Synthesis of 6-(2’ or 4’- nitrophenyl)benzo[b]thiophenes by Palladium-catalyzed cross-coupling

The palladium-catalyzed cross-coupling reactions of organoboron compounds are very useful for carbon-carbon bond formation. Compounds 1 were synthesized by a palladium-catalyzed cross-coupling of bromo or iodonitrobenzenes with boronic esters 2, which were prepared from methylated 6- bromobenzo[b]thiophenes2 by halogen-metal exchange and transmetalation. The intermediates esters 2 were not isolated but directly, after evaporation of the ether, coupled in acetone/water using palladium acetate in the presence of sodium hydrogencarbonate. Yields of isolated compounds 1 were about 40%

Synthesis of diarylamines in the benzo[b]thiophene series bearing electron donating or withdrawing groups

The synthesis of diarylamines has attracted a great deal of interest due to their importance in diverse fields as natural biological active products and analogues, photography and materials science. Herein we report the synthesis of diarylamines 1 bearing electron donating or withdrawing groups by palladium catalyzed amination, in good yields (50%-quantitative yield) using two different bases and choosing the right components

QSAR model for predicting radical scavenging activity of di(hetero)arylamines derivatives of benzo[b]thiophenes

A QSAR study was developed in order to model the antioxidant activity, specifically the radical scavenger activity (RSA), of 26 di(hetero)arylamines’ derivatives of benzo[b]thiophenes. The QSAR model was constructed, using the partial least squares projection of latent structures (PLS) method, and its robustness and predictability were verified by internal and external cross-validation methods. A total of 4 molecular descriptors, belonging to RDF (Radial Distribution Function) descriptors (RDF020e and RDF045e) and 2D-autocorrelation descriptors (GATS8p and MATS5e) were selected to build the QSAR model. RDF descriptors seem to relate the presence of electronegative atoms at the inner atmosphere of the compounds to increase RSA. 2D-Autocorrelation descriptors associate the presence of polarizable and electronegative pairs of atoms, at specific topological distance, with the RSA of the compounds. Finally this QSAR model proved to be a useful tool in the prediction of radical scavenger activity of congeneric compounds and will be used to guide the synthesis of new diarylamines in our laboratory

QSAR studies on di(hetero)arylamines derivatives of benzo[b]thiophenes as free radical scavengers

Synthetic antioxidants are widely used in food industry y, but because of toxic and carcinogenic effects revealed by some compounds such as BHA and BHT, their use is being restricted. The pursuit for novel compounds with antioxidant properties gained higher significance, since these compounds may contribute for the prevention of diseases in which free radicals are implicated

Palladium-catalyzed amination of electron-rich or poor benzo[b]thienyl bromides

Recently we have applied the palladium-catalyzed amination to the synthesis of ortho-bromodiarylamincs in the benzo[blthiophene series . Here we describe the application of this methodology to the amination of electron-rich or poor 3-bromobenzo[b}thiophcnes, using the same conditions for both cases

Synthesis and characterization of textile azo dyes derivatives of methoxyphenols

Azo dyes are used extensively in the textile and dyestuff industries and effluents from these industrial processes are usually resistant to biological treatment. Textile azo dyes with bioaccessible groups such as guaiacol (2-methoxyphenol) and 2,6--dimethoxyphenol, for lignin-degrading fungus were synthesized using aminobenzoic and aminosulfonic acids as diazocomponents

Composição química e propriedades antioxidantes de duas espécies silvestres de camomila do Nordeste de Portugal: camomila-alemã e camomila-romana.

Este trabalho teve como objetivo avaliar a composição química e as propriedades antioxidantes de duas espécies de camomila, camomila-alemã (Matricaria recutita) e camomila-romana (Chamaemelum nobile), de forma a comprovar a utilidade do seu uso na medicina tradicional. A composição química das duas espécies foi determinada através da quantificação em açúcares livres (HPLC-RI), ácidos gordos (GC-FID) e tocoferóis (HPLC-fluorescência). A atividade antioxidante foi avaliada através de quatro métodos diferentes: capacidade captadora de radicais DPPH (1,1-difenil-2-picril-hidrazilo), poder redutor, inibição da descoloração do β-caroteno e inibição da peroxidação lipídica em homogeneizados cerebrais de animais pelo ensaio TBARS (espécies reativas do ácido tiobarbitúrico). Assim sendo, este trabalho contribui para a caracterização química das espécies silvestres presentes na flora Transmontana, conferindo-lhe assim um valor acrescentado devido ao potencial antioxidante que apresentam

Radical scavenging activity, lipid peroxidation inhibition and redox profile of aminodiarylamines in the thieno[3,2-b]pyridine series

The reducing properties of diarylamines make them very important as antioxidants, especially as radical scavengers as it has been demonstrated by our and other research groups [1 -3]. Three di(hetero)arylamines were prepared by C- N coupling of the methyl3-amino-6-bromothieno(3,2- b]pyridine-2-carboxylate with bromonitrobenzenes and further reduced to the amino compounds 1a-c (Scheme) (4].FCT for financial support through the NMR Portuguese network (Bruker 400 Avance 111-Univ Minho). To FCT and FEDER-COMPETE/QREN/EU for financial support through the research unities PEstC/ QUI/UI686/2011 and PEst-OE/AGR/UI0690/2011 , the research project PTDC/QUI-QUI/111 060/2009 and the post-Doctoral grant attributed to R.C.C. (SFRH/SPD/68344/201 0) also financed by POPH and FSE

MOLA: a tool for automation of parallel virtual docking using AutoDock Vina in a heterogeneous set of computer clusters

The use of molecular docking lo search large databases of compounds for possible ligands of a protein receptor is usually termed virtual screening and has been successfully applied in several therapeutic programs at the lead discovery stage. However, large scale virtual screening is lime demanding and usually requires dedicated High Performance Computing (H PC) systems

New insights on the effects of formulation type and compositional mixtures over the antioxidant and cytotoxic activities of dietary supplements based-on hepatoprotective plants

Artichoke (A), borututu (B) and milk thistle (M) are included in several supplements to provide beneficial effects. Different formulations (infusions, pills and syrups), as also different proportions of A, B and M (1:1:1, 2:1:1, 1:2:1, 1:1:2) within each formulation were assayed to optimize the desired benefits. The antioxidant activity, anti-hepatocellular carcinoma activity, hepatotoxicity and bioactive compounds contents were evaluated. Syrups tended to be the formulation with highest antioxidant activity and total phenolics and flavonoids content; otherwise, pills were the worst formulation. In what concerns A:B:M ratios, the results did not reveal so pronounced differences. None of the assayed mixtures resulted to be toxic (up to the maximum assayed dose) for liver primary cells (PLP2), but some samples, especially infusions, showed toxicity for the hepatocellular carcinoma cell line (HepG2). With no exception, the mixtures for all formulations gave synergistic effects in antioxidant activity, when compared to the activity of single plants.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011). J.C.M. Barreira and R.C. Calhelha thank FCT, POPH-QREN and FSE for their grants (SFRH/BPD/68344/2010 and SFRH/BPD/72802/2010, respectively). L. Barros thanks “Compromisso para a Ciência 2008” for her contract