C([C@@H]1C(OC)=[N:8][C@@H:7]([CH2:12][CH2:13][CH:14]([C:19]2[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=2)[C:15]([F:18])([F:17])[F:16])[C:6]([O:25][CH3:26])=N1)(C)C.O.FC(F)(F)C(O)=[O:31].[Cl-].[NH4+]>C(#N)C>[CH3:26][O:25][C:6](=[O:31])[C@@H:7]([NH2:8])[CH2:12][CH2:13][CH:14]([C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1)[C:15]([F:18])([F:17])[F:16]To a solution of (2R,5S)-2-isopropyl-3,6-dimethoxy-5-(4,4,4-trifluoro-3-phenyl-butyl)-2,5-dihydro-pyrazine (1.86 g) in acetonitrile (18 ml) were added water (7 ml) and trifluoroacetic acid (3.8 ml). The mixture was stirred overnight at 40° C. Saturated ammonium chloride solution was added and the mixture was extracted with dichloromethane three times. The combined organic layers were dried (MgSO4), filtered and evaporated. The residue was purified by column chromatography (SiO2, EtOAc/MeOH=98:2 to yield a light yellow solid, (0.98 g, 71%); MS (ISP): 276.1 ((M+H)+).
Wird geladen…