[C:1]([O:5][C:6]([NH:8][CH:9]([CH:13]([CH3:15])[CH3:14])[C:10]([OH:12])=[O:11])=[O:7])([CH3:4])([CH3:3])[CH3:2].[C:16]([O-])(O)=O.[Na+].[CH2:21]([Cl:23])Cl>O>[C:1]([O:5][C:6]([NH:8][CH:9]([CH:13]([CH3:15])[CH3:14])[C:10]([O:12][CH:21]([Cl:23])[CH3:16])=[O:11])=[O:7])([CH3:4])([CH3:3])[CH3:2]The title compound was prepared according to the procedure as described in Example 17 step 1 using 2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (3 g, 13.81 mmol) in DCM (75 mL) and H2O (75 mL), NaHCO3 (4.64 g, 55.23 mmol), TBAHSO4 (469 mg, 1.38 mmol) and a solution of 1-chloroethyl sulfochloridate (2.97 g, 16.57 mmol) in DCM (15 mL). The crude product was purified by a silica gel column chromatography (PE/EtOAc (v/v)=100/1 to 50/1) to afford the title compound as a white solid (3 g, 78%). The title compound was characterized by 1H NMR as shown below:
Wird geladen…
