Hydrochloric Acid → 4-(9,10-dihydro-4-oxo-4H-benzo[4,5]cyclohepta[1,2-b]thiophen-2-yl)-4-oxobutyric acid

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Reaction Steps

A solution of 3.0 g of 4-(9,10-dihydro-4- oxo-4H-benzo[4,5]cyclohepta[1,2-b]thiophen-2-yl)-4- oxobutyric acid methyl ester and 1.5 g of potassium hydroxide in 60 cc of dioxane and 30 cc of water is stirred at room temperature for 3 hours, dilution is effected with 200 cc of water and the pH of the solution is adjusted to 1 with concentrated hydrochloric acid at 10°-15°. The resulting title compound is extracted with methylene chloride, the organic solution is washed with water, dried over magnesium sulphate, concentrated by evaporation, and the title compound is recrystallized from dimethyl formamide/acetone. M.P. 167°-168°.

Provenance & Evidence