Ethyl sulfate process in which ethylene is reacted with sulfuric acid to produce ethyl sulfate followed by hydrolysis, but this method has been mostly replaced by direct hydration of ethylene. Ethyl sulfate can be produced in a laboratory setting by reacting ethanol with sulfuric acid under a gentle boil, while keeping the reaction below 140 °C. The sulfuric acid must be added dropwise or the reaction must be actively cooled because the reaction itself is highly exothermic. If the temperature exceeds 140 °C, the ethyl sulfate product tends to react with residual ethanol starting material, producing diethyl ether. If the temperature exceeds
Ethyl cyanohydroxyiminoacetate to HOAt without presenting an explosion risk such as the benzotriazoles. With water-soluble derivatives of ethyl cyanohydroxyiminoacetate (glyceroacetonide-oxyma) as additive and DIC as coupling reagent even in weakly basic aqueous solutions the linking of protected amino acids to oligopeptides is possible with a yield of 95% and a diastereomeric excess of> 99% using the model substances Z-"L"-Phg-OH and "L"-H-Pro-NH. In the coupling of amino acids, frequently occurring secondary reactions largely suppressed, which would be the formation of symmetrical acid anhydrides, racemization and epimerization and the cyclization to oxazolinones or - especially for dipeptides - to 2,5-diketopiperazines. Ethyl cyanohydroxyiminoacetate Ethyl cyanohydroxyiminoacetate