Chloroacetyl chloride → (R)-4-chloroacetyl-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine

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Reaction Steps

To a suspension of (R)-(+)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine (1.30 g, 0.005 mole) and triethylamine (1.66 ml, 0.012 mole) in dichloromethane (16 ml) is added dropwise a solution of chloroacetyl chloride (0.79 ml, 0.01 mole) in dichloromethane (4 ml) under ice cooling, and the mixture is stirred at room temperature for 45 minutes. After the solvent is distilled off, to the residue are added ethyl acetate and water, and the ethyl acetate layer is washed with aqueous sodium hydrogen carbonate solution, water and saline, dried over sodium sulfate and distilled to remove the solvent to give (R)-4-chloroacetyl-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine (1.84 g) as caramel.

Provenance & Evidence