Sulfuric Acid → 5-Bromo-2-fluoro-1,3-dimethylbenzene

Beteiligte Stoffe

Reaktionsschritte

To a mixture of 4-Bromo-2,6-dimethylaniline (8.3 g, 42 mmol) at 5° C. and H2O (50 mL) was added conc H2SO4 (6.25 mL). NaNO2 (4.1 g) was added in portions until an excess was indicated by starch iodide paper. Water (30 mL) was added to make the mixture homogeneous. After transferring to a plastic container, HBF4 (50%, 13.7 g) was added dropwise with stirring. The resultant white precipitate was collected by vacuum filtration, washed with H2O (30 mL), MeOH (30 mL), and Et2O (60 mL), and dried over P2O5 under vacuum for 16 h. The solid was then heated in a glass flask with an open flame until all the solid had decomposed. The remaining liquid was diluted with Et2O (50 mL) and 0.5 M NaOH (30 mL). The organic layer was separated, washed with 0.5 M NaOH (25 mL), H2O (25 mL), brine (25 mL), dried (MgSO4), and concentrated in vacuo yielding 6.06 g (72%) of 1-bromo-4-fluoro-3,5-dimethylbenzene as a pale yellow liquid.

Herkunft & Nachweise