"Glutaric acid is the organic compound with the formula C3H6(COOH)2 . Although the related "linear" 
dicarboxylic acids adipic and succinic acids are water-soluble only to a few percent at room temperature, the water-solubility of glutaric acid is over 50%."
"Glutaric acid can be prepared by the ring-opening of butyrolactone with potassium cyanide to give the mixed potassium carboxylate-nitrile that is hydrolyzed to the diacid.[1] Alternatively hydrolysis, followed by oxidation of dihydropyran gives glutaric acid. It can also be prepared from reacting 1,3-dibromopropane with sodium or potassium cyanide to obtain the dinitrile, followed by hydrolysis."