Piperazine → 3-(1-Piperazinyl)-1,2-benzisothiazole
Reaction equation
[NH:1]1[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.[C:7]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[S:15]Cl)#[N:8]>ClC1C=CC=CC=1>[N:1]1([C:7]2[C:9]3[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=3[S:15][N:8]=2)[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
86.2 g (1.00 mol) of piperazine and 7.5 g of chlorobenzene were placed in a four-neck 500 ml flask equipped with a stirrer, a thermometer, a dropping funnel and a condenser, 53.5 g (0.25 mol) of 2-cyanobenzenesulfenyl chloride was added dropwise in the melted state at about 130° C. over 1 hour while stirring, which was thereafter stirred for 4 hours to complete the reaction. After excess piperazine was removed with water, the reaction mixture was made acidic with hydrochloric acid, extracted into an aqueous layer, which was made alkaline with aqueous sodium hydroxide to obtain 40.9 g (m.p. 89 to 90° C.) of 3-(1-piperazinyl)-1,2-benzisothiazole as crystals. Yield from 2-cyanobenzenesulfenyl chloride was 74.7%.