N-bromobutanimide → Methyl 2-(3-bromo-5-formyl-4-hydroxyphenyl)acetate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a 2 L round bottom flask with magnetic stirrer, thermocouple, and ice water bath was added (3-formyl-4-hydroxyphenyl)acetic acid methyl ester (308 g, 1.59 mol) and N,N-dimethylformamide (1 L). The reaction mixture was stirred and cooled to −5 to 5° C. A solution of N-bromosuccinimide (311 g, 1.75 mol) in DMF (1.5 to 2 L) was added dropwise, at such a rate to keep the internal temperature between 5 and 10° C. Once the addition was complete, the reaction mixture was allowed to warm to room temperature and monitored for completion by HPLC analysis. The reaction time was about 4 h. The reaction mixture was diluted with isopropylacetate (3 L), and the resulting solution was extracted with water to remove the DMF. Concentration of the organic phase afforded a reddish solid that was dissolved in hot isopropanol (400 mL) and allowed to cool while stirring. The resulting off-white crystalline product was filtered and washed with cold IPA (−20° C.; 400 mL) to yield methyl (3-bromo-5-formyl-4-hydroxyphenyl)acetate (368 g, 84.7%) as off-white crystals.

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