A head-to-head dimer of cholic acid linked at C3 carbon atoms by a urea bridge was synthesized and the crystal structure was studied. The crystal belongs to the monoclinic crystal system, space group I₂. The packing shows a bilayer structure with alternating hydrophobic and hydrophilic layers. The horizontal and vertical planes of the two cholic residues are almost parallel to each other, the vertical ones being perpendicular to the bilayers. The hydrogen bond network is two-dimensional as it does not propagate in the direction perpendicular to the bilayers. It is noteworthy that the nitrogen atoms of the urea bridge do not participate in that network. The carbonyl urea group and only one of the ester of the two side chains form hydrogen bonds with two other dimers through the steroid hydroxy O7-H and O12-H groups. This means that each dimer forms eight hydrogen bonds but only four are different.

The thiazolidinones and correlated motifs have high biological relevance since they are present in both natural products and pharmaceutical compounds.Microwave irradiation is an alternative heating method based on the ability of some compounds to transform electromagnetic energy into heat. This method, which increases chemical reaction rates and forms cleaner products, can be successfully applied in pharmaceutical chemistry.We present here the study of selective synthesis of 1,3-thiazolidin-4-ones via microwave-assisted multi-component reaction under solvent-free conditions. Although, theoretically two different products are possible (benzothiazepinones 4 and thiazolidinones 5), the reaction yielded only two diasteroisomers of 1,3-thiazolidin-4-ones (48-97%)in the three-component reaction between 2,3 : 4,5-di-O-isopropiliden-β-D-arabino-hexos-2-ulo-2,6-piranosa 1, different heteroaromatics anilines 3 and mercaptoacetic acid 2 (Scheme 1). The synthesized compounds were characterized by IR, 1H-, 13C y DEPT and HSQC - RMN. The stereochemistry of both the diasteroisomers was elucidated with the help of NOE experiments.

The genus Lippia (Verbenaceae) is represented in Argentina by 31 species. Many of these species are traditionally used as medicinal plants or for culinary purposes. A wide range of biological activities has been reported for plants belonging to this genus. Lippia salsa Griseb. is an endemic species from Argentina that has been scarcely studied. As part of our continuing investigation of natural products as leads for inhibiting acetylcholinesterase (AChE), an enzyme relevant for the treatment of Alzheimer's disease (AD), L. salsa was selected based on the results of a screening of AChE inhibition. The ethanolic extract obtained from the aerial parts elicited an interesting enzymatic activity with an IC50 value of 0.89 mg/ml, determined by Ellman's method. A bioassay-guided fractionation of this extract led to a semi-purified fraction with higher AChE inhibition (79.2% at 0.45 mg/ml). From this active fraction two known flavones, apigenin and luteolin, have been isolated and identified, so far. Since the ability of these flavones to inhibit cholinesterase has already been proven, it is reasonable to think that the AChE inhibition observed for L. salsa can be, at least in part, attributed to these metabolites. Apigenin and luteolin are reported here for the first time in this species. Apigenin has gained particular interests in recent years as a beneficial and health promoting agent due to its low intrinsic toxicity. On the other hand, luteolin has been identified as a potent inhibitor of Aβ fibrils, strongly implicated in AD pathology and the neurotoxicity observed with this disease. These observations suggest that L. salsa can be a source of potential multi-targets agents against AD.

The development of colorimetric chemosensors is an area in great expansion due to the simplicity of assay and lower cost compared with others sensing methods. Sensing devices for the analysis of toxic or heavy metal ions play an important role in clinical toxicology, environmental, bioorganic chemistry, bioremediation, and waste management. Until now, most of the chemosensors developed involve laborious and expensive procedures and there is an interest in strategies for single step synthesis, optimizing the efficiency of the chemical reaction and avoiding time-consuming processes of separation and purification. Therefore, the development of a small molecule-based colorimetric chemosensors with simple synthetic and isolation procedures has received much attention in the last decade. The current interest in azine derivatives arises from their wide range of applications in diverse areas such as material and environmental sciences, biomedical, analytical, supramolecular chemistry and catalysis. Additionally, azine ligands bearing N, O and S heteroatoms in their structure should exhibit improved coordination ability. Following our previous work, azine ligands functionalized with heterocycles such as thiophene L1, pyrrole L2 and furan L3, were used in a cation chemosensory study in ACN and ACN-water mixtures. L2 exhibited a selective and high sensitive colorimetric response in the presence of Hg(II) and Pd(II) (colourless to yellow or colourless to orange, respectively).Acknowledgements: thanks are due to FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the research center, CQ/UM [PEst-C/QUI/UI0686/2013 (F-COMP-01-0124-FEDER-037302). FCT is also acknowledged for financial support to the NMR Portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho) and for the post-doctoral grant of R.M.F. Batista (SFRH/BPD/79333/2011). We are also grateful to the Instituto da Educação of Universidade do Minho for providing the laboratory infrastructure necessary for the development of this work.

supercapacitiveperformances of carbon nanotube (CNT) based electrodes, before and afterelectrochemical deposition of polyaniline (PANI) were compared. The PANImodified CNT/Nickel foam based electrodes were compared with the bare carbonnanotubes/Ni foam based electrodes. The modified electrode prepared by coatingCNT based electrodes which were directly grown on a Ni-foam framework by aChemical Vapor deposition (CVD) technique. The PANI modified electrode exhibitsbetter capacitive performance and lower internal resistance than the bareCNT/Ni foam electrode. The specific capacitance of this CNT/PANI based electrodeis 70 F/g which is 37 percent higher than the value of the CNT/Nifoam electrode before deposition of PANI. This work proposes that modificationCNTs with PANI is a simple, effective and economical approach for preparing asuitable supercapacitor electrode which possess enhanced capacitance and rateperformance.

Herein, we report an efficient and facile synthesis of a new triptycene based tripodal ligand containing both imine functionality and phenolic pendant arms. This tripodal unit is a potential building block for constructing novel supramolecular architectures. The newly synthesized 2,6,14-triaminotriptycene derivative, which was characterized by FT-IR, UV−Vis absorption, mass and NMR spectroscopic techniques has interesting properties such as high solubility in common organic solvents and fluorescence emission in THF solution (λ = 550 nm).

Hybridization of nucleic acids is considered the cornerstone for many biomedical applications as antigene and antisense. Recently, much effort has been devoted to regulation nucleic acid hybridization using external stimuli as light. Azobenzene, photochromic molecule, has been widely used for photoregulation of nucleic acid through geometrical structural change from trans to cis isomer and reverse with response of optical excitation with light at suitable wavelength. Despite the efficiency of azobenzenes in reversible photoswitching of nucleic acid-related activities, there are some drawbacks arising from the non-nucleosidic nature of the attached azobenzen. 4-(dimethylamino)azobenzene-4'-carboxylic acid (DABCYL), universal quencher, one of azobenzene derivatives that widely used as a quencher for nucleic acid detection using fluorescent probes technique. Here we report the synthesis of novel azo-based uracil derivatives that may have the potential dual-purposes as photo trigger and/or as a quencher that mimics the structure of the universal quencher DABCYL. The modified uracil is designed to have 4-(dimethylamino)phenylazo moiety at C5 position because of at this position there is no interference with the hydrogen bonding sites of uracil and therefore retain the base pairing ability with adenine.

A novel and simple strategy for the synthesis of N-vinylazoles has been developed starting from vinyl selenones. This reaction occurs via aza-Michael addition/elimination cascade. This method is applicable to a wide range of vinyl selenones and mono and di-azoles. N-vinylazoles were obtained in good yields under mild reaction conditions. They are important building blocks in organic synthesis and also key structural motif in medicinal chemistry. Moreover, N-vinylazoles have been shown to serve as monomers for the synthesis of poly(N-vinylazoles).

Hygrophila spinosa T. Anders (Acanthaceae) is traditionally used in Indian medicine for the treatment of microbial infections, liver diseases, cancer, inflammation, rheumatism, diabetes, pain, fever etc. The aim of the present study is to evaluate the anti-inflammatory activity of chloroform and alcoholic extracts of the leaves of H. spinosa in chronic inflammation models in rats as our previous study revealed that these two extracts had anti-inflammatory activity in carrageenan induced paw oedema model. Anti-inflammatory activity was evaluated by cotton pellet-induced granuloma and Freund's adjuvant-induced arthritis in rats. Antioxidant activity of the extracts was revealed by their scavenging activity of the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and a flavonoid compound (apigenin) was also isolated and characterized from the alcoholic extract of the plant. Chloroform and alcoholic extracts showed anti-inflammatory activity both in cotton pellet-induced granuloma and Freund's adjuvant-induced arthritis in a dose dependent manner. The decrease in body weight due to injection of CFA was improved significantly by the above two extracts also. Both the extracts also exhibited antioxidant activity. The results demonstrated that H. spinosa has anti-inflammatory activity in chronic models of inflammation which support the traditional use of H. spinosa in the treatment of rheumatism.

Present work is a continuation of our previous research done in the field of transformation reaction of isothiuronium salts derived from various lactones and lactames giving substituted 2-iminothiazolidin-4-ones or 2-aminothiazolin-4-ones. These compounds are known e.g. for their significant biological activity but they do not possess any fluorescence behaviour. On the other hand some substituted 1,3-thiazol-4-oles are good fluorophores in solutions and sometimes also in solid state. It is also known that the presence of some ionizable groups (OH, NH2 etc.) can significantly affect the shift of their UV absorption/fluorescence band. Therefore we have prepared a new set of substituted 5-(2-hydroxyphenyl)-1,3-thiazol-4-oles and studied their spectral properties under various conditions.