Study on changes in optical properties of phenylbenzothiazole derivatives on metal ion binding

The UV-visible and fluorescence properties of hydroxy substituted benzothiazole derivatives change on interactions with zinc(II), cadmium(II) and mercury(II) ions. The binding of 2-(2'-hydroxyphenyl)benzothiazole is specific to zinc(II) over cadmium(II) and mercury(II). Similar type of interactions of zinc(II), cadmium(II) and mercury(II) with 2-(2',3',4'-trihydroxyphenyl)benzothiazole is observed in their UV-visible absorptions, whereas 2-(4'-hydroxyphenyl)benzothiazole shows interactions with mercury(II) over the other two ions.

Aromatic N-oxide bridged copper(II) coordination polymers: Synthesis, characterization and magnetic properties

The complexes [Cu2(o-NO2-C6H4COO)4(PNO)2] (1), [Cu2(C6H5COO)4(2,2'-BPNO)] n (2), [Cu2(C6H5COO)4(4,4'-BPNO)] n (3), [Cu(p-OH-C6H4COO)2(4,4'-BPNO)2·H2O] n (4), (where PNO = pyridine N-oxide, 2,2'-BPNO = 2,2'-bipyridyl-N,N'-dioxide, 4,4'-BPNO = 4,4'-bipyridyl-N,N'-dioxide) are prepared and characterized and their magnetic properties are studied as a function of temperature. Complex 1 is a discrete dinuclear complex while complexes 2-4 are polymeric of which 2 and 3 have paddle wheel repeating units. Magnetic susceptibility measurements from polycrystalline samples of 1-4 revealed strong antiferromagnetic interactions within the {Cu2}4+ paddle wheel units and no discernible interactions between the units. The complex 5, [Cu(NicoNO)2·2H2O] n ·4nH2O, in which the bridging ligand to the adjacent copper(II) ions is nicotinate N-oxide (NicoNO) the transmitted interaction is very weakly antiferromagnetic.

Structure-activity studies on therapeutic potential of Thymoquinone analogs in pancreatic cancer

PURPOSE

Pancreatic cancer (PC) is one of the deadliest of all tumors. Previously, we were the first to show that Thymoquinone (TQ) derived from black seed (Nigella sativa) oil has anti-tumor activity against PC. However, the concentration of TQ required was considered to be high to show this efficacy. Therefore, novel analogs of TQ with lower IC(50) are highly desirable.

METHODS

We have synthesized a series of 27 new analogs of TQ by modifications at the carbonyl sites or the benzenoid sites using single pot synthesis and tested their biological activity in PC cells.

RESULTS

Among these compounds, TQ-2G, TQ-4A1 and TQ-5A1 (patent pending) were found to be more potent than TQ in terms of inhibition of cell growth, induction of apoptosis and modulation of transcription factor-NF-kappaB. We also found that our novel analogs were able to sensitize gemcitabine and oxaliplatin-induced apoptosis in MiaPaCa-2 (gemcitabine resistant) PC cells, which was associated with down-regulation of Bcl-2, Bcl-xL, survivin, XIAP, COX-2 and the associated Prostaglandin E2.

CONCLUSION

From our results, we conclude that three of our novel TQ analogs warrant further investigation against PC, especially in combination with conventional chemotherapeutic agents.

Solvatochromicity of 3-hydroxy-4-(1-(2,4-dihydroxyphenyl)-2-hydroxy-2,2-diphenylethylidene)cyclohexa-2,5-dienone for screening of solvents

The quinonic compound 3-hydroxy-4-(1-(2,4-dihydroxyphenyl)-2-hydroxy-2,2-diphenylethylidene)cyclohexa-2,5-dienone (I) is synthesised by the reaction of benzil with 1,3-dihydroxybenzene in basic medium. Solution of this compound shows visibly distinct colour differences in different solvents. From the different absorption maxima of the compound in visible spectra it can be used as an excellent analytical reagent to screen different solvents.

Solvent induced reactivity of 3,5-dimethylpyrazole towards zinc (II) carboxylates

The reactions of 3,5-dimethylpyrazole with zinc(II)acetate dihydrate and varieties of aromatic carboxylic acids led to formation of mono-nuclear zinc complexes of composition [Zn(HDMP)2(RCO2)2] (R = C6H5, p-CH3-C6H4, p-NO2-C6H4 etc. HDMP = 3,5-dimethylpyrazole) in methanol, whereas the same reactants in dimethylformamide (DMF) gave binuclear 3,5-dimethylpyrazolato bridged zinc carboxylate complexes containing monodentate 3,5-dimethylpyraozole ligands with composition [Zn2(mu-DMP)2(HDMP)2(RCO2)2]. The mononuclear complexes can be converted to the corresponding binuclear complexes by simply dissolving in DMF. The reaction of zinc(II)acetate dihydrate with p-nitrobenzoic acid and 3,5-dimethylpyrazole in different solvents gave solvated mononuclear complexes of the corresponding solvent. All these solvated complexes having the core [Zn(HDMP)2(p-NO2-C6H4CO2)2] contain two structurally independent molecules in the asymmetric unit (Z' = 2).