The present paper covers the synthesis and the characterization of ligand 2-decyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid,H_5L,and its Gd(Ⅲ) chelate. The protonation constants for H_5L(lg K H_...The present paper covers the synthesis and the characterization of ligand 2-decyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid,H_5L,and its Gd(Ⅲ) chelate. The protonation constants for H_5L(lg K H_ i =10.90,8.50,4.55,2.92,2.20) and the stability constant for GdL 2- (lg K _ GdL 2- =22.80) were determined by means of potentiometric titration. They are similar to the corresponding values of DTPA and Gd-DTPA,respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after the introduction of a linear chain decyl group into the terminal acetic acid residue of DTPA. The Gd(Ⅲ) chelate may be a potential contrast agent with liver-specificity for magnetic resonance imaging(MRI).展开更多
Synthesis and characterization of the ligand,[10-( α -tetradecylcarboxymethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid,H 4 L]and its Gd (Ⅲ) chelate are described.Protonation constants for H 4 L(lgK iH =1...Synthesis and characterization of the ligand,[10-( α -tetradecylcarboxymethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid,H 4 L]and its Gd (Ⅲ) chelate are described.Protonation constants for H 4 L(lgK iH =10.62,9.50,4.74,4.12)and the stability constant for GdL - (lgK GdL - =24.60)were determined by potentiometric titrations.The results obtained show that the basicity of the ligand is not significantly altered and the ligand still maintains the strong chelating properties of the parent DOTA after introduction of a linear chain tetradecyl group at the acetic side chain of DOTA.展开更多
Synthesis and characterization of the ligand, [2-tetradecyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid, H5L] and its Gd(Ⅲ) chelate are described. Protonation constants for H5L (lgKiH = 10.80, 8.40,...Synthesis and characterization of the ligand, [2-tetradecyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid, H5L] and its Gd(Ⅲ) chelate are described. Protonation constants for H5L (lgKiH = 10.80, 8.40, 4.30, 2.80, 2.15) and the stability constant for GdL2- (lgK■ = 22.75) were determined by potentiometric titration and are similar with the related values of DTPA and Gd-DTPA respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after introduction of a linear chain tetradecyl group at the terminal acetic acid residue of DTPA.展开更多
Synthesis and characterization of the ligand, 10-(-hexadecylcarboxymethyl)-1,4,7,10-tetraazacyclododecane- 1,4,7-triacetic acid (H4L), and its Gd(III) chelate are described. Protonation constants for H4L (HlgiK=10.52,...Synthesis and characterization of the ligand, 10-(-hexadecylcarboxymethyl)-1,4,7,10-tetraazacyclododecane- 1,4,7-triacetic acid (H4L), and its Gd(III) chelate are described. Protonation constants for H4L (HlgiK=10.52, 9.45, 4.74, 4.10) and the stability constant for GdL- (-GdLlg K=24.50) were determined by potentiometric titrations. The results obtained show that the ligand still maintains the strong chelating properties of the parent DOTA (1,4,7,10-tetraazacyclododecane-N,N',N''N'''-tetraacetic acid) after introduction of a linear chain hexadecyl group at the acetic side chain of DOTA, and its basicity is not significantly altered.展开更多
文摘The present paper covers the synthesis and the characterization of ligand 2-decyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid,H_5L,and its Gd(Ⅲ) chelate. The protonation constants for H_5L(lg K H_ i =10.90,8.50,4.55,2.92,2.20) and the stability constant for GdL 2- (lg K _ GdL 2- =22.80) were determined by means of potentiometric titration. They are similar to the corresponding values of DTPA and Gd-DTPA,respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after the introduction of a linear chain decyl group into the terminal acetic acid residue of DTPA. The Gd(Ⅲ) chelate may be a potential contrast agent with liver-specificity for magnetic resonance imaging(MRI).
文摘Synthesis and characterization of the ligand,[10-( α -tetradecylcarboxymethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid,H 4 L]and its Gd (Ⅲ) chelate are described.Protonation constants for H 4 L(lgK iH =10.62,9.50,4.74,4.12)and the stability constant for GdL - (lgK GdL - =24.60)were determined by potentiometric titrations.The results obtained show that the basicity of the ligand is not significantly altered and the ligand still maintains the strong chelating properties of the parent DOTA after introduction of a linear chain tetradecyl group at the acetic side chain of DOTA.
文摘Synthesis and characterization of the ligand, [2-tetradecyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid, H5L] and its Gd(Ⅲ) chelate are described. Protonation constants for H5L (lgKiH = 10.80, 8.40, 4.30, 2.80, 2.15) and the stability constant for GdL2- (lgK■ = 22.75) were determined by potentiometric titration and are similar with the related values of DTPA and Gd-DTPA respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after introduction of a linear chain tetradecyl group at the terminal acetic acid residue of DTPA.
基金Project supported by the Department of Science and Technology of Hunan Province (No. OOSSY 1013-51).
文摘Synthesis and characterization of the ligand, 10-(-hexadecylcarboxymethyl)-1,4,7,10-tetraazacyclododecane- 1,4,7-triacetic acid (H4L), and its Gd(III) chelate are described. Protonation constants for H4L (HlgiK=10.52, 9.45, 4.74, 4.10) and the stability constant for GdL- (-GdLlg K=24.50) were determined by potentiometric titrations. The results obtained show that the ligand still maintains the strong chelating properties of the parent DOTA (1,4,7,10-tetraazacyclododecane-N,N',N''N'''-tetraacetic acid) after introduction of a linear chain hexadecyl group at the acetic side chain of DOTA, and its basicity is not significantly altered.
