Reacción #5934

Ecuación de reacción

ethyl acetate

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

(S)-N-(2-naphthalenesulfonyl)prolyl chloride

→

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

Rendimiento 51.5%

Disolventes

pyridine

Condiciones de reacción

Tratamiento posterior

1. 1
   Lavadothe mixture is washed with 5 % hydrochloric acid, water, aqueous sodium hydrogen carbonate solution, water and saline in this order
2. 2
   Otrothe ethyl acetate layer is separated
3. 3
   Secadodried over sodium sulfate
4. 4
   workup.DISTILLATIONdistilled
5. 5
   Otroto remove the solvent
6. 6
   LavadoFrom the fraction eluted first there

Procedimiento

To a solution of (±)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine (10.01 g, 0.038 mole) in pyridine (150 ml) is added (S)-N-(2-naphthalenesulfonyl)prolyl chloride (18.57 g, 0.057 mole), and the mixture is stirred at room temperature for 4 hours. To the reaction mixture is added ethyl acetate, and the mixture is washed with 5 % hydrochloric acid, water, aqueous sodium hydrogen carbonate solution, water and saline in this order, and the ethyl acetate layer is separated, dried over sodium sulfate and distilled to remove the solvent. The resulting caramel is subjected to silica gel column chromatography (hexane:ethyl acetate=5:1 - 3:1). From the fraction eluted first there is obtained (R)-2-(4-chlorophenyl)-4-[(S)-N-(2-naphthalenesulfonyl)prolyl]-3,4-dihydro-2H-1,4-benzothiazine (10.75 g, 51 %) as crystals. M.p. 147°-151° C.

Fuente