[C:1]([NH:9][C:10]1[CH:15]=[CH:14][N:13]([CH2:16][C:17]([O:19]C(C)(C)C)=[O:18])[C:12](=[O:24])[N:11]=1)(=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C1(C)C=CC=CC=1>FC(F)(F)C(O)=O>[C:1]([NH:9][C:10]1[CH:15]=[CH:14][N:13]([CH2:16][C:17]([OH:19])=[O:18])[C:12](=[O:24])[N:11]=1)(=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1The product from Example 18 is dissolved in trifluoroacetic acid (170 ml) and left at room temperature for 1 h 45 min. Subsequently, the mixture is codistilled five times with toluene and the product is dried in a desiccator over phosphorus pentoxide/potassium hydroxide for 24 h. Yield: 11.8 g (93%).
Wird geladen…