Methyl chloroacetate → 7-Bromobenzofuran-2-carboxylic acid

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Reaction Steps

13.5 g (40.3 mmol) of 3-bromo-2-hydroxybenzaldehyde (Example 28A, 62% pure) are heated together with 9.18 g (84.62 mmol) of methyl chloroacetate, 1.49 g (4.03 mmol) of tetra-n-butylammonium iodide and 22.28 g (161.18 mmol) of potassium carbonate at 130° C. for 6 h. After cooling to RT, 100 ml of water and 100 ml of THF, and 13.57 g (241.77 mmol) of potassium hydroxide are added, and the mixture is stirred at RT overnight. The solvent is removed under reduced pressure, and the residue is taken up in 400 ml of water and washed four times with a total of 400 ml of diethyl ether. While cooling in ice, the pH is adjusted to 0 with concentrated hydrochloric acid and five extractions with a total of 700 ml of ethyl acetate are carried out. The organic phase is washed with 100 ml of saturated sodium chloride solution and then dried over magnesium sulphate. The crude product is completely freed of residual solvents under high vacuum and is stirred with 80 ml of diethyl ether. The product is filtered off and washed with a little ice-cold diethyl ether. 4.8 g (47% of theory) of the title compound are isolated.

Provenance & Evidence