565 mg (2.82 mmol) of the compound from Example 171A and 0.26 ml (3.39 mmol) of trifluoroacetic acid were added to 500 mg (2.82 mmol) of the compound from Example 8A in 20 ml of dichloromethane. The reaction mixture was stirred at RT for 30 min, the solvent was removed in vacuo, and the crude product was then purified by preparative HPLC (mobile phase: acetonitrile/water gradient) and subsequent flash chromatography on silica gel (mobile phase: dichloromethane). 632 mg (62% of theory) of the title compound were obtained.
