Réaction #5935

Équation de réaction

(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

Rendement 58.7%

Solvants

ethanol water

Conditions de réaction

Traitement

1. 1
   Températurethe mixture is refluxed for 30 minutes
2. 2
   Extractionthe mixture is extracted with ethyl acetate
3. 3
   LavageThe ethyl acetate layer is washed with water and saline
4. 4
   Séchagedried over sodium sulfate
5. 5
   workup.DISTILLATIONdistilled
6. 6
   Autreto remove the solvent
7. 7
   AutreThe residue is purified by silica gel column chromatography (CHCl3)
8. 8
   Autrerecrystallized from ethyl acetate-hexane twice

Mode opératoire

(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%).

Source