Heterociclos 1,2,3-triazólicos: histórico, métodos de preparação, aplicações e atividades farmacológicas

The 1,2,3-triazole, known since the end of 19th century, is a very widely used heterocyclic system present in many synthetic substances and commercial pharmaceutical compounds. In fact, 1,2,3-triazoles show several applications in many areas especially as medicines against many diseases like cancer, AIDS, Parkinson and Alzheimer. Nowadays there is a large variety of known methods to obtain these heterocyclic compounds comprising mainly three synthetic routes. Nevertheless, there is no article that gives an objective overview of the synthetic methods for obtaining these kinds of azoheterocycles. This paper presents a brief history of this class of compounds, and a synthetic discussion concerning the main synthetic methods for its preparation, such as cyclization through hydrazones, concerted cycloadditon [2+3] and pseudopericyclic cyclization - and some others of restricted application, but also important. Finally, this paper also provides a brief overview on pharmacological applications of some 1,2,3-triazoles.

Eficácia do glyphosate e 2,4-d no controle de espécies de trapoerabas (commelina spp.)

The aim of this study was to evaluate the efficacy of glyphosate and 2,4-D for the Commelina benghalensis, Commelina diffusa and Commelina erecta. Three experiments were conducted in a greenhouse in a completely randomized in factorial scheme 3x7+1 (three herbicides x seven periods - hour after application) for two methods for measuring absorption of herbicides (simulated rain and cut the leaves applied), and a control without application, with four replications. The herbicides used were: glyphosate (1,080 g ha(-1)), 2,4-D amine (720 g ha(-1)) and, mixture glyphosate + 2,4-D (720 + 720 g ha(-1)). It was evaluated seven time intervals for washing (simulating rainfall after application) and cut (simulation abortion as a strategy of defense) the leaves applied: 0, 2, 4, 6, 8, 12 and 24 hours after herbicide application (HHA). The minimum period for absorption of glyphosate alone and in mixture with 2,4 -D presented a satisfactory control (> 90.0%) was around 12 HHA to C. benghalensis, C. diffusa and C. erecta, independently of washing or cut the leaves applied. This observed behavior can influence the time required without rain after herbicide application, besides that, the plants aborted part of the stem with injuries to avoid the herbicide translocation, especially when was used the 2,4-D alone. Concluded that glyphosate alone and in mixture with 2,4-D were efficient and that the differences in the control of species may be due to variation of time to absorb the herbicide.

Eficácia do glyphosate e 2,4-D no controle de Commelina villosa

O objetivo do presente trabalho foi avaliar a eficácia de glyphosate e 2,4-D, isolados e em mistura, no controle de Commelina villosa. Foram estudadas duas metodologias de avaliação de absorção de herbicidas em oito intervalos de tempo para a lavagem (simulando chuva após a aplicação) e corte (simulando abortamento, como estratégia de defesa) das folhas: 2, 4, 6, 8, 12, 24 e 48 horas após a aplicação dos herbicidas, além de um tratamento sem lavagem ou corte das folhas, em delineamento experimental inteiramente casualizado com quatro repetições, dispostos em um esquema fatorial 3 x 7 + 1 (três herbicidas x sete períodos - horas após a aplicação). Os herbicidas e doses testados foram: glyphosate (1.440 g ha-1), 2,4-D (720 g ha-1) e a mistura glyphosate + 2,4-D (1.080 + 720 g ha-1). A simulação de chuva interferiu de forma negativa no controle das plantas com o herbicida glyphosate. O controle com o herbicida 2,4-D foi influenciado apenas no período de 2 horas. Os períodos de simulação de chuva não influenciaram no controle das plantas com a mistura de glyphosate + 2,4-D. Para o estudo com corte das folhas tratadas, todos os tratamentos independente do período para corte das folhas foram influenciados de forma negativa no controle, sendo que as plantas apresentaram rebrotas quando tratadas com o herbicida 2,4-D isolado.

Absorption and translocation of 2,4-D in plants of Memora peregrina

The objective of this work was to evaluate absorption and translocation of the herbicide 2,4-D in plants of Memora peregrina. The herbicide 2,4-D was used alone with the formulation DMA 806 BR and associated with the herbicide picloram in the commercial product Padron. Levels of radioactivity on the treated leaves were determined in sample obtained after washing them with methanol and chloroform at different times after the application of the radiolabelled formulation (1, 2, 4, 8, 24, and 48 h). Translocation was evaluated by cutting plants between stem and root. The parts obtained were: root, stem, leaf treated, leaves above the leaf treated, leaves below the leaf treated, and leaf opposite of the leaf treated. These parts were weighted, dried, ground, burnt, and radioactivity in the samples was determined. The results suggest that the translocation of the radioactive herbicide 2,4-D was insignificant in plants of M. peregrina in the two treatments evaluated. Absorption of 14C 2,4-D in the treatment with DMA 806 BR and the mixture of DMA 806 BR plus Padron had the same behavior. These observations explain the inefficient control obtained with this herbicide in plant species under study.

Eficácia do glyphosate e 2,4-d no controle de commelina villosa

The aim of this study was to evaluate the efficacy of glyphosate and 2,4-D alone and in combination, in the control of Commelina villosa. We studied two methodologies for evaluating herbicide absorption in eight time intervals for washing (simulating rainfall after application) and cutting of leaves (simulating abortion as a defense strategy): 2, 4, 6, 8, 12, 24 and 48 hours after herbicide application, and a treatment without washing or cutting the leaves in a completely randomized design with four replications in a 3 x 7 + 1 factorial design (three herbicides x seven periods – hours after application). Herbicides and doses tested were: glyphosate (1,440 g ha-1), 2,4-D (720 g ha-1) and a mixture of glyphosate + 2,4-D (1,080 + 720 g ha-1). The simulation of rain interfered negatively in the plant control with glyphosate. The control with the herbicide 2,4-D was affected only for the period of 2 hours. Periods of rain simulation did not influence the control of plants with a mixture of glyphosate + 2,4-D. For the study with the cutting of treated leaves, all treatments regardless of the period of cutting the leaves were influenced negatively in terms of plant control, the plants showing regrowth when treated with 2,4-D alone.

Hybrid polystyrene based electrospun fibers with spin-crossover properties

We have succeeded in the preparation of electrospun fibers of polystyrene incorporating a metallo-organic polymer of [Fe (II) (4-octadecyl-1,2,4-triazole)3(ClO4)2]n. The obtained fibers have diameters in the range 2–4 µm and show the characteristic spin-crossover transition associated with the metallo-organic polymer. The structure of both, polystyrene and the metallo-organic polymer, in the fibers was also studied.

Coordenação entre as respostas da catalase e da ascorbato peroxidade em folhas de feijão caupi submetidas a diferentes fontes de peróxido de hidrogênio

The plants are often exposed to variations in environmental conditions that may trigger metabolic disturbances leading to a consequent loss in productivity of crops. These stressful conditions usually induce an accumulation of reactive oxygen species (ROS) in the cell, a condition known how oxidative stress. Among these species, hydrogen peroxide (H2O2) is an important molecule involved in numerous signaling mechanisms. The present study aimed to understand the relationship between the different enzymatic mechanisms of elimination of H2O2 by catalase (CAT) and ascorbate peroxidase (APX) in leaf tissues of seedlings of the species Vigna unguiculata L. Walp, under conditions of oxidative stress induced by application of CAT inhibitor, 3-amino-1,2,4-triazole (3-AT), and H2O2 itself on the roots. Three experiments were conducted. The first experiment was performed applying the compound 3-AT (5 mM) during the time (hours). In the second experiment, seedlings were exposed to different concentrations of H2O2 (2.5, 5.0, 7.5, 10 mM) for 48 h. The third strategy included the pre-treatment with H2O2 (2.5 mM) for 24 h, followed by subsequent treatment with the inhibitor 3-AT and recovery control condition. Treatment with 3-AT causes a strong inhibition of CAT activity in leaf tissues accompanied by an increase of activity of APX. However a decrease in oxidative damage to lipids is not observed as indicated by TBARS. It was observed that activity of APX is directly linked to the content of peroxide. Inductions in the activities of CAT and APX were observed mainly in the seedlings treated with 2.5 mM H2O2. This can be associated with a decrease in oxidative damage to lipids. In contrast, one same tendency was not observed in treatments with higher concentrations of this ROS. These results suggest that the concentration of 2.5 mM H2O2 can induce responses antioxidants later in seedling cowpea. This concentration when applied as pre-treatment for 24 h promoted an induction systems removers CAT and APX, both in activity and in terms of gene expression. However this increment was not observed in the recovered plants and the plants subsequently subjected to 3-AT. Additionally, the pretreatment was not sufficient to attenuate the inhibition of CAT activity and oxidative damage to lipids caused by the subsequent application of this inhibitor. The results showed that the application of 3-AT and H2O2 in the root systems of seedlings of cowpea promote changes in the parameters analyzed in leaf tissues that indicate a direct response to the presence of these factors or systemic signaling mecanisms. H2O2 appears to activate the responses of two antioxidant systems in this study thar does not promote greater protection in case of additional treatment with 3-AT. This demonstrates the importance of the CAT system. In this work, complete results indicate that there is a difference between the signaling and the effects caused by exposure to H2O2 and by treatment with 3-AT

Preparation, characterization, and CuX2 and CoX2 (X = Cl-, Br-, ClO4-) adsorption behavior of a polyhedral oligomer silsesquioxane functionalized with an organic base

In this paper we report on the synthesis, characterization, and adsorption properties of the first 3-amino-1,2,4-triazole-modified porous silsesquioxane (ATPS). The isotherms of adsorption of MX2 (M = Cu(II), Co(II); X = Cl-, Br-, ClO4-) by ATPS were studied in ethanol and aqueous solutions at 298 K. The results showed that there is a good fit between the experimental data and the Langmuir isotherm. The adsorption capacity in both solvents followed the sequence Cu(II) >> Co(II). The lowest adsorption for Co(II) should be related to the largest hydration volume, which obstructs the adsorption capacity of the surface, and consequently causes a decrease in the number of cations adsorbed. For the salts with different anions the sequence was MCl2 > MBr2 > M(ClO4)2 in both solvents. The low affinity for M(ClO4)(2) toward the solid phase is a consequence of the poorer coordination ability of the ClO4-. Adsorptions from ethanol solutions were higher than those from aqueous solutions due to the higher polarity of water, which can more strongly solvate the solute and the basic sites on the surface. The following adsorption capacities (in mmol g(-1)) were determined: 0.24 (aq) and 0.84 (eth) for CuCl2, 0.09 (aq) and 0.16 (eth) for CuBr2, and 0.08 (aq) and 0.11 (eth) for Cu(ClO4)(2); 0.02 (aq) and 0.07 (eth) for CoCl2, 0.02 (aq) and 0.06 (eth) for CoBr2, and 0.01 (aq) and 0.05 (eth) for Co(ClO4)(2). (c) 2007 Elsevier B.V. All rights reserved.

Structure of copper(II) complexes adsorbed on functionalized polyhedral oligomeric silsesquioxane

The 3-amino-1,2,4-triazole-modified silsesquioxane nanoplatforms have been prepared and characterized. The silsesquioxane nanocages readily react with CuX(2) in aqueous solution to form copper complex-substituted silsesquioxanes. Adsorption isotherms of CuX(2) from aqueous solution were studied at 25 degrees C. The electronic and ESR spectral parameters indicated that the copper ion is in a distorted-tetragonal symmetry field. (C) 2007 Elsevier B.V. All rights reserved.

Adsorption of transition-metal ions in ethanol solution by a nanomaterial based on modified silsesquioxane

The material octakis[3-(3-amino- 1,2,4-triazole)propyl]octasilsesquioxane (ATZ-SSQ) was synthesized and its potential was assessed for Cu(II), Ni(II), Co(II), Zn(II) and Fe(III) from their ethanol solutions and compared with related 3-amino-1,2,4-triazole-propyl modified silica gel (ATZ-SG). The adsorption was performed using a batchwise process and both organofunctionalized surfaces showed the ability to adsorb the metal ions from ethanol solution. The Langmuir model allowed to describe the sorption of the metal ions on ATZ-SSQ and ATTZ-SG in a satisfactory way. The equilibrium is reached very quickly Q min) for ATZ-SSQ, indicating that the adsorption sites are well exposed. The maximum metal ion uptake values for Cu(II), Co(II), Zn(II), Ni(II) and Fe(III) were 0.86, 0.09, 0.19, 0.09 and 0.10 mmol g(-1), respectively, for the ATZ-SSQ, which were higher than the corresponding values 0.21, 0.04, 0.14, 0.05 and 0.07 mmol g(-1) achieved with the ATZ-SG. In order to obtain more information on the metal-ligand interaction of the complexes on the surface of the ATZ-SSQ, Cu(II) was used as a probe to determine the arrangements of the ligands around the central metal ion by electron spin resonance (ESR). The ATZ-SSQ was used for the separation and determination (in flow using a column technique) of the metal ions present in commercial ethanol. (c) 2008 Elsevier B.V. All rights reserved.

Sidestream cigarette smoke effects on cardiovascular responses in conscious rats: involvement of oxidative stress in the fourth cerebral ventricle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cardiovascular responses to hydrogen peroxide into the nucleus tractus solitarius

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inhibition of central angiotensin II-induced pressor responses by hydrogen peroxide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Endogenous hydrogen peroxide in the hypothalamic paraventricular nucleus regulates sympathetic nerve activity responses to L-glutamate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of the administration of a catalase inhibitor into the fourth cerebral ventricle on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke

OBJECTIVE: ,,,,,Previous studies have demonstrated a relationship between brain oxidative stress and cardiovascular regulation. We evaluated the effects of central catalase inhibition on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke. ,,,, ,,,, ,,,,,METHODS: ,,,,,Male Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SH) (16 weeks old) were implanted with a stainless steel guide cannula leading into the fourth cerebral ventricle (4th V). The femoral artery and vein were cannulated for arterial pressure and heart rate measurement and drug infusion, respectively. The rats were exposed to sidestream cigarette smoke for 180 minutes/day, 5 days/week for 3 weeks (CO: 100-300 ppm). The baroreflex was tested using a pressor dose of phenylephrine (8 μg/kg, bolus) and a depressor dose of sodium nitroprusside (50 μg/kg, bolus). Cardiovascular responses were evaluated before and 5, 15, 30 and 60 minutes after injection of a catalase inhibitor (3-amino-1,2,4-triazole, 0.001 g/100 μL) into the 4th V. ,,,, ,,,, ,,,,,RESULTS: ,,,,,Vehicle administration into the 4th V did not affect the cardiovascular response, whereas administration of the central catalase inhibitor increased the basal HR and attenuated the bradycardic peak (p<0.05) to a greater extent in WKY rats exposed to sidestream cigarette smoke than in WKY rats exposed to fresh air. However, in spontaneously hypertensive rats, the effect of the catalase inhibitor treatment was stronger in the fresh air condition (p<0.05). ,,,, ,,,, ,,,,,CONCLUSION: ,,,,,Administration of a catalase inhibitor into the 4th V combined with exposure to sidestream cigarette smoke has a stronger effect in WKY rats than in SH rats.