Hassan Allouchi

Influence of 6-or 8-substitution on the antiviral activity of 3-arylalkylthiomethylimidazo[1.2-a]pyridine against human cytomegalovirus (CMV) and varicella-zoster virus (VZV) : Part II

The synthesis of original imidazo[1,2-a]pyridines bearing a thioether side chain at the 3 position and diversely substituted on the 6 or 8 position, and their antiviral activities are reported. From the synthesized compounds, the imidazo[1,2-a]pyridines bearing a 5 membered heterocycle (thiophene, furane or pyrrole) in the 6 position or a phenylthio group in the 6 or 8 position were the most potent against human cytomegalovirus (CMV) and varicella-zoster virus (VZV), whereas several other congeners, while less potent, were more selective in their inhibitory activity against VZV and CMV. These compounds showed similar activity against thymidine kinase competent (TK+) and deficient (TK-) VZV strains, demonstrating a mechanism of action independent of the viral thymidine kinase.

Influence of 2-substituent on the activity of imidazo[1,2-a] pyridine derivatives against human cytomegalovirus.

The synthesis of various 2-substituted imidazo[1,2-a]pyridine bearing a thioether side chain in position 3 was reported. The new compounds were characterized by 1H and 13C NMR spectra. A conformational study was obtained by X-ray crystallographic analysis for 2-biphen-4-ylimidazopyridine 7. The antiviral activity against human cytomegalovirus (HCMV) was investigated. It was strongly influenced by the nature of C-2 substituent.

A new hexagonal phase of fullerene C60

Abstract A new phase of fullerene C 60 with a simple hexagonal unit cell with 6/mmm symmetry was grown by slowly evaporating solutions of C 60 in dichloromethane. X-ray measurements reveal that the c / a ratio is 1.616 at 298 K and increases as temperature decreases. At low temperature, it seems to extrapolate to 1.633, the ideal ratio for a close-packed hexagonal lattice. The unit cell volume which is higher than that of the usual cubic C 60 phases at high temperature decreases near 90 K. A structural model is proposed according to which a 3-fold molecular axis is parallel to the 6-fold crystallographic z -axis. This suggests that the molecules could reorient around this axis at high temperature.

Pressure-induced dimerization of fullerene C60: a kinetic study

Abstract The kinetics of pressure-induced dimerization of fullerite C60 at 1.5 GPa in the 373–473 K temperature interval was studied by X-ray diffraction, infrared and Raman spectroscopy. Kinetic curves of the dimerization reaction in the fcc and sc phases of C60 were obtained by monitoring the dimeric (C60)2 IR line at 796 cm−1. The value of the dimerization activation energy was determined to be E a ( dim ) =134±6 kJ mol −1 , assuming the second order irreversible reaction. The peculiarities of the dimerization processes in the fcc and sc phases of C60 fullerite are also discussed.

Decagonal C60 crystals grown from n-hexane solutions: solid-state and aging studies

Abstract Decagonal C60 crystals grown from n-hexane solutions correspond to an orthorhombic 1:1 solvate (a=10.249 A, b=31.308 A, c=10.164 A). It forms with negative excess volume ( −55.5 A 3 per formula unit) and transforms on heating into fcc C60 (desolvation enthalpy of +50.6 kJ per solvate mole, close to the sublimation enthalpy for pure n-hexane) while n-hexane desorption from fcc C60 is accompanied by an enthalpy of +48.6 kJ per solvent mole. Thus solvate formation is preferred to solvent adsorption. Orthorhombic C 60 ·1 n -hexane undergoes no degradation when stored in air for 9 years at room temperature in the dark.

Spectroscopic properties of individual pressure-polymerized phases of C60

Abstract The Raman and IR spectra of pure polymerized phases of C 60 obtained at high pressure and temperature were investigated. Our data showed that some previous spectra were obtained from a mixture of different polymeric states. Determination of the characteristic bands of dimer, chain and layer polymers permit the use of the IR and Raman spectra in the molecular fractional analysis of different polymerized states of C 60 .

Dramatic Solid-State Humidity-Induced Modification of the Magnetic Coupling in a Dimeric Fluorous Copper(II)−Carboxylate Complex

The very fast and efficient water vapor absorption of the dimeric fluorous copper(II)-carboxylate complex [Cu(2)(C(8)F(17)CO(2))(4)(acetone)(2)] (1) leads, in the solid state, to a dramatic decrease of the exchange magnetic coupling between the copper(II) ions and to a drastic change of its powder EPR spectrum.

Striking Correlation between the Unusual Trigonal Crystal Packing and the Ability to Self-Assemble into Nanofibers of 2,3-Di-n-alkyloxyanthracenes

The space group of the crystals of derivatives of 2,3-dialkoxyanthracenes is monoclinic P2(1)/a (herringbone structure) with the linear ethyl or propyl chains but abruptly changes to the trigonal P3 or R3 space group for butyl to heptyl chains. Strikingly, this switch is correlated with the capacity of these compounds to self-assemble into nanofibers and organogels. Besides, compounds with a chain length exceeding seven carbon atoms could not be crystallized in accordance with the analysis of the projected crystal structure but are nevertheless excellent organogelators. The study of this series of compounds suggests a tight link between the molecular structure of the crystals and that of the organogels.

On the nature of the smectic mesophase in 8CB + 10CB binary mixtures. Evidences for a smectic A to nematic tricritical point

The two-component system octylcyanobiphenyl(8CB) + decylcyanobiphenil(10CB) has been studied by means of Modulated Differential Scanning Calorimetry, optical microscopy and X-ray diffraction. Although the general trends of the phase diagram are similar to that proposed by Marynissen et al., additional evidences for the existence of TCP have been reported, the composition being about 0.2, which is slightly lower than that proposed in the aforementioned work. Additionally, the smectic mesophase of the 8CB + 10CB mixtures has been characterised through X-ray diffraction and optical measurements as smectic A for the whole composition range. Such a result is against the recent work of Oweimreen and Hwang.

Synthesis of 3‐Nitrosoimidazo[1,2‐a]pyridine Derivatives as Potential Antiretroviral Agents

Ten 2‐aryl or heteroaryl‐3‐nitrosoimidazo[1,2‐a]pyridine derivatives were synthesised as potential antiretroviral agents. The new compounds were characterized by elemental analysis, 1H NMR, and by crystallography for (14). The compounds were devoid of any activity against HIV‐1 or HIV‐2.