[CH2:1]([O:3][C:4]1[CH:5]=[C:6]([N:13]2[CH2:18][CH2:17][NH:16][CH2:15][CH2:14]2)[CH:7]=[CH:8][C:9]=1[N+:10]([O-:12])=[O:11])[CH3:2].[CH3:19][C:20]([CH3:22])=O.C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+].CC(O)=O>ClCCCl.C(Cl)Cl.C([O-])(O)=O.[Na+]>[CH2:1]([O:3][C:4]1[CH:5]=[C:6]([N:13]2[CH2:14][CH2:15][N:16]([CH:20]([CH3:22])[CH3:19])[CH2:17][CH2:18]2)[CH:7]=[CH:8][C:9]=1[N+:10]([O-:12])=[O:11])[CH3:2]A mixture of 1-[3-(ethyloxy)-4-nitrophenyl]piperazine (Example 143, step A) (0.285 g, 1.13 mmol)) and acetone (0.13 g, 2.26 mmol) was stirred in DCE (5 mL) at rt under N2. To this mixture was added sodium triacetoxyborohydride (0.60 g, 2.8 mmol) and HOAc (0.136 g, 2.26 mmol). The reaction was stirred for approximately 24 h. The reaction was diluted with DCM and aqueous (saturated) NaHCO3. The aqueous layer was extracted with DCM (2×). The combined organic layers were dried over MgSO4, filtered, concentrated, and chromatographed on silica gel to give the title compound of step A (291 mg, 0.99 mmol, 88%) as a yellow solid. MS (ESI): 294 [M+H]+.
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