[F:1][C:2]1[CH:16]=[CH:15][C:5]2[C:6]([CH:9]3[CH2:14][CH2:13][NH:12][CH2:11][CH2:10]3)=[N:7][O:8][C:4]=2[CH:3]=1.C([O-])([O-])=O.[K+].[K+].Br[CH2:24][C:25]([NH2:27])=[O:26]>C(#N)C>[F:1][C:2]1[CH:16]=[CH:15][C:5]2[C:6]([CH:9]3[CH2:10][CH2:11][N:12]([CH2:24][C:25]([NH2:27])=[O:26])[CH2:13][CH2:14]3)=[N:7][O:8][C:4]=2[CH:3]=1The mixture of 4-(6-fluoro-1,2-benzisoxazol-3-yl)piperidine (6.77 g, 30.7 mmol), K2CO3 (5 g, 36.2 mmol) and 2-bromoacetamide (4.46 g, 32.3 mmol) in acetonitrile (250 ml) was heated to reflux for 4 hours. The insolubles were filtered and rinsed with dichloromethane (DCM). The solvents were removed. The residual solid was dissolved in DCM and upon concentration of this solution, 2.3 g of product crystallized out and was collected when the volume was reduced to about 50 ml. The rest of the product in DCM was purified by flash chromatography over a silica gel column (80 gm, SiO2 ; eluted with DCM and 1% CH3OH in DCM). The total product (4.2 g) thus purified was recrystallized from ethanol to yield 2.82 g of white crystals, m.p. 170°-172° C. dec.
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