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Fritzberg, Alan R.; Berninger, Ronald W.; Hadley, Stephen W.; Wester, D. W.

doi:10.1023/a:1015995208444

Cited by 61 publications

(11 citation statements)

References 39 publications

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“…The current interest in the radiolabeling of biologically important molecules (proteins, antibodies, and peptides) with 99m Tc stems from the desire to develop a target-specific diagnostic radiopharmaceutical. − The advantages of using 99m Tc in diagnostic nuclear medicine are well-known, − and a number of techniques have been developed for the 99m Tc labeling of biologically important molecules. − One obvious approach is to coordinate a 99m Tc metal directly with the targeting molecule. This approach is known as the direct labeling method, and it involves the use of a reducing agent to convert disulfide linkages into free thiolates, which then bind to the 99m Tc metal.…”

Section: Introductionmentioning

confidence: 99%

Rhenium(V) and Technetium(V) Oxo Complexes of an N₂N‘S Peptidic Chelator: Evidence of Interconversion between theSynandAntiConformations

et al. 1997

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Neutral Re(V) and Tc(V) oxo complexes of the peptide dimethylglycyl-L-seryl-L-cysteinylglycinamide (RP294) were prepared and characterized by HPLC, spectroscopic techniques, and X-ray crystallographic analysis. The peptide was prepared as a single peptide chain using solid phase methods and characterized by HPLC and various spectroscopic techniques. The water-soluble Re(V) oxo complex of dimethylglycyl-L-seryl-L-cysteinylglycinamide [ReO(RP294)] was prepared from the reaction of the peptide with either [ReO(2)(en)(2)]Cl or ReOCl(3)(PPh(3))(2) in the presence of base. The complex exists as two isomers, the serine CH(2)OH group being in the syn oranti conformation with respect to the Re-oxo bond. The ratio of the isomers at room temperature is 1:1.1. The isomers were separated by reverse-phase HPLC, but the isolation of each isomer was complicated by their rapid interconversion in aqueous solution at room temperature. The molecular structure of the syn isomer of the Re complex was determined by X-ray crystallography. Crystals of syn-[ReO(RP294)] (C(12)H(20)N(6)O(5)ReS) are orthorhombic, of space group P2(1)2(1)2(1), with a = 6.954(1) Å, b = 8.0472(1) Å, c = 32.9183(4) Å, and Z = 4. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.0327 (R(w) = 0.0838) for 10 447 reflections with I > 2sigma(I). The Re metal was coordinated in a distorted square pyramidal geometry with the oxo moiety in the apical position. The peptide coordinated to ReO(3+) via the N(amine) atom of dimethylglycine, the S(thiolate) atom of cysteine, and the two N(amide) atoms of serine and cysteine (an N(2)N'S donor atom set). The Re atom lies approximately 0.74 Å above the distorted plane formed by the N(2)N'S donor atom set. Variable-pH (1)H NMR spectral data showed the Re complex was stable from pH 5 to 8.5. The reaction of (99)TcO(4)(-) with SnCl(2), sodium gluconate, and RP294 produced the (99)Tc(V) oxo RP294 complex, [(99)TcO(RP294)]. Like the [ReO(RP294)] complex, [(99)TcO(RP294)] also exists in the syn and anti conformations in a ratio of approximately 1:1. The (99m)Tc complex of RP294 was prepared at the tracer level from the reaction of Na[(99m)TcO(4)] with excess SnCl(2), sodium gluconate, and RP294. The (99m)Tc and Re RP294 complexes behaved similarly under identical HPLC conditions.

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Section: Introductionmentioning

confidence: 99%

Rhenium(V) and Technetium(V) Oxo Complexes of an N₂N‘S Peptidic Chelator: Evidence of Interconversion between theSynandAntiConformations

et al. 1997

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“…[NEt 4 ] 2 [Re(CO) 3 Br 3 ] was prepared by the published procedure [9] . 1 [10] with only slight modifications. 31 1953, 1945, 1925, 1907 (CO).…”

Section: Methodsmentioning

confidence: 99%

“…There are two distinct environments for the four protons, due both to the equatorial/axial distinction in the chair conformation, and to the position of the bromide ligand. The 1 H- 1 H ROESY spectrum of complex 7 is shown in Fig. 4 as a representative spectrum.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

“…There is much current interest in the development of radiopharmaceuticals through the radiolabeling of monoclonal antibodies with 186/188 Re. [1][2][3] Although much emphasis had been placed on the development of ligand systems for chelation to the Re(V) oxo core, [ref] the design of radiopharmaceuticals based on Re(I)-tricarbonyl complexes has gained considerable attention recently. [refs] The advantages of this organometallic approach and the methodology for generating the [Re(CO) 3 ] + synthon have also been established.…”

Section: Introductionmentioning

confidence: 99%

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Tricarbonylrhenium(I) complexes of phosphine-derivatized amines, amino acids and a model peptide: structures, solution behavior and cytotoxicity

Zhang

Vittal

Henderson

et al. 2002

Journal of Organometallic Chemistry

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Modified Mannich reactions of amines, amino acids and a model peptide with Ph 2 PH and CH 2 O gave bis(diphenylphosphinomethyl)amines (Ph 2 PCH 2) 2 NR [R= Ph (1), CH 2 CH 2 OH (2), CH 2 COOCH 2 Ph (3), CH 2 CONHCH 2 COOCH 2 Ph (4), CH 2 COOH (5)] and (Ph 2 PCH 2) 2 NCH 2 CH 2 N(CH 2 PPh 2) 2 (6). Reaction with [ReBr 3 (CO) 3 ] 2under mild conditions led to ReBr(CO) 3 {(Ph 2 PCH 2) 2 NR} [R= Ph (7), CH 2 CH 2 OH (8), CH 2 COOCH 2 Ph (9), CH 2 CONHCH 2 COOCH 2 Ph (10), CH 2 COOH (11)] and [ReBr(CO) 3 Ph 2 PCH 2) 2 NCH 2 ] 2 (12). All new complexes have been characterized by NMR and IR spectroscopy and for 7, 9 and 10, single-crystal X-ray diffraction analyses. Stability studies by Electrospray Mass Spectrometry, showed that other than solvolysis, the complexes are fairly stable in neutral and acidic methanol. Cytotoxicity testing of 7-10 and 12 showed that all the complexes are active against specific tumour cell lines.

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“…Direct labeling applies primarily to proteins and involves the initial reduction of endogenous disulfide bonds to generate thiol binding sites. Though simple and efficient, direct labeling suffers from being site-unspecific and the label is often unstable [5][6][7][8][9][10]. Indirect labeling differs from direct labeling in the use of an exogenous chelator.…”

Section: Introductionmentioning

confidence: 99%

Labeling Biomolecules with Radiorhenium - A Review of the Bifunctional Chelators

Liu

Hnatowich

2007

ACAMC

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For radiotherapy, biomolecules such as intact antibodies, antibody fragments, peptides, DNAs and other oligomers have all been labeled with radiorhenium ((186)Re and (188)Re). Three different approaches have been employed that may be referred to as direct, indirect and integral labeling. Direct labeling applies to proteins and involves the initial reduction of endogenous disulfide bridges to provide chelation sites. Indirect labeling can apply to most biomolecules and involves the initial attachment of an exogenous chelator. Finally, integral labeling is a special case applying only to small molecules in which the metallic radionuclide serves to link two parts of a biomolecule together in forming the labeled complex. While the number of varieties for the direct and integral radiolabeling approaches is rather limited, a fairly large and diverse number of chelators have been reported in the case of indirect labeling. Our objective herein is to provide an overview of the various chelators that have been used in the indirect labeling of biomolecules with radiorhenium, including details on the labeling procedures, the stability of the radiolabel and, where possible, the influence of the label on biological properties.

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Untitled

Cited by 61 publications

References 39 publications

Rhenium(V) and Technetium(V) Oxo Complexes of an N₂N‘S Peptidic Chelator: Evidence of Interconversion between theSynandAntiConformations

Rhenium(V) and Technetium(V) Oxo Complexes of an N₂N‘S Peptidic Chelator: Evidence of Interconversion between theSynandAntiConformations

Tricarbonylrhenium(I) complexes of phosphine-derivatized amines, amino acids and a model peptide: structures, solution behavior and cytotoxicity

Labeling Biomolecules with Radiorhenium - A Review of the Bifunctional Chelators

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Cited by 61 publications

References 39 publications

Rhenium(V) and Technetium(V) Oxo Complexes of an N2N‘S Peptidic Chelator: Evidence of Interconversion between theSynandAntiConformations

Rhenium(V) and Technetium(V) Oxo Complexes of an N2N‘S Peptidic Chelator: Evidence of Interconversion between theSynandAntiConformations

Tricarbonylrhenium(I) complexes of phosphine-derivatized amines, amino acids and a model peptide: structures, solution behavior and cytotoxicity

Labeling Biomolecules with Radiorhenium - A Review of the Bifunctional Chelators

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Rhenium(V) and Technetium(V) Oxo Complexes of an N₂N‘S Peptidic Chelator: Evidence of Interconversion between theSynandAntiConformations

Rhenium(V) and Technetium(V) Oxo Complexes of an N₂N‘S Peptidic Chelator: Evidence of Interconversion between theSynandAntiConformations