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PubMed2002

An efficient enantioselective fluorination of various beta-ketoesters catalyzed by chiral palladium complexes.

Reflecting the importance of fluorinated organic compounds in medicinal chemistry, development of an efficient method for catalytic enantioselective fluorination is increasingly desirable. Using a novel palladium complex 2 (1-2.5 mol %), various beta-ketoesters including cyclic and acyclic substrates were fluorinated with excellent enantioselectivity in the range of 83-94% ee. It is environmentally advantageous that this reaction proceeds well in solvents such as EtOH, rather than usual organic solvents. Furthermore, the product was successfully tranformed into both alpha-fluoro beta-hydroxy and beta-amino acid derivatives, which should be extremely useful in developing novel drugs.

Catalysis↗
PubMed2002

Combined ab initio/empirical approach for optimization of Lennard-Jones parameters for polar-neutral compounds.

The study of small functionalized organic molecules in aqueous solution is a useful step toward gaining a basic understanding of the behavior of biomolecular systems in their native aqueous environment. Interest in studying amines and fluorine-substituted compounds has risen from their intrinsic physicochemical properties and their prevalence in biological and pharmaceutical compounds. In the present study, a previously developed approach which optimizes Lennard-Jones (LJ) parameters via the use of rare gas atoms combined with the reproduction of experimental condensed phase properties was extended to polar-neutral compounds. Compounds studied included four amines (ammonia, methylamine, dimethylamine, and trimethylamine) and three fluoroethanes (1-fluoroethane, 1,1-difluoroethane, and 1,1,1-trifluoroethane). The resulting force field yielded heats of vaporization and molecular volumes in excellent agreement with the experiment, with average differences less than 1%. The current amine CHARMM parameters successfully reproduced experimental aqueous solvation data where methylamine is more hydrophilic than ammonia, with hydrophobicity increasing with additional methylation on the nitrogen. For both the amines and fluoroethanes the parabolic relationship of the extent of methylation or fluorination, respectively, to the heats of vaporization were reproduced by the new parameters. The present results are also discussed with respect to the impact of parameterization approach to molecular details obtained from computer simulations and to the unique biological properties of fluorine in pharmaceutical compounds.

Amines↗
PubMed2005

Characterization of a closed-shell fluorine-fluorine bonding interaction in aromatic compounds on the basis of the electron density.

A bond path linking two saturated fluorine atoms is found to be ubiquitous in crowded difluorinated aromatic compounds. The bond path is shown to persist for a range of internuclear distances (2.3-2.8 A) and a range of relative orientations of the two C-F internuclear axes. The F. . .F bonding is shown to exhibit all the hallmarks of a closed-shell weak interaction. The presence of such a bond path can impart as much as 14 kcal/mol of local stabilization to the molecule in which it exists, a stabilization that can be offset or even overwhelmed by destabilization of other regions in the molecule. Several other weak closed-shell interactions were also found and characterized including F. . .C, F. . .O, and C. . .C interactions, hydrogen bonding, dihydrogen bonding, and hydrogen-hydrogen bonding. This study represents another example of the usefulness and richness of the bond path concept and of the theory of atoms in molecules in general.

Journal Article↗
PubMed1993

Synthesis and PET studies of fluorine-18-BMY 14802: a potential antipsychotic drug.

BMY 14802 is a compound containing fluorine developed as a potential antipsychotic drug. It has a moderate affinity for the sigma binding site and a very low affinity for dopamine D2 receptors and has been predicted to have antipsychotic properties without the side effect potential of existing drugs. To assess the brain uptake, pharmacokinetics, stereoselectivity and binding properties of this potential antipsychotic drug, enantiomerically pure samples of (-) and (+)-[18F]BMY 14802 were examined in a baboon with PET. A tissue distribution with racemic labeled BMY 14802 was also carried out in mice. Radiochemical yields of 15% at the end of bombardment (EOB) for the racemic mixture, and 5% for each enantiomer with a specific activity of 2-5 Ci/mumol at EOB were obtained. In baboons, [18F]BMY 14802 cleared rapidly from the plasma and the glucuronidated [18F]BMY 14802 appeared. Radioactivity peaked (0.04-0.07% dose/cc) in all areas of the brain examined at about 5 min postinjection. It then rapidly cleared to about 30% of peak value by 20 min postinjection and to less than 10% of peak by 60 min postinjection in all regions. A similar rapid clearance from brain was also observed in mice. Pretreatment with unlabeled BMY 14802 (7 mg/kg), did not produce the expected reductions in distribution volume and clearance halftimes consistent with receptor binding. Although the rapid kinetics of [18F]BMY 14802 made it difficult to resolve the processes of transport and binding of the labeled drug, the lack of regional distribution consistent with the known distribution of sigma binding sites as well as the lack of stereoselectivity suggest that the behavior of BMY 14802 in the brain is dominated by its transport properties in tissue rather than its binding to sigma sites. Moreover, its rapid clearance from brain may be a limiting factor in its use as an antipsychotic drug.

Animals↗
PubMed2005

Antiviral and cytostatic evaluation of the novel 6-acyclic chain substituted thymine derivatives.

A series of the novel 5-methyl pyrimidine derivatives with an acyclic side chain at the C-6 position were synthesized using lithiation of a 2,4-dimethoxy-5,6-dimethyl pyrimidine and subsequent nucleophilic addition or substitution reactions of the organolithium intermediate thus obtained with acetaldehyde, epichlorhydrine, fluorinated ketones and fluorinated ester. The novel compounds were evaluated for their cytostatic and antiviral activities. Among all the compounds evaluated, two fluorinated acyclic pyrimidine derivatives showed the highest cytostatic activities. The compound containing a 2-hydroxy-3,3,3-trifluoro-1-propenyl side chain exhibited a pronounced effect against breast carcinoma (MCF-7, IC50=8.38 micorg/ml), while the compound with a 2-fluoromethyl-2-acetoxypropyl chain exhibited moderate effect against cervical carcinoma (HeLa, IC50=19.73 microg/ml).

Antineoplastic Agents↗
PubMed2005

Experimental design for a basic mixture on a fluorinated packing. The effect of composition of the mobile phase.

An optimization methodology is introduced for investigating the separation and the retention behavior of analytes on a new fluorinated reversed-phase packing. Ten basic compounds were selected as test probes to study the predictive models developed by using SPSS and MATLAB software. A two-level orthogonal array design (OAD) was used to extract significant parameters. The significant factors were optimised using a central composite design to obtain the quadratic relationship between the dependent and the independent variables. Using this strategy, response surfaces were derived as the 3D and contour plots, and mathematical models were defined for the separation. The models had a satisfactory coefficient (R(2) > 0.97, n = 16). For the test compounds, the best separation condition was: MeCN/30 mM phosphate buffer pH 7.1(55.5:44.5, v/v) and 10 basic solutes were resolved in 22 min. The significant influence of the concentration of buffer shows that different mechanisms of separation for basic compounds on the fluorinated packing exist compared with a common ODS stationary phase.

Chromatography, High Pressure Liquid↗
PubMed2004

State-of-the art of selective detection and identification of I-, Br-, Cl-, and F-containing compounds in gas chromatography and liquid chromatography.

This review article presents an overview of halogen-specific detection in gas chromatography (GC) and liquid chromatography (LC). Attention is primarily focused on the use of plasma emission spectroscopy and plasma mass spectrometry as detectors, but other halogen-selective detection principles are also mentioned. Different instrumental configurations are discussed both with respect to technical set-up and performance, the principal reasons for halogen-selective detection are highlighted, and recent applications are reviewed from areas such as environmental chemistry, petroleum characterization, and drug analysis.

Animals↗
PubMed2000

[Studies on organofluorine compounds: an overview of our 30 years].

This review article covers our research activities over 30 years in organofluorine chemistry. The followings are briefly summarized researches in this memorandum: (1) Trifluoromethylation of organic halides with trifluoromethyl copper complex and its application to trifluoromethylated nucleosides, (2) a systematic study on reactivity of aromatic trifluoromethyl compounds, (3) valence bond isomers of aromatic compounds stabilized by the trifluoromethyl groups, and (4) synthesis of fluorinated bioactive compounds which involve vitamin D3, arachidonic acid and its metabolites, and retinal.

Chemistry, Organic↗
PubMed2004

Responses of the olfactory receptor neurons of the corn stalk borer Sesamia nonagrioides to components of the pheromone blend and their inhibition by a trifluoromethyl ketone analogue of the main component.

Two types of olfactory hairs and three types of olfactory receptor neurons (ORN) have been characterized on the antennae of male Sesamia nonagrioides Lef for the first time. Type A sensilla housed a cell which fired large spikes in response to (Z)-11-hexadecenyl acetate (Z11-16:Ac), the major component of the sex pheromone, and a second cell firing smaller spikes in response to (Z)-11-hexadecenal (Z11-16:Ald), a minor component of the pheromone blend. Type B sensilla housed one cell firing large spikes to Z11-16:Ac and a cell firing smaller spikes to another minor component of the pheromone blend, (Z)-11-hexadecenyl alcohol (Z11-16:OH). No cell responding to dodecyl acetate, another minor component of the natural extract, was found. Fluorinated ketones were tested as inhibitors of the cell responses to pheromone compounds. The fluorinated derivatives tested, (Z)-11-hexadecenyl trifluoromethyl ketone (Z11-16:TFMK), n-hexadecyl trifluoromethyl ketone (16:TFMK), (Z,E)-9,11-tetradecadienyl trifluoromethyl ketone (Z9,E11-14:TFMK), 3-octylthio-1,1,1-trifluoropropan-2-one (OTFP), (Z)-11-tetradecenyl trifluoromethyl ketone (Z11-11:TFMK) and 1,1-difluoro-(Z)-11-hexadecenyl methyl ketone (Z11-16:DFMK), had no or only weak excitatory effects. However, the neuron responses to the pheromone compounds were significantly decreased in the presence of a constant stimulation with Z11-16:TFMK and the effect was reversible. The latencies of the responses to the acetate and aldehyde cells were significantly increased. The effects were not specific, since Z11-16:TFMK also inhibited the responses of the ORNs of Spodoptera littoralis Boisd. Correspondingly, Z9,E11-14:TFMK, an analogue of the main component of the pheromone of this latter insect, inhibited responses of S nonagrioides ORNs. Implications of these results on the utilization of Z11-16:TFMK as a communication disruptant are discussed.

Aldehydes↗
PubMed2002

Fluorinated anthracyclines: synthesis and biological activity.

Organic structures with fluorine atom are slightly diffuse in nature. Starting 80s researchers have discovered that the selective introduction of fluorine into biologically active molecules exercised an influence on activity. So an important endeavour in drug design have been described and numerous compounds incorporating fluorine as either a bioisosteric replacement for hydrogen or an isoelectronic replacement for the hydroxyl group have been reported. Parallely, an enormous literature on anthracyclines exists, a class of compounds used in clinical since 70s, as antitumor drugs. Unfortunately, the anthracyclines are known as well for several toxical effects that frequently condition the clinical use. In the last decade a lot of anthracycline derivatives has been described in which has been introduced a fluorine atom in different position of molecule. This review wishes to represent an updated collection of compounds with anthracycline structure where a fluorine atom has been introduced on aglycon or/and sugar moiety. Together with the chemical structures, the synthetic indications are furnished and succinct explanations of biological activity are summarised (if available).

Animals↗
PubMed2003

High-performance liquid chromatography/inductively coupled plasma mass spectrometry with iodine-specific detection for profiling the metabolites produced in the earthworm Eisenia veneta by exposure to 2-fluoro-4-iodoaniline.

High-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICPMS) provided a rapid and specific means for profiling the iodine-containing metabolites produced by the earthworm Eisenia veneta following exposure to 2-fluoro-4-iodoaniline. Profiles were obtained, using gradient reversed-phase HPLC, from extracts of whole earthworms and from coleomic fluid with as little as 25 ng/peak of iodine detected. The use of ICPMS in this way provides a convenient means of determining the metabolic fate of iodinated compounds without the need for radiolabelled compounds.

Aniline Compounds↗