Reaction #5922

Reaction equation

oxalic acid

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

allyl bromide

potassium carbonate

→

4-(N-allyl-N-methylaminoacetyl)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine oxalate

Solvents

water

dimethylformamide

ether

Conditions

Workup

1. 1
   Extractionthe mixture is extracted with ethyl acetate
2. 2
   workup.DISTILLATIONAfter the solvent is distilled off
3. 3
   Otherthe residue is purified by silica gel column chromatography (solvent, chloroform:methanol=40:1)
4. 4
   OtherThe caramel thus obtained
5. 5
   WashThe resulting precipitate is washed with ether
6. 6
   Otherdried

Procedure

A mixture of 2-(4-chlorophenyl)-4-(N-methylaminoacetyl)-3,4-dihydro-2H-1,4-benzothiazine (1.80 g), allyl bromide (0.52 ml), potassium carbonate (2.25 g) and dimethylformamide (20 ml) is stirred at room temperature for 3.5 hours. The reaction mixture is poured into water, and the mixture is extracted with ethyl acetate. After the solvent is distilled off, the residue is purified by silica gel column chromatography (solvent, chloroform:methanol=40:1). The caramel thus obtained is dissolved in ether and thereto is added 1.1 equivalent of oxalic acid. The resulting precipitate is washed with ether and dried to give 4-(N-allyl-N-methylaminoacetyl)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine oxalate as powder.

Source