反应详情

(R)-2-(4-Chlorophenyl)-4-[(S)-N-(2-naphthalene-sulfonyl)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%).

1. temperaturethe mixture is refluxed for 30 minutes
2. extractionthe mixture is extracted with ethyl acetate
3. washThe ethyl acetate layer is washed with water and saline
4. dry with materialdried over sodium sulfate
5. distillationdistilled
6. customto remove the solvent
7. customThe residue is purified by silica gel column chromatography (CHCl3)
8. customrecrystallized from ethyl acetate-hexane twice