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Efficient conversion of tetrahydro-2-pyranyl (THP)protected alcohols into the corresponding halides using dichlorophosgeniminium chloride in the presence of tetraalkylammonium halide.

The synthesis of the first two haptens designed to elicit catalytic hydrolytic antibodies for the dynamic kinetic resolution of racemic 4-substituted 4H-oxazolin-5-ones is reported. A cyclic phosphinate and a 2,5-dihydro-1H-pyrrolium derivative were chosen as "first generation" haptens. The cyclic phosphinate was designed to mimic the higher energy transition state along the reaction coordinate for the hydrolytic process, while the dihydro-1H-pyrrolium group of the second hapten was selected to generate hydrolytic antibodies that might use a "bait and switch" mechanism. These two haptens were prepared successfully by use of a ring-closing metathesis reaction as the key step. This study is the first pilot investigation towards an antibody-promoted dynamic kinetic resolution and should allow the development of a new biocatalytic route to enantiomerically pure natural and unnatural amino acids.

(2S,3R,4S)-4-Hydroxyisoleucine, which exhibits remarkable insulinotropic activity, is expected to be a potent drug to treat type II diabetes. We propose herein a four-step synthesis of the enantiopure natural product on the basis of successive Mannich condensation, catalytic epimerization, N-para-methoxyphenyl deprotection, and diastereoselective reduction. This compact economical and scalable sequence enables to perfectly control three contiguous chiral centers. It does not involve any chromatographic purification, and the desired compound is obtained in >99 % de, >99 % ee, and 22 % overall yield under our optimized conditions.

Because they have a great propensity to aggregation in water, solubilization of carbon nanotubes (CNTs) in aqueous media remains an important challenge. Our laboratory has reported the self-organization of synthetic lipids into hemi-micellar structures at the carbon nanotubes surface. Subsequent stabilization of these carbon nanotube/lipid assembly (CNT/LA) constructs is achieved through photopolymerization of the diyne motif of the pentacosa-10,12-diynoic lipids. Herein we investigate the scope of this coating procedure for CNT solubilization. A panel of CNTs was selected according to the method of production and the characteristics of CNTs. The study revealed that it is possible to reach a complete lipid adsorption. The TEM analyses demonstrate that lipid hemi-micellar self-assemblies can be formed around SWNTs as well as around DWNTs and MWNTs, particularly for carbon nanotubes produced by the arc-discharged method. The nanotube suspensions show a very good stability and are homogeneous for months even at a high nanotubes concentration.

WOS:000274843100020; International audience; alpha-Mono- or alpha-dialkylated aldehydes undergo cyclotrimerization in the presence of dibromotriphenylphosphorane (PPh(3)Br(2)) to afford cyclopentenones or tetrasubstituted tetrahydrofurans in good yields. These transformations proceed by a tandem aldol dimerization/Nazarov reaction or a tandem aldol dimerization/Prins cyclization.

An expeditious, three-step synthesis of rhein (2) was optimized starting from bis(N,N-diethyl)-5-methoxybenzene-1,3-dicarboxamide. The key final step, involving deprotection/cyclization of ortho-benzoylbenzoic acid 9 in acidic chloroaluminate molten salts, yielded the desired natural product with high selectivity and good overall yield by precluding the competitive Hayashi rearrangement.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

According to literature reports and our own findings, the binding of new Ni(2+)-preloaded bis(nitrilotriacetic acid) (NTA) ligands with polyhistidine-tagged proteins has been found to be accompanied by a one- to two-order-of-magnitude increase in affinity, compared to the binding of a single Ni(2+)-preloaded NTA moiety. In spite of the introduction of a second NTA chelating group, a cooperative effect that is less than the theoretical maximum has been observed. Herein, we present a rational explanation for the observed stability of the ternary complex involving the postulated bis-NTA-(Ni(2+))(2) species and multivalent polyhistidine tags. We have found that prior to the formation of the ternary complex, the Ni(2+)-preloading step of bis-NTA ligands does not form the expected bis-NTA-(Ni(2+))(2) exclusively. Instead of the major formation of bis-NTA-(Ni(2+))(2) species, it appears that cyclic discrete 1:1 and 2:2 entities are predominantly formed. It is proposed that these species interact upon ring-opening with multivalent histidine tags. The occurrence of this phenomena accounts for the overall one- to two-order-of-magnitude increase in affinity of ternary complexes involving bis-NTA ligands.

No abstract available

The synthesis of various permethacrylated mono- and disaccharides in acceptable yields is reported. The reactivity of these unusual polymerizable compounds has been investigated in diverse glycosidation reaction conditions. New original polymerizable donor sugars have been prepared successfully in good to excellent yields.

The bundling state of several dry single-walled carbon nanotube (SWNT) samples is compared using isothermal microcalorimetry (IMC). So as to get different dry samples with various bundling states, the pristine SWNTs were pretreated with a solution of an aromatic amphiphile with or without sonication, washed and dried before being studied by IMC. The bundling state of the different SWNT samples, which was first analyzed by TEM, was then correlated to the obtained IMC data thanks to the interpretation of the observed energy transfer phenomena. From our results, IMC appears to be an interesting technique for the surface probing of dry SWNT samples, and herein for the evaluation of the bundling state.

Syntheses of chiral 6,15-dihydronaphtho[2,3-c]pentaphene derivatives of opposite configurations are reported. Starting from anthracene, the strategy involves two key steps: a Diels-Alder reaction on a prochiral dianthraquinone, and an enantiomeric resolution using (-)-menthol. The final molecules exhibit very strong optical activity, as shown by their circular dichroism spectra, and are examples of chiral facial amphiphiles. Their adsorption at the surface of single-walled carbon nanotubes (SWNTs) has also been studied, and has been found to occur preferentially on 0.8-1.0 nm diameter nanotubes among the population of a high-pressure CO conversion (HiPco) SWNT sample (0.8-1.2 nm). The synthesised facial amphiphiles act as nano-tweezers for the diameter-selective solubilisation of SWNTs in water. The expected optical activities of the SWNT samples solubilised by each of the chiral amphiphiles have been studied by circular dichroism spectroscopy, but the results are not yet conclusive.

The synthesis and application of (E)-1,2-disilylethene 5 as a central functional building block in a sequential Hiyama coupling/Narasaka acylation reaction are described. Its use in the rapid and versatile construction of α,β-unsaturated carbonyl motifs found in a number of polyunsaturated natural products has been demonstrated. It was observed that due to the differential intrinsic reactivity of the two carbon–silicon bonds, this bis-metallated lynchpin-type reagent is activated selectively and sequentially by Pd and Rh catalysis, negating the need for any protecting group. A number of (E)-α,β-unsaturated ketones were efficiently synthesized with complete chemoselectively in the presence of a variety of halides and anhydride acids. Conjugated polyunsaturated ketones and diversely α′-functionalized α,β-enones, such as chalcones, a heterocyclic dienone and the highly conjugated ethyl (2Z,4E)-6-oxo-6-(2-thienyl)hexa-2,4-dienoate, were obtained in good overall yields. Thus, this coupling sequence provides a high degree of modularity, that is, a single template is likely to produce a large number of synthetic targets.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

This paper describes a new type of surface imprinting technique that combines the advantages of both the semi-covalent approach and one-stage miniemulsion polymerization. This process has been successfully applied for the preparation of glucose surface-imprinted nanoparticles. The selective artificial receptors for glucopyranoside were fully characterized by IR, TEM and BET analyses, and their molecular recognition abilities by binding experiments carried out in batch processes. The molecular affinity and selectivity of the glucose molecularly imprinted polymers were accurately quantified. These characteristics are essential for verification of the efficiency of the developed surface imprinting process. The imprinting effect was clearly demonstrated using the batch rebinding method. We have found that the glucose imprinted polymers produced using the optimized one-stage mini-emulsion exhibited quite fast kinetics of binding and equilibration with glucopyranoside templates, compared to polymers prepared by bulk polymerization technique, as well as extremely low levels of unspecific bindings. We also demonstrated that glucose molecular imprinted polymer (MIP) exhibited very good selectivity for its original template compared to other glycopyranoside derivatives, such as galactose. Finally, the extraction of the binding properties from isotherms of binding by fitting to the bi-Langmuir and Freundlich models allowed the determination of the affinity constant distribution of the binding sites. This imprinting protocol allowed the determination of an affinity constant (K D ), involving exclusively H-bonding interactions, for the glucose MIP (P2C) with the best template 1, in CH 3 CN as the solvent system.

The natural mushroom pigment Norbadione A and three other pulvinic acids were shown by our group to display very efficient antioxidant properties by comparison with a collection of potent molecules including catechols, flavonoids, stilbenes, or coumarins. Despite numerous publications on robust and straightforward synthetic access to pulvinic acids by us and others, no report has been made to unravel the structure-activity relationships that govern the striking antioxidant activity. Herein is presented the synthesis of 18 diverse pulvinic acid derivatives and the study of their radical scavenging capacities by four different assays. The influence of each of the two phenyl rings, of their substituents and of the lateral chain on the antioxidant properties, was explored to reveal a simplified structure of excellent activity. These results, along with the absence of cytotoxicity, make the synthesized compounds interesting to evaluate for several biological activities and especially for anti-inflammatory effects and skin protection against UV induced oxidative stress.

Methyl (Z)-a-methoxyacrylates are generated in good yields by a mild, stereospecific two-carbon homologation of a wide variety of aldehydes utilizing commercial methyl 2,2-dichloro-2-methoxyacetate and CrCl2 under Barbier conditions at room temperature. A rational mechanism based upon a Reformatskytype addition pathway or an in situ generated (E)-trioxo-chromium vinylidene carbenoid is proposed. 2008 Elsevier Ltd. All rights reserved. 2-Alkoxyacrylic moieties are present in many natural and semisynthetic products, 1 and have been used as key intermediates for the preparation of biologically active compounds. 2 The derivatives of arylalkadienes are useful in the treatment of osteoporosis and other diseases. 3 Moreover, the C–C double bond present in these compounds can be used for diverse transformations such as Claisen rearrangement, 4 Diels–Alder, 2a,5 and Heck reactions. 2b,6 Several methods are available in the literature for the preparation of 2-alkyloxy-a,b-unsaturated alkenoates, and most of them rely either on Horner–Emmons condensations using a-alkoxy phosphono acetates, 2e–g,3,7 or on reactions of aldehydes with alkyl esters under basic conditions. 1d,2j,8 Other methods used for this purpose are palladium cross-coupling with vinylic electrophiles 9 via alkenyl metallic species 10 and phosphine-catalyzed addition of arylpropiolates to oxygen nucleophiles. 11 However, some of these methods present quite often serious drawbacks such as multistep transformations, low yields, and more importantly low selectivity. Moreover, some reaction conditions are not compatible with common functional groups. During the past few years we have been engaged with the studies of organochromium compounds for stereoselective C–C bond forming reactions. 12 In this connection, recently we reported the preparation of (Z)-methyl 2-methoxy-3-phenylacrylate by the reaction of benzaldehyde and 2,2-dichloro-2-methoxy acetate in presence of CrCl2. 13 With this background and considering the importance of methoxyacrylates, we report herein, the generality of the reaction for the preparation of (Z)-a-methoxyacrylates via two-carbon homologation of a large panel of aldehydes utilizing

Amphiphilic molecules—molecules that have both hydrophobic and hydrophilic properties—can self-assemble in water to form diverse structures such as micelles, vesicles and tubes1,2,3, and these nanostructures can be used for delivering drugs4,5, stabilizing membrane proteins6 or as nanoreactors7. We have previously shown that lipids can self-organize on the surface of single-walled carbon nanotubes into regular ring-shaped assemblies8. Here we show that these lipid assemblies can be polymerized and isolated from the nanotube template by application of an electric field. We also demonstrate that these assemblies are monodispersed, water-soluble, and can dissolve various hydrophobic rylene dyes, fullerenes and membrane proteins. The stability of these constructs and their diverse applications will be useful in the fields of cosmetics, medicine and material sciences. Carbon nanotubes used as templates for polymerizing lipids into regular ring-shaped water-soluble assemblies that can dissolve various hydrophobic compounds and membrane proteins, could have applications in cosmetics, medicine and materials science.

A common precursor, tetronic acid, was used in the synthesis of several vulpinic acids and pulvinic acids, which are pigments found in several lichens and mushrooms. The key features of this method are a two-step alkylidenation of benzyl tetronate and a Suzuki–Miyaura cross-coupling. The synthesis of several natural products, vulpinic acid, pinastric acid, xerocomic acid is described.

Treatment of unfunctionalized acyclic ketoaldehydes with a catalytic amount of 1,5,7-triazabicyclo[4.4.0]dec-5-ene induces a direct intramolecular 5- and 6-enolexo aldolization, furnishing 2-ketocyclopentanols and 2-ketocyclohexanols in good-to-excellent yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

A novel solid-phase synthesis of tetrasubstituted 2-imino-1,3-thiazolines using a functionalizing cleavage strategy is described. The synthetic route utilized the ambident reactivity of a dithiocarbamate functionality to synthesize the key resin-bound electrophilic thiazolium intermediate. The desired products were efficiently obtained in high purity by the reaction of various amines with the thiazolium salt.

Ionic liquids are remarkably suitable and clean media for performing nonenzymatic kinetic resolution (KR) of amines through enantioselective N-acetylation: high levels of selectivity were obtained with a large variety of amines at room temperature (up to S = 30).

A short, convergent synthesis of the mushroom pigment norbadione A is described. The construction of an appropriately substituted naphtholactone intermediate involved a regioselective Diels-Alder reaction between a bis(triisopropylsilyloxy)diene and 2,6-dichlorobenzo-1,4-quinone. A double Suzuki-Miyaura cross-coupling between a diboronate and two identical enol triflates was another key feature of the synthesis.

We report herein a general method enabling specific immobilization and orientation of histidinetagged proteins on multiwalled carbon nanotubes. We describe the design and the synthesis of a series of seven water-soluble molecules containing an increasing number of aromatic rings link to a nitrilotriacetic acid (NTA)polar head. Among the molecules prepared, Tbf-NTA built with a tetrabenzofluorenyl group was found to induce a stable suspension of carbon nanotubes in water. Adsorption of this new reagent (Tbf-NTA)on multiwalled carbon nanotubes was demonstrated using transmission electron microscopy and UV/visible spectroscopy. Chelation of nickel ions by multiwalled carbon nanotubes coated with Tbf-NTA was also evidenced by energy dispersive X-ray microanalysis. Finally, immobilization of histidine-tagged DNA gyrase A protein on the surface of carbon nanotubes functionalized by Ni/Tbf-NTA complexes could be visualized by electron microscopy whereas little protein binding was observed in the absence of reagent.

Continuous laser vaporization of a BN target under N2 atmosphere is up to now the unique route to single-walled boron nitride nanotubes (BN-SWNTs). Although grams of product can be obtained by this technique, the raw material contains in addition to the BN-SWNTs, different by-products made of boron and nitrogen. Since these materials are undesirable for the studying of the intrinsic properties of the nanotubes, we have undertaken a purification process using chemical and physical methods to separate the different components. We show here that most impurities can be removed by successive cycles of washing, sonication, and centrifugation. Furthermore, the two different types of boron nitride nanostructures i.e., BN-SWNTs and BN-cages can be isolated. Efficiency of the separation was monitored by transmission electron microscopy (TEM) at the different steps of the process. Finally, we envisage the further purification of the nanotubes-enriched fraction by functionalizing the nanotubes in a non covalent manner by specific polymers as for carbon nanotubes and BN multi-walled nanotubes.

Several vulpinic acids were synthesized in a few steps from a single precursor, the tetronic acid. This commercial compound was converted in a few steps to an iodide. Suzuki–Miyaura cross-couplings involving this common intermediate and various arylboronates allowed to gain access to several vulpinic acids (or methyl pulvinates). Among them, two natural products, vulpinic acid and pinastric acid, were prepared.

We describe the first effective H/D exchange reaction with acidic substrates in CDCl(3) at room temperature. The particularly mild reaction conditions involved (solvent, base, and temperature) allow the chemoselective deuteration of ketones over esters. An NMR study was conducted with the aim of rationalizing the results obtained in the presence of TBD as catalyst.

Using CrCl 2 in THF at room temperature, trichloromethyl carbinols and trichloromethylalkanes are readily transformed to the highly reactive α-chlorocarbenes, carbynes and α-chloro-α-chromium(III) vinylidene carbenoids. A mechanistic study is carried out to determine the nature of the intermediates.

New conditions for the preparation of trimethylsilyl-protected 2,2,2-trichloromethylcarbinols 2 from aldehydes and ketones are reported. Compounds 2, which are important intermediates in organic synthesis, were obtained in excellent yields by use of a combination of trichloromethyltrimethylsilane (TMSCCl3), and a catalytic amount of sodium formate (HCOONa) in dimethylformamide (DMF). Substrates bearing highly sensitive protecting groups have been successfully subjected to our conditions. We also describe a one-pot procedure that gives direct access to 2,2,2-trichloromethylcarbinols 3. This methodology avoids the use of strong bases usually required for the synthesis of 3 (Wyvratt et al. J. Org. Chem. 1987, 52, 944; Aggarwal and Mereu, J. Org. Chem. 2000, 65, 7211).

[Structure: see text] A polyionic gel-soaked Rh catalyst allows the formation of synthetically useful diphenylsilyl (DPS) enols under mild conditions. The reaction proceeds through dehydrogenative silylation of ketones, affording the kinetic silyl enol ether in good to excellent yields. The in situ formed DPS enols were directly involved, without purification, in one-pot aldol and Mannich condensations.

Aza-Michael addition of optically pure 4-phenyl-2-oxazolidinone to 3,3,3-trifluoro-1-nitropropene proceeds smoothly at low temperature with a high yield. Diastereoselectivity of the addition depends on the base used and lithiated species proved to be highly efficient affording 92% de. Optically pure 1,2-diamino-3,3,3-trifluoropropane is prepared in 58% yield from the aza-Michael addition product through a three-step procedure.

CrCl2-mediated condensation of γ-chloro-gem-trichloroalkanes with aldehyde generates homoallylic alcohols through a hydride rearrangement followed by a Nozaki–Hiyama allylation.

Herein, we describe short and efficient syntheses of isoxazole-3-carboxylic acid 3a and imino-oxopentanoic acid 8 achiral precursors of 4-hydroxyisoleucine. The developed procedures involve readily available and cheap starting materials and can easily be transposed to the large scale.

Pulvinic acid and norbadione A analogues can be prepared by Suzuki–Miyaura cross-coupling of functionalized arylboronic esters with appropriate vinyl triflates, in which the hydroxy functions are protected either with methyl or benzyl groups, the latter being cleaved in a more reliable fashion at the end of the synthetic sequence. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

[reaction: see text] A new method of deprotection of N-p-methoxyphenylamines using anodic oxidation in acidic medium is presented. The process furnishes a high yield of amine and is compatible with several oxidable functional groups.

In this letter, we describe the design and the synthesis of an organophosphorus hapten aimed at a mixed biotechnological–chemical strategy for the mild decontamination of exceedingly toxic nerve agent VX. Hapten will be used to raise and select monoclonal antibodies (mAbs) able to bind both the nerve agent, and an oxime, derived from pyridinaldoxime, able to specifically hydrolyze its P–S bond. In order to significantly increase the hydrolysis reaction rate, the controlled respective positioning of the oxime and of the substrate will be achieved through the immunization, and in a second step, the oxime will be bound to the mAb in a reactive position towards the reactive thiophosphate functionality of the substrate.

[reaction: see text] Several natural pulvinic acids were synthesized. Silyl ketene acetals derived from methyl arylacetates (4 equiv) reacted with oxalyl chloride at -78 degrees C, without the need of adding a catalyst. After treatment of the crude diketones with DBU and acidification with hydrochloric acid, symmetrical pulvinic acids methyl esters were obtained. Saponification of the methyl esters afforded the corresponding pulvinic acids in 60-70% overall yields from oxalyl chloride.

The polymerization of several allylic triphenylarsonium ylides, which contain a pendant R group at the 2-position, in the presence of triethylborane, is described. Three initial molar ratios of ylide to triethylborane (15, 30, 60) were used, leading to different degrees of polymerization. The ylide was generated from the corresponding arsonium salt, in THF at -78 °C, using either tert-butyllithium (when R = alkyl) or lithium hexamethyldisilazide (when R = tBuMe 2 SiOCH 2 CH 2 -) as the base. After addition of triethylborane at 0 °C, the deep-red solution of ylide was readily discolored. Then oxidation of the resulting polymeric borane led to linear skipped polyenes containing a terminal alcohol function. These polymers can be called poly(2-substituted-1-propenylene)s. Molecular weights have been determined from both 1 H NMR analyses and size exclusion chromatography (SEC). In most cases, the molecular weight of the polymers increases linearly with the initial ylide/triethylborane molar ratio, which gives credit to a controlled polymerization process. Block copolymers were also obtained from triethylborane by successive additions of two different 2-substituted allylic arsonium ylides, followed by oxidation (yield: 62-85%).

The present work describes a simple one pot access to α-(gem-difunctional) acrylic esters and to polysubstituted dihydrothiophenes exploiting the addition of activated methylenes to alkynoates rerouted by triphenyl phosphine.

International audience; A straightforward mono-selective and C-specific alkylation of phloroglucinol with activated alkyl halides is presented. The use of water as solvent limits the amount of over-alkylated by-products. Provided some minor changes in the experimental conditions, hydrophobic cinnamyl halides can also be reacted, thus giving a direct access to advanced intermediates of natural flavonoids.

In living organisms, Ca2+ signalling is central to cell physiology. The Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) has been widely used as a probe to test the role of calcium in a large variety of cell functions. Here we show that in most cell types BAPTA has a potent actin and microtubule depolymerizing activity and that this activity is completely independent of Ca2+ chelation. Thus, the depolymerizing effect of BAPTA is shared by a derivative (D-BAPTA) showing a dramatically reduced calcium chelating activity. Because the extraordinary depolymerizing activity of BAPTA could be due to a general depletion of cell fuel molecules such as ATP, we tested the effects of BAPTA on cellular ATP levels and on mitochondrial function. We find that BAPTA depletes ATP pools and affects mitochondrial respiration in vitro as well as mitochondrial shape and distribution in cells. However, these effects are unrelated to the Ca2+ chelating properties of BAPTA and do not account for the depolymerizing effect of BAPTA on the cell cytoskeleton. We propose that D-BAPTA should be systematically introduced in calcium signalling experiments, as controls for the known and unknown calcium independent effects of BAPTA. Additionally, the concomitant depolymerizing effect of BAPTA on both tubulin and actin assemblies is intriguing and may lead to the identification of a new control mechanism for cytoskeleton assembly.

We present a new high-throughput screening method for the selection of powerful water-soluble antiradiation compounds. This method, which uses conventional immunoassay techniques, allowed the capacity of a given compound to protect thymidine from irradiation to be evaluated. By applying this assay to an antioxidant library, we showed for the first time that norbadione A, a well-known mushroom pigment, has pronounced atypical antiradiation properties.

In a reinvestigation of the reactivity of carbenoids derived from epoxides, we studied the factors that could influence the chemoselectivity of the carbenoid insertion into vicinal C–H or CC bond in cyclic α-alkoxy epoxides bearing an alkenyl side chain. This reaction gives access to bi- or tricyclic systems, respectively.

An effective traceless solid-phase synthesis of chloro-diaminopyrimidines via an amino-de-chlorination reaction of polymer-bound 4-alkoxycarbonylamino-2,6-dichloropyrimidines has been developed. After release from the polymer the target molecules were obtained in good to excellent purity, although with modest regiocontrol. Further reaction of solid-supported N -alkoxycarbonyl-chloro-diaminopyrimidines with secondary amines afforded triaminopyrimidines in good purity under mild conditions, whereas less nucleophilic primary amines did not perform well under the conditions explored so far.

Herein, we describe a mild and efficient two-step procedure to introduce a thiol group on aromatic substrates. First, reaction with an activated sulfoxide leads to an arylsulfonium salt intermediate. Then, two successive beta-elimination-based dealkylation reactions afford the desired arylthiols in good to excellent yields.

The reaction of sulfone anions with trialkylboranes followed by thermal isomerization of the obtained boron compounds in the presence of excess borane–methyl sulfide complex and by alkaline hydroperoxide oxidation yields primary alcohols.

Images of the assembly of surfactants and synthetic lipids on the surface of carbon nanotubes were obtained by transmission electron microscopy. Above the critical micellar concentration, sodium dodecyl sulfate (SDS) forms supramolecular structures made of rolled-up half-cylinders on the nanotube surface. Depending on the symmetry and the diameter of the carbon nanotube, we observed rings, helices, or double helices. Similar self-assemblies were also obtained with several synthetic single-chain lipids designed for the immobilization of histidine-tagged proteins. At the nanotube-water interface, permanent assemblies were produced from mixed micelles of SDS and different water-insoluble double-chain lipids after dialysis of the surfactant. Such arrangements could be further exploited for the development of new biosensors and bioelectronic nanomaterials.

We describe a new strategy for the preparation of catalytic antibodies based on a two-step procedure. Firstly, monoclonal antibodies are selected only if displaying the following binding features: binding both the substrate and a reactive group in such a way that the two groups are in a reactive position towards each other. Secondly, the selected monoclonal antibodies (mAbs) are chemically engineered by covalently binding the reactive group into the binding pocket of the antibody. Using previously isolated monoclonal antibodies, we have focused our studies on the control of this second step.

Straightforward access to anhydrovinblastine starting from the parent alkaloid leurosine is reported. The key deoxygenation step was first optimized on a model substrate. However, applied to leurosine, only the low-valent Cp2TiCl gave satisfactory results.