2,3,4-Trimethoxy-6-methylbenzaldehyde → 2,3,4-Trimethoxy-6-methylbenzoic acid

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Reaction Steps

45.6 g (217 mmol) of 2,3,4-trimethoxy-6-methylbenzaldehyde was dissolved in 130 ml of dimethyl sulfoxide, and an aqueous solution (50 ml) of 5.2 g (44 mmol) of sodium dihydrogen phosphate was dropwise added over a period of 20 minutes. Then, an aqueous solution (180 ml) of 28 g (305 mmol) of sodium chlorite was dropwise added over a period of 3 hours, followed by stirring for 2 hours. A saturated sodium hydrogencarbonate aqueous solution was added until no bubbling occurred, followed by stirring for 1 hour. Then, the reaction solution was washed with 50 ml of ethyl acetate twice, and concentrated hydrochloric acid was added to make the aqueous layer acidic, followed by extraction with ethyl acetate. The organic layer was washed with a saturated sodium chloride solution, dried over anhydrous sodium sulfate and subjected to filtration, and the solvent was distilled off under reduced pressure. The obtained crystals were washed with hexane to obtain 45.6 g (yield: 93%) of 2,3,4-trimethoxy-6-methylbenzoic acid (melting point 95 to 97° C.).

Provenance & Evidence