Ethyl cyanohydroxyiminoacetate Ethyl cyanohydroxyiminoacetate Ethyl cyanohydroxyiminoacetate (oxyma) is the oxime of ethyl cyanoacetate and finds use as an additive for carbodiimides, such as dicyclohexylcarbodiimide (DCC) in peptide synthesis. It acts as a neutralizing reagent for the basicity or nucleophilicity of the DCC due to its pronounced acidity (pKa 4.60) and suppresses base catalyzed side reactions, in particular racemization. Ethyl cyanohydroxyiminoacetate is obtained in the reaction of ethyl cyanoacetate and nitrous acid (from sodium nitrite and acetic acid) in 87% yield. Because of the rapid hydrolysis of the ester, the reaction should be carried out at pH 4.5, in buffered phosphoric acid the
Ethyl sulfate 170 °C in a considerable excess of sulfuric acid, the ethyl sulfate breaks down into ethylene and sulfuric acid. The mechanism of the formation of ethyl sulfate, diethyl ether, and ethylene is based on the reaction between ethanol and sulfuric acid, which involves protonation of the ethanolic oxygen to form the oxonium ion. Ethyl sulfate acculates in hair after chronic alcohol consumption and its detection can be used as a biomarker for alcohol consumption. Ethyl sulfate can exist in salt forms, such as sodium ethyl sulfate, potassium ethyl sulfate, and calcium ethyl sulfate. The salt can be formed by adding