Kayed A. Abu Safieh

New palladium(II) complexes bearing pyrazole-based Schiff base ligands: Synthesis, characterization and cytotoxicity

Reactions of 5-hydrazino-1,3-dimethyl-4-nitro-1H-pyrazole (1) with substituted benzaldehydes (2-5) in methanol gave the new substituted benzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone Schiff base ligands (6-9) benzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (H-BDH, 6), 2,3-dimethoxybenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (MeO-BDH, 7), 4-chlorobenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (Cl-BDH, 8), and 4-hydroxybenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (OH-BDH, 9) in moderate to excellent yields. Reactions of these pyrazole-based Schiff bases with [PdCl(2)(NCPh)(2)] in acetone at room temperature gave the trans-palladium(II) complexes trans-[PdCl(2)(L)(2)] (10-13) (L=6-9). The isolated compounds were characterized by their physical properties, elemental analysis, IR-, MS (EI)- and NMR-spectroscopy. The cytotoxic effect of these complexes against the fast growing head and neck squamous carcinoma cells SQ20B and SCC-25 has been studied. The influence was dose dependent and varies by cell type. The complexes 11, 12, and 13 had higher clonogenic cytotoxic effect than cisplatin when tested on SQ20B cell line.

Selective removal of dibenzothiophene from commercial diesel using manganese dioxide-modified activated carbon: a kinetic study

With a total concentration of 7055 mgS/kgfuel, the content of organosulphur compounds (OSCs) in local diesel is 20 times higher than the regulated value. Analysis revealed that 30% of OSC is originated from dibenzothiophene (DBT). It is known that DBT is a hardly removable compound and selective adsorbents are often needed for its removal with low affinity for other diesel components. In this work, a selective adsorbent based on surface modification of activated carbon (AC) by MnO2 is prepared for DBT removal from diesel. The porous nature of AC enabled carrying large amounts of MnO2 particles to end up with a selective adsorber for DBT. The best performance was observed at a surface loading of 26.8% of Mn and DBT is favourably removed over mono- and diaromatics hydrocarbons in diesel. Adsorption kinetics of DBT is studied under a high initial concentration of 835–11,890 mg/kg and at a ratio of 11 cm3/g (diesel:carbon). The results indicated a fast removal process after surface modification where 96% of the surface is occupied within 30 min of interaction. Kinetic data were best presented by reaction-based models with low prediction error sum of squares values 0.5–47.0, while, diffusion-based models showed limited application for modelling DBT adsorption. Accordingly, adsorption process is controlled by surface reactions and pore diffusion has a minor role in the overall process. The modified adsorbent is satisfactorily regenerated using n-hexane at 65°C.

Synthesis, characterization, and antimicrobial activity of some new coumarin derivatives

A number of new [(4-methyl-2-oxo-2H-chromen-7-yl)amino]methylcoumarins (5a–c), benzofuran (6), and benzoxazol (7) were synthesized through the reaction of 7-amino-4-methylcoumarin (1) with a number of organic halides. In addition, series of N-substituted 2-[(4-methyl-2-oxo-2H-chromen-7-yl)oxy]acetohydrazide (11a–h) and (12a–d) were prepared from the reaction of 2-[(4-methyl-2-oxo-2H-chromen-7-yl)oxy]acetohydrazide (8) with corresponding heteroaryl/alkyl halides (2–4, 9, and 10). The synthesized compounds were characterized by elemental analysis and by spectroscopic techniques such as 1H-NMR, 13C-NMR, and mass spectrometry and were tested for their in vitro antimicrobial activity. The newly synthesized compounds exerted significant inhibitory activity against the growth of tested bacterial strains and a few of them are found to be potent antimicrobial agents.

Progress in the chemistry of 5-acetylthiazoles

ABSTRACT This review deals with the synthesis and reactions of 5-acetylthiazoles. Some of these reactions have been used successfully for the production of biologically important compounds. The main purpose of this review is to present a survey of the literature on the chemistry of 5-acetylthiazoles and to provide useful and up-to-date information on their applications because these compounds have not been previously reviewed. GRAPHICAL ABSTRACT

Synthesis of Some 1,3-Dimethyl-6-substituted-1H-pyrazolo[3,4-b]pyrazin-5(4H)-ones

A series of new 6-substituted-1,3-dimethyl-1H-pyrazolo[3,4-b]pyrazin-5(4H)-ones (13a - e) and 1,3-dimethyl-5a,6a,7,8-tetrahydro-1H-pyrazolo[4,3-e]pyrrolo[1,2-a]pyrazin-5(4H)-one (15) have been synthesized. The synthetic strategy involves direct interaction of D,L-α-amino acids with 5- chloro-1,3-dimethyl-4-nitro-1H-pyrazole (10) to produce the respective N-(1,3-dimethyl-4-nitro-1Hpyrazol- 5-yl) D,L-α-amino acids 11a - e and 14. The latter compounds underwent reductive lactamization to deliver the corresponding target heterocyclic systems 13a - e and 15 Graphical Abstract Synthesis of Some 1,3-Dimethyl-6-substituted-1H-pyrazolo[3,4-b]pyrazin-5(4H)-ones

Preparation of some alkenoic acid derivatives as new plant growth regulators

A number of 3-alkoxy-5-substituted-2,4-alkadienoic acids (4a–f) have been synthesized from the reaction of ethyl (E)-3-alkoxy-2-butenoate with different ketones in the presence of KOH in DMSO. Similarly, several (2Z,4E)-5-[4-(benzylthio)phenyl]-3-alkoxyhexa-2,4-dienoic acids were prepared via condensation of ethyl (E)-3-alkoxy-2-butenoate with 4-(benzylthio)acetophenone in the presence of KOH in DMSO. The structures of all synthesized compounds were confirmed by IR, 1H NMR, 13C NMR, and MS spectra and by elemental analysis.