The resistance of weeds is a problem which can be overcome by finding new herbicides. For this purpose, beyond the experimental methods, in silico approaches can be helpful, as a starting point. In this regard, pharmacophore mapping and 3D-QSAR studies were carried out on several series of herbicide, already known to act on the Photosystem II (PS II) D1 protein. Using PHASE software, three pharmacophore features, H-bond acceptor (A), hydrophobic (H) and aromatic ring (R) were taken into account to be the best hypothesis. For this hypothesis an atom-based 3D-QSAR model was generated with statistically significant parameters (the correlation coefficient of regression (R²) of 0.839, the standard error of estimates (SD) of 0.370, the Fisher test (F) of 53.7 for the training set, the external explained variance Q² = 0.640, the Pearson-R = 0.916 and Root Mean Square Error (RMSE) = 0.572, for the test set). This hypothesis, validated by the 3D atom-based QSAR approach, assures the selection of novel scaffolds of herbicide derivatives and can be used for the design of new chemical entities active on the PS II D1 protein.

ILs commercialization has exponentially increased in recent years because of their very different industrial utilities. Tetrafluoroborate 1-butyl-3-methylimidazolium [BMIM][BF₄] is a widely used ionic liquid in different applications. However, the number of studies about the toxic effects of [BMIM][BF₄] on the environment is very limited, especially for soils. This is striking since terrestrial ecosystems would be the first to be reached by this compound as a result of any possible accidental spill. Soil biochemical properties, and particularly the enzymatic activities, are very sensitive parameters to detect any perturbation in soil functioning. Among all the enzymes, the urease is one of the most widely used because it is highly sensitive to the presence of different exogenous agents. In this study, we carried out laboratory experiments with two soils of contrasting pH to adjust the parameters and experimental conditions of the method to determine urease activity in soils spiked with [BMIM][BF₄].

Ligands containing azole rings are interesting as ligands for coordination chemistry, especially as building blocks for metal-organic frameworks. Adamantane can serve as a rigid linker for the construction of multidentate ligands. In this work we describe the synthesis of 3-azolyl-1-adamantanecaroboxylic acid derivatives starting from 3-bromo-1-adamantanecaroboxylic acid and the corresponding azoles (pyrazole, imidazole, 1,2,4-triazole, benzimidazole, 1,2,3-benzotriazole). The structure of products was confirmed by NMR and mass-spectrometry.

A series of nine new 1,5-disubstituted-1H-tetrazoles were synthesized via MCR Ugi-azide in moderate to excellent yields (80 - 95%), using propargyl amine as component varying the aldehyde and isocyanide components. 1,5-DS-T are useful heterocyclic moieties present in many bioactive compounds and drugs. Morever 1,5-DS-T are used as bidentate ligands, in coordination chemistry, metal-organic framework science, bioimaging, photo-imaging, explosives, propellants, high energy materials.

Liquid temperature range of two ionic liquids (ILs) with the common cation, Choline, is determined in this work. The selected ILs are Choline tosylate [Chol][Tos] and Choline dicyanamide [Chol] [DCN].

The lower limit of liquid range is given by solid-liquid transitions and it is determined using differential scanning calorimetry (DSC) [1]. Upper limit is given by degradation temperature which is determined using the thermogravimetric technique (TGA) [2]. Dynamic and isothermal methods have been combined to estimate the maximum operation temperature.

Additionally, a deeper study of the effect of the heating and cooling rate on the temperature and shape of the transitions observed in DSC curves of [Chol] [DCN] was performed.

A common trend has been observed for melting and degradation temperatures of selected liquids:

[Chol][DCN]< [Chol][Tos]

 

Acknowledgments

This study was financed by the project EM2013/031 (Xunta de Galicia, Spain) and the network REGALIS R2014/015 (Xunta de Galicia, Spain).

 

References

[1] M. Villanueva, J. J. Parajó, P.B. Sánchez, J. García, J. Salgado, J. Chem. Thermodyn. 91, 127 (2015).

[2] J. Salgado, J. J. Parajó, J. Fernández, M. Villanueva, J. Chem. Thermodyn. 74, 51(2014).

Some novel 1,4,5,2-oxadiazaphosphinines, 1,3,2-benzoxazaphosphinines and α-hydrazino-phosphonic acid bearing a chromone ring have been obtained from reaction of 2-hydroxy-N^`-[(4-oxo-4H-chromen-3-yl)methylidene]benzohydrazide (2) with some phosphorus reagents such as phosphonic acid and its diesters, phosphorus sulfides and phosphorus halides in dry dioxane. The compounds were evaluated for their anticancer activities and on the expression of VEGF inhibition. Among the synthesized compounds, compounds 3 and 7 exhibited high effect against breast cancer cells MCF-7 in comparison with the standard drug and on the expression of VEGF inhibition.

1,3-alkyl-imidazolium-based ionic liquids show a wide range of applications from use as a "designer solvent", in catalysis^1-3 up to material science^4-6. The interaction between cation and anion can be investigated by analyzing the crystal structure.⁷ In our work, we synthesized various 1,3-functionalized imidazolium and choline based Ils for the use as drying agent in sorption systems. Here especially substances with organic anion such as acetate, lactate and formate were quiet interesting because they expected, among other beneficial properties, a low melting point and a strongly pronounced hygroscopic behavior. However, the purification of the synthesized compounds showed a number of previously unknown crystal structures which offers interesting thermodynamic aspects, as well as the interaction of cations and anions could be examined. In addition, the crystal structure data provided the molecular volume of the ions, which is used to predict thermodynamic aspects.

1. P. Wasserscheid and W. Keim, Angew. Chem. Int. Ed., 2000, 39, 3772-3789.
2. S. Peleteiro, S. Rivas, J. L. Alonso, V. Santos and J. C. Parajó, Bioresour. Technol., 2016, 202, 181-191.
3. H.-P. Steinrück and P. Wasserscheid, Catal. Lett., 2014, 145, 380-397.
4. Y. Chen, Y. Cao and T. Mu, Chem. Eng. Technol., 2014, 37, 527-534.
5. P. Wasserscheid and M. Seiler, ChemSusChem, 2011, 4, 459-463.
6. S. Herrmann, M. Kostrzewa, A. Wierschem and C. Streb, Angew. Chem., 2014, 126, 13814-13817.
7. T. Brünig, K. Krekić, C. Bruhn and R. Pietschnig, Chem. Eur. J., 2016, DOI: 10.1002/chem.201602723, n/a-n/a.

Xanthones and dihydroxanthones are important mycotoxin-related compounds present in many plants, fungi and lichens, and have been demonstrated to be able to interact with different biological targets. But their synthesis are tedious and through a multistep procedures. We have developed a one pot application for the synthesis of this kind of products with up to 4 diversification structural positions.

Starting from easily available 3-carbonylchromones¹, isocyanides and different dienophiles we have teamed up to obtain Xanthones and dihydroxanthones in a one pot tandem procedure through a [4 + 1]−[4 + 2] cycloaddition leading these complex structures. This synthesis efficiently affords a variety of both monomeric and dimeric polysubstituted dihydroxanthones structurally similar to bioactive ergochromes.²

 

                (1)          Bornadiego, A.; Diaz, J.; Marcos, C. F. Adv Synth Catal 2014, 356, 718.

                (2)          Bornadiego, A.; Diaz, J.; Marcos, C. F. J Org Chem 2015, 80, 6165.

 

Natural polyphenols and their derivatives from diet have been reported by their pro-oxidant and clastogenic activities. In an aim of elucidating structural alerts for this genotoxicity endpoint, a QSTR study was conducted under the TOPS-MODE approach. It was possible to establish structural alerts from the DNA oxidative damage as an endpoint of clastogenicity at optimum leaders with high probability of being clastogenic. Some important fragments to obviate this activity were also identified. The results constitute a reference system for designing new food or pharmaceutical matrices as an alternative to the experimental toxicology.

Synthesis of a novel 1,3,5-triazine derivatives, starting from cyanuric chloride, is reported. Target structural motives are involved in the s-triazine skeleton via substitution of chlorine atoms by amino group in various aminobenzensulfonamides, piperazines, amino alcoholes and other amino compounds. It was found that substitution of the chlorine atoms of cyanuric chloride can be carried out as C-N coupling catalyzed by Cu(I) supported on weakly acidic macroporous cation exchanger resin of polyacrylate type via the oxidative addition - heterolytic addition - reductive elimination processes. The reaction could proceed as a one-pot/ one-step synthetic process that is carried out under temperature control. Higher and excellent yields with shorter reaction times in comparison with similar usual syntheses realized step by step were obtained. Synthetic procedures optimized by this way can be applied in the preparation of the further various s-triazine with respect to the chemical behaviour of the individual nucleophilic reagents.