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PubMed2004

Hybrid fluorocarbon-hydrocarbon CO2-philic surfactants. 1. synthesis and properties of aqueous solutions.

Six different hybrid fluorocarbon-hydrocarbon (F-H) sulfate and sulfonate surfactants, with variations in the relative F/H carbon chain length, have been synthesized and characterized in aqueous solution. These compounds have been targeted for potential activity in densified CO2. Tensiometric data and chemical analyses were consistent with surfactants of high chemical purity. Fluorination in terms of the F/H ratio exerts a strong control over all the surfactant physicochemical properties, including critical micelle concentrations (cmc's) and adsorption isotherms. One of these partially fluorinated surfactants (the sulfonate phi-F6H4) achieves very low surface tensions in water (gamma(cmc) approximately 19 mN m(-1)) more reminiscent of fully fluorinated double-chain compounds. Detailed 19F NMR studies revealed that omega'-CF3 groups can exhibit separate signals for monomeric and micellized forms, hence facilitating cmc determinations. Small-angle neutron scattering investigations confirmed the presence of ellipsoidal or extended disklike micelles, depending on the F-H chain asymmetry. For example, a symmetric hybrid F8H8 generates disklike micelles, whereas chain asymmetry in F8H4 or phi-F6H4 tends to drive cylindrical aggregation structures. These changes are consistent with variations in the surfactant packing parameter caused by the different chain F/H ratios. Hence, adsorption and aggregation are shown to respond in a predictable way to the molecular structure of these unusual surfactants.

Journal Article↗
PubMed1992

Fluorine-substituted corticosteroids: synthesis and evaluation as potential receptor-based imaging agents for positron emission tomography of the brain.

We have prepared eight fluorine-substituted corticosteroids representing ligands selective for Type I and Type II corticosteroid receptor subtypes as potential imaging agents for corticosteroid receptor-containing regions of the brain. Receptor binding affinity assays show that fluorine substitution for hydroxyl or hydrogen in these steroids generally results in some reduction in affinity, with the result that the absolute affinity of these fluorine-substituted ligands for receptor is less than that typical for steroid hormones that show receptor-based, target selective uptake in vivo. Five of these compounds were prepared in fluorine-18 labeled form by a simple sulfonate ester displacement reaction, and their tissue distribution was studied in the adrenalectomized rat. There is no selective accumulation nor selective retention of the Type I selective corticosteroids (18F-RU 26752, 21-[18F]fluoroprogesterone, 21-[18F]fluoro-11 beta-hydroxyprogesterone) in either the brain, or other target tissues (pituitary, kidney, liver). The Type II selective corticosteroids (18F-RU 28362, 18F-triamcinolone acetonide) show uptake into the hippocampus which can be partially blocked by a competing ligand; in target tissues outside the brain, the blocking is more complete. All of the 18F-labeled compounds show considerable defluorination, evident as high bone activity levels. These results, coupled with earlier findings in the literature, suggest that radiolabeled corticosteroid receptor ligands with both greater metabolic stability and higher receptor binding affinity and selectivity are needed for imaging corticosteroid receptors in the hippocampus.

Adrenal Cortex Hormones↗
PubMed2004

Identification of biogenic organotellurides in Escherichia coli K-12 headspace gases using solid-phase microextraction and gas chromatography.

Escherichia coli JM109 cells, expressing the genes encoded in a 3.8-kb chromosomal DNA fragment from Geobacillus stearothermophilus V, produced volatile organotellurium compounds which were released into the headspace gas above liquid cultures when amended with tellurite anions in micromolar amounts. Headspace sampling was achieved using gas-syringe extraction or solid-phase microextraction using carboxen-polydimethysiloxane fibers. In addition to dimethyl telluride and dimethyl ditelluride, two new organometalloidal compounds were detected using gas chromatograph with mass spectrometric or fluorine-induced chemiluminescence detection. These compounds are methanetellurol and dimethyl tellurenyl sulfide. The significance of these findings with regard to the current knowledge about bacterial tellurite resistance is discussed.

Adaptation, Biological↗
PubMed1985

Synthesis of 4-[18F]fluoroantipyrine and its biodistribution in mice.

The synthesis of 4-[18F]fluoroantipyrine (1) and its biodistribution in mice are described. Compound 1 was synthesized either by direct fluorination of antipyrine with [18F]F2 or CH3CO2 18F, or by an isotopic exchange method. While direct fluorination of antipyrine with [18F]F2 gave compound 1 in about a 20% yield, the isotopic exchange method gave compound 1 in only a 1%-2% yield. The biodistributions of compound 1 and 4-[131I]iodoantipyrine (3) in mice indicated that both compounds reached apparent equilibrium concentration in the bloodstream at approximately 0.5 min postinjection and compound 1 was found in higher concentrations than the iodinated analog in the well-perfused tissues. The 18F activity in the mouse brain persisted for about 2 min. The ratio of activity in the brain to bone was approximately 2:1. After 10 min, the 18F activity in the brain decreased markedly while the 18F activity in bones rose sharply resulting in a brain to bone ratio of approximately 1:2. This would suggest that compound 1 defluorinated in vivo to give fluoride as one of the metabolites. The mean octanol/pH 7 buffer solution partition coefficients of 4-[18F]fluoroantipyrine and 4-[131I]iodoantipyrine were 5.18 +/- 0.10 and 11.34 +/- 0.28, respectively.

Animals↗
PubMed2002

Structural properties of a series of photochromic fluorinated indolylfulgides.

Fluorinated indolylfulgides are a class of photochromic organic compounds that meet many of the requirements for use as optical memory media and optical switches. The X-ray crystal structures of a series of five photochromic fluorinated indolylfulgides have been determined, namely (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,2-trifluoroethylidene]-4-(1-methylethylidene)dihydrofuran-2,5-dione (trifluoromethylisopropylideneindolylfulgide), C(19)H(16)F(3)NO(3), (I), (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,3,3,3-pentafluoropropylidene]-4-(1-methylethylidene)dihydrofuran-2,5-dione (pentafluoroethylisopropylideneindolylfulgide), C(20)H(16)F(5)NO(3), (II), (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,3,3,4,4,4-heptafluorobutylidene]-4-(1-methylethylidene)dihydrofuran-2,5-dione (heptafluoropropylisopropylideneindolylfulgide), C(21)H(16)F(7)NO(3), (III), (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,2-trifluoroethylidene]-4-(tricyclo[3.3.1.1(3,7)]decylidene)dihydrofuran-2,5-dione (trifluoromethyladamantylideneindolylfulgide), C(26)H(24)F(3)NO(3), (IV), and (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,3,3,4,4,4-heptafluorobutylidene]-4-(tricyclo[3.3.1.1(3,7)]decylidene)dihydrofuran-2,5-dione (heptafluoropropyladamantylideneindolylfulgide), C(28)H(24)F(7)NO(3), (V). The photochromic property of fulgides is based on the photochemically allowed electrocyclic ring closure of a hexatriene system to form a cyclohexadiene. For each fulgide examined, the bond lengths within the hexatriene system alternate between short and long, as expected. Comparing the structures of the five fulgides with each other demonstrates no significant difference in bond lengths, bond angles or dihedral angles within the hexatriene systems. The distance between the bond-forming C atoms at each end of the hexatriene system does vary. Correlations of structural properties with optical properties are addressed.

Adamantane↗
PubMed2004

The unique role of fluorine in the design of active ingredients for modern crop protection.

The task of inventing and developing active ingredients with useful biological activities requires a search for novel chemical substructures. This process may trigger the discovery of whole classes of chemicals of potential commercial interest. Similar biological effects can often be achieved by completely different compounds. However, compounds within a given structural family may exhibit quite different biological activities depending on their interactions with different intracellular proteins like enzymes or receptors. By varying the functional groups and structural elements of a lead compound, its interaction with the active site of the target protein, as well as its physicochemical, pharmacokinetic, and dynamic properties can be improved. In this context, the introduction of fluorine into active ingredients has become an important concept in the quest for a modern crop protection product with optimal efficacy, environmental safety, user friendliness, and economic viability. Fluorinated organic compounds represent an important and growing family of commercial agrochemicals. A number of recently developed agrochemical candidates represent novel classes of chemical compounds with new modes of action; several of these compounds contain new fluorinated substituents. However, the complex structure-activity relationships associated with biologically active molecules mean that the introduction of fluorine can lead to either an increase or a decrease in the efficacy of a compound depending on its changed mode of action, physicochemical properties, target interaction, or metabolic susceptibility and transformation. Therefore, it is still difficult to predict the sites in a molecule at which fluorine substitution will result in optimal desired effects.

Animals↗
PubMed2006

Nucleophilic fluoroalkylation of epoxides with fluorinated sulfones.

The unprecedented nucleophilic fluoroalkylation of simple epoxides with fluorinated sulfones was achieved to give the beta-fluoroalkyl alcohols in one step. The negative "fluorine effect" in the nucleophilic fluoroalkylation of epoxides with fluorinated carbanions was probed by the reactivity comparison between carbanions PhSO2CF2- (3) and PhSO2CCl2- (4) and between carbanions PhSO2CHF- (7) and PhSO2CHCl- (13). The mediation of this fluorine effect by introducing another electron-withdrawing benzenesulfonyl group was found to be an effective way to significantly increase the nucleophilicity of the fluorinated carbanions, with the reactivity order [(PhSO2)2CF-] (16) > PhSO2CFH- (7) >> PhSO2CF2- (3).

Anions↗
PubMed2001

CYP2E1-mediated modulation of valproic acid-induced hepatocytotoxicity.

OBJECTIVES: To determine the cytotoxicity of valproic acid (VPA) and its metabolite, 4-ene-valproic acid (4-ene-VPA) in human hepatoblastoma cells (Hep G2), and to study the modulatory effect of cytochrome P450 2E1 induction in this model. METHODS: Cells were exposed to VPA or 4-ene-VPA in the presence of either ethanol (EtOH), or EtOH combined with disulphiram (DS). Some cells were exposed to alpha-fluoro-VPA or to alpha-fluoro-4-ene-VPA in the absence of CYP2E1 inducers. Apoptosis and necrosis were measured by analyzing 6000 cells per sample using transmission electron microscopy, while cytokine release and apoptosis were quantitated by ELISA. RESULTS: VPA + EtOH increased VPA cytotoxicity. 4-ene-VPA + EtOH significantly increased toxicity, while DS + EtOH significantly reduced this toxicity. Alpha-fluorinated analogues reduced cytotoxicity compared to the corresponding VPA compounds. Neither VPA nor alpha-fluorinated VPA increased the release of IL-6 or TNF-alpha in media. A significant increase in the release of TNF-alpha was observed in cells exposed to 4-ene-VPA that further increased with EtOH exposure. CONCLUSIONS: Cells exposed to 4-ene-VPA experience greater cytotoxicity than those treated with VPA. Cytochrome P450 2E1 inducers enhance toxicity in VPA-exposed cells, while alpha-fluorination of VPA diminishes cytotoxicity by directly interfering with the beta-oxidation of the 4-ene-VPA metabolite.

Anticonvulsants↗
PubMed2006

Identification of monomenthyl succinate in natural mint extracts by LC-ESI-MS-MS and GC-MS.

Fresh and dried mint leaves Mentha piperita (peppermint) and Mentha spicata (spearmint) were extracted in two different ways and the extracts investigated by high performance liquid chromatography-tandem mass spectrometry. All the ethanolic extracts prepared with Soxhlet apparatus were used in the identification of monomenthyl succinate as previously reported. The highest level was found in fresh spearmint leaves. The analysis of the extractions, prepared under mild conditions using a fluorinated solvent (HFC 134-a), confirmed the natural occurrence of monomenthyl succinate in the leaves, ruling out the hypothesis that this constituent could be an artifact of the Soxhlet extraction process. A method for identifying this compound in such a fluorinated solvent extract of mint leaf using preliminary esterification with diazomethane and then GC-MS is described.

Chromatography, High Pressure Liquid↗
PubMed2005

New antitubulin derivatives in the combretastatin A4 series: synthesis and biological evaluation.

Two series of combretastatin A4 derivatives (acrylamide=carboxamide and carbamate) were synthesized in order to improve the water solubility and stabilize the cis-configuration of the double bond. Their cytotoxic effects were evaluated against MCF-7, KB-3-1 and IGROV human cancer cell lines, as well as their inhibitory activity on tubulin polymerization. Results were compared to those of carboxamide 1, chosen as reference. Potent inhibitions were observed on both tests in the carboxamide series, particularly for compound 4d bearing a fluorine group in replacement of the 3-hydroxyl of CA4. In contrast, most of the carbamates were either inactive or displayed only moderate cytotoxicities. Interestingly, a submicromolar IC(50) was measured on MCF-7 cells for 6g, although this compound was totally devoid of antitubulin activity.

Biopolymers↗
PubMed2006

Semiautomated synthesis of a novel [18F] amine fluorocyanoborane for PET imaging studies. Radiosynthesis and in vivo characterization in rats.

A novel fluorine-18 labeled amine fluorocyanoborane derivative was synthesized from the bromo-derivative precursor in 22% radiochemical yield. The [18F] labeling was accomplished by a semiautomatic method that is based on the synthesis of Ag 18F from Ag2CO3 and H 18F in a platinum dish followed by sonication of the bromo-precursor with Ag 18F in dry benzene to produce [18F] labeled amine fluorocyanoborane which was used with no further purification. A total of 50 microCi of the [18F] labeled amine fluorocyanoborane was injected into normal, female Sprague-Dawley rats (250-300 g) via the tail vein and monitored by Positron emission tomography (PET)/CT to detect its biodistribution in the rat body. The images showed an uptake of this compound in the bones of rats.

Animals↗
PubMed1994

[Fluorine and lead content in selected vegetables grown within the range of emission of compounds containing these elements by the glass plant"Irena" in Wrocław].

By means of spectroscopy fluorine and lead were determined in selected vegetables gathered in 1990 from Workers' Gardening Plots "Transportowiec" lying about 500 m from the Irena glass plant and similar plots "Irena" situated about 2600 m from the emitters of the plant. The obtained results were compared with those of similar measurements in the preceding 8 years, and with analogous determinations in the vegetables gathered in 1989 from "Podzamcze" gardening plots in Szczytna in immediate vicinity of the glass plant "Sudety". The study extended over many years showed that in the vicinity of such plants, the soil, the vegetables and fruit are contaminated with fluorine and lead. Moving of "Irena" gardening plots from 50-350 m from the plant to a distance of 1800 m from it caused that only the parts of the vegetables above soil level contained higher amounts of fluorine and lead. Certain above-soil parts of the plants from the "Podzamcze" gardening plots contained fluorine in amounts exceeding the acceptable level. Most vegetables, both roots and higher parts, were contaminated with lead, indicating that the soil was contaminated with lead also.

Environmental Exposure↗
PubMed2004

Use of 19F-nuclear magnetic resonance and gas chromatography-electron capture detection in the quantitative analysis of fluorine-containing metabolites in urine of sevoflurane-anaesthetized patients.

1: The use of fluorine-19 nuclear magnetic resonance (19F-NMR) and gas chromatography-electron capture detection (GC-ECD) in the analysis of fluorine-containing products in the urine of sevoflurane-exposed patients was explored. 2: Ten patients were anaesthetized by sevoflurane for 135-660 min at a flow rate of 6 l min(-1). Urine samples were collected before, directly after and 24 h after discontinuation of anaesthesia. 3: 19F-NMR analysis of the urines showed the presence of several fluorine-containing metabolites. The main oxidative metabolite, hexafluoroisopropanol (HFIP)-glucuronide, showed two strong quartet signals in the 19F-NMR spectrum. HFIP concentrations after beta-glucuronidase treatment were quantified by (19)F-nuclear magnetic resonance. Concentrations directly after and 24 h after discontinuation of anaesthesia were 131 +/- 41 (mean +/- SEM) and 61 +/- 19 mol mg(-1) creatinine, respectively. Urinary HFIP excretions correlated with sevoflurane exposure. 4: Longer scanning times enabled the measurement of signals from two compound A-derived metabolites, i.e. compound A mercapturic acid I (CAMA-I) and compound A mercapturic acid II (CAMA-II), as well as products from beta-lyase activation of the respective cysteine conjugates of compound A. The signals of the mercapturic acids, 3,3,3-trifluoro-2-(fluoromethoxy)-propanoic acid and 3,3,3-trifluorolactic acid were visible after combining and concentrating the patient urines. CAMA-I and -II excretions in patients were completed after 24 h. 5: Since 19F-nuclear magnetic resonance is not sensitive enough, urinary mercapturic acids concentrations were quantified by gas chromatography-electron capture detection. CAMA-I and -II urinary concentrations were 2.3 +/- 0.7 and 1.4 +/- 0.4 mol mg(-1) creatinine, respectively. Urinary excretion of CAMA-I showed a correlation with sevoflurane exposure, whereas CAMA-II did not. 6. The results show that 19F-nuclear magnetic resonance is a very selective and convenient technique to detect and quantify HFIP in non-concentrated human urine. 19F-nuclear magnetic resonance can also be used to monitor the oxidative biotransformation of sevoflurane in anaesthetized patients. Compound A-derived mercapturic acids and 3,3,3-trifluoro-2-(fluoromethoxy)-propanoic acid and 3,3,3-trifluorolactic acid, however, require more sensitive techniques such as gas chromatography-electron capture detection and/or gas chromatography-mass spectrometry for quantification.

Anesthesia, Inhalation↗
PubMed2006

Synthesis of novel tricyclic oxazolidinones by a tandem SN2 and SNAr reaction: SAR studies on conformationally constrained analogues of Linezolid.

A series of conformationally constrained analogues of Linezolid were synthesised by employing a tandem SN(2) and SNAr reaction as the key step and tested for antibacterial activity. While the hexahydroazolo-quinoxaline compounds were inactive, the tetrahydroazolo-benzothiazine compounds exhibited interesting antibacterial activity. The introduction of fluorine in the aromatic ring further made the compounds more potent in acetamide compounds resulting in an interesting analogue 32. However, the introduction of fluorine (analogue 34) on the already potent non-fluorine thiocarbamate 21 did not have any influence on the activity.

Acetamides↗
PubMed1990

Reaction pathways for biodehalogenation of fluorinated anilines.

Pathways for biodehalogenation of fluorinated aniline derivatives were investigated. Microsomal NADPH-dependent dehalogenation of fluoroanilines was shown to proceed by three different reaction pathways. The first route appeared to result in monooxygenation at a fluorinated position and release of the fluorine atom as a fluoride anion. The primary additional reaction product formed is the reactive quinoneimine, not the 4-hydroxyaniline. In NADPH-containing microsomal systems with 4-fluoro-substituted anilines, formation of the 4-hydroxyaniline derivative is observed because NADPH chemically reduces this quinoneimine metabolite. A second pathway for dehalogenation proceeds by protein binding of a fluoro-containing (semi)quinoneimine metabolite, the formation of which may result from the mono-oxygenase reaction (pathway 1) and/or from (re)oxidation of a hydroxyaniline metabolite by superoxide anion radicals produced by the microsomal system. This latter reaction pathway becomes more important with increasing number of fluoro-substituents in the fluoroaniline derivative. The higher ratio of fluoride anion formed to 4-hydroxyaniline derivative detected in incubations with liver microsomes from dexamethasone-treated rats, as compared to incubations with liver microsomes from control rats, can in part be explained by the higher production of superoxide anion radicals observed in the dexamethasone systems. The third mechanism was shown to proceed by formation of a hydroxylated metabolite that loses fluoride anion upon exposure to oxygen. The reactive intermediate formed upon oxygen exposure might be the semiquinoneimine which loses its fluorine atom as a fluoride anion upon dimerization or polymerization and/or protein binding. The fluorohydroxyanilines, in which the hydroxyl group is ortho or para with respect to the fluoro substituent, appear especially to be highly unstable and lose fluoride anion in the presence of oxygen. Finally, it is concluded that all three pathways for dehalogenation of fluorinated aniline derivatives are bioactivation pathways. The reactivity of the (semi)quinoneimines formed in these reactions is dependent on their substitution pattern and increases with increasing number of fluoro-substituents. Therefore, bioactivation for a series of fluorinated aniline derivatives, can be expected to vary with the substitution pattern and to increase with increasing number of halogen substituents.

Aniline Compounds↗
PubMed1995

Evaluation of cannabinoid receptor binding and in vivo activities for anandamide analogs.

Recent evidence implicates anandamide as the endogenous ligand for the cannabinoid receptor. One purpose of this study was to determine the structural requirements for anandamide's receptor interaction and the influence of phenylmethylsulfonyl fluoride (PMSF), an enzyme inhibitor, on receptor affinity. A second objective was evaluation of the correlation between affinities of the analogs and in vivo pharmacological activities. The ability of anandamide and analogs to displace [3H]CP-55,940 ([3](-)-3-[2-hydroxyl-4-(1,1-dimethylheptyl)phenyl]-4-[3- hydroxylpropyl]cyclohexan-1-ol) was determined by a filtration assay. Displacement curves for anandamide in the presence of PMSF produced a Ki of 89 +/- 10 nM; without PMSF the Ki increased to 5400 +/- 1600 nM. Anandamide analogs were evaluated for their ability to produce antinociception and hypomotility. The levels of saturation of the anandamide structure were critical to receptor affinity and in vivo potency, with complete saturation and hydroxyl substitution with a fluorine moiety resulting in a compound with increased potency in the spontaneous activity and antinociception assays. Substitution of the hydroxyl with a fluorine atom increased affinity only in the presence of PMSF and reduced potency in the antinociception assay. Ethanolamide substitution with bromobenzenesulfonamide produced an inactive compound in all assays. Increasing the length of the N-substituent by one or two carbons decreased receptor binding affinity and potency in the tail-flick assay only. Certain structural modifications, such as methylations, allowed the analogs to retain affinity without the addition of PMSF. Linear correlation between the behavioral and binding assays were performed, and the greatest correlation was obtained with compounds that were either very potent or inactive.

Animals↗