Water → 1,4,7,10-Tetraazacyclododecane

Participants

Reaction Steps

50 g of triethylenetetramine (0.342 mol) is dissolved in 1 l of ethanol and mixed at room temperature with 39 ml of 40% glyoxal in water (0.342 mol). After 20 hours of stirring, the solvent is distilled off in a vacuum, and an orange-colored oil is obtained, which then is taken up in 400 ml of dimethylformamide and mixed with 88.5 ml (192.8 g=1.026 mol) of 1,2-dibromoethane. After 6 hours of stirring at 40° C., it is concentrated by evaporation in a vacuum, the residue is taken up in 400 ml of ethanol and acidified to pH=3-4 with 37% aqueous hydrochloric acid. 166 ml (171 g=3.42 mol) of hydrazine hydrate is added to this reaction solution at room temperature, and it is heated under reflux for 30 hours. The reaction solution is set at pH=13 with solid potassium hydroxide. The reaction solution is subsequently concentrated by evaporation in a vacuum, taken up once more in 100 ml of ethanol, and the solvent is removed again in a vacuum. The residue is mixed with 25 g of activated carbon and 150 ml of formaldehyde diethylacetal, and it is heated under reflux for some time before the hot solution is filtered through a membrane. After the solution is cooled, the product is isolated by filtration.

Provenance & Evidence