Cl[C:2]1[CH:7]=[N:6][CH:5]=[C:4]([Cl:8])[N:3]=1.[OH:9][CH:10]1[CH2:15][CH2:14][N:13]([C:16]([O:18][C:19]([CH3:22])([CH3:21])[CH3:20])=[O:17])[CH2:12][CH2:11]1>CCN(CC)CC>[Cl:8][C:4]1[N:3]=[C:2]([O:9][CH:10]2[CH2:11][CH2:12][N:13]([C:16]([O:18][C:19]([CH3:22])([CH3:21])[CH3:20])=[O:17])[CH2:14][CH2:15]2)[CH:7]=[N:6][CH:5]=1A mixture of 2,6-dichloropyrazine (5.00 g, 33.6 mmol), tert-butyl 4-hydroxy-1-piperidinecarboxylate (6.76 g, 33.6 mmol) and K-t-BuO (1 M in tert-butanol; 35 mL, 35 mmol) in Et3N (200 mL) was stirred at room temperature for 12 h. The reaction was quenched with water (50 mL) and concentrated in vacuo. The residue was dissolved in ethyl acetate, washed with saturated aqueous KH2PO4, dried (MgSO4), and concentrated in vacuo. The residue was recrystallized from ethanol/water to give 9.50 g (90%) of the title compound as a white solid: mp 86-87° C.; MS m/z 313 (M)+. Anal. (C14H20ClN3O3) C, H, N.
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