Réaction #5937

Équation de réaction

(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

Rendement 63.1%

Solvants

ethanol water

Conditions de réaction

Traitement

1. 1
   Températureis refluxed under argon for one hour
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

Mode opératoire

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.

Source