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Some terpolymeric stabilizers based on polymerizable derivatives of 2,4‐dihydroxy‐benzophenone were prepared and evaluated as photostabilizers for rigid poly(vinyl chloride) (PVC). The prepared terpolymers, namely, (methyl methacrylate)/(2‐hydroxyethyl methacrylate)/2‐hydroxy‐4‐methacryloxybenzophenone (MMA/HEMA/HBMA) and (methyl methacrylate)/(2‐hydroxyethyl methacrylate)/2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxypropoxy)benzophenone (MMA/HEMA/PBMA), were characterized, and their structures were confirmed by GPC, thermogravimetric analysis, FTIR, and ultraviolet‐visible (UV–vis) spectroscopy. The results revealed that the stabilizing effect of these terpolymers increased upon increasing the stabilizer concentration and the content of UV absorber units in the terpolymers. Promising results were achieved, and the prepared terpolymers showed higher stabilizing efficiency than the corresponding monomeric UV absorbers of low molecular weight. J. VINYL ADDIT. TECHNOL., 2011.© 2011 Society of Plastics Engineers

in Wiley Online Library (wileyonlinelibrary.com).Hexahydroquinolines 1a,b reacted with carbon disulphide in different conditions to yield the corresponding adducts 2a,b and 3a,b. Carrying out the same reactions in acetone as solvent produced the modified new products 4a,b. The interaction of pyrazolopyridine derivatives 5a-d with carbon disulphide under the same previous conditions furnished the isolated products 6a-d, 7a-d, and 8a-d. Studying the behavior of 1a,b or 5a-d toward Lawesson's reagent (LR) formed the final adducts 11a,b or 12a-d. The structure of synthesized compounds was confirmed with the spectroscopic and microanalytical data. The biological activities of 2a, 4a, 4b, 7a, 7c, 8d, 11a, 11b, 12b, and 12c were tested for antimicrobial evaluation.

Certain cytosine-rich (C-rich) DNA sequences can fold into secondary structures as four-stranded i-motifs with hemiprotonated base pairs. Here we synthesized C-rich TINA-intercalating oligonucleotides by inserting a nonnucleotide pyrene moiety between two C-rich regions. The stability of their i-motif structures was studied by using UV melting temperature measurements and circular dichroism spectra at different pH values under noncrowding and crowding conditions (20% poly(ethylene glycol)). When TINA ((R)-3-((4-(1-pyrenylethynyl)benzyl)oxy) propane-1,2-diol) is inserted, the oligonucleotides could form an i-motif at a higher pH than observed for the corresponding wildtype oligonucleotide.

In continuation of our investigation of characteristics and thermodynamic properties of the i‐motif 5′‐d[(CCCTAA)3CCCT)] upon insertion of intercalating nucleotides into the cytosine‐rich oligonucleotide, this article evaluates the stabilities of i‐motif oligonucleotides upon insertion of naphthalimide (1H‐benzo[de]isoquinoline‐1,3(2H)‐dione) as the intercalating nucleic acid. The stabilities of i‐motif structures with inserted naphthalimide intercalating nucleotides were studied using UV melting temperatures (Tm) and circular dichroism spectra at different pH values and conditions (crowding and non‐crowding). This study indicated a positive effect of the naphthalimide intercalating nucleotides on the stabilities of the i‐motif structures compared to the wild‐type structure which is in contrast to a previous observation for a pyrene‐intercalating nucleotide showing a decrease in Tm values.

Two Schiff base derivatives, 4-[(2, 5-dimethoxy phenylimino)-methyl] phenol, SB1 and 4-[(2-hydroxy benzylidine)-amino] phenolSB2, have been prepared and used as modifiers for polyvinyl chloride (PVC). Chemical modification of PVC was performed using these Schiff base sin presence ofAgNO3to obtain two modified PVC nanocomposite,PVC-SB1/AgNPs and PVC-SB2/AgNPs, and their chemical structures were confirmed by FTIR, 1 H-NMR, 13 C NMR and Mass spectroscopy. Scanning and transmission electron microscopy were performed for the modified polymer nanocomposites. The SEM and TEM micrographs of PVC-SB/AgNPs showed homogeneous surface polymeric matrix with uniform distribution of AgNPs, and their diameters are in the nanoscale. Moreover, thermal and photostabilities as well as mechanical properties of the modified polymer nanocomposites were also investigated. Moreover, mechanical properties of PVC-SB/AgNPs were also investigated. Antimicrobial activity of the modified PVC was evaluated against two Gram +ve bacteria (Bacillus subtitles and Staphylococcus aurous) and two Gram -ve bacteria (Escherichia coli and Pseudomonas aeruginosa) as well as Candida albicans as fungus.

C HEMICAL modification of poly(vinyl chloride), PVC, was performed via its substitution reaction with 6-amino-2-thioxo-tetrahydropyrimidin-4-one (1) and three of its derivatives (1A-C). The chemical structures of the modified PVC samples have been confirmed via FTIR and 1 HNMR spectroscopic analyses. Photostability of the modified PVC were investigated by following the rates of dehydrochlorination of the 6-aminopyrimidine derivatives modified PVC samples conductometrically in comparison with both blank PVC and that stabilized with 2-hydroxy-4-(octyloxy)-phenyl-benzophenone as reference UV absorber. Moreover, thermal stability as well as physicomechanical properties of all investigated PVC samples have also been determined. Modified PVC samples exhibited enhanced photo and thermal stability as well as mechanical properties when compared to the blank unmodified sample. Antimicrobial properties of the tested PVC samples were explored against Gram +ve bacteria (Staphylococcus aureus), Gram-ve bacteria (Escherichia coli) as well as A. flavus and C. albicans as fungi. However, incorporation of 6-aminopyrimidine derivatives to the PVC backbone chains enhanced their inhibitory effect against the examined microorganisms.

Over the last few decades, significant efforts have been put forth towards the C−H bond group functionalization by transition-metalcatalysis and organocatalysis. Several efficient strategies to convert C-H bond to other groups C-C, C-N, C-O bonds have been implemented. The most attractive C-H bond functionalization was the C-H heterocyclic compounds activation that is practical method in organic synthesis. The new C–C, C–N and C–O bond as formed from the C-H bond activation by two diverse ways metal catalysis and/or organocatalysis. The most important is the synthesis of new bioactive heterocyclic compounds by easy and less expensive materials. In this review, we will cover most of the syntheses of heterocyclic derivatives by the functionalization of C-H bond in metal and organocatalytic reagents.