[F:1][C:2]1([F:13])[O:6][C:5]2[CH:7]=[CH:8][C:9]([CH:11]=O)=[CH:10][C:4]=2[O:3]1.[N+:14]([CH3:17])([O-:16])=[O:15].C([O-])(=O)C.[NH4+]>C(O)(=O)C>[F:1][C:2]1([F:13])[O:6][C:5]2[CH:7]=[CH:8][C:9]([CH:11]=[CH:17][N+:14]([O-:16])=[O:15])=[CH:10][C:4]=2[O:3]1To a solution of 2,2-difluoro-benzo[1,3]dioxole-5-carbaldehyde [5.48 g, 29.44 mmol, Intermediate (60)] and nitromethane (4.78 mL, 88.32 mmol) in acetic acid (90 mL) is added ammonium acetate (5.67 g, 73.6 mmol). The reaction mixture is heated to reflux for 5.5 hours. Acetic acid is removed in vacuo and the residue is added water (20 mL) and extracted with DCM (3×50 mL), organic layers are combined and washed with 2 N sodium hydroxide, water and brine, dried over sodium sulfate and concentrated. The solid obtained is crystallized in methanol/DCM (1:1) to yield intermediate 2,2-difluoro-5-(2-nitro-vinyl)-benzo[1,3]dioxole [3.83 g, Intermediate (61)] as a solid.
Wird geladen…
