反应详情

To 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.

1. temperatureThe reaction mixture is heated
2. temperatureto reflux for 5.5 hours
3. customAcetic acid is removed in vacuo
4. additionthe residue is added water (20 mL)
5. extractionextracted with DCM (3×50 mL), organic layers
6. washwashed with 2 N sodium hydroxide, water and brine
7. dry with materialdried over sodium sulfate
8. concentrationconcentrated
9. customThe solid obtained
10. customis crystallized in methanol/DCM (1:1)