Hydroxyethylidene diphosphonate HEDP

Synthesis by Substitution Routes. Many of the limitations inherent in the redox route described above can be avoided by preparation of technetium-99m radiopharmaeeutieals by a substitution route, i.e. the classical substitution of ligands onto a pre-reduced and isolated technetium center. Substitution routes allow control over the oxidation state and ligand environment of the technetium product, and permit the synthesis of complexes containing different ligands. By substitution routes it should be possible to prepare series of complexes in which some ligands are held fixed while others are varied in a systematic fashion to affect biological specificity. 

Recent work has focused on the use of two specific reduced technetium centers as substrates for substitution reactions TcXg and TcOXi (X = Cl, Br). The chemistry of the TcOXij system has been developed principally by Davison and co-workers ( ). Both of these centers are synthesized from pertechnetate, the starting material for all radiopharmaceutical preparations (2,5), by simple HX reduction e.g.. 

The only difference between the two preparations is the temperature at which the reduction is conducted at low temperatures the Tc(V) species TcOX is kinetically trapped and can be isolated, whereas at higher temperatures the Tc(V) complex suffers further reduction to yield the Tc(IV) species TcXg (10,11). Other potential substances for radiopharmaceutical synthesis by substitution reactions include the undefined, reduced Tc-glucoheptonate complex (12) and the recently reported, lipophilic technetium(V) species Tc(HBPz Cl2 O (HBPz3 = hydrotris(l-pyra-zolyDborato ligand) (13). 

ACS Symposium Series American Chemical Society Washington, DC, 1980. 

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Zheng L.-M., Duan C.-Y, Ye X.-R., Zhang L.-Y, Wang C. and Xin X.-Q., Synthesis, crystal structure and magnetic properties of a novel mixed-valence copper phosphonate Na2Cui5(hedp)6(OH)2(H20) (hedp = 1-hydroxyethylidene- diphosphonate), J. Chem. Soc., Dalton Trans. (1998) pp. 905-908. 

A,A -l,2-ethanediylbis(L-cysteine-ethylester) HEDP = 1-hydroxyethylidene diphosphonic acid = 0=P(0H)2C(0H) MeP(=0)(0H)2l HIDA = A-(2,6-dimethylphenylcarbam-oylmethyl)iminodiacetate HM-PAO = hexamethylpropyl-eneamine oxime MAG3 = mercaptoacetyltriglycine mtp = 2-(mercaptomethyl)thiophenolate noet = A-ethyl-A-... 

A useful nitrogen-free sequestrant for H2O2 and peracids is HEDP (1-hydroxyethylidene diphosphonic acid). In general, solutions containing both peracids and free hydrogen peroxide are more prone to catalytic decomposition than either component alone [60], since the two peroxides themselves represent a redox couple. 

Synonyms Acetodiphosphonic acid ADPA Ethane-1-hydroxy-1,1-diphosphonate 1,1,1-Ethanetriol diphosphonate HEDP HEDPA 1-Hydroxy-1,1-diphosphonoe-thane Hydroxyethanediphosphonic acid (1-Hydroxyethylidene) bisphosphonic acid (1-Hydroxyethylidene) diphosphonic acid 1-Hydroxyethylidene-1,1-diphos-phonic acid Oxyethylidenediphosphonic acid Classification Organic diphosphonic acid Empirical CjHgO Pj Formula CH3C(0H)(P03H2)2... 

Phosphonates, especially aminotri(methylenephosphonic acid) (ATMP) and l-hydroxyethylidene-l,l-diphosphonic acid (HEDP). Organophosphonates have the ability to control both scaling and corrosion by a combination of chelation and crystal nuclei growth supression (threshold) mechanisms they also provide scale control by crystal distortion. 

A typical representative of geminal diphosphonic acids is 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP, DEQUEST 2010), which is often employed in practical applications. As shown in Eigure 3.192, this compound may be analyzed in the same run with other aminopolyphosphonic acids. 

The syntheses of nitrilotris(methylenephosphonic acid) (NTM ), " l-hydroxyethylidene-l,l-diphosphonic acid (HEDP), bis(phosphonyl-methyl) phosphinic acid (PMPA) and tris(phosphonylmethyl) phosphine oxide (PMPO) have been reported. 

Some antisealants, such as those containing 1-hydroxyethylidene-l, 1-diphosphonic acid (HEDP) are sensitive to chlorine and other oxidizers. They should be fed downstream of the dechlorination point. Most other antisealants are not affected by chlorine at typical 0.5-1.0 ppm concentrations. ... 

Complexation and pyrolysis is another soft chemistry method to prepare nano-LiFeP04. LiOH H2O, Fe(N03)-9H20, and l-hydroxyethylidene-1,1-diphosphonic acid [CFl3C(0H)(H2P03)2 HEDP] are mixed in a molar ratio of 2 2 1, and ethylene glycol is used as a carbon source. After heating the precursors at 700°C for 5 h, a nano-LiFeP04/C material in the 50-300 nm... 

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