Nesreen S. Ahmed

An eco-friendly N-sulfonylation of amines using stable and reusable Zn–Al–hydrotalcite solid base catalyst under ultrasound irradiation

Synthetic nanosized Zn-Al-hydrotalcite (Zn-Al-HT) with 20 nm crystallite size and 61 m(2)/g BET-surface area is found to be a mild and efficient catalyst for N-sulfonylation of amines in quantitative yields under ultrasound irradiation. Exclusive synthesis of sulfonamides, using Zn-Al-HT, under ultrasound irradiation, was realized by compatible basic sites of catalyst used. The products were isolated after simple work-up in high yields and purity.

An Efficiently Sonochemical Synthesis of Novel Pyrazoles, Bipyrazoles and Pyrazol-3-ylPyrazolo[3,4-d]pyrimidines Incorporating 1H-benzoimidazole Moiety

Novel pyrazoles, bipyrazoles and pyrazol-3-ylpyrazolo[3,4-d]pyrimidines were synthesized using the versatil synthon 2-(1H-benzimidazol-2-yl)-3,3-bis(methylthio) acrylonitrile (1). Reactions were carried out under silent and ultrasonic conditions. In general, improvement in rates and yields were observed when reactions were carried out under ultrasonic irradiation compared with silent condition. Structures of the products were established on analytical and spectral data.

Simple and efficient protocol for synthesis of pyrido[1,2-a]pyrimidin-4-one derivatives over solid heteropolyacid catalysts

Aluminium exchanged tungstophosphoric acid salts with Keggin structure (AlxH3−xPW12O40) were prepared by simple ion exchange method. The prepared heteropolyacid salts were characterized by various techniques such as elemental analysis, XRD, FTIR, UV-vis, N2-physisorption, NH3-TPD and FTIR-pyridine adsorption. All the prepared catalysts possess both Bronsted and Lewis acid sites, however increase of surface area and Lewis acid sites was observed with increase of Al content. The catalysts have been applied as heterogeneous catalysts to synthesize pyrido[1,2-a]pyrimidines under mild reaction conditions. A variety of biologically active pyrido[1,2-a]pyrimidines were obtained in best yields ever (above 90%) by using a simple, eco-friendly and efficient protocol catalyzed by AlxH3−xPW12O40 catalysts. Al3PW12O40 catalyst showed highest activity due to introduction of more number of Lewis acid sites to parent H3PW12O40 by complete exchange of H+ ions by Al3+ ions.

A Green Mechanochemical One-Pot Three-Component Domino Reaction Synthesis of Polysubstituted Azoloazines Containing Benzofuran Moiety: Cytotoxic Activity Against HePG2 Cell Lines

ABSTRACT A one-pot procedure for the synthesis of azolopyrimidine derivatives by a three-component reaction of β-ketosulfone, aldehyde, and 2-aminoben-zimidazole over synthetic magadiite clay (SMC-H) under ball milling in the absence of any solvent and additive has been developed. The catalyst was re-used for consequent reactions. The novel manufactured compounds were verified for HePG2 cell development inhibition. A pronounced inhibitory effect on the growth of HePG2 cell line was recorded. This protocol offers a broad scope for an access to a variety of diversely substituted azolopyrimidines of high inhibition activity against HePG2 cell line. The use of non-hazardous organic solvent, ball milling, cost efficiency, recyclability of the catalyst up to six runs without appreciable loss of activity, and high yields of products make this procedure greener.

Chitosan Decorated Copper Nanoparticles as Efficient Catalyst for One-Pot Multicomponent Synthesis of Novel Quinoline Derivatives: Sustainable Perspectives

Chitosan decorated copper nanoparticles catalysts (CSCuNPs) were synthesized via 12 reduction methods utilizing green protocol. The CSCuNPs catalysts were tested for the synthesis of 13 quinoline derivatives utilizing one-pot multicomponent reaction (MCR) under ultrasonic 14 irradiation. The best catalyst (Cu-CS-NPs) that provided good conversion reaction yield and high 15 turnover frequency (TOF) was characterized using FTIR, TGA, XRD, TEM and XPS techniques. 16 Generalization of the scope of the proposed catalytic process was studied using different aldehydes. 17 Excellent products yield and high TOF in even shorter reaction time (~5 min) was attained. 18 Recyclability performance of the catalyst over five times re-use without detectable loss in product 19 yield was recorded. The current method is green process utilizing environmentally benign catalyst 20 and considered to be promising sustainable protocol for the synthesis of fine chemicals. 21