43 mg (0.08 mmol) of the compound from Example 132 were initially charged in 1 ml of DMF, and 14 mg (0.10 mmol) of HOBt and 19 mg (0.10 mmol) of EDC were added. After 10 min of stirring at RT, 0.41 ml (0.20 mmol) of ammonia solution (35% strength in water) was added, and the mixture was stirred at RT for 16 h. Under reduced pressure, the reaction solution was then freed of excess ammonia, about 3 ml of water were added and the mixture was extracted three times with in each case 5 ml of ethyl acetate. The combined organic phases were dried over magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified chromatographically on silica gel (mobile phase: cyclohexane/ethyl acetate 1:3→1:5). This gave 19 mg (42% of theory) of the target compound.
