Synthesis of polyfunctionally substituted heteroaromatic compounds via benzotriazolyl chalcones with antimicrobial and antifungal activities

The utility of both 3‐(1‐benzotriazolyl) chalcone derivatives 3a‐c and 2‐(1‐benzotriazolyl)‐1,4‐pentadien‐3‐one (18) in the synthesis of some new 2‐(1H)‐pyridone, pyridine, pyrazole and isoxazole derivatives is reported. Antimicrobial and antifungal screening of some selected examples from the synthesized products were carried out. The structure of the newly synthesized compounds was elucidated by elemental analysis, ir, ¹H and ¹³C nmr investigations.     

Determination of Some Metal Ions in Aquatic Environs by Atomic Absorption Spectrometry after Concentration with Modified Silica

The uptake behavior of porous silica modified with N‐propylsalicylaldimine (IE11) for Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) metal ions were studied. The Log k_d values were found to be within the range 2.19–5.16 depending on pH and time of stirring. IE11 was used in the separation and preconcentration of Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) from some natural water samples. The data were compared with those obtained by the solvent extraction method (APDC/MIBK). The method was found to be accurate and precise and not subject to random error.     

New routes to the synthesis of pyridazinone,ethoxypyridine, pyrazole and pyrazolo[1,5‐a]pyrimidine derivatives incorporating a benzotriazole moiety

A new approach to the synthesis of pyridazinone, ethoxypyridine, pyrazole and 7‐aminopyrazolo‐[1,5‐a]pyrimidine derivatives. The structure of the newly synthesized compounds was elucidated by elemental analyses, ir, ¹H nmr spectra and in some cases by ¹³C nmr investigations.     

On the Formation of 2‐Sulfonylbenzo[a]heptalene‐1,3‐diols as Precursors for the Synthesis of Colchicinoids

The benzo[a]heptalene formation from 4‐[(R‐sulfonyl)acetyl]heptalene‐5‐carboxylates 15 and 5‐[(R‐sulfonyl)acetyl]heptalene‐4‐carboxylates 16 (R=Ph or morpholino) in the presence of R′SO₂CH₂Li and BuLi has been investigated (Scheme 6). Only the sulfonyl moiety linked to the C?O group at C(4) of the heptalene skeleton is found at C(3) of the formed benzo[a]heptalene‐2,4‐diols 3 in accordance with the general mechanism of their formation (Scheme 3). Intermediates that might rearrange to corresponding 2‐sulfonylbenzo[a]heptalene‐1,3‐diols lose HO^? under the reaction conditions to yield the corresponding cyclopenta[d]heptalenones of type 11 (Schemes 6 and 7). However, the presence of an additional Me group at C(α) of the lithioalkyl sulfones suppresses the loss of HO^?, and 4‐methyl‐2‐sulfonylbenzo[a]heptalene‐1,3‐diols of type 4c have been isolated and characterized for the first time (Schemes 8 and 10). A number of X‐ray crystal‐structure analyses of starting materials and of the new benzo[a]heptalenes have been performed. Finally, benzo[a]heptalene 4c has been transformed into its 1,2,3‐trimethoxy derivative 23 , a benzo[a]heptalene with the colchicinoid substitution pattern at ring A (Scheme 11).     

Radiation synthesis of poly[(dimethylaminoethyl methacrylate)-co-(ethyleneglycol dimethacrylate)] hydrogels and its application as a carrier for anticancer delivery

The use of hydrogels as carriers for anticancer delivery has been a subject of significant recent research. In our recent work, we have shown that diffusion-controlled delivery of flutamide from hydrogels containing poly (dimethylaminoethyl methacrylate (DMAEMA)/ethyleneglycol dimethacrylate (EGDMA)) can be possible and controlled by the three-dimensional structure. Hydrogels based essentially on dimethylaminoethyl methacrylate and different ratios of ethyleneglycol dimethacrylate monomers were synthesized using gamma radiation copolymerization. The influence of copolymer composition and pH value of the surrounding medium on swelling behavior into the glassy polymer were discussed. The results showed that the ratio of EGDMA in the comonomer feeding solution has a great effect on the gel fraction and water content in the final hydrogel. In this regard, it was observed that the increase of EGDMA ratio decreased these properties. The ability of the prepared copolymer to be used as drug carrier for anticancer drug-delivery system was estimated using flutamide as a model drug. In vitro drug-release studies in different buffer solutions show that the basic parameters affecting the drug release behavior of hydrogel are the pH of the solution and DMAEMA content of hydrogel.     

Synthesis and E/Z configuration determination of novel derivatives of 3-aryl-2-(benzothiazol-2'-ylthio) acrylonitrile, 3-(benzothiazol-2'-ylthio)-4-(furan-2'-yl)-3-buten-2-one and 2-(1-(furan-2'-yl)-3'-oxobut-1'-en-2-ylthio)-3-phenylquinazolin-4(3H)-one

Knoevenagel condensation of 2-(benzothiazol-2-ylthio) acetonitrile (2) with either furan-2-carbaldehyde or thiophene-2-carbaldehydes leads to E-isomers 4a-b exclusively, while the condensation of the compound 2 with benzaldehyde or para-substituted benzaldehydes with an electron-donating group afforded E/Z mixtures 4c-e with preferentially formation of the E-isomer. Condensation of furan-2-carbaldehyde (3a) with either 1-(benzothiazol-2'-ylthio) propan-2-one (5) or 2-(2'-oxo propylthio)-3-phenyl-quinazolin-4(3H)-one (9) leads exclusively to the Z-isomers of 6 and 10, respectively. The structures of the newly synthesized compounds were elucidated by elemental analyses, 1H-NMR and 13C-NMR spectra, COSY, HSQC, HMBC, NOE, MS and X-ray crystallographic investigations.     

Synthesis and characterization of chitosan–poly(acrylamide–co-acrylic acid) magnetic nanocomposite hydrogels for use in catalysis

A novel hydrogel based on chitosan–poly(acrylamide-co-acrylic acid) (CAA) with different formulations were synthesized by the effect of gamma radiation. The magnetic CAA hydrogels were also synthesized and characterized by using different techniques, e.g., TEM and XRD. The prepared hydrogels and magnetic hydrogel nanocomposite were utilized for in situ cobalt nanoparticle preparation and employed as a reaction media in catalytic reduction of 2-nitrophenol (2-NP), to 2-aminophenol (2-AP). The experimental parameters that affect the reduction rates such as temperature and amount of catalyst were also, investigated.     

1,3,4‐Thiadiazole, 1,3,4‐thiadiazine, 1,3,6‐thiadiazepane and quinoxaline derivatives from symmetrical hydrazine‐1,2‐dicarbothioamide as well as N,N″‐ethane‐1,2‐diylbis(thiourea) derivatives

Reactions of N,N′‐disubstituted hydrazine‐1,2‐carbothioamides 8a‐c and substituted N,N″‐ethane‐1,2‐diylbis(thioureas) 9a‐c with 2,3,5,6‐tetrachloro‐1,4‐benzoquinone (chloranil, 10a ) and 2,3,5,6‐tetrabromo‐1,4‐benzoquinone (bromanil, 10b ) to form N,N′‐disubstituted 1,3,4‐thiadiazole‐2,5‐diamines 11a‐c , substituted 3‐amino‐6,7‐dichloro‐2,3‐dihydro‐1H‐4,2,1‐benzothiadiazine‐5,8‐diones 12a‐c , 2,3,7,8‐tetrahalothianthrene‐1,4,6,9‐tetrones 13a,b , substituted 5,6,8‐trihalo‐7‐oxo‐3,7‐dihydroquinoxaline‐2H‐carbothioamides 14a‐c, 15a‐c and 7‐substituted imino‐1,3,6‐thiadiazepane‐2‐thiones 16a‐c are reported.     

Initial Carbon−Carbon Bond Formation during the Early Stages of Methane Dehydroaromatization

Methane dehydroaromatization (MDA) is among the most challenging processes in catalysis science owing to the inherent harsh reaction conditions and fast catalyst deactivation. To improve this process, understanding the mechanism of the initial C?C bond formation is essential. However, consensus about the actual reaction mechanism is still to be achieved. In this work, using advanced magic‐angle spinning (MAS) solid‐state NMR spectroscopy, we study in detail the early stages of the reaction over a well‐dispersed Mo/H‐ZSM‐5 catalyst. Simultaneous detection of acetylene (i.e., presumably the direct C?C bond‐forming product from methane), methylidene, allenes, acetal, and surface‐formate species, along with the typical olefinic/aromatic species, allow us to conclude the existence of at least two independent C?H activation pathways. Moreover, this study emphasizes the significance of mobility‐dependent host–guest chemistry between an inorganic zeolite and its trapped organic species during heterogeneous catalysis.     

Pharmacological Evaluation of Novel Organoiron Dendrimers as Antimicrobial and Anti‐Inflammatory Agents

The synthesis of a novel and attractive class of nonsteroidal anti‐inflammatory and antimicrobial organoiron dendrimers attached to the well‐known drug ibuprofen is achieved. The structures of these dendrimers are established by spectroscopic and analytical techniques. The antimicrobial activity of these dendrimers is investigated and tested against five human pathogenic Gram‐positive and Gram‐negative bacteria, and minimum inhibitory concentrations are reported. Some of these synthesized dendrimers exhibit higher inhibitory activity against methicillin‐resistant Staphylococcus aureus, vancomycin‐resistant Enterococcus faecium, and Staphylococcus warneri compare to the reference drugs. As well, the in vitro and in vivo anti‐inflammatory activities of these dendrimers are evaluated. The results of in vivo anti‐inflammatory activity and histopathology of inflamed paws show that all dendrimers display considerable anti‐inflammatory activity; however, second‐generation dendrimer ( G2‐D6 ) shows the best anti‐inflammatory activity, which is more potent than the commercial drug ibuprofen at the same tested dose. Results of the toxicity study reveal that G2‐D6  is the safest drug on biological tissues.