A mixture of 200 mg (1.4 mmol) of the compound from Example 11A, 238 mg (1.7 mmol) of 3,3-difluoropyrrolidine hydrochloride and 289 μl (215 mg, 1.7 mmol) of N-ethyl-N-(propan-2-yl)propane-2-amine in 3 ml of water is stirred at 100° C. for 16 h. Following the addition of 53 μl (79 mg, 0.7 mmol) of trifluoroacetic acid and 324 mg (1.4 mmol) of the compound from Example 6A, the reaction mixture is stirred at 100° C. for 16 h. 1 ml of 1 N hydrochloric acid is added to the reaction mixture. The resulting precipitated hydrochloride of the crude product is filtered off, washed with diethyl ether and dried. The crude product still contains unreacted starting material (compound from Example 11A). Accordingly, the crude product is reacted with 108 μl (80 mg, 0.6 mmol) of N-ethyl-N-(propan-2-yl)propane-2-amine, 10 mg (0.1 mmol) of 3,3-difluoropyrrolidine hydrochloride and 2 ml of water in a single mode microwave (Emrys Optimizer) at 170° C. for 15 min. The reaction solution purified by preparative HPLC (RP18 column; mobile phase: acetonitrile/water gradient). Yield: 30 mg (6% of theory)
