5-Fluoro-1,2,3-triazole motif in peptides and its electronic properties.

The 5-fluoro triazole amino acid scaffold prepared by halogen exchange has been incorporated into peptides. From the X-ray diffraction of the 5-fluoro triazole motif, the main observation was an important localization on one side of the negative potential surface. The fluorine atom reveals a cylindrical shape in its deformation electron density.

Tiny dexamethasone palmitate nanoparticles for intravitreal injection: Optimization and in vivo evaluation.

Tiny nanoparticles of dexamethasone palmitate (DXP) were designed as transparent suspensions for intravitreal administration to treat age-related macular degeneration (AMD). The influence of three surfactants (PEG-40-stearate and Pluronic block copolymers F68 and F127) on nanoparticles size and stability was investigated and led to an optimal formulation based on Pluronic F127 stabilizing DXP nanoparticles. Size measurements and TEM revealed tiny nanoparticles (around 35 nm) with a low opacity, compatible with further intravitreal injection.

Thermodynamic and Structural Powder Diffraction Studies of the Polymorphism of Florfenicol.

Florfenicol is an antimicrobial drug used in veterinary medicine and aquaculture. Two polymorphic forms called A and B have been reported in literature, but the relation between these two forms are unknown. In order to get a better understanding of the behavior of solid florfenicol and the possible evolution from a metastable form to a stable one, an accurate thermodynamic study has been carried out by calorimetric measurements.

Molecular Potential Energies from Experimental Electric Field and Electrostatic Potential at Nuclei.

In this paper, the molecular electrostatic potential energy V is first estimated from the electric field generated by an experimental electron density. Once the high resolution X-ray diffraction data are fitted against the Hansen-Coppens multipole model, the electric field E is analytically computed on every point inside and around the molecule by using our own software FIELD. The potential energy is then obtained by a numerical and robust integration of E/2.

Unexpected Oxidative Ring Opening of Electron-Rich 3-Aminobenzofurans into α-Ketoimines Derivatives.

An unexpected ring opening of 3-aminobenzofurans promoted by NaO tBu in hot toluene, leading to a variety of α-ketoimines, is described. In the presence of 3-iodobenzofurans, NaO tBu mediates the 3-aminobenzofurans ring opening via a possible radical pathway without the help of any external radical sources.

Intramolecular Pd-Catalyzed Anomeric C(sp)-H Activation of Glycosyl Carboxamides.

An expedient method for the synthesis of fused glycosylquinolin-2-ones and glycosylspirooxindoles through an unprecedented intramolecular Pd-catalyzed anomeric C-H activation of the sugar moiety of 2-bromophenyl glycosylcarboxamides is reported. The scope of the reaction is broad and tolerates a wide range of functional groups.

Experimental evidence of charge transfer in a functionalized hexavanadate: a high resolution X-ray diffraction study.

A high resolution X-ray diffraction study has been carried out on [(CH)N] [VO{(OCH)CCHOCCHCH}] (V6-C3) at 100 K. The V6 core possesses a negative charge, leading to a strong polarization of the anion. A nucleophilic region localized near the organic moiety and an electrophilic region in the vicinity of the V6 core provide an overall description of charge-transfer behavior.

Revealing the electrophilicity of N-Ac indoles with FeCl: a mechanistic study.

Herein, we report a mechanistic exploration of the unusual FeCl-mediated hydroarylation of N-Ac indoles. Electron density topology analysis of a crystal, in situ IR monitoring, Hammett and Taft studies as well as DFT computations allowed us to determine that activation of acetyl with FeCl and of the C2[double bond, length as m-dash]C3 bond with a proton is involved.

Conversion of 3-Bromo-2H-coumarins to 3-(Benzofuran-2-yl)-2H-coumarins under Palladium Catalysis: Synthesis and Photophysical Properties Study.

An intriguing conversion of 3-bromo-2H-coumarins to 3-(benzofuran-2-yl)-2H-coumarins under palladium catalysis is reported. The process involves, from only one single starting material, three transformations and two bond formations in one pot: C-C bond formation via C-H activation and C-O bond formation through 2H-coumarin-to-benzofuran ring contraction under palladium catalysis. Moreover, the photophysical properties of all synthesized compounds were studied.

Experimental electron density study of tetrakis-mu-(acetylsalicylate)dicopper(II): a polymeric structure with Cu...Cu short contacts.

The electron density, its topological features, and the electrostatic potential of tetrakis-mu-(acetylsalicylate)dicopper(II), Cu[C(9)H(7)O(4)](2), have been derived from an accurate high-resolution diffraction experiment at 100 K. This complex exhibits a polymeric structure involving one acetyl oxygen atom as a bridge in the solid state. Only van der Waals interactions between the polymeric chains are observed.

Electronic properties of a cytosine decavanadate: toward a better understanding of chemical and biological properties of decavanadates.

We have synthesized and crystallized a cytosine-decavanadate compound, Na(3) [V(10)O(28)] (C(4)N(3)OH(5))(3)(C(4)N(3)OH(6))(3).10H(2)O, and its crystal structure has been determined from a single-crystal X-ray diffraction. A high resolution X-ray diffraction experiment at 210 K (in P1 space group phase) was carried out.

Charge density and electrostatic potential analyses in paracetamol.

The electron density of monoclinic paracetamol was derived from high-resolution X-ray diffraction at 100 K. The Hansen-Coppens multipole model was used to refine the experimental electron density. The topologies of the electron density and the electrostatic potential were carefully analyzed.

Advances in electric field and atomic surface derived properties from experimental electron densities.

The present study is devoted to a general use of the Gauss law. This is applied to the atomic surfaces derived from the topological analysis of the electron density. The method proposed here is entirely numerical, robust and does not necessitate any specific parametrization of the atomic surfaces.

Topological features of both electron density and electrostatic potential in the bis(thiosemicarbazide)zinc(II) dinitrate complex.

The experimental electron density of the bis(thiosemicarbazide)zinc(II) dinitrate complex, [Zn(CH5N3S)2](NO3)2,was studied. The Hansen-Coppens multipole model was used to extract the electron density from high-resolution X-ray diffraction data collected at 100 K. Careful strategies were designed for the electron density refinements regarding the charge transfer between the anionic and the cationic parts of the complex.

Electronic properties of 3,3'-dimethyl-5,5'-bis(1,2,4-triazine): towards design of supramolecular arrangements of N-heterocyclic Cu(I) complexes.

A new efficient and safe synthesis of 3,3'-dimethyl-5,5'-bis-(1,2,4-triazine) is presented. The electron-density distribution and electrostatic properties (charge, electrostatic potential) of this molecule were analyzed. These properties were derived from a high-resolution single-crystal X-ray diffraction experiment at 100 K and compared to the results obtained from ab initio DFT quantum-mechanical calculations.

Busulfan loading into poly(alkyl cyanoacrylate) nanoparticles: physico-chemistry and molecular modeling.

The busulfan is an alkylating agent widely used for the treatment of haematological malignancies and nonmalignant disorders. For a long time, it has been available only in an oral form. This treatment leads to a wide variability in bioavailability and side effects such as the veino-occlusive disease.

Experimental/theoretical electrostatic properties of a styrylquinoline-type HIV-1 integrase inhibitor and its progenitors.

We have established that polyhydroxylated styrylquinolines are potent inhibitors of HIV-1 integrase (IN). Among them, we have identified (E)-8-hydroxy-2-[2-(4,5-dihydroxy-3-methoxyphenyl)-ethenyl]-7-quinolinecarboxylic acid (1) as a promising lead. Previous molecular dynamics simulations and docking procedures have shown that the inhibitory activity involves one or two metal cations (Mg2+), which are present in the vicinity of the active center of the enzyme.

Elusive contribution of the experimental surface molecular electrostatic potential and promolecule approximation in the empirical estimate of the crystal density.

The aim of this study is to probe the crystal density (D(c)) description in terms of pertinent molecular characteristics and properties. In this purpose, the electrostatic potential was derived from available experimental electron density multipole parameters of molecular compounds with different D(c) magnitudes. The surface electrostatic potential has been analyzed through the positive and negative statistical variances.

7-Carboxylato-8-hydroxy-2-methylquinolinium monohydrate and 7-carboxy-8-hydroxy-2-methylquinolinium chloride monohydrate at 100 K.

Both 7-carboxylato-8-hydroxy-2-methylquinolinium monohydrate, C11H9NO3.H2O, (I), and 7-carboxy-8-hydroxy-2-methylquinolinium chloride monohydrate, C11H10NO3+.Cl-.

Crystallographic/experimental electron density characterizations and reactions with nucleophiles of beta-enaminonitriles possessing a pyrrolobenzazepine core.

In connection with a total synthesis of cephalotaxine (1a), we have examined the addition of various nucleophilic reagents to [ABC] subunits 2 and 7 possessing a pyrrolobenzazepine core. In fact, this reaction implicates invariably the carbonyl group of 2. Regarding the reaction of 7 with nucleophiles, the most striking aspect is the complete lack of reactivity of the enaminonitrile moiety.

Molecular reactivity of busulfan through its experimental electrostatic properties in the solid state.

Purpose: In the route of developing novel liquid phase formulations based on the encapsulation of busulfan into liposomes in nontoxic solvents, drug crystallization inevitably occurs. In order to better understand the reactivity of busulfan, the characterization of its molecular properties was therefore considered as a key point. Also, preliminary attempts to prevent crystallization using cyclodextrins were explored.