A facile and mild method for the synthesis of terminal bromofluoroolefins via diethylzinc-promoted Wittig reaction

[reaction: see text] Synthesis of 1-bromo-1-fluoroolefins was achieved in good yields via a Wittig reaction promoted by diethylzinc, even with nonactivated aldehydes and ketones as starting materials.     

First synthesis of 5,6-dihydro-4H-furo[3,2-f]pyrrolo- [1,2-a][1,4]diazepines

The synthetic pathway leading to 5,6-dihydro-4H-furo[3,2-f]pyrrolo[1,2-a][1,4]diazepines is described in four steps starting from α-bromophenones via 2-amino-3-furonitriles.     

Relation between silico-aluminous fly ash and its coal of origin

Fly ashes are typical complex solids which incorporate at the same time intrinsic properties derived from the layers (various mineralogical and dimensional spectra) and major transformations generated during prior processing. To use fly ashes in various applications, it is necessary to characterise them completely. The first research to date carried out on silico-aluminous fly ashes in order to characterise them physically,morphologically, chemically and mineralogically, resulted in the recognition that they are relatively simple materials. In the present study, a silico-aluminous fly ash coming from the power station of Albi (France) was selected. Heat treatment at 450 and 1200 ~C together with coal simulated the treatment undergone by coal in the power station in order to mimic real coal residue. In conclusion, the diversity of the particles contained in fly ash could only be explained by the relation existing between the fly ash and its coal of origin.     

Blowing up: application to $G^2$-continuous 8-sided filling patch

Summary. We propose a method for filling a n-sided hole, , that interpolates n connected boundary curves of a given net of patches. This method allows the joining with patches defined in many different ways. A new class of blowing up pole-functions is introduced in order to build a G-continuous n-sided filling surface. This filling surface is in one piece, image of . Received February 21, 2000 / Revised version received January 2, 2001 / Published online December 18, 2001     

Stability of penicillin antibiotic residues in meat during storage. Ampicillin

Incurred samples from a pig treated with ampicillin, one of the most important penicillin antibiotic drugs used in food-producing animal treatments, were analyzed at the residue level of the drug in muscle tissue (approximately 100 microg kg(-1)) during their freezing storage and using three different techniques: quantitative microbiological assay, HPLC-UV and LC-MS. Two parameters have been specifically monitored: storage temperature (-20 and -75 degrees C) and storage packaging (ground meat or bulk meat). No significant decrease was observed during the first 3 months of storage monitoring at -20 and -75 degrees C. On the contrary, the sample preparation significantly affected the drug concentration in muscle from the very beginning of the storage. Grinding the meat before storage allowed to keep the drug near the higher level of concentration (approximately 100 microg kg(-1)) when bulk meat stored frozen systematically led to a decreased value (approximately 75 microg kg(-1)). After 8 months of storage at -20 degrees C, a significant decrease arose and was never observed at -75 degrees C. All the results were similarly obtained with the three different techniques used simultaneously, which allows to indicate a good correlation between the techniques.     

Surface chemical modifications and surface reactivity of nanodiamonds hydrogenated by CVD plasma

The present study focuses on the interaction of hydrogen microwave CVD plasma with nanodiamonds (NDs). Hydrogen treated NDs (H-NDs) were characterized using electron spectroscopies (XPS, AES) without air exposure. A surface temperature higher than 700 °C is needed to remove the oxygen present on raw NDs. The kinetics of oxygen removal were investigated. Moreover, UHV annealings of H-NDs after ageing in ambient air clearly underline that 75% of the oxygen is related to physisorbed species. Finally, H-NDs were efficiently grafted using photochemical reaction with alkenes and a spontaneous coupling of aryldiazonium salts. These results confirm similar electronic surface properties between bulk and nano diamond materials.     

Generation of a mesoporous silica MSU shell onto solid core silica nanoparticles using a simple two-step sol-gel process

Silica core-shell nanoparticles with a MSU shell have been synthesized using several non-ionic poly(ethylene oxide) based surfactants via a two step sol-gel method. The materials exhibit a typical worm-hole pore structure and tunable pore diameters between 2.4 nm and 5.8 nm.     

Synthesis of New Avenalumic Carboxamide Derivatives in the Ferulic Series

A seven-step synthesis of (2E,4E)-5-[4-hydroxy-3-methoxyphenyl]penta-2,4-dienoic acid from ferulic acid was developed. The use of a natural by-product found in rice bran as a raw material provided the ferulic acid vinylogous in an overall high yield. This compound will be useful for the preparation of a wide variety of avenalumic carboxamide derivatives.     

Stimulus-responsive self-assembly: reversible, redox-controlled micellization of polyferrocenylsilane diblock copolymers

In depth studies of the use of electron transfer reactions as a means to control the self-assembly of diblock copolymers with an electroactive metalloblock are reported. Specifically, the redox-triggered self-assembly of a series of polystyrene-block-polyferrocenylsilane (PS-b-PFS) diblock copolymers in dichloromethane solution is described. In the case of the amorphous polystyrene(n)-b-poly(ferrocenylphenylmethylsilane)(m) diblock copolymers (PS(n)-b-PFMPS(m): n = 548, m = 73; n = 71, m = 165; where n and m are the number-averaged degrees of polymerization), spherical micelles with an oxidized PFS core and a PS corona were formed upon oxidation of more than 50% of the ferrocenyl units by [N(C(6)H(4)Br-4)(3)][SbX(6)] (X = Cl, F). Analogous block copolymers containing a poly(ferrocenylethylmethylsilane) (PFEMS) metalloblock, which has a lower glass transition temperature, behaved similarly. However, in contrast, on replacement of the amorphous metallopolymer blocks by semicrystalline poly(ferrocenyldimethylsilane) (PFDMS) segments, a change in the observed morphology was detected with the formation of ribbon-like micelles upon oxidation of PS(535)-b-PFDMS(103) above the same threshold value. Again the coronas consisted of fully solvated PS and the core consisted of partially to fully oxidized PFS associated with the counteranions. When oxidation was performed with [N(C(6)H(4)Br-4)(3)][SbF(6)], reduction of the cores of the spherical or ribbon-like micelles with [Co(η-C(5)Me(5))(2)] enabled full recovery of the neutral chains and no significant chain scission was detected.