Synthesis, separation, and equilibrium characterization of racemic and meso forms of a new multidentate ligand: N,N'-trimethylenebis[2-(2-hydroxy-3,5-dimethylphenyl)glycine], TMPHPG

Bannochie, C. J.; Martell, Arthur E.

doi:10.1021/ic00006a041

Cited by 23 publications

(22 citation statements)

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“…The indium complex of H,L' has a stability constant of about 4.5 log units higher than that of the gallium one, as has been found for other polyaminopolycarboxylates.37~49~50 The reverse trend in these constants would be expected because the interactions involved in these complexes are mostly electrostatic, the In3+ ion having the larger effective ionic radius,51 as is found for complexes involving 'harder' ligands (like some ligands containing phenol derivatives). 7, 49 The trend observed for polyaminopolycarboxylates is attributed in part to the fact that carboxylate is less hard than phenolate for co-ordination,37*49,50 but also to higher co-ordination numbers of In3+ relative to Ga3 + (six for Ga3 + , eight for In3 + , see NMR studies below).…”

Section: Resultsmentioning

confidence: 98%

Complexes of Ga³⁺and In³⁺with the N,N″-bis(butylamide) derivative of diethylenetriaminepentaacetic acid: stability constants and nuclear magnetic resonance studies in aqueous solution

Geraldes¹,

Delgado²,

Urbano³

et al. 1995

J. Chem. Soc., Dalton Trans.

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Potentiometric titrations showed that the sum of the first three protonation constants of diethylenetriaminepentaacetate N,N"-bis( butylamide) ( L1) decreases by 6.6 units when compared to the diethylenetriaminepentaacetate (dtpa), and that the complexes of Ga3+ and In3+ of L1 have stability constants 6.1 -6.3 log units lower than those of dtpa. The decreased basicity of the bis(amide) derivative thus correlates with the lower stability of its complexes. However, at pH 7.4 the lower overall basicity of L1 compared to dtpa partly compensates the lower stability of its complexes, thus causing their conditional stability constants to be comparable to those of the dtpa complexes. The efficacy of L' in binding Ga3+ and In3+ under physiological conditions is discussed by comparing pM values at pH 7.4, showing that this compound can withstand the competition of transferrin for In3+ in biological media relevant to medical applications. The 13C and l H NMR shifts were measured for the complexes of A13+, Ga3+, In3+ and Y3+ with L1 and compared with 13C shifts for the dtpa complexes. The complexes of A13+ and Ga3+ are hexadentate, possibly of octahedral geometry, and form various structural isomers, whereas those of In3+ and Y3+, with a single structural isomer of eight-co-ordination, are very similar to the lanthanide complexes. The complexes of A13+ and Ga3+ of L1 have considerable populations of isomers with bound amide groups, whereas the single structural isomer of the complexes of In3+ and Y3+ with both amide groups co-ordinated yield a variety of enantiomers in solution. studies on complexes of La3+ and Lu3+ with the corresponding bis(propy1amide) H3L2,22*23 as well as with our studies and literature data on complexes of A13+, G a 3 + , In3+, Y 3 + , La3+ and Lu3+ with dtpa.'9,25*30 ExperimentalReagents.-All chemicals were of analytical grade, used as received unless specifically noted, and obtained from the following sources: diethylenetriaminepentacetic acid dianhydride, pentasodium and di-sodium or -potassium salts of H,dtpa (Sigma); butylamine, aluminium nitrate hydrate, gallium nitrate hydrate, indium nitrate pentahydrate, yttrium chloride (Aldrich); solvents (Prolabo). Other materials are cited under specific sections.Synthesis and Characterization of the N,N "-Bis(buty1amide) of H,dtpa, H3L'.-Butylamine (0.327 cm3, 3 mmol) was added dropwise with stirring to a solution of diethylenetriaminepentaacetic acid dianhydride (0.536 g, 1.5 mmol) in dry dimethylformamide (50 cm3, 40 "C). The colourless reaction mixture was stirred (4OoC, 1 h) and filtered. Chloroform (50 cm3) was added and, after cooling at 4 "C for 2 h, the white solid was filtered off, washed with diethyl ether (100 cm3) and dried at 40 "C overnight. The compound was recrystallized, from hot ethanol-hexane (1 10: 110 cm3), after cooling at 4 "C overnight. The white crystals were filtered off, washed with acetone (10 cm3) and diethyl ether (10 cm3) and dried overnight at 40 "C.

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Section: Resultsmentioning

confidence: 98%

Complexes of Ga³⁺and In³⁺with the N,N″-bis(butylamide) derivative of diethylenetriaminepentaacetic acid: stability constants and nuclear magnetic resonance studies in aqueous solution

Geraldes¹,

Delgado²,

Urbano³

et al. 1995

J. Chem. Soc., Dalton Trans.

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“…Thus, the larger the pM value, the higher is the affinity of the ligand for the metal ion under the given condition. 30 Table 2 shows that 4a-c exhibit higher pM values with Gd(III) than with Ca(II), Zn(II), or Cu(II), indicating that the Gd(III) complexes of 4a-c are stable enough to avoid any interference by other endogenous metal ions.…”

Section: Resultsmentioning

confidence: 99%

Gd-Complexes of 1,4,7,10-Tetraazacyclododecane-N,N′,N′′,N′′′-1,4,7,10-tetraacetic Acid (DOTA) Conjugates of Tranexamates as a New Class of Blood-Pool Magnetic Resonance Imaging Contrast Agents

Kim²,

Lee³

et al. 2010

J. Med. Chem.

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Gd-complexes of the type [Gd(L)(H(2)O)]·xH(2)O (5a-c), where L is DOTA conjugates of tranexamic acid (4a) and tranexamic esters (4b,c), have been prepared as a new class of MRI blood-pool contrast agents (BPCAs). Thermodynamic stability (K(GdL)) and pharmacokinetic inertness of 5 compare well with or better than those of analogous MRI contrasting agents (CAs) such as Gd-DOTA and Gd-DTPA-BMA. Their R(1)-relaxivities are significantly higher than those of any of the clinically used MRI CAs. T(1)-weighted MR images of mice administered by 5c demonstrate high blood-pool effect with simultaneous contrast enhancement in liver. The structural uniqueness of 5c lies in the fact that it adopts macrocyclic DOTA instead of acyclic DTPA. In addition, 5c is nonionic and makes no resort to aromatic substituent(s) in the chelate backbone for the blood-pool enhancement. The nature of hepatobiliary uptake demonstrated by 5c may be explained in terms of lipophilicity of tranexamate in the chelate (4c). The cell cytotoxicity test shows no toxicity found with 5, suggesting their use as a practical MRI BPCAs.

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“…The decrease of the fluorescence intensity is owing to the fact that gallium(III) breaks the intramolecular O…H-O hydrogen bonds of salicylic acid. Martell et al 26,27 have measured the formal stability constants for gallium complexes of both HBED and EHPG to be lg K Ga-HBED ＝39.57, lg K rac-Ga-EHPG ＝33.89 and lg K meso-Ga-EHPG ＝32.40, respectively, but the formation of Ga(OH) n species and acidic effect were not taken into account in the calculation. If the formation of Ga(OH) n species and acidic effect were considered, regardless of the side reaction of predominant chelate species of Ga-HBED and Ga-EHPG, the results of our work were clearly demonstrated that the conditional binding constant of HBED or EHPG to gallium was lg K Ga-HBED ＝19.08 or lg K Ga-EHPG ＝19.18 at pH＝7.4, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…If the formation of Fe(OH) n species and acidic effect were considered, the conditional binding constant of HBED or EHPG to ferric ion was 20.96 and 18.03 logarithmic units at pH＝ 7.4, respectively, where ferric ion hydrolysis constant was adopted from Harris 29 and the formal stability constants for ferric ion complexes of both HBED and EHPG were from the literature. 26 According to the LFER equation, it implies that our method of calculating conditional binding constant of HBED or EHPG to gallium is feasible. At neutral or acidic pH, the phenolic oxygens of EHPG or HBED were completely protonated.…”

Section: Discussionmentioning

confidence: 99%

Tyrosine Hydrogen Bond Properties for the Two Binding Sites of Apoovotransferrin

Qiao

Yang

et al. 2005

Chin. J. Chem.

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The interaction of gallium(III) with the ligands containing phenolic group(s), such as salicylic acid, N, N,glycine (EHPG), and ovotransferrin, was studied, respectively, by means of fluorescence in 0.01 mol/L Hepes at pH 7.4 and room temperature. Fluorescence intensity showed an increase when gallium(III) was bound to 8-hydroxyquinoline and HBED. In contrast, it was decreased with the interaction of gallium(III) with salicylic acid and EHPG. At pH 7.4, there was N…H-O type intramolecular hydrogen bond in the former, and the latter existed O…H-O type intramolecular hydrogen bond. Fluorescence titration of apoovotransferrin with gallium(III) displayed that the fluorescence intensity was decreased at the N-terminal binding site, while enhanced at the C-terminal binding site. It can account for the O…H-O type intramolecular hydrogen bonds for the phenolic groups of Tyr92 and Tyr191 residues at the N-terminal binding site. And there are N…H-O type intramolecular hydrogen bonds for Tyr431 and Tyr524 residues at the C-terminal binding site. In addition, under the same conditions, the conditional binding constant of gallium(III) with EHPG or HBED determined by fluorescence method is lg K Ga-EHPG ＝19.18 or lg K Ga-HBED ＝19.08.

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Synthesis, separation, and equilibrium characterization of racemic and meso forms of a new multidentate ligand: N,N'-trimethylenebis[2-(2-hydroxy-3,5-dimethylphenyl)glycine], TMPHPG

Cited by 23 publications

References 0 publications

Complexes of Ga³⁺and In³⁺with the N,N″-bis(butylamide) derivative of diethylenetriaminepentaacetic acid: stability constants and nuclear magnetic resonance studies in aqueous solution

Complexes of Ga³⁺and In³⁺with the N,N″-bis(butylamide) derivative of diethylenetriaminepentaacetic acid: stability constants and nuclear magnetic resonance studies in aqueous solution

Gd-Complexes of 1,4,7,10-Tetraazacyclododecane-N,N′,N′′,N′′′-1,4,7,10-tetraacetic Acid (DOTA) Conjugates of Tranexamates as a New Class of Blood-Pool Magnetic Resonance Imaging Contrast Agents

Tyrosine Hydrogen Bond Properties for the Two Binding Sites of Apoovotransferrin

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Synthesis, separation, and equilibrium characterization of racemic and meso forms of a new multidentate ligand: N,N'-trimethylenebis[2-(2-hydroxy-3,5-dimethylphenyl)glycine], TMPHPG

Cited by 23 publications

References 0 publications

Complexes of Ga3+and In3+with the N,N″-bis(butylamide) derivative of diethylenetriaminepentaacetic acid: stability constants and nuclear magnetic resonance studies in aqueous solution

Complexes of Ga3+and In3+with the N,N″-bis(butylamide) derivative of diethylenetriaminepentaacetic acid: stability constants and nuclear magnetic resonance studies in aqueous solution

Gd-Complexes of 1,4,7,10-Tetraazacyclododecane-N,N′,N′′,N′′′-1,4,7,10-tetraacetic Acid (DOTA) Conjugates of Tranexamates as a New Class of Blood-Pool Magnetic Resonance Imaging Contrast Agents

Tyrosine Hydrogen Bond Properties for the Two Binding Sites of Apoovotransferrin

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Resources

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Complexes of Ga³⁺and In³⁺with the N,N″-bis(butylamide) derivative of diethylenetriaminepentaacetic acid: stability constants and nuclear magnetic resonance studies in aqueous solution

Complexes of Ga³⁺and In³⁺with the N,N″-bis(butylamide) derivative of diethylenetriaminepentaacetic acid: stability constants and nuclear magnetic resonance studies in aqueous solution