Potassium Hydroxide → 3-(5-Bromobenzothiazole-2-ylmethyl)-4-oxo-3H-phthalazin-1-ylacetic acid

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Reaction Steps

A mixture of ethyl 3-(5-bromobenzothiazol-2yl- methyl)-4-oxo-3-H-phthalazin-1-ylacetate (15.0 g) and dioxane (150 ml) was brought to solution by warming on a steam bath and to this solution was added a solution of 10% potassium hydroxide (20 ml) in ethanol (50 ml.). The resulting dark purple solution was stirred at room temperature for 2 hours and concentrated to remove excess dioxane and ethanol. The concentrate was diluted with water (100 ml) and the resulting solution was washed with ether (2×100 ml). The aqueous layer was collected and acidified to pH 2.0 by addition of concentrated HCl. The precipitated solid was crystallized from methylene chloride/ethanol (400 ml/40 ml) to obtain the product (Yield 7.65 g; m.p. 214° C.).

Provenance & Evidence