Fazia Derridj

Palladium-Catalyzed Direct Arylation of Free NH2-Substituted Thiophene Derivatives

The palladium-catalyzed direct 2- or 5-arylation of some free NH(2)-substituted thiophene derivatives was found to proceed in high yields using a variety of aryl bromides. In the course of these reactions, no coupling of the aryl bromide with the thiophene NH(2) substituent was detected. The presence of an ester substituent on C2 of thiophene was found to be useful to block this highly reactive carbon.

Iron and nickel complexes with heterocyclic ligands: stability, synthesis, spectral characterization, antimicrobial activity, acute and subacute toxicity.

The synthesis and characterization by elemental analysis, emission atomic spectroscopy, TG measurements, magnetic measurements, FTIR, (1)H NMR, UV-visible spectra and conductivity of a series of iron (II) and nickel (II) complexes with two heterocyclic ligands (L(1)(SMX): sulfamethoxazole and L(2)(MIZ): metronidazole) used in pharmaceutical field and with a new ligand derived benzoxazole (L(3)(MPBO): 2-(5-methylpyridine-2-yl)benzoxazole), were reported. The formulae obtained for the complexes are: [M(L(1))2 Cl2]·nH2O, [M(L(2))2Cl2(H2O)2]·H2O and [M(L(3))2(OH)2]·nH2O. Stability constants of these complexes have been determined by potentiometric methods in water-ethanol (90:10, v/v) mixture at a 0.2 mol L(-1) ionic strength (NaCl) and at 25.0±0.1 °C. Sirko program was used to determine the protonation constants as well as the binding constants of three species [ML2H2](2+), [ML2] and [ML](2+). The antimicrobial activity of the ligands and complexes was evaluated in vitro against different human bacteria and fungi using agar diffusion method. Iron sulfamethoxazole complex showed a remarkable inhibition of bacteria growth especially on Staphylococcus aureus and P. aeruginosa. The iron metronidazole complex is active against yeasts especially on Candida tropicalis strain. Nickel complexes presented different antibacterial and antifungal behaviors against bacteria and fungal. The acute toxicity study revealed that the iron complexes are not toxic at 2000 mg/kg dose orally administrated. LD50 for nickel complexes was determined using graphical method. No significant differences in the body weights between the control and the treated groups of both rat sexes in subacute toxicity study using for iron complexes. Hematological and clinical blood chemistry analysis revealed no toxicity effects of the iron complexes. Pathologically, neither gross abnormalities nor histopathological changes were observed for these complexes.

Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp2)–H bond arylations

Summary We report herein a two or three step synthesis of fluorinated π-conjugated oligomers through iterative C–H bond arylations. Palladium-catalyzed desulfitative arylation of heteroarenes allowed in a first step the synthesis of fluoroaryl-heteroarene units in high yields. Then, the next steps involve direct arylation with aryl bromides catalyzed by PdCl(C3H5)(dppb) to afford triad or tetrad heteroaromatic compounds via regioselective activation of C(sp2)–H bonds.

Effective modulation of the photoluminescence properties of 2,1,3-benzothiadiazoles and 2,1,3-benzoselenadiazoles by Pd-catalyzed C–H bond arylations

A one step procedure towards the synthesis of 4-aryl-2,1,3-benzothiadiazoles, 4,7-diaryl-2,1,3-benzothiadiazoles and 4-aryl-2,1,3-benzoselenadiazoles using palladium-catalyzed regioselective C–H bond arylations of 2,1,3-benzothiadiazole and 2,1,3-benzoselenadiazole was developed. A donor–acceptor compound was also synthesized via two successive C–H bond arylations at C4 and C7 positions of the 2,1,3-benzothiadiazole unit. One of the major achivements of this methodology arises from the fine modulation of the fluorescence wavelength with emission colors covering blue to red regions of the visible spectrum by the simple introduction of the suitable aryl group on the 2,1,3-benzothiadiazole unit.

Quinoxaline as an integrated directing group in palladium-catalyzed ortho-C–H bond arylation of the aryl unit of 2-arylquinoxalines

We report the Pd-catalyzed C–H bond arylation at the ortho-position of the aryl unit of 2-arylquinoxalines. The reaction proceeds with complete regioselectivity using phosphine-free Pd(OAc)2 as the catalyst and potassium acetate as inexpensive base. In contrast to previously employed directing groups, quinoxaline is an integrated directing group in the final product that only promotes ortho-mono-arylation without the formation of bis-arylated products. A wide variety of (hetero)aryl bromides, including bromopyridine derivatives, has been successfully employed.