[OH:1][N:2]=[C:3]([NH2:7])[CH:4]([OH:6])[CH3:5].[Cl:8][C:9]1[CH:10]=[C:11]([CH:15]=[CH:16][CH:17]=1)[C:12](Cl)=O.CCOCC.C([O-])(=O)C.[Na+]>C1COCC1.O>[Cl:8][C:9]1[CH:10]=[C:11]([C:12]2[O:1][N:2]=[C:3]([CH:4]([OH:6])[CH3:5])[N:7]=2)[CH:15]=[CH:16][CH:17]=1The title compound from Example 1 (6.45 g) was cooled on an ice-bath with 23.5 mL DEA in THF (200 mL). To this slurry 21.94 g 3-chlorobenzoyl chloride was added. The mixture was warmed to r.t. and stirred for 2 h. Addition of Et2O (200 mL), washing with sat. aq. NH4Cl and re-extraction of the aq. layer gave after combining and concentration of the org. layers followed by drying in vacuo 27.24 g, which was directly used in the next step. The material was dissolved in ethanol (250 mL) and refluxed for 1 h, followed by addition of 14.0 g (170 mmol) sodium acetate in water (40 mL). After refluxing over night, cooling to RT and addition of water (250 mL) the mixture was concentrated in vacuo to about half of its volume, resulting in a precipitate which was filtered off and recrystallized from EtOAc/heptane to yield 6.45 g (25%) of the title compound.
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