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Phosphonates and its derivatives widely represent important pharmacophores in various classes of therapeutic agents from antivirals to antibiotics. Among these phosphonylated compounds, 1-hydroxymethylene-1,1-bisphosphonates (HMBPs) have occupied a very important place for thirty years now and are currently used in medicine for their inhibitory properties of bone resorption. HMBPs also exhibit direct and indirect antitumor effects in vitro against a broad variety of tumor cell lines, including melanoma, mesothelioma, prostate and breast, lung and myeloma cancer cells. This review will discuss the various syntheses of bisphosphonates with the goal of illustrating their potential interest for the development of therapeutic agents. We will also disclose our latest achievements in phosphinate chemistry.

International audience; The design of high-performance energy-converting materials is an essential step for the development of sensors, but the production of the bulk materials currently used remains costly and difficult. Therefore, a different approach based on the self-assembly of nanoparticles has been explored. We report on the preparation by solvothermal synthesis of highly crystalline CeF 3 nanodiscs. Their surface modification by bisphosphonate ligands led to stable, highly concentrated, colloidal suspensions in water. Despite the low aspect ratio of the nanodiscs (∼6), a liquidcrystalline nematic phase spontaneously appeared in these colloidal suspensions. Thanks to the paramagnetic character of the nanodiscs, the nematic phase was easily aligned by a weak (0.5 T) magnetic field, which provides a simple and convenient way of orienting all of the nanodiscs in suspension in the same direction. Moreover, the more dilute, isotropic, suspensions displayed strong (electric and magnetic) fieldinduced orientation of the nanodiscs (Kerr and Cotton−Mouton effects), with fast enough response times to make them suitable for use in electro-optic devices. Furthermore, an emission study showed a direct relation between the luminescence intensity and magnetic-field-induced orientation of the colloids. Finally, with their fast radiative recombination decay rates, the nanodiscs show luminescence properties that compare quite favorably with those of bulk CeF 3. Therefore, these CeF 3 nanodiscs are very promising building blocks for the development and processing of photosensitive materials for sensor applications.

The synthesis of a new set of triazole bisphosphonates 8a-d and 9a-d presenting an alkyl or phenyl substituent at the C-4 or C-5 position of the triazole ring is described. These compounds have been evaluated for their antiproliferative activity against MIA PaCa-2 (pancreas), MDA-MB-231 (breast) and A549 (lung) human tumor cell lines. 4-hexyl- and 4-octyltriazole bisphosphonates 8b-c both displayed remarkable antiproliferative activities with IC50 values in the micromolar range (0.75–2.4 μM) and were approximately 4 to 12-fold more potent than zoledronate. Moreover, compound 8b inhibits geranylgeranyl pyrophosphate biosynthesis in MIA PaCa-2 cells which ultimately led to tumor cells death.

We present a 1H Nuclear Magnetic Resonance (NMR) relaxometry experimental investigation of two series of magnetic nanoparticles, constituted of a maghemite core with a mean diameter dTEM = 17 &plusmn, 2.5 nm and 8 &plusmn, 0.4 nm, respectively, and coated with four different negative polyelectrolytes. A full structural, morpho-dimensional and magnetic characterization was performed by means of Transmission Electron Microscopy, Atomic Force Microscopy and DC magnetometry. The magnetization curves showed that the investigated nanoparticles displayed a different approach to the saturation depending on the coatings, the less steep ones being those of the two samples coated with P(MAA-stat-MAPEG), suggesting the possibility of slightly different local magnetic disorders induced by the presence of the various polyelectrolytes on the particles&rsquo, surface. For each series, 1H NMR relaxivities were found to depend very slightly on the surface coating. We observed a higher transverse nuclear relaxivity, r2, at all investigated frequencies (10 kHz &le, &nu, L &le, 60 MHz) for the larger diameter series, and a very different frequency behavior for the longitudinal nuclear relaxivity, r1, between the two series. In particular, the first one (dTEM = 17 nm) displayed an anomalous increase of r1 toward the lowest frequencies, possibly due to high magnetic anisotropy together with spin disorder effects. The other series (dTEM = 8 nm) displayed a r1 vs. &nu, L behavior that can be described by the Roch&rsquo, s heuristic model. The fitting procedure provided the distance of the minimum approach and the value of the N&eacute, el reversal time (&tau, &asymp, 3.5 &divide, 3.9&middot, 10&minus, 9 s) at room temperature, confirming the superparamagnetic nature of these compounds.

A general synthetic procedure was developed for H-α-hydroxyphosphinates via Abramov reaction. The present work is a complementary study to those reported till now. This methodology has the advantage that it can be applied to various aliphatic and (hetero)aromatic substrates. The H-α-hydroxyphosphinates were easily purified and obtained in good to excellent yields in shorter times. A 31P NMR spectroscopy study has shown that only 2 equivalents of a silylating agent were required.

The use of phosphonate ligands to modify the nanoparticle (NPs) surface has attracted a strong interest in the last years for the design of highly functional hybrid materials. Here, we applied a methodology to synthesize bisphosphonates having functionalized PEG side chains with a specific length in order to design a novel class of hybrid nanomaterials composed by tetraphosphonate-complex-gold COOH-terminated PEG-coated NPs (Bis-PO-PEG-AuNPs). The synthetic approach consist in three steps: (1) Complexation between new phosphonate ligands (Bis PO) and tetrachloroauric acid (HAuCl4) to form gold clusters; (2) adsorption of COOH-terminated PEG molecules (PEG) onto Bis PO-Au complex; (3) reduction of metal ions in that vicinity, growth of gold particles and colloidal stabilization. The obtained snow-shape-like hybrid nanoparticles, have been characterized by ultra-violet/visible, Raman spectroscopies, and electron microscopy imaging, involving their optical properties and photothermal activity in pancreatic adenocarcinoma cancer cells (PDAC).

A practical generalisable procedure to synthesize hydroxymethylene H-bisphosphinates has been optimised. Unlike previous reports, numerous alkyl (including an alendronate bisphosphinate analogue) or (hetero)aryl compounds were rapidly obtained in satisfactory to excellent yields. A side product could have been identified as a phosphino-phosphonate isomer and plausible mechanistic pathways are proposed here. Moreover to check the literature data, a pKa value study was also performed.

A fast and sensitive colorimetric assay for the determination of prostatic acid phosphatase (PAP) levels using biphosphonates-PEG-coated gold nanoparticles (BP-PEG-AuNPs) has been developed. Addition of different amounts of PAP to the AuNPs results in a significant change of color, from a red-wine color to purple, and finally to blue. The PAP should bind onto the AuNPs surface and crosslink the AuNPs inducing their aggregation and as a consequence a color change of the solution from wine red to purple/blue. The color change was monitored by UV–vis spectrophotometry or with the naked eye. The ensuing concentration-dependent red-shift of surface plasmon resonance absorption allows the determination concentration within the fg range in 10 min. Importantly, the visual detection limit (1 ng/mL) allows the rapid differential diagnosis with naked eye or image analyzer. This demonstrates that the color modification observed with BP-PEG-AuNP is effectively due to an interaction between PAP and BP. Keywords: Prostatic acid phosphatase, Gold nanoparticles, Bisphosphonates, Colorimetric detection, Localized surface plasmon resonance

A convenient and generalizable procedure has been optimized to access to 1-hydroxymethylene-1,1-bisphosphinate compounds. Several alkyl, including an alendronate bisphosphinate analog, and (hetero)...

Large series of novel N-bis-1,2,3-triazolo-linked-1,5-benzodiazepin-2-ones (BZD) have been synthesized under microwave irradiation through a Cu(I)-catalyzed double 1,3-dipolar alkyne-azide coupling reaction. This process is of considerable synthetic advantages in terms of time saving and remarkable yields. The chemical structures of the isolated compounds have been elucidated on the basis of extensive spectroscopic methods including 1D & 2D NMR, IR and HRMS. All the synthesized compounds have been evaluated for their antimicrobial and antioxidant activities. In vitro antimicrobial environment, almost all of compounds have shown an interesting activity. Among the dimers of 1,5-benzodiazepine-1,2,3-triazole compounds tested, the results revealed that the potent antibacterial was recorded to compounds 3g,l for Gram-positive (within MIC = 31.25 and 125 μg/mL), and 3h,k for Gram-negative (within MIC = 31.25 and 125 μg/mL). Besides, the results demonstrate that compounds 3h,k have demonstrated the strongest potential against all the tested fungus (within MIC = 62.5 and 125 μg/mL). The antioxidant evaluation indicated that most compounds exhibited a moderate to good biological activity.

Bisphosphonates are well established pharmaceutical drugs with wide applications in medicine. Nevertheless, the side chain and the nature of phosphorous groups could induce a poor aqueous solubility and act on their bioavailability. At the same time, cyclodextrins are cage molecules that facilitate transport of hydrophobic molecules to enhance the intestinal drug absorption of these molecules by forming inclusion complexes. Here we demonstrate that cyclodextrins could be used as a bisphosphonate carrier. The formation of cyclodextrins-bisphosphonate complexes was characterized by 1D and 2D NMR spectroscopy, Isothermal Titration Calorimetry and UV-vis spectroscopy. The results revealed that only the side chain of bisphosphonate was involved in the inclusion phenomenon and its length was a crucial parameter in the control of affinity. Findings from this study suggest that cyclodextrin will be a useful carrier for bisphosphonates.

International audience; Real time in vivo detection of Amyloid β (Aβ) deposits at an early stage may lead to faster and more conclusive diagnosis of Alzheimer’s disease (AD) and can facilitate the follow up of the effect of therapeutic interventions. In this work, the capability of new hybrid nanomaterials to target and detect Aβ aggregates using magnetic resonance (MRI) and fluorescence imaging is demonstrated. These smart contrast agents contain paramagnetic nanoparticles surrounded by luminescent conjugated oligothiophenes (LCOs) known to selectively bind to Aβ aggregates, with emission spectra strongly dependent on their conformations, opening the possibilities for several fluorescence imaging modes for AD diagnostics. Relaxivity is evaluated in vitro and ex vivo. The capability of these contrast media to link to Aβ fibrils in stained sections is revealed using transmission electron microscopy and fluorescence microscopy. Preliminary in vivo experiments show the ability of the contrast agent to diffuse through the blood–brain barrier of model animals and specifically stain amyloid deposits.

Eighteen different bisphosphonates, including four clinically used bisphosphonate acids and their phosphoesters, were studied to evaluate how the bisphosphonate structure affects binding to bone. Bisphosphonates with weak bone affinity, such as clodronate, could not bind to hydroxyapatite after the addition of one ester group. Medronate retained its ability to bind after the addition of one ester group, and hydroxy-bisphosphonates could bind even after the addition of two ester groups. Thus, several bisphosphonate esters are clearly bone binding compounds. The following conclusions about bisphosphonate binding emerge: (1) a hydroxyl group in the geminal carbon takes part in the binding process and increases the bisphosphonate's ability to bind to bone; (2) the bisphosphonate's ability to bind decreases when the amount of ester groups increases; and (3) the location of the ester groups affects the bisphosphonate's binding ability.

Controlling the interactions of functional nanostructures with water and biological media represents high challenges in the field of bioimaging applicationS. Large contrast at low doses, high colloidal stability in physiological conditions, the absence of cell cytotoxicity, and efficient cell internalization represent strong additional needs. To achieve such requirements, we report on high-payload magnetofluorescent architectures made of a shell of superparamagnetic iron oxide nanoparticles tightly anchored around fluorescent organic nanoparticles. Their external coating is simply modulated using anionic polyelectrolytes in a final step to provide efficient magnetic resonance imaging (MRI) and fluorescence imaging of live cells. Various structures of PEGylated polyelectrolytes have been synthesized and investigated, differing from their iron oxide complexing units (carboxylic vs phosphonic acid), their structure (block-or tomblike), their hydrophobicity; and their fabrication process [conventional:or reversible addition fragmentation chain transfer (RAFT)-controlled radical polymerization] while keeping the central magnetofluorescent platforms the same. Combined photophysical, magnetic, NMRD, and structural investigations proved the superiority of RAFT polymer coatings containing carboxylate units and a hydrophobic tail to impart the magnetic nanoassemblies (NAs) with enhanced-MRI negative contrast, characterized by a high r(2)/r(1) ratio and a transverse relaxation r(2) equal to 21 and 125 s(-1) mmol(-1) L, respectively, at 60 MHz clinical frequency (similar to 1.5 T). Thanks to their dual Modality, cell internalization of the NAs in mesothelioma cancer cells could be evidenced by both confocal fluorescence microscopy and magnetophoresis. A 72 h follow-up showed efficient uptake after 24 h with no notable cell mortality. These studies again pointed out the distinct behavior of RAFT polyelectrolyte-coated bimodal NAs that internalize at a slower rate with no adverse cytotMdcity. Extension to multicellular tumor cell spheroids that mimic solid tumors revealed the successful internalization of the NAs in the periphery cells, which provides efficient deep-imaging labels thanks to their induced T-2* contrast, large emission Stokes shift, and bright dotlike signal, popping out of the strong spheroid autofluorescence.

The synthesis of new series of oxazolidinones having sulfonamide moieties is described. These compounds are synthesized in good yield starting prochiral 1,3-dichloro-2-propanol and chlorosulfonyl isocyanate. This strategy involves the formation of carboxylsulfamide by carbamoylation–sulfamoylation reaction followed by intermolecular cyclization. In order to determine the enantioselectivity during the cyclization step, X-ray studies of products are performed.

A new synthesis of unsymmetrical phosphinic acids R′P(O)OHR″ has been evaluated. The first P–C bond was formed by base-promoted H-phosphinate alkylation of a protected H-phosphinate, which is easier and safer to handle. A one-pot methodology was developed for the second P–C bond formation reaction that involves the sila-Arbuzov reaction. This methodology was then extended to the synthesis of a dialkylphosphinic acid with an amino functionality. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

International audience; The use of nanotechnologies for biomedical applications took a real development during these last years. To allow an effective targeting for biomedical imaging applications, the adsorption of plasmatic proteins on the surface of nanoparticles must be prevented to reduce the hepatic capture and increase the plasmatic time life. In biologic media, metal oxide nanoparticles are not stable and must be coated by biocompatible organic ligands. The use of phosphonate ligands to modify the nanoparticle surface drew a lot of attention in the last years for the design of highly functional hybrid materials. Here, we report a methodology to synthesize bisphosphonates having functionalized PEG side chains with different lengths. The key step is a procedure developed in our laboratory to introduce the bisphosphonate from acyl chloride and tris(trimethylsilyl)phosphite in one step. 1366

International audience; Anovel bifunctional organocatalyst library combiningboth aminocatalysis and phosphonic acid activation was used for the first time as an efficient tool for the stereoselective Michael addition of aldehydes with several aromaticnitroalkenes with good selectivities up to 95:5 dr and 93:7 er. Due to their high water solubility,the catalysts were easily recyclable andcould be reused over several cycles without anysignificant lo ss of selectivity.

A novel bifunctional organocatalysts library was developed as efficient tool for the stereoselective Michael addition of aldehydes with several aromatic nitroalkenes. Therefore, a phosphonic acid w...

International audience; L’analyse UPLC-MS/MS de l’extrait brut hydroacétonique des feuilles de Zanthoxylum gilletii a permis l’identification de composés phénoliques tels l’acide gallique et dérivés (9,40 mg EAG/g ms), l’acide protocatéchique (0,22 mg EAP/g ms), des flavonoïdes (6,34 mg EQ/g ms) et des acides hydroxycinnamiques (4,24 mg EAC/g ms). L’étude de la cytotoxicité a montré que cet extrait possède une activité antiproliférative sur les cellules cancéreuses C6, SNB 75, GLI7 et GLI4F11 (CI50 < 0,01 mg/ml).

This paper reports the design and synthesis of C-glycoside mimetics (d-glycero-d-talo- and d-glycero-d-galactopyranose analogues), a subset of the recently published phostines, belonging to the [1,2]oxaphosphinane core. Eighteen new compounds were tested against 11 cancer cell types belonging to six categories of tumor tissues and three different species. The hit compound 5.3d inhibited invasion and migration of both GBM stem cells (Gli7 and Gli4) and GBM cancer cell lines (C6, SNB75) on fibronectin, vitronectin, and laminin. Ki values for Gli7 and Gli4 migration inhibition on fibronectin were 16 and 31 nM respectively. Ki values for invasion inhibition in a 3D system were 46 nM for Gli7 and 290 nM for Gli4. These activities were associated with an antiproliferative effect on Gli4 (EC50 = 5.20 μM) and Gli7 (EC50 = 2.33 μM). In conclusion, the heptopyranose mimetic 5.3d, devoid of toxicity on astrocyte and cortical neuron cultures at concentrations below 100 μM, opens new therapeutic perspectives against glioblastoma.

International audience; Superparamagnetic fluorescent nanoparticles targeting αvβ3 integrins were elaborated using two methodologies: carbodiimide coupling and click chemistries (CuACC and thiol-yne). The nanoparticles are first functionalized with hydroxymethylenebisphonates (HMBP) bearing carboxylic acid or alkyne functions. Then, a large number of these reactives functions were used for the covalent coupling of dyes, poly(ethylene glycol) (PEG), and cyclic RGD. Several methods were used to characterize the nanoparticle surface functionalization, and the magnetic properties of these contrast agents were studied using a 1.5 T clinical MRI. The affinity toward integrins was evidenced by solid-phase receptor-binding assay. In addition to their chemoselective natures, click reactions were shown to be far more efficient than the carbodiimide coupling. The grafting increase was shown to enhance targeting affinity to integrin without imparing MRI and fluorescent properties.

International audience; This paper reports the design and the synthesis of a new family of compounds, the phostines, belonging to the [1,2]oxaphosphinane family. Twenty-six compounds have been screened for their antiproliferative activity against a large panel of NCI cancer cell lines. Because of its easy synthesis and low EC50 value (500 nM against the C6 rat glioma cell line), compound 3.1a was selected for further biological study. Moreover, the specific biological effect of 3.1a on the glioblastoma phylogenetic cluster from the NCI is dependent on its stereochemistry. Within that cluster, 3.1a has a higher antiproliferative activity than Temozolomide and is more potent than paclitaxel for the SF295 and SNB75 cell lines. In constrast with paclitaxel and vincristine, 3.1a is devoid of astrocyte toxicity. The original activity spectrum of 3.1a on the NCI cancer cell line panel allows the development of this family for use in association with existing drugs, opening new therapeutic perspectives.

International audience; The magnetic behavior at room temperature of maghemite nanoparticles of variable sizes (from 7 to 20 nm) is compared using a conventional super quantum interference device (SQUID) and a recently patented technology, called MIAplex. The SQUID usually measures the magnetic response versus an applied magnetic field in a quasi-static mode until high field values (from -4000 to 4000 kA m(-1)) to determine the field-dependence and saturation magnetization of the sample. The MIAplex is a handheld portable device that measures a signal corresponding to the second derivative of the magnetization around zero field (between -15 and 15 kA m(-1)). In this paper, the magnetic response of the size series is correlated, both in diluted and powder form, between the SQUID and MIAplex. The SQUID curves are measured at room temperature in two magnetic field ranges from -4000 to 4000 kA m(-1) (-5T to 5T) and from -15 to 15 kA m(-1). Nonlinear behavior at weak fields is highlighted and the magnetic curves for diluted solutions evolve from quasi-paramagnetic to superparamagnetic behavior when the size of the nanoparticles increases. For the 7-nm sample, the fit of the magnetization with the Langevin model weighted with log-normal distribution corresponds closely to the magnetic size. This confirms the accuracy of the model of non-interacting superparamagnetic particles with a magnetically frustrated surface layer of about 0.5 nm thickness. For the other samples (10-nm to 21-nm), the experimental weak-field magnetization curves are modeled by more than one population of magnetically responding species. This behavior is consistent with a chemically uniform but magnetically distinct structure composed of a core and a magnetically active nanoparticle canted shell. Accordingly the weak-field signature corresponds to the total assembly of the nanoparticles. The impact of size polydispersity is also discussed.

1 - Article; We describe an innovative multimodal system, which combines magnetic targeting of therapeutic agents with both magnetic resonance and fluorescence imaging into one system. This new magnetic nanoplatform consists of superparamagnetic gamma Fe(2)O(3) nanoparticles, used clinically as an MRI contrast agent, conjugated to therapeutic molecules of the hydroxylmethylene bisphosphonate family (HMBPs): alendronate with an amine function as the terminal group. In vitro tests with breast cancer cells show that the gamma Fe(2)O(3)@alendronate hybrid nanomaterial reduces cell viability and acts as a drug delivery system. We also investigated the anti-tumoural properties in vivo in nude mice xenografted with MDA-MB-231 tumours. We show that the presence of both gamma Fe(2)O(3)@alendronate and a magnetic field significantly reduced the development of tumours. The amine functionalities can be used as precursor groups for the covalent coupling of peptides or monoclonal antibodies for specific biological targeting. The feasibility of this process was demonstrated by coupling rhodamine B, a fluorescence marker, to the gamma Fe(2)O(3)@alendronate nanohybrid. The system showed fluorescent properties and high affinity for cells. Flow cytometry and fluorescence microscopy were used to study the kinetics of gamma Fe(2)O(3)@alendronate uptake by cells. The magnetic and fluorescent nanoparticles are potential candidates for smart drug-delivery systems. Also, the superparamagnetic behaviour of such nanoparticles may be exploited as MRI contrast agents to improve therapeutic diagnostics.

1 - Article; A new type of multifunctional magnetic nano-platform for bioassays, diagnosis and therapy applications was designed using superparamagnetic gamma Fe(2)O(3) nanoparticles conjugated to hydroxylmethylene bisphosphonate (HMBPs) molecules. The nanoparticle has two essential roles: to act as a probe owing to its specific magnetic properties and to carry on its surface antitumoral molecules (therapeutic applications) or precursor groups for the covalent coupling of biological recognition molecules, such as antibodies, nucleic acids (in vitro & in vivo diagnosis).

The crystal structures of three 3-benzyl-2-phenyl-1,3,2-oxazaphospholidin-2-one derivatives have been determined by X-ray diffraction. Synthesis of compound (I), a racemic mixture of (2S) and (2R)-3-benzyl-2-phenyl-1,3,2-oxazaphospholidin-2-one, compound (II), (2S,4S)-3-benzyl-2-phenyl-4-(propan-2-yl)-1,3,2-oxazaphospholidin-2-one and compound (III), a mixture of (2S,4S) and (2R,4S)-3,4-dibenzyl-2-phenyl-1,3,2-oxazaphospholidin-2-one were easily carried out starting from the corresponding N-protected amino alcohols and phenyl-phosphonic dichloride. Crystal structure of (I) and (III) exhibit monoclinic symmetries as (II) exhibits orthorhombic symmetry. Their packings are ensured by a combination of different types of weak non-covalent and competitives effects, in particular, π/π stacking against CH/π hydrogen bonds. The significance of this study lies in the comparison drawn between these crystal structures and those of several of its simple analogues.

Diethyl phosphonates and tetraethyl alkyldiphosphonates were efficiently and rapidly prepared via the Michaelis–Becker reaction, under microwave irradiation. These compounds were then hydrolyzed to phosphonic and diphosphonic acids or selectively monodealkylated to give monoesters of phosphonic acids and symmetrical diethyl esters of diphosphonic acids. These reactions were also achieved rapidly in satisfactory yields with microwave methodology. This methodology was applied with success to the functionalization of a polymer resin. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:369–377, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20561

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9 - conference paper: Seventh International Conference on the Scientific and Clinical Applications of Magnetic Carriers; 20-24 May 2008; Vancouver (Canada); Magnetic nanoparticles differing by their size have been synthesized to use them for multiparametric testing, based on their differing magnetic properties. The nanoparticle has two essential roles: to act as a probe owing to its specific magnetic properties and to carry on its surface precursor groups for the covalent coupling of biological recognition molecules, such as antibodies, nucleic acids. A totally unique, newly patented, method has been used to characterize magnetic signatures using the MIAplex technology. The MIAplex reader, developed by Magnisense, measures the non-linear response of the magnetic labels when they are exposed to a multi-frequency alternating magnetic field. This specific signature based on d2B(H)/dH2 was correlated to other more conventional magnetic detection methods (superconducting quantum interference devices (SQUID) and Mössbauer).

1 - Article; 1-Hydroxymethylene-1,1-bisphosphonic acids (or bisphosphonates) are compounds that have interesting pharmacological applications. However, few mass spectrometric investigations have been carried out to determine their fragmentation patterns. Herein, we evaluated different matrices for the study by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of the formation and fragmentation of the protonated, the cationized (MNa+ and MK+) and the deprotonated bisphosphonates. Some in-source fragmentations were observed both in positive and in negative ion modes. The fragmentation patterns obtained in post-source decay mode are also discussed. In contrast to previous electrospray ionization/multi-stage mass spectrometry (ESI-MSn) studies, some new fragmentation pathways were deduced and the effects of alkali ions on the fragmentation patterns were shown. The results summarized here completed the data previously recorded by ESI-MSn and could be used for the characterization of bisphosphonates as alkali complexes in biological mixtures. Copyright (C) 2009 John Wiley & Sons, Ltd.

1 - Article; New upper-rim polyphosphorylated calix[4]arenes were designed for decorporation of uranium in case of nuclear contamination. A ligand system containing four preorganized 1-hydroxymethylene-1,1-bisphosphonic acid moieties anchored onto a calix[4]arene platform has been developed. Three calix[4]arene-bisphosphonates were efficiently prepared in multi-step syntheses with a variable carbon chain length between the bisphosphonate and the calix[4]arene. Affinity constants towards uranyl ion were determined and compared with those of bis(HEDP) and tris(HEDP) phosphonates, known as efficient ligands for uranyl.

1 - Article; 1-Hydroxymethylene-1,1-bisphosphonic acids (HMBPs) are important drugs for the treatment of a variety of bone diseases. Since these compounds have no chromophore, their detection is challenging and mass spectrometry (MS) appears to be an appropriate sensitive tool. Our work deals with the analysis by electrospray ionization tandem mass spectrometry (ESI-MSn) of the well-known nitrogen-containing HMBP alendronate and of three analogues, considered as potential prodrugs. These four molecules share a common structure with different protecting groups on the phosphonic acid and on the amine functions. We describe the dissociation mechanisms of nitrogen-containing HMBPs in positive ion mode and we compare, in negative ion mode, our results with literature data. In both modes, the dissociations are essentially losses of ROH, and of phosphorus-containing species (HPO2, ROP(OH)(2) and ROPO(OH)(2)), where R = H, C6H5, or CH3OC6H5. These fingerprints will be of great value for differentiating alendronate from its potential prodrugs in complex biological mixtures. Copyright (c) 2008 John Wiley & Sons, Ltd.

0891-5849; The reaction of the free radical diphenylpicrylhydrazyl (DPPH[dot above]) with the anesthetic agent 2,6-diisopropylphenol (propofol, PPF) was investigated in buffered hydroalcoholic media. The kinetics was followed using a stopped-flow system. DPPH[dot above] was reduced to the hydrazine analogue DPPH-H with a measured stoichiometry (DPPH[dot above]/PPF) of 2. The main product of the reaction, 3,5,3',5'-tetraisopropyl-(4,4')-diphenoquinone (PPFDQ) was isolated by chromatography and its structure was fully characterized. The reaction mechanism was inferred from the stoichiometry, kinetics, and product identification. The first step, which primarily determines the kinetics, is the reaction of DPPH[dot above] with PPF to produce DPPH-H and the PPF radical. The rate constant was found to be 31.8, 207, and 908 M- 1 s- 1 at pH 6.4, 7.4, and 8.4, respectively. The pH dependence is indicative of a higher reactivity of the phenolate form of PPF. Then, PPF radicals combine to form dipropofol, which is quickly oxidized to PPFDQ by the remaining DPPH[dot above]. This reaction scheme is corroborated by numerical simulations of the kinetics. In the course of this study we also disclosed an unexpected effect, the photochemical degradation of PPFDQ. The need to compare antioxidants on a kinetics basis is again emphasized. In our hands, PPF presents a significantly weaker reactivity than Trolox.

1 - Article; 1-Hydroxymethylene-1,1-bisphosphonic acids (HMBPs) are compounds that have interesting pharmacological applications. Unfortunately few studies exist on their analyses by mass spectrometry (MS). In this work, we have analyzed new aromatic HMBPs and their prodrugs with electrospray tandem mass spectrometry (ESI-MSn). We describe, for the first time, a complete study of fragmentation patterns, in both positive and negative-ion modes. In positive mode, the cation dissociations are mainly elimination of water and phosphorus fragments. In negative mode, losses of ROH (R=H, C6H5, CH3OC6H5) and HPO2 were observed. The results have revealed specific structural fingerprints for the screening of these compounds in complex biological mixtures. Copyright (C) 2008 John Wiley & Sons, Ltd.

1 - Article; Several synthetic pathways for obtaining phosphonic esters of the amino bisphosphonic acids (NBPs) pamidronate, alendronate and neridronate were investigated. The general guideline was to react N-protected amino acids activated as phthalimide esters or as acyl chlorides. Succinimide esters were found less reactive and quickly abandoned. gamma-Lactam formation arises when starting from Boc- or Cbz-protected amino acids. The phthalimide N-protecting group allowed access to alkyl or aryl mono-, di- (symmetric or not) and tri-esters of these three NBPs in high yields. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).

0040-4039; Efficient synthetic routes for preparation of a new family of aldehyde-bisphosphonate conjugates were presented. These compounds appeared as promising intermediates for incorporation of bisphosphonate moiety in various substrates under mild conditions. We report here a first application to the synthesis of a series of three phosphonated tripods designed for actinides chelation therapy.

New tripodal uranyl ion chelators containing gem -bisphosphonic units have been synthesized. All bisphosphonic units present a side chain with 0, 1, or 2 methylene group terminated by –NH 2 or –CO 2 H group. These units were respectively coupled with a –CO 2 H or –NH 2 functions of a suitable tri-functional platform. The shape and size of the new designed ligands were selected and validated through computer molecular modelization.

1 - Article; A new type of multifunctional magnetic nano-platform for diagnosis and therapy applications was designed using bisphosphonate/carboxylic ligands.

Enamine catalysis is a widespread activation mode in the field of organocatalysis and is often encountered in bifunctional organocatalysts. We previously described H-Pro-Pro-pAla-OMe as a bifunctional catalyst for Michael addition between aldehydes and aromatic nitroalkenes. Considering that opposite selectivities were observed when compared to H-Pro-Pro-Glu-NH2 , an analogue described by Wennemers, the activation mode of H-Pro-Pro-pAla-OMe was investigated through kinetic, linear effect studies, NMR analyses, and structural modifications. It appeared that only one bifunctional catalyst was involved in the catalytic cycle, by activating aldehyde through an (E)-enamine and nitroalkene through an acidic interaction. A restrained tripeptide structure was optimal in terms of distance and rigidity for better selectivities and fast reaction rates. Transition-state modeling unveiled the particular selectivity of this phosphonopeptide.