethyl acetate. The ethyl acetate layer is washed with water and saline, dried over sodium sulfate and distilled to remove the solvent. The residue is purified by silica gel column chromatography (CHCl3) and thereafter recrystallized from ethyl acetate-hexane twice to give (R)-(+)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine (2.61 g, 58%).

Quelle