Sulfamic Acid → 3-bromo-4,5-dimethoxybenzoic acid

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Reaction Steps

To a stirred solution of 3-bromo-4,5-dimethoxybenzaldehyde (5.0 g, 20.5 mmol, 1 eq.) in CH3CN (192 mL) at room temperature was added a solution of sulfamic acid (2.55 g, 26.3 mmol) in H2O (32 mL) followed by a dropwise addition of a solution of NaClO2 (3.03 g, 26.8 mmol, 1.3 eq.) in H2O (32 mL) over 20 min period. After stirring for 30 min at room temperature, the solvent was removed in vacuo. The residue was dissolved in 1.0 M aqueous HCl (300 mL) and extracted with EtOAc (3×100 mL). The combined organic layer was washed with brine (300 mL), dried over Na2SO4 and concentrated in vacuo to give 3-bromo-4,5-dimethoxybenzoic acid (5.0 g). The product was used without further purification.

Provenance & Evidence