title: The thulium complex of 1,4,7,10-tetrakis{[N-(1H-imidazol-2-yl)carbamoyl]methyl}-1,4,7,10-tetraazacyclododecane (dotami) as a ParaCEST contrast agent.
abstract: 1,4,7,10-Tetrakis{[N-(1H-imidazol-2-yl)carbamoyl]methyl}-1,4,7,10-tetraazacyclododecane (dotami), a tetra(1H-imidazol-2-yl) derivative of the well-studied octadentate 1,4,7,10-tetrakis[(carbamoyl)methyl]-1,4,7,10-tetraazacyclododecane (dotam) ligand, was synthesized by reaction of 1,4,7,10-tetraazacyclododecane with N-(1H-imidazol-2-yl)chloroacetamide in high yield. Its tricationic thulium complex was isolated as a water-soluble chloride salt. The detection of the mildly acidic amide and amine protons by direct proton NMR in aqueous solution was unsuccessful, but such exchangeable protons could be detected via their chemical exchange-dependent saturation transfer (CEST) effect. The observed CEST effect was distinctly different from that found for respective dotam complexes and is, therefore, ascribed to exchangeable protons associated with the imidazole substituent.
authors: Department of Bio-Molecular Engineering, Philips Research, High Tech Campus 11, NL-5656 AE Eindhoven (phone: +31-40-27-48254; fax: +31-40-27-44906).
authors: Dirk
authors: D
authors: Burdinski
authors: Department of Bio-Molecular Engineering, Philips Research, High Tech Campus 11, NL-5656 AE Eindhoven (phone: +31-40-27-48254; fax: +31-40-27-44906).
authors: Johan
authors: J
authors: Lub
authors: Department of Materials Analysis, Philips Research, High Tech Campus 11, NL-5656 AE Eindhoven.
authors: Jeroen A
authors: JA
authors: Pikkemaat
authors: Department of Bio-Molecular Engineering, Philips Research, High Tech Campus 11, NL-5656 AE Eindhoven (phone: +31-40-27-48254; fax: +31-40-27-44906).
authors: Sander
authors: S
authors: Langereis
authors: Department of Bio-Molecular Engineering, Philips Research, High Tech Campus 11, NL-5656 AE Eindhoven (phone: +31-40-27-48254; fax: +31-40-27-44906).
authors: Holger
authors: H
authors: Grüll
authors: Syncom B. V., Kadijk 3, NL-9747 AT Groningen.
authors: Wolter
authors: W
authors: Ten Hoeve
mesh_terms: D000577:Amides / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry*; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011522:Protons; D012015:Reference Standards; D013237:Stereoisomerism; D013932:Thulium / Q000737:chemistry*
chemical_list: C533989:(1,4,7,10-tetrakis((N-(1H-imidazol-2-yl)carbamoyl)methyl)-1,4,7,10-tetraazacyclododecane)thulium(III); D000577:Amides; D000588:Amines; D003287:Contrast Media; D008024:Ligands; D009942:Organometallic Compounds; D011522:Protons; D013932:Thulium