Wael A. A. Arafa

Synthesis and application of alizarin complexone functionalized polyurethane foam: Preconcentration/separation of metal ions from tap water and human urine

A new chelating sorbent has been synthesized by the covalent condensation of alizarin complexone (ALC) to polyurethane foam (PUF) through -N=C- group. The material was characterized by IR, (1)H NMR and chemical proof. Iminodiacetic acid groups are found in the prepared sorbent and the reaction proceeded via condensation between the toluidine moieties in the PUF and non-hydrogen bonded carbonyl group in ALC. Also, the possibility of elimination reaction between the groups (NH(2), NH and OH) in the polymer and carboxylic groups in the reagent was excluded. The material has been used to separate/preconcentrate Cu(2+), Zn(2+) and Cd(2+) prior to their determination by flame atomic absorption spectrometry (FAAS). Chemical and flow variables such as sample pH, sorbent capacity, sample flow rate and interference from co-existing ions were investigated. All metal ions are quantitatively desorbed by 0.1 mol L(-1) nitric acid solution. The procedure provides concentration factor 100 and limits of detection 0.013 microg mL(-1). The method was validated by the analysis of certified reference materials and real samples such as tap water and human urine.

Ultrasound-Mediated Three-Component Reaction “On-Water” Protocol For the Synthesis of Novel Mono- and bis-1,3-Thiazin-4-one Derivatives

Green synthetic and catalyst-free strategy towards the synthesis of novel mono- and bis-1,3-thiazin-4-one scaffolds through a one pot, reaction of carbon disulfide, monoacetylenic esters and amines ...

Ultrasound mediated green synthesis of rhodanine derivatives: Synthesis, chemical behavior, and antibacterial activity

GRAPHICAL ABSTRACT ABSTRACT A variety of rhodanine derivatives were synthesized via a three-component reaction of carbon disulfide, amines, and dialkyl acetylenedicarboxylate in polyethylene glycol under conventional stirring or ultrasound irradiation. The sonochemical-assisted procedure provides an improved and accelerated conversion when compared to the conventional reaction, with increased rate of reaction and quality of product obtained. The product formed, 2a, could be readily converted to bis-rhodanine under microwave conditions. Moreover, the pyranothiazoles 9a,b were prepared from the corresponding rhodanines 2a,b and malononitrile. Fifteen compounds were screened for their antibacterial activities against nine human, animal and plant pathogenic Gram-positive and Gram-negative bacteria using the agar well diffusion method. Out of these derivatives, compounds 2g and 2h were the most effective against all tested bacteria.

A sustainable strategy for the synthesis of bis-2-iminothiazolidin-4-ones utilizing novel series of asymmetrically substituted bis-thioureas as viable precursors

A novel series of asymmetrically substituted bis-thioureas has been synthesized in an effective pattern via the reaction of diamines with isothiocyanates utilizing the ultrasonic irradiation as a sustainable energy source. This reaction performs well at mild conditions to give the products in quantitative yields for a broad scope of substrates. The bis-thiourea derivatives are used for the design of unprecedented series of bis-2-iminothiazolidin-4-ones promoted by the ultrasonic irradiation. The reaction affords the formation of regioselective products, which depends on the pKas of the diamines. The diamine linked to the thiourea possessing lower pKa is involved in the imino part, and the diamine having higher pKa is a part of the other heterocyclic nitrogen. Moreover, this new strategy has excellent environmental parameters, demonstrating that this protocol is a green and sustainable process.

An eco-compatible pathway to the synthesis of mono and bis-multisubstituted imidazoles over novel reusable ionic liquids: an efficient and green sonochemical process

Novel and environmentally benign ionic liquids (ILs) comprised of DABCO were successfully synthesized. These ILs were used as robust catalysts for the sonochemical one pot multi-component synthetic route for the functionalized annulated imidazoles in water with excellent yields. The present protocol scored well in terms of yield economy as compared with the conventional procedures. The merits of the current green method include simplicity, applicability, broad functional groups tolerance, clean reaction profiles, and no tedious work-up and they give high-to-quantitative yields. From the environmental viewpoint, these eco-friendly green catalysts can be effortlessly retrieved and reused at least seven successive times without substantial loss in catalytic activity.

An eco-compatible access to diversified bisoxazolone and bisimidazole derivatives

An efficient, straight-forward and eco-friendly synthetic strategy for the assembly of novel bisoxazolones via a four-component, sequential reaction of dialdehydes, glycine, benzoyl chloride and ac ...