[Cl:1][C:2]1[CH:7]=[C:6]([N+:8]([O-:10])=[O:9])[C:5]([Cl:11])=[CH:4][C:3]=1[CH2:12][CH:13]=O.C(O)(=O)C.[C:19]([O:23][C:24]([N:26]1[CH2:31][CH2:30][NH:29][CH2:28][CH2:27]1)=[O:25])([CH3:22])([CH3:21])[CH3:20].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>C(Cl)Cl>[Cl:11][C:5]1[CH:4]=[C:3]([CH2:12][CH2:13][N:29]2[CH2:28][CH2:27][N:26]([C:24]([O:23][C:19]([CH3:22])([CH3:21])[CH3:20])=[O:25])[CH2:31][CH2:30]2)[C:2]([Cl:1])=[CH:7][C:6]=1[N+:8]([O-:10])=[O:9]A methylene chloride solution of the title compound of Example 10 was stirred at room temperature under nitrogen. Acetic acid (8.8 ml, 153 mmol) was added in one portion followed by t-butylpiperazinecarboxylate (8.4 g, 50 mmol). Sodium triacetoxy-borohydride (16.2 g, 77 mmol) was added in portions as a solid and the reaction mixture stirred at room temperature for three hours. The reaction mixture was washed two times with excess saturated sodium carbonate solution and one time each with water and brine. The organic layer was dried over magnesium sulfate, filtered and evaporated to afford the title product as an oil 15.6 g, (98% crude yield). This was suitable for use in the next reaction without further purification. NMR (CDCl3) δ 7.92 (s, 1), 7.48 (s, 1), 3.43 (m, 4), 2.97 (t, 2), 2.62 (t, 2), 2.49 (m, 4), 1.43 (s, 9).
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