Synthesis of DTPA Analogues Derived from Piperidine and Azepane:  Potential Contrast Enhancement Agents for Magnetic Resonance Imaging

Hs, Chong; Garmestani, Kayhan; Lh, Bryant; Mw, Brechbiel

doi:10.1021/jo0106344

Cited by 36 publications

(26 citation statements)

References 38 publications

(24 reference statements)

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“…There are few published reports on the r 2 NMRD profiles of Gd 3þ -based small molecular or macromolecular complexes. 29,30 Gd-SWCNTs have distinctly different r 2 NMRD profiles than Gd 3þ -based small molecular or macromolecular complexes. At clinically relevant 1.5 T magnetic field (proton Larmor frequency ¼ 61.73 MHz), the r 2 value is 170 mM À1 s À1 , which is an order of magnitude greater than any current Gd 3þ -based FDA-approved MRI …”

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confidence: 96%

The magnetic, relaxometric, and optical properties of gadolinium-catalyzed single walled carbon nanotubes

Sitharaman

Jacobson

Wadghiri

et al. 2013

Journal of Applied Physics

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We report the magnetic behavior, relaxometry, phantom magnetic resonance imaging (MRI), and near-infrared (NIR) photoluminescence spectroscopy of gadolinium (Gd) catalyzed single-walled carbon nanotubes (Gd-SWCNTs). Gd-SWCNTs are paramagnetic with an effective magnetic moment of 7.29 l B . Gd-SWCNT solutions show high r 1 and r 2 relaxivities at very low (0.01 MHz) to clinically relevant (61 MHz) magnetic fields (). Analysis of nuclear magnetic resonance dispersion profiles using Solomon, Bloembergen, and Morgan equations suggests that multiple structural and dynamic parameters such as rotational correlation time s R , rate of water exchange s M , and the number of fast-exchanging water molecules within the inner sphere q may be responsible for the increase in r 1 and r 2 relaxivity. The T 1 weighted MRI signal intensity (gradient echo sequence; repetition time (TR) ¼ 66 ms, echo time (TE) ¼ 3 ms, flop angle ¼ 108 ) of Gd-SWCNT phantom solution is 14 times greater than the Gd-based clinical MRI contrast agent Magnevist. Additionally, these nanotubes exhibit near infrared fluorescence with distinct E 11 transitions of several semiconducting SWCNTs. Taken together, these results demonstrate that Gd-SWCNTs have potential as a novel, highly efficacious, multimodal MRI-NIR optical imaging contrast agent. V C 2013 American Institute of Physics. [http://dx

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mentioning

confidence: 96%

The magnetic, relaxometric, and optical properties of gadolinium-catalyzed single walled carbon nanotubes

Sitharaman

Jacobson

Wadghiri

et al. 2013

Journal of Applied Physics

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“…The same reaction in CH 3 CN was slightly more efficient in providing the product ( S )- 11 (53%). Later, ( R )- 3b was subjected to the reaction with AgClO 4 for formation of aziridinium ion ( S )- 4b’ that was reacted with different amines in the regiospecific and stereospecific manner. The ring opening reaction of ( S )- 4b’ at the less hindered carbon (C3) with the amines at room temperature for 2 h afforded the substitution vicinal amine analogues 11, 13 , and 14 in excellent isolated yield (>92%).…”

Section: Resultsmentioning

confidence: 99%

“…1,7–8,11–12 It should be noted that substitution of a functional group onto the carbon backbone of DTPA will lead to generation of a stereocenter, and the stereochemistry in chelating agents was demonstrated to affect stability and biological activity of their metal complexes. 4,13–15 …”

Section: Introductionmentioning

confidence: 99%

Application of aziridinium ring opening for preparation of optically active diamine and triamine analogues: highly efficient synthesis and evaluation of DTPA-based MRI contrast enhancement agents

Sun

Chen

et al. 2015

RSC Adv.

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Ring opening of aziridinium ions with nitrogen nucleophiles was applied to the highly efficient synthesis of optically active vicinal diamines and diethylene triamine pentaacetic acid (DTPA) analogues as potential magnetic resonance imaging (MRI) contrast enhancement agents. The synthetic method features a column-free isolation of the regiospecific and stereospecific nucleophilic substitution products of enantiomerically enriched aziridinium ions in excellent yield.

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“…Therefore, the increase in rigidity of the ligand backbone has been investigated as a possible strategy to achieve a higher stability of the corresponding Gd III complex as found for rigidified DTPA derivatives. 5,6 In these cases the increased ligand rigidity was shown to enhance mainly the kinetic inertness of the Gd III complexes and thus to improve the in vivo stability as compared to their parent compounds. 5,6 We have recently demonstrated that the "rigidification" of the oxyethylenic bridge of EGTA by incorporation of an aromatic group does not significantly alter the thermodynamic stability and the structural properties of the Ln III complexes.…”

Section: Introductionmentioning

confidence: 99%

Solution properties of the LnIII complexes of a novel octadentate chelator with rigidified iminodiacetate arms

et al. 2012

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A novel octadentate ligand derived from the core structure of EGTA (ethyleneglycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid) with two piperidine-cis-dicarboxylic acid moieties spaced by a triethylenedioxy chain (L1) has been synthesised with the aim to assess the effect of the structural rigidity on the thermodynamic and kinetic stabilities of its Ln(III) complexes. The stability constants of [Ln(L1)](-) complexes show a weaker binding affinity for Ln(3+) ions of L1 than EGTA. On the other hand, the selectivity of L1 for Ca(2+) over Mg(2+) is one of the highest ever reported. The kinetic inertness has been also investigated and faster rates of both acid catalysed and metal assisted decomplexation have been measured for [Gd(L1)](-) as compared to [Gd(EGTA)](-). The (1)H- and (13)C NMR spectra of the diamagnetic La(3+), Y(3+) and Lu(3+) complexes in aqueous media show pronounced stereochemical rigidity and the occurrence of a structural change across the lanthanide series. Finally, a complete (1)H and (17)O NMR relaxometric study indicates that [Gd(L1)](-) possesses a nine-coordinate ground state with one inner coordination sphere water molecule characterized by a fast rate of exchange ((298)k(ex) = 59 × 10(6) s(-1)).

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Synthesis of DTPA Analogues Derived from Piperidine and Azepane: Potential Contrast Enhancement Agents for Magnetic Resonance Imaging

Cited by 36 publications

References 38 publications

The magnetic, relaxometric, and optical properties of gadolinium-catalyzed single walled carbon nanotubes

The magnetic, relaxometric, and optical properties of gadolinium-catalyzed single walled carbon nanotubes

Application of aziridinium ring opening for preparation of optically active diamine and triamine analogues: highly efficient synthesis and evaluation of DTPA-based MRI contrast enhancement agents

Solution properties of the LnIII complexes of a novel octadentate chelator with rigidified iminodiacetate arms

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