Synlett 2006(17): 2815-2817  
DOI: 10.1055/s-2006-950281
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of a Novel Lipophilic Gadolinium Complex as a Potential MRI Contrast Agent

Andrea Masotti*a, Laura Remollinoa, Maria Carafab, Carlotta Marianeccic, Eleonora Santuccic, Giancarlo Ortaggia
a Department of Chemistry, University ‘La Sapienza’, 00185 Rome, Italy
Fax: +39(06)233234321; e-Mail: andrea.masotti@uniroma1.it ;
b Department of Scienze del Farmaco, Faculty of Pharmacy, University ‘G. D’Annunzio’, 66100 Chieti, Italy
c Department of Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Faculty of Pharmacy, University ‘La Sapienza’, 00185 Rome, Italy
Further Information

Publication History

Received 6 July 2006
Publication Date:
09 October 2006 (online)

Abstract

The synthesis of a novel lipophilic diethylentriamino­tetracetic(DTTA)-dodecane gadolinium complex is reported. The Gd-DTTA-dodecane complex is able to form mixed micelles with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and a non-ionic surfactant like Tween 80. This novel multicomponent system can find potential application in magnetic resonance angiography (MRA).

    References and Notes

  • 1 Rinck PA. Magnetic Resonance in Medicine   Blackwell Scientific Publications; Oxford, UK: 1993. 
  • 2 Merbach AE. Tóth É. The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging   John Wiley & Sons Ltd; Chichester: 2001. 
  • 3 Caravan P. Ellison JJ. McMurry TJ. Lauffer RB. Chem. Rev.  1999,  99:  2293 
  • 4 Masotti A. Mangiola A. Sabatino G. Maira G. Denaro L. Conti F. Ortaggi G. Capuani G. Int. J. Immunopathol. Pharmacol.  2006,  19:  11 
  • 5 Reichert DE. Lewis JS. Anderson CJ. Coord. Chem. Rev.  1999,  184:  3 
  • 6 Thunus L. Lejeune R. Coord. Chem. Rev.  1999,  184:  125 
  • 7 Lattuada L. Lux G. Tetrahedron Lett.  2003,  44:  3893 
  • 8 Kroft LJM. de Roos A. J. Magn. Reson. Imaging  1999,  10:  395 
  • 9 Bogdanov AA. Lewin M. Weissleder R. Adv. Drug Deliv. Rev.  1999,  37:  279 
  • 10 Ladd DL. Hollister R. Peng X. Wei D. Wu G. Delecki D. Snow RA. Toner JL. Kellar K. Eck J. Desai VC. Raymond G. Kinter LB. Desser TS. Rubin DL. Bioconjugate Chem.  1999,  10:  361 
  • 11 Krause W. Hackmann-Schlichter N. Maier FK. Müller R. Top. Curr. Chem.  2000,  210:  261 
  • 12 Glogard C. Stensrud G. Hovland R. Fossheim SL. Klaveness J. Int. J. Pharm.  2002,  233:  131 
  • 13 Alhaique F. Bertini I. Fragai M. Carafa M. Luchinat C. Parigi G. Inorg. Chim. Acta  2002,  331:  151 
  • 14 Tournier H. Hyacinthe R. Schneider M. Acad. Radiol.  2002,  9 (Suppl. 1):  S20 
  • 15 Glogard C. Hovland R. Fossheim SL. Aasen AJ. Klaveness J. J. Chem. Soc., Perkin Trans. 2  2000,  1047 
  • 16 Anelli PL. Lattuada L. Lorusso V. Schneider M. Tournier H. Uggeri F. MAGMA  2001,  12:  114 
  • 17 Lauffer RB. Chem. Rev.  1987,  87:  901 
  • 18 Gouin S. Winnik FM. Bioconjugate Chem.  2001,  12:  372 
  • 19 Hovland R. Glogard C. Aasen AJ. Klaveness J. Org. Biomol. Chem.  2003,  1:  644 
  • 20 Hovland R. Aasen AJ. Klaveness J. Org. Biomol. Chem.  2003,  1:  1707 
21

Compound 2: A solution of 1-bromododecane (20 g, 80 mmol) in EtOH (100 mL) was added over 1 h to a stirred solution of diethylentriamine 1 (8.25 g, 80 mmol) in EtOH (100 mL) at r.t. NaOH (0.1 M) was added to the reaction mixture until the pH >7. The resulting solution was heated at 95 °C for 6 h, stirred at r.t. for 18 h, and then the solvent was evaporated under reduced pressure. The crude oil was purified by distillation collecting the fraction with a boiling point of 265-270 °C, which furnished 2 as a transparent oil (9.46 g, 41%). 1H NMR (300 MHz, D2O): δ = 0.96 (CH3, t, 3 H), 1.37 (CH2, br, 18 H), 1.56 (CH2, m, 2 H), 2.51 (CH2N, t, 2 H), 2.73 (CH2N, t, 2 H), 2.83 (CH2N, br, 4 H), 2.87 (CH2N, t, 2 H). 13C NMR (300 MHz, D2O): δ = 13.41, 22.03, 26.88, 28.97, 29.19 (br m), 29.55, 31.28, 41.08, 48.73, 48.90, 49.40, 51.86. ESI-MS: m/z = 272.3 [M + H]+. Anal. Calcd for C16H37N3: C, 70.77; H, 13.74; N, 15.48. Found: C, 71.01; H, 13.93; N, 15.53. Compound 3: To a solution of 2 (2.7 g; 10 mmol) in THF (250 mL), was added bromoacetic acid (13.9 g, 0.1 mol, 10 equiv) in H2O (100 mL) over 2 h; the pH of the reaction mixture was maintained at 12 by the constant addition of NaOH (0.1 M). The mixture was heated at 95 °C for 6 h, then the solvent was evaporated under reduced pressure. The milky residue was treated with HCl until the solution was pH 1 and the resulting acidic solution was filtered. The solid was washed several times with cold EtOH and dissolved again in H2O (pH 8). The solution was treated with HCl until a precipitate formed. The white solid was filtered, washed several times with cold H2O, and dried in a vacuum desiccator (1.1 g; 22%). 1H NMR (300 MHz, D2O): δ = 0.65 (CH3, t, 3 H), 1.04 (CH2, br, 20 H), 2.24 (CH2N, m, 2 H), 2.32 (CH2N, m, 8 H), 2.83 (CH2COOH, br, 8 H). 13C NMR (300 MHz, D2O): δ = 14.18, 22.77, 25.22, 27.82, 29.52, 29.80 (br m), 32.06, 51.18, 52.26, 52.65, 55.10, 58.46, 59.02, 59.41, 179.34. ESI-MS: m/z = 262.96 [M + Na]2+. Anal. Calcd for C24H45N3O8: C, 57.24; H, 9.01; N, 8.34. Found: C, 57.17; H, 9.24; N, 8.33. Compound 4: A solution of GdCl3·6H2O (0.148 g, 0.4 mmol) in H2O (20 mL) was added dropwise to a solution of 3 (0.2 g, 0.4 mmol) in H2O (100 mL) and NaOH (2 M, 5 mL); the pH of the reaction mixture was maintained at 12 by the constant addition of NaOH (2 M). After 6 h the solution was concentrated to 25 mL and absolute EtOH (100 mL) was added. The precipitate was washed several times with EtOH, filtered, and dried in vacuo to obtain the complex 4 as a white solid (0.12 g, 46%). ESI-MS: m/z = 219.20 [M + Gd]3+. Anal. Calcd for C24H41N3O8Gd·4H2O: C, 39.55; H, 6.78; N, 5.76. Found: C, 40.01; H, 6.93; N, 5.84.