Ferrocene-derivatized dithiophosphonate salts and their gold(I) and palladium(II) complexes
- Authors: Pieterse, Hendriëtte
- Date: 2010-04-12T10:20:05Z
- Subjects: Ferrocene , Phosphonates , Salts , Gold compounds , Palladium compounds
- Type: Thesis
- Identifier: uj:6768 , http://hdl.handle.net/10210/3179
- Description: M.Sc. , The dimeric structure of Lawesson’s reagent, (RPS2)2 (R = 4–MeOC6H4), or its ferrocenyl analogue (R = ferrocenyl, Fc) leads to symmetrical cleavage through nucleophillic attack by alcohols to form dithiophosphonic acids, which can be readily deprotonated by ammonia to form the corresponding ammonium salts, which can be further reacted with transition-metal halides to form new metal complexes. Among the phosphor-1,1-dithiolates as a generic class of compounds, the dithiophosphates, [S2P(OR)2]-, have been most intensely studied and the dithiophosphonates [S2PR(OR’)]-, the subject of the present study, to a far lesser extent. In this study, a large variety of new dithiophosphonate salts were synthesized from diverse alcohol functionalities derived from cholesterol, estrone, estradiol, pentaerythritol, ethandiol, hydroquinone, resorcinol, glucose and ribose. The salts were oxidized with iodine to yield various S-S oxidative products, of which two X-ray crystal structures of such compounds, the ethandiol and pentaerythritol derivatives, were obtained and they were subjected to further investigation by cyclic voltammetry due to the ferrocenyl-rich functionalities they contain. The reaction of these [S2PR(OR’)]- type salts with a number of gold(I) and palladium(II) precursors, yielded a variety of new complexes. The compounds containing multiple alcohol (hydroxy) sites have been reacted with gold(I) and palladium(II) starting materials ClAu(tht) and PdCl2(PPh3)2, respectively and also with other gold(I) variants, including the mono- and dinuclear phosphines ClAuPPh3, Au2Cl2dppe and Au2Cl2dppa. A new X-ray single crystal structure of a gold(I) complex could be obtained as a decomposition product. New products have been characterized through a combination of solution 1H and 31P NMR, EIS mass spectrometry, IR, elemental analysis, electro-chemistry and single crystal X-ray crystallographic studies.
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Synthesis of and potentiometric studies with bisphosphonate ligands APDDAM and PolyHEDP as potential carriers of radionuclides : in attempt to develop effective 117MSn radio pharmaceuticals for bone metastases
- Authors: Ranqhai, Tsekiso
- Date: 2014-08-18
- Subjects: Radiochemistry , Bone metastasis - Radiotherapy , Phosphonates , Radioisotopes
- Type: Thesis
- Identifier: uj:12077 , http://hdl.handle.net/10210/11824
- Description: M.Sc. (Chemistry) , Secondary cancer tumour formation, often called metastasis, remains one of the great scientific challenges in public health. Patients with skeletal metastases have a low survival rate, with great discomforts experienced by the sufferers. Pain, decreased mobility, pathologic bone fractures are some of the effects that these patients have to live with. Significant inroads have been made in using radio pharmaceuticals as a pain palliation treatment for bone metastases. They comprise of a bone seeking phosphonate ligand and a radionuclide. The structural variation of the phosphonate affects to a great extend the effectiveness of the radiopharmaceutical with the greatest shortfall being myelosuppression at high doses. In this study an attempt is made at synthesizing novel bisphosphonates, APDDAM and APDDPE. After several synthetic steps from the protected β-alanine tert butyl ester, the free acid precursor was achieved (as shown in the NMR and elemental analysis) in good yields. Unfortunately the final reaction step to form the bisphosphonate ligand was unsuccessful, with the free acid precursor dissociating in the acidic conditions to form salts. A polymer ligand poly-HEDP was synthesized from its free acid form in relatively low yields. The ligand was used in potentiometric studies with the metal ions Ca(II), Mg(II), Cu(II), Zn(II), Sn(II) and Sn(IV) to evaluate its potential as radiopharmaceutical candidate. The ESTA model formation constants obtained were used in the ECCLES blood plasma model to evaluate the competitive stability of the complexes against biological metal ions and ligands. The Sn(IV)-poly-HEDP complex was shown to be unstable, with a 100 % dissociation. On the other hand the Sn(II)-poly-HEDP showed much improved stability with 100 % of the metal ion remaining bound to the ligand.
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Synthesis, reactivity studies and biological evaluation of novel bisphosphonates
- Authors: Djuidje Fotsing, Marthe Carine
- Date: 2014-10-08
- Subjects: Phosphonates , Phosphonates - Struture-activity relationships
- Type: Thesis
- Identifier: uj:12551 , http://hdl.handle.net/10210/12343
- Description: Ph.D. (Chemistry) , This thesis was devoted to the synthesis of new bisphosphonates molecules, the study of their reactivity and the evaluation of their biological activities. The synthesis of epoxyalkylgembisphosphonates was carried out in three steps. The first step was the synthesis of arynyl and alkynylphosphonates by metallation of alkyl and aryl acetylenes followed by condensation with diethylchlorophosphate at low temperature. The second step was the synthesis of vinylgembisphosphonates by a tributylphosphine catalyzed phosphorylation of arynylphosphonates. The last step to epoxyalkylgembisphosphonates was achieved by oxidation of vinylgembisphosphonates using ethylmethyldioxirane generated in situ from potassium monopersulfate (caroate) and butanone in a phase transfer system. The synthesized epoxyalkylgembisphosphonates were studied in order to assess their reactivity with different nucleophiles and their chemical usefulness. All the synthesized compounds were characterized by nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy and mass spectrometry (GCxGC-TOF-MS). In term of reactivity, epoxyalkylgembisphosphonates were found to be less reactive than epoxyphosphonates. As far as their biological activities are concerned, epoxyalkylgembisphosphonates were found to be more potent than some commercially available antibiotics.
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Synthesis of disubstituted vinyl bisphosphonates using the Michaelis-Becker reaction
- Authors: Donga, Cabangani
- Date: 2017
- Subjects: Phosphonates , Phosphonates - Structure-activity relationships , Palladium catalysts
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235704 , uj:24109
- Description: M.Sc. (Chemistry) , Abstract: A novel work on the synthesis of a series of disubstituted vinyl gembisphosphonates from 1-iodo-vinyl phosphonates through a tetrakis (triphenylphosphine) palladium (0) catalyzed Michaelis-Becker reaction is reported.In this study, the Michaelis-Becker reaction involves attack of a diethyl phosphite anion on a 1-iodo vinyl phosphonatecontaining a phenyl substituent to yield disubstituted vinyl gembisphosphonates by nucleophilic substitution. Characterization of all the synthesised compounds was done by Fourier Transmission Infrared (FT-IR),1H, 13C and 31P Nuclear Magnetic Resonance (NMR) spectroscopy.
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