Study of copper complexes absorbed on a silica gel surface chemically modified with 5-amino-1,3,4-thiadiazole-2-thiol

The isotherms of adsorption of CuX2 (XCl-, Br-, ClO4-) by silica gel chemically modified with 5-amino-1,3,4-thiadiazole-2-thiol were studied in acetone and ethanol solutions, at 25 degrees C. The following equilibria constants (in L mol(-1)) were determined: (a) CuCl2, 3.2 x 10(3) (ac), 2.5 x 10(3) (eth); (b) CuBr2, 2.9 x 10(3) (ac), 2.3 x 10(3) (eth); (c) Cu(ClO4)(2), 1.8 x 10(3) (ac), 1.2 x 10(3) (eth); ac, acetone; eth, ethanol. The electron spin resonance spectra of the surface complexes indicated a tetragonal-distorted structure in the case of lower degrees of metal loading on the chemically modified surface. The d-d electronic transition spectra showed that for the ClO4- complex, the peak of absorption did not change for any degree of metal loading and for Cl- and Br- complexes, the peak maxima shifted to higher energy with lower metal loadings. (C) 1998 Academic Press.

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.

The 2:1 cycloadducts from [3+2] 1,3-dipolar cycloaddition of nitrile oxide and vinylacetic acid. Synthesis and liquid crystal behaviour

Four liquid crystals (LC) 3,7a-bis(4-alkyloxyphenyl)-7,7a-dihydro-6H-isoxazolo[2,3-d][1,2,4]oxadiazol-6-yl)acetic acid (7a-d) were synthesised and the mesomorphic behaviour reported. The LCs were characterised as 2: 1 bisadducts, which were obtained from a double [3+2] 1,3-dipolar cycloaddition. In the first step, the cycloaddition of 4-alkyloxyphenylnitrile oxide (4a-d) and vinylacetic acid (5) gave the initial unobserved 1:1 cycloadducts 2-[3-(4-alkyloxyphenyl)-4,5-dihydroisoxazol-5-yl]acetic acid (6a-d). In the second step, the addition of a second equivalent of 4 to 6 yielded the 2: 1 bisadducts 7a-d without any traces of 6. All compounds 7a-d were unstable during the transition from the mesophase to the isotropic state upon first heating as evidenced by the large peaks in the differential scanning calorimetry traces. Due to the chemical instability of the compounds upon heating, the transition temperature related to the smectic C to smectic A transitions was acquired by means of an image processing method. X-Ray diffraction experiments were also used to analyse the liquid-crystalline phases. A theoretical calculation was performed using density functional theory (DFT) methods at the PBE1PBE/6-311+G(2d,p) level (with solvent effect) in order to get information about the energetic profile of the 2: 1 cycloaddition. DFT studies revealed that the cycloaddition process is controlled by the HOMO(dipolarophile) - LUMO(1,3-dipole), and that the double [3+2] 1,3-dipolar cycloaddition reaction is quite possible.

Reduction in the level of Gal(alpha1,3)Gal in transgenic mice and pigs by the expression of an alpha(1,2)fucosyltransferase.

Hyperacute rejection of a porcine organ by higher primates is initiated by the binding of xenoreactive natural antibodies of the recipient to blood vessels in the graft leading to complement activation. The majority of these antibodies recognize the carbohydrate structure Gal(alphal,3)Gal (gal epitope) present on cells of pigs. It is possible that the removal or lowering of the number of gal epitopes on the graft endothelium could prevent hyperacute rejection. The Gal(alpha1,3) Gal structure is formed by the enzyme Galbeta1,4GlcNAc3-alpha-D-galactosyltransferase [alpha(1,3)GT; EC 2.4.1.51], which transfers a galactose molecule to terminal N-acetyllactosamine (N-lac) present on various glycoproteins and glycolipids. The N-lac structure might be utilized as an acceptor by other glycosyltransferases such as Galbeta1,4GlcNAc 6-alpha-D-sialyltransferase [alpha(2,6)ST], Galbeta1,4GlcNAc 3-alpha-D-Sialyltransferase [alpha(2,3)ST], or Galbeta 2-alpha-L-fucosyltransferase [alpha(1,2)FT; EC 2.4.1.691, etc. In this report we describe the competition between alpha(1,2)FT and alpha(1,3)GT in cells in culture and the generation of transgenic mice and transgenic pigs that express alpha(1,2)Fr leading to synthesis of Fucalpha,2Galbeta- (H antigen) and a concomitant decrease in the level of Gal(alpha1,3)Gal. As predicted, this resulted in reduced binding of xenoreactive natural antibodies to endothelial cells of transgenic mice and protection from complement mediated lysis.

Synthesis and evaluation of N-(3-oxo-2,3-dihydro-1H-pyrazol-4-yl)-1H-indole-carboxamides as cholecystokinin antagonists

The structure-activity relationship optimization of the pyrazoline template 3a resulted in novel 3-oxo-1,2-diphenyl-2,3-dihydro-1H-pyrazol-4-yl)-indole carboxamides 4a-4e. These non-peptidal CCK ligands have been shown to act as potent CCK 1 ligands in a [125]I-CCK-8 receptor binding assay. The best amides (4c and 4d) of this series displayed an IC50 of 20/25 CCK 1 for the CCK 1 receptor. In a subsequent in-vivo evaluation using various behaviour pharmacological assays, an anxiolytic effect of these novel 3-oxo-1,2-diphenyl-2,3-dihydro-1H-pyrazol-4-yl)-indole carboxamides was found at high doses in the elevated plus-maze. In the despair swimming test, a model for testing antidepressants, an ED50 of 0.33/0.41 mg kg -1 was determined for amide 4c/4d and the antidepressant effect had a magnitude comparable to desimipramine. © 2006 The Authors.

(E)-2-[2-(2-Aminofenil)vinil]-1-metilquinolin-4(1H)-ona como precursor de novos compostos heterociclicos

Esta dissertação reporta a síntese de novos derivados de 4-quinolonas com potencial atividade biológica e está dividida em 3 capítulos. No primeiro capítulo é feita uma breve introdução aos compostos do tipo 4quinolona, azepina e indol, focando a nomenclatura, atividade biológica e métodos de síntese mais comuns deste tipo de compostos, e é apresentada a nomenclatura dos compostos sintetizados ao longo deste trabalho. No segundo capítulo são descritas as metodologias desenvolvidas para obtenção dos compostos pretendidos. Foram sintetizados novos derivados de 4-quinolonas via reações de N-metilação seguida de ciclização in situ da (E)-N(2-acetilfenil)-3-(2-nitrofenil)acrilamida, via reações de redução da 1-metil-2-[2(2-nitrofenil)vinil]quinolin-4(1H)-ona e reações de halogenação da 1-metil-2-[2(2-nitrofenil)vinil]quinolin-4(1H)-ona e da 2-[2-(2-aminofenil)vinil]-1metilquinolin-4(1H)-ona. Posteriormente, fizeram-se estudos de reatividade da 1-metil-2-[2-(2-nitrofenil)vinil]quinolin-4(1H)-ona e da 2-[2-(2-aminofenil)vinil]-3bromo-1-metilquinolin-4(1H)-ona. Na reação de redução in situ seguida de ciclização intramolecular da 1-metil-2-[2-(2-nitrofenil)vinil]quinolin-4(1H)-ona obteve-se a 2-(1H-indol-2-il)-1-metilquinolin-4(1H)-ona. Partindo da 2-[2-(2aminofenil)vinil]-3-bromo-1-metilquinolin-4(1H)-ona via reações de BuchwaldHartwig obteve-se a 11-metil-5H-benzo[6,7]azepino[3,2-b]quinolin-6(11H)-ona. Novas N-[2-(2-(3-bromo-1-metil-4-oxo-1,4-di-hidroquinolin-2il)vinil)fenil]alquilamidas foram obtidas via reações de acilação da 2-[2-(2aminofenil)vinil]-3-bromo-1-metilquinolin-4(1H)-ona em piridina seca usando diferentes cloretos de acilo. Numa tentativa de ciclização intramolecular da N[2-(2-(3-bromo-1-metil-4-oxo-1,4-di-hidroquinolin-2-il)vinil)fenil]-hexanamida via reação de Ullmann intramolecular foi obtida a 2-(1-hexanoil-1H-indol-2-il)-1metilquinolin-4(1H)-ona. Após a descrição detalhada das metodologias de síntese são apresentadas as principais conclusões deste trabalho e perspectivas futuras. Por último, no terceiro capítulo, são apresentados os procedimentos experimentais usados para obtenção dos compostos sintetizados e os dados relativos à sua caracterização estrutural, que foi sendo discutida ao longo do segundo capítulo. Os compostos sintetizados foram caracterizados por espetroscopia de ressonância magnética nuclear monodimensional (1H e 13C) e bidimensional (HSQC, HMBC) e por espetrometria de massa e sempre que possível por espetrometria de massa de alta resolução.

Crystallization and preliminary X-ray diffraction analysis of recombinant chlorocatechol 1,2-dioxygenase from Pseudomonas putida

Chlorocatechol 1,2-dioxygenase from the Gram-negative bacterium Pseudomonas putida (Pp 1,2-CCD) is considered to be an important biotechnological tool owing to its ability to process a broad spectrum of organic pollutants. In the current work, the crystallization, crystallographic characterization and phasing of the recombinant Pp 1,2-CCD enzyme are described. Reddish-brown crystals were obtained in the presence of polyethylene glycol and magnesium acetate by utilizing the vapour-diffusion technique in sitting drops. Crystal dehydration was the key step in obtaining data sets, which were collected on the D03B-MX2 beamline at the CNPEM/MCT - LNLS using a MAR CCD detector. Pp 1,2-CCD crystals belonged to space group P6(1)22 and the crystallographic structure of Pp 1,2-CCD has been solved by the MR-SAD technique using Fe atoms as scattering centres and the coordinates of 3-chlorocatechol 1,2-dioxygenase from Rhodococcus opacus (PDB entry 2boy) as the search model. The initial model, which contains three molecules in the asymmetric unit, has been refined to 3.4 A resolution.

Quinolizine-2,4-diones by reversible dimerisation 2-pyridylketenes

Quinolizine-2,4-diones 11 are obtained by ash vacuum thermolysis (FVT) of 3-acyl-1,2,3-triazolo[1,5-a]pyridines 7. The reaction takes place via methyl- and phenyl(2-pyridyl)ketenes 10, which are directly observable by infrared spectroscopy in low temperature matrices. FVT of 11 regenerates the ketenes 10.

Espectro infravermelho e análise conformacional do composto 3-fenil-2-oxo-1,2,3-oxatiazolidina

The infrared (IR) spectra of the four distict conformers located on the multidimensional potential energy surface (PES) for the 3-phenyl-1,2,3-oxathiazolidine 2-oxide compound have been calculated using the semiempirical quantum-mechanical method PM3. The band spectra are reported and compared directly with the experimental spectrum. The IR intensities are shown to be much more sensitive to conformational changes than the vibrational frequencies and so, the theoretical analysis of the IR spectrum can be used as a tool for helping in the elucidation of the structure of heterocyclic compounds.

Synthesis of 1H-benzoxazine-2,4-diones from heterocyclic anhydrides: evaluation of antioxidant and antimicrobial activities

A facile one-step synthesis of 1H-benzoxazine-2,4-diones from heterocyclic anhydrides and TMSA was described. This paper determines their antimicrobial activity against nine human bacterial pathogens by the broth microdilution method; antioxidant activity by DPPH• inactivation and a ferric-reducing power assay; and toxicity by a brine shrimp, Artemia salina, assay. The 1H-benzoxazine-2,4-dione yields were in the range of 57 to 98%. The novel compound 1H-pyrazino[2,3- 3;[1,3 3;oxazine-2,4-dione 4c showed the highest antioxidant capacity (DPPH 35.4% and FRAP 0.063 µmol TEs/µmol).

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.

Propriedades analíticas e eletroanalíticas de um silsesquioxano nanoestruturado organofuncionalizado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Quantificação eletroquímica de analitos de interesse ambiental e biológico, empregando novos materiais preparados a partir de silsesquioxanos funcionalizados

Pós-graduação em Ciência dos Materiais - FEIS

Ex vivo torsional properties of the Targon Vet Nail System in canine femurs: comparison with the 2.4 mm LC-DCP Plate

Pós-graduação em Cirurgia Veterinária - FCAV

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.