Br[C:2]1[S:3][C:4]2[CH:10]=[C:9]([C:11]([O:13][CH3:14])=[O:12])[CH:8]=[CH:7][C:5]=2[N:6]=1.C([N:22]1[CH2:27][CH2:26][NH:25][CH2:24][CH2:23]1)(OC(C)(C)C)=O.C(=O)([O-])[O-].[K+].[K+].FC(F)(F)C(O)=O.ClCCl>C(#N)C>[N:22]1([C:2]2[S:3][C:4]3[CH:10]=[C:9]([C:11]([O:13][CH3:14])=[O:12])[CH:8]=[CH:7][C:5]=3[N:6]=2)[CH2:27][CH2:26][NH:25][CH2:24][CH2:23]1Methyl 2-bromobenzo[d]thiazole-6-carboxylate (0.52 g, 1.90 mmol), Boc-piperazine (0.44 g. 2.38 mmol) and potassium carbonate (0.53 g, 3.80 mmol) were suspended in acetonitrile (21 ml) and refluxed overnight. The resulting mixture was then cooled to room temperature, concentrated in vacuo to approximately 2 ml, diluted with water and extracted with ethyl acetate. The organic layer was dried (MgSO4) and concentrated in vacuo to yield a residue which was treated with trifluoroacetic acid/dichloromethane (6 ml, 1:1) for 1.5 hrs. The resulting mixture was concentrated in vacuo, the resulting residue was dissolved in dichloromethane and washed with saturated sodium bicarbonate to yield methyl 2-(piperazin-1-yl)benzo[d]thiazole-6-carboxylate.
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