Sodium Hydroxide → 6-Bromo-2-hydroxynaphthalene-1-carboxylic acid

Participants

Reaction Steps

To a ice-cooled mixture of 6-Bromo-2-hydroxy-1-naphthaldehyde (24.0 g) and aqueous NaH2PO4 solution (3.2 g in 30 mL of water) in DMSO (160 mL) was added dropwise a solution of NaClO2 (80%; 15.1 g) in water (150 mL) over 1 h. After being stirred for 5 h at room temperature, a solution of NaClO2 (80%; 2.16 g) in water (20 mL) was added, and the reaction mixture was further stirred for 2 h at room temperature. The mixture was alkalized with 1N-NaOH, and the precipitate was filtered off. The filtrate was washed with AcOEt and iPr2O, and then the aqueous phase was acidified with conc. HCl. The precipitate was filtered, washed with water, and dried in vacuo to give the title compound (22.3 g) as a brown powder.

Provenance & Evidence