Bromide ion → 3-Methyl-6-tetradecyloxybenzofuran-2-carboxylic acid

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Reaction Steps

10.9 g (0.0292 mole) of 7-tetradecyloxy-4-methyl-coumarin and 250 ml of dry methylene chloride is stirred at room temperature. 4.68 g (0.0292 mole) of bromide and 100.0 ml of dry methylene chloride are added over a period of 20 minutes. The mixture is stirred at room temperature for 1 hour and refluxed for 15 minutes. The mixture is then cooled and extracted with 10% Na2SO3. It is washed with a saline solution, dried (Na2SO4) and evaporated to dryness. The product obtained is stirred into a cold solution of 60 g KOH and 150 ml of ethanol. The mixture is heated to reflux for 2 hours and then is diluted with water. After refluxing is continued for about 10 minutes, it is poured into 1 liter of water, acidified with concentrated HCl and extracted with diethyl ether. The ether layer is washed with water and saline solution, dried (Na2SO4) and evaporated with replacement of the solvent with a total volume of 150 ml of hexane. The mixture is allowed to stand at room temperature. The product is collected and dried, yielding 10.4 g (92%) of 3-methyl-6-tetradecyloxybenzofuran-2-carboxylic acid, m.p. 108°-110° C. The mother liquor is concentrated to about 50 ml and cooled, yielding an additional 0.4 g of the 3-methyl-6-tetradecyloxy-benzofuran-2-carboxylic acid, m.p. 105°-108° C. (Overall yield -- 96%.)

Provenance & Evidence