Hydrogen Bromide → 9-[[(o-carboethoxy)benzyl]oxy]-4-oxo-4H-pyrido[1,2-alpha]-pyrimidine-3-carboxylic Acid, Ethyl Ester, Hydrobromide

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Reaction Steps

To a solution of 5.0 g of ethyl α-bromo-o-toluate, 4.7 g of 9-hydroxy-4-oxo-4H-pyrido[1,2-α]pyrimidine-3-carboxylic acid, ethyl ester, and 200 ml of ethyl methyl ketone is added 3.9 g of anhydrous dipotassium hydrogen phosphate and the mixture stired and heated under reflux for 18 hours. The cooled mixture is filtered, and the filtrate is concentrated in vacuo to give a semi-solid product. To this product, 3.9 g, in 10 ml of acetic acid is added a solution of 0.81 g of hydrogen bromide in 4 ml of glacial acetic acid, dropwise, with agitation. The crystalline product that separates is filtered, washed with anhydrous ether, and recrystallized from acetonitrile to give the named product.

Provenance & Evidence