Sodium ethyl xanthate Sodium ethyl xanthate Sodium ethyl xanthate (SEX) is an organosulfur compound with the chemical formula CHCHOCSNa. It is a pale yellow powder, which is usually obtained as the dihydrate. Sodium ethyl xanthate is used in the mining industry as a flotation agent. A closely related potassium ethyl xanthate (KEX) is obtained as the anhydrous salt. As with most xanthates, sodium ethyl xanthate can be prepared by treating sodium ethoxide with carbon disulfide: Sodium ethyl xanthate is a pale yellow powder. It is relatively stable in water at high pH if not heated. It rapidly hydrolyses at pH <9 at 25
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