Sodium Hydroxide → [(6,7-Dichloro-2-(1-hydroxyethyl)benzo[b]thien-5-yl)oxy]acetic acid

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Reaction Steps

To 16 g of ethyl[(6,7-dichloro-2-(1-hydroxyethyl)benzo[b]thien-5-yl)oxy]acetate in 300 ml 95% ethanol is added 300 ml of a 6N sodium hydroxide and the mixture is refluxed at 100° for 30 mins. The cooled mixture is concentrated to a white slurry which is diluted with 200 ml of ice-water and 200 ml of ethyl ether. With stirring and efficient cooling, the mixture is acidified with 6N hydrochloric acid. The acidic mixture is extracted with ethyl ether. The ether extracts are washed, dried over anhydrous magnesium sulfate, filtered and the solvent is removed. Recrystallization of the crude product from acetone and hexane gives 11.4 g of [(6,7-dichloro-2-(1-hydroxyethyl)benzo[b]thien-5-yl)oxy]acetic acid, mp 173°-175°.

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