Tandem palladium-catalyzed borylation and Suzuki coupling (BSC) to thienocarbazole precursors

Substituted 2-methyl-2 -nitro diaryl compounds in the benzo[b]thiophene series were prepared by palladium-catalyzed, two-step, one-pot borylation/Suzuki coupling (BSC) reaction in good to high yields. The borylation reaction was performed on methylated 6-bromobenzo[b]thiophenes using pinacolborane and was followed by in situ Suzuki coupling with substituted (CF3, OMe) 2-bromonitrobenzenes. The compounds obtained were cyclized to the corresponding ring A substituted thienocarbazoles which can have biological activity or/and be used as biomarkers due to their fluorescence properties and possible DNA intercalation.Thanks are due to the Foundation for Science and Technology, IBQF, University of Minho (Portugal), to the Research Incitment Programme of the Calouste Gulbenkian Foundation (Portugal) for financial support and to the Escola Superior Agra ´ria, Instituto Polite ´cnico de Braganc ¸a for supporting in part I.C.F.R.F. (Ph.D.).info:eu-repo/semantics/publishedVersio

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

Screening of antimicrobial activity of diarylamines in the 2,3,5-trimethylbenzo[b]thiophene series : a structure-activity evaluation study

Gram positive (Bacillus cereus, Bacillus subtilis), Gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria and Candida albicans as a representative of fungi were used for screening the in vitro antimicrobial activity of diarylamines in the 2,3,5-trimethyl benzo[b]thiophene series bearing different substituents, synthesised by us using the palladium-catalyzed C-N coupling methodology. The minimal inhibitory concentration (MIC) and structure-activity relationships (SARs) were evaluated.Fundação Calouste Gulbenkian. Fundação para a Ciência e Tecnologia

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

Lipid peroxidation inhibition, free radical scavenging activity and electrochemical behaviour of a dihydroxylated di(hetero)arylamine

The skin provides the first line of defense against oxidative damage induced by environmental factors, having an elaborated antioxidant system designed to deal with free radicals and oxidative stress. However, under severe stress conditions this biological response is not sufficient, leading to oxidative damage and, in consequence, to skin disorders, immunosuppresion, premature skin aging and ultimately cancer