Reaktion #5937

Reaktionsgleichung

(R)-3-(4-chlorophenyl)-1-[(S)-N-(2-naphthalenesulfonyl)prolyl]-2,3-dihydro-1H-naphtho[2,1-b][1,4]thiazine

potassium hydroxide

→

(R)-(+)-3-(4-chlorophenyl)- 2,3-dihydro-1H-naphtho[2,1-b][1,4]thiazine

Ausbeute 63.1%

Lösungsmittel

ethanol water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturis refluxed under argon for one hour
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

Vorschrift

A mixture of (R)-3-(4-chlorophenyl)-1-[(S)-N-(2-naphthalenesulfonyl)prolyl]-2,3-dihydro-1H-naphtho[2,1-b][1,4]thiazine (11.50 g, 0.019 mole), 86 % potassium hydroxide (15.0 g, 0.227 mole) and ethanol-water (10:1, 230 ml) is refluxed under argon for one hour. 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 to give (R)-(+)-3-(4-chlorophenyl)- 2,3-dihydro-1H-naphtho[2,1-b][1,4]thiazine (3.74 g, 63%). M.p. 205°-206° C.

Quelle