Cyclen (1,4,7,10-Tetraazacyclododecane)

About This Product

Cyclen, 1,4,7,10-tetraazacyclododecane, has the formula C8H20N4, a molecular weight of 172.3 and CAS number 294-90-6. It is a white to off-white powder: a twelve-membered ring in which four nitrogen atoms alternate with ethylene bridges. The four ring nitrogens point inward and are held in a geometry that suits large metal ions, so cyclen and its N-substituted derivatives bind lanthanides, including gadolinium, and many other metals with exceptional kinetic stability. Almost every macrocyclic gadolinium contrast agent starts from it: tetra-alkylation with acetic acid groups gives DOTA, the ligand of gadoteric acid, while tri-alkylation gives DO3A, the route to gadoteridol and gadobutrol. The same chemistry supplies the DOTA-type chelators used to attach radiometals to targeting molecules in nuclear medicine. Impurities in the ring compound, such as open-chain polyamines, carry through into the ligand and compete for the metal, which is why identity is confirmed both by copper complex formation and by chromatographic retention, with water held to 1.0 percent and residue on ignition to 0.5 percent. It is used in the synthesis of DOTA, DO3A and related chelating ligands, in gadolinium contrast-agent manufacture, in radiopharmaceutical chelator development and in coordination chemistry research. Bio Green Chem supplies cyclen at 98 percent minimum to specification on appearance, identification, appearance of solution, water, residue on ignition and alkalinity, packed in fibre drums or bags. Regulatory documentation for pharmaceutical use is confirmed at enquiry.