(6-Bromobenzo[d][1,3]dioxol-5-yl)methanamine

Synthesis

General procedure for the synthesis of (6-bromo-benzo[d][1,3]dioxol-5-yl)methanamine from the compound (CAS: 65417-74-5): hydrochloric acid (2 N, 35.3 mL; 70.7 mmol, 10 eq.) was added to a tetrahydrofuran (THF, 80 mL) solution of hydroxylamine (7 mmol, 1 eq.), followed by zinc powder ( 4.62 g, 70.7 mmol, 10 equiv). The reaction mixture was stirred vigorously under reflux conditions until the reaction was complete. Upon completion of the reaction, the mixture was cooled to room temperature, filtered through a pad of diatomaceous earth and concentrated under reduced pressure to remove THF. The aqueous layer was extracted with ethyl acetate (EtOAc, 30 mL), followed by adjusting the pH of the aqueous layer to >10 by addition of saturated aqueous ammonia solution, and then extracted with ethyl acetate (3 x 30 mL). The organic layers were combined, dried with anhydrous potassium carbonate (K2CO3), filtered and the solvent evaporated to give the crude product. The crude product was purified by silica gel fast column chromatography (eluent: ethyl acetate/2% triethylamine) to afford 2-bromo-4,5-dimethoxybenzylamine (7) (1.43 g, 83% yield) as a white powder.1H NMR (300 MHz, CDCl3) δ (ppm): 6.98 (s, 1H), 6.89 (s, 1H), 3.85-3.81 (m, 8H). 8H). 13C NMR (75 MHz, CDCl3) δ (ppm): 148.5, 148.4, 134.2, 115.6, 113.2, 112.0, 56.2, 56.0, 46.6.

References

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