Synthesis of 6- and 7-acyl-4H-benzothiazin-3-ones

Synthesis of 6- and 7-substituted benzoxazin-3-ones was already described in the literature by acylation of the corresponding benzoxazin-3-ones or cyclization of the corresponding 4- or 5-acyl-2-aminophenols. This paper describes original synthetic pathways to afford the 6- and 7-acyl products in the benzothiazin-3-one series, respectively, via Stille coupling reaction and by acylation.     

Interactions of hairy latex particles with cationic copolymers

Interactions between polycations and core-corona particles are governed by ion-exchange reactions, entropically favored by the release of counterions. This complexation process allows the chains to penetrate into the shell, leading to adsorbed amounts greater than 1 mg m(-2). The destabilization occurs quickly, the domain of flocculation becomes larger when the concentration of monovalent salts is increased, and aggregates are composed of small and very compact clusters in a more or less self-similar structure at large scale. The adsorption of copolymers of low cationicity is characterized by still larger adsorbed amounts and layers thicker than the radius of gyration of the macromolecules. Depending on the charge content, the enhancement of the ionic strength can either promote the destabilization of the suspension or conversely induce the desorption of the chain. In pure water the structure of the flocs is long-range ordered and it becomes more heterogeneous in ionic media.     

Phosphinine stabilised gold nanoparticles; synthesis and immobilisation on mesoporous materials

The first synthesis of gold nanoparticles stabilised by a sub-stoichiometric amount of sp(2) phosphorus containing ligands was performed, as well as their immobilisation on mesostructured silica and titania hosts.     

Benzaldehyde lyase-catalyzed enantioselective carboligation of aromatic aldehydes with mono- and dimethoxy acetaldehyde

[reaction: see text] Benzaldehyde lyase from the Pseudomonas fluorescens catalyzes the reaction of aromatic aldehydes with methoxy and dimethoxy acetaldehyde and furnishes (R)-2-hydroxy-3-methoxy-1-arylpropan-1-one and (R)-2-hydroxy-3,3-dimethoxy-1-arylpropan-1-one in high yields and enantiomeric excess via acyloin linkage. Aromatic aldehydes and benzoins are converted into enamine-carbanion-like intermediates prior to carboligation.     

Solid-phase syntheses of 6-arylpyridazin-3(2H)-ones

The 3-chloropyridazine moiety was immobilized on a Wang resin, using two different methodologies. The first of these involved direct nucleophilic substitution of 3,6-dichloropyridazine with the alcoholate of Wang resin. The experimental conditions were optimized. The second method involved a Mitsunobu reaction between the Wang resin and 6-chloropyridazin-3-ol during which a problem of regioselectivity was observed. The so-obtained chloropyridazine-containing resins were subsequently reacted with various arylboronic acids under Suzuki conditions. Acid cleavage yielded 6-arylpyridazin-3(2H)-ones with high chemical purity.     

Ionic liquid crystal precursors for inorganic particles: phase diagram and thermal properties of a CuCl nanoplatelet precursor

We have recently reported (Angew. Chem. Int. Ed. 2004, 43 (40), 5380) the formation of CuCl nanoplatelets from an ionic liquid crystal precursor (ILCP) consisting of a 50/50 (wt/wt) mixture of bis(dodecylpyridinium) tetrachlorocuprate 1 and 6-O-palmitoyl ascorbic acid 2. Here we present the full ILCP phase diagram and the thermal behavior from a mixing ratio of 1/0 (i.e., pure 1) to 0/1 (i.e., pure 2). The ILCP exhibits a crystalline-smectic-isotropic phase transition at all mixing ratios, and the liquid crystal region is up to 90 degrees C wide. DSC shows a broad exothermic peak between ca. 70 and 170 degrees C, which is associated with the thermally induced CuCl formation. The reaction enthalpies reach -150 kJ/mol at around 50/50 (wt/wt) mixtures of the two components, and the activation energy for CuCl formation is ca. 190 kJ/mol. Thermogravimetric analysis shows that the samples degrade above ca. 200 degrees C.     

Synthesis and studies of piperidinone,the major metabolite of a new antidepressant drug S 3344

The synthesis of 1-(4-fluorobenzyl)-6-isopropyl-2-piperidinone 7a , a major metabolite of a new antidepressant S 3344, is described and then substituted with various substituents. The ¹H and ¹³C nmr provide information on their structure.     

Tetrathiafulvalene-based podands bearing one or two thiol functions: immobilization as self-assembled monolayers or polymer films, and recognition properties

The synthesis of various thiol and dithiol derivatives of a tetrathiafulvalene-based receptor is presented, as well as their immobilization on gold as self-assembled monolayers (SAMs). The formation of films incorporating TTF units is also shown by electrooxidation of TTF-dithiol derivatives. The ability of the monolayers to electrochemically recognize Pb²⁺ is demonstrated.     

New hybrid bidentate ligands as precursors for smart catalysts

1-Phosphanorbornadiene derivatives were grafted onto various periodically organized mesoporous powders, including a new zirconia/silica mixed oxide synthesized by aerosol techniques. After complexation with the [Rh(CO)2]+ fragment, these materials were revealed to be more active in olefin hydrogenation than their homogeneous counterparts. The reasons for this higher activity are discussed in the light of theoretical modeling. Various surface treatments, such as esterification, drying, and functionalization with PhSi(OEt)3, provided insights into the nature and mechanism of formation of the active species. Zirconia-based materials were found to be active in internal olefin hydroformylation. Investigation of the mechanism of this reaction shows that the isomerization step is catalyzed by the Lewis acidic support, whereas the hydroformylation step is driven by the rhodium catalyst. Dissociation of these two steps leads to enhancement of activity.     

An Expeditious One-Pot Synthesis of N-Substituted 6-Nitroindoles from Indolines

Summary.  This paper reports an one-pot method for the concomitant alkylation – oxidation (aromatization) of indolines, particularly effective to get easy access to N-alkyl-6-nitroindoles, which are useful platforms in medicinal chemistry. N-alkyl-6-nitroindoles are obtained in good yield (64–91%) by reaction at room temperature in non-degassed DMF of 6-nitroindoline, an alkyl halide, and NaH as base. The presence of NaH appears to be essential for a high yield conversion. Corresponding author. E-mail: pdepreux@phare.univ-lille2.fr Received December 3, 2002; accepted December 9, 2002 Published online May 26, 2003