C([BH-](CC)CC)C.[Li+].[NH2:9][C:10]1[N:15]=[C:14]([OH:16])[C:13]([CH2:17][C:18]2[CH:27]=[CH:26][C:21]([C:22](OC)=[O:23])=[CH:20][C:19]=2[O:28][CH3:29])=[C:12]([CH3:30])[N:11]=1.O.Cl>C1COCC1>[NH2:9][C:10]1[N:15]=[C:14]([OH:16])[C:13]([CH2:17][C:18]2[CH:27]=[CH:26][C:21]([CH2:22][OH:23])=[CH:20][C:19]=2[O:28][CH3:29])=[C:12]([CH3:30])[N:11]=1Lithium triethylborohydride (93 mL) was added to a solution of the product from step (ii) (5.0 g) in THF (25 mL) over 5 min and the reaction mixture was stirred at RT for 3.5 h. Water (60 mL) and 2M-hydrogen chloride (40 mL) was added to the mixture. The organic solvent was removed by evaporation. 2M-hydrogen chloride (16 mL) was added and the mixture was stirred at RT for 4 h. The mixture was neutralized by saturated aqueous sodium hydrogen carbonate. The precipitate was collected by filtration, washed with water and dried in vacuo at 50° C. to afford the sub-title compound (4.7 g) as a white solid; 1H NMR (300 MHz, d6-DMSO); 10.76 (1H, br s), 6.89 (1H, s), 6.77-6.70 (2H, m), 6.30 (2H, br s), 5.10 (1H, t), 4.42 (2H, d), 3.79 (3H, s), 3.51 (2H, s), 1.91 (3H, s).
Wird geladen…