[CH2:1]=[C:2]1[CH2:5][CH:4]([C:6](=O)[CH2:7][C:8](=O)[C:9]([O:11][CH2:12][CH3:13])=[O:10])[CH2:3]1.Cl.[CH:17]([NH:20][NH2:21])([CH3:19])[CH3:18]>CCO>[CH:17]([N:20]1[C:6]([CH:4]2[CH2:5][C:2](=[CH2:1])[CH2:3]2)=[CH:7][C:8]([C:9]([O:11][CH2:12][CH3:13])=[O:10])=[N:21]1)([CH3:19])[CH3:18]Compound 8b (6.29 g, 29.9 mmol) was dissolved in dry EtOH (65 mL, denaturated with 5% of MeOH) and isopropyl hydrazine hydrochloride (3.97 g, 35.9 mmol) was added. The reaction mixture was stirred for 3 h at rt. The solvent was removed and to the oily residue were added EA (100 mL), water (50 mL) and sat. NaHCO3 (50 mL) sequentially. The layers were separated and the aq. phase was re-extracted with EA (50 mL). The combined organic phases were washed with brine (70 mL) and dried over anh. Na2SO4. The solvent was removed under vacuum and the residue was dried under reduced pressure. Yield: 7.23 g (contains 3.4% of EtOAc by NMR, recalculated pure yield: 6.98 g, 94%). Crude product 8c is 98% pure by HPLC and NMR. 1H-NMR (CDCl3), δ (ppm): 6.62 (s, 1H), 4.88-4.82 (m, 2H), 4.42-4.32 (m, 3H), 3.56-3.45 (m, 1H), 3.17-3.07 (m, 2H), 2.88-2.79 (m, 2H), 1.49 (d, J=8.0 Hz, 6H), 1.37 (t, J=8.0 Hz, 3H).
Wird geladen…