Cl[C:2]1[S:3][C:4]2[CH:10]=[C:9]([C:11]#[N:12])[CH:8]=[CH:7][C:5]=2[N:6]=1.[CH:13]1([N:16]2[CH2:21][CH2:20][NH:19][CH2:18][CH2:17]2)[CH2:15][CH2:14]1.[Cl-].[NH4+]>C(O)CCC>[CH:13]1([N:16]2[CH2:21][CH2:20][N:19]([C:2]3[S:3][C:4]4[CH:10]=[C:9]([C:11]#[N:12])[CH:8]=[CH:7][C:5]=4[N:6]=3)[CH2:18][CH2:17]2)[CH2:15][CH2:14]1A suspension of 2-chlorobenzothiazole-6-carbonitrile (3.5 g, 18 mmol), 1-cyclopropyl-piperazine (3.63 g, 28.8 mmol) and ammonium chloride (0.96 g, 18 mmol) in butan-1-ol (112 mL) was heated at reflux for 48 h. The solvent was removed under reduced pressure and the residue was diluted with water (30 mL). The mixture was made alkaline with potassium carbonate and extracted with CH2Cl2 (3×20 mL). The combined organic extracts were concentrated to give a residue which was purified by column chromatography on silica gel (20% ethyl acetate in petroleum ether) to give 2.2 g (43 5) of 2-(4-cyclopropylpiperazin-1-yl)-benzothiazole-6-carbonitrile.
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