Reactions of various aromatic nitro-compounds and anthraquinones with selected bases and nucleophiles

The Introducti on deals mainly with hi storical studies on aryne chemi stry and ring closure via arynes , hydride replacement from aromatic rings by nucleophi les, c l eavage of anthr aquinones in basic medium and the Leuckart reaction . This work can be divided into two main s ect i ons. Section I is concerned with the investigation of t he reaction of some aromatic ni t ro-compounds with potassamide in l iquid ammonia. 3-Amino-4- nitrobenzophenone was obtained from the reacti on of 4-nitrobenzophenone with t his reagent, toge t her with benzoic acid formed in a competing Haller-Bauer reaction. Nitrobenzene under these conditions gave a complex mixture from which 2-phenylphenol was isolated; a reaction i nvolving benzyne may be i nvo l ved. 4-Nitrodiphenyl sulfone gave 4-aminodiphenyl sulfone and 4-nitroani l ine. 4-Ethoxydiphenyl sulfone and 4-ethoxynitrobenzene were isolated when ethanol was used as a co-solvent in the reaction. Oxidative coupling reactions were observed with nitrotoluenes. 4-Nitrotoluene gave 4,4t-dinitrobibenzyl which i n a pro longed reaction gave 4,4t-dinitros t ilbene . 2-Nitrotoluene gave 2 , 2 t-dinitrobibenzyl, but not the corresponding stilbene derivative even after a longer time . A rather i nteresting result was obtained with 1-nitro-2,4,6- trimethylbenzene which gave a stilbene derivative only. Also the corresponding stilbene was obtained from bis-(4-nitrophenyl)-methane in a rather slow r eaction with this reagent . Section II deals wi th (i) the preparation of 5-chloro- 1-N-methyl aminoanthraquinone and a new synthesis of N-methyl acridones and (ii) treatment of chloro-anthraquinones with fo rmamide and a new synthesis of chloro-anthracenes . 5-Chloro-1 -N-methylaminoanthraqui none was synthesised f rom 1,5-dichloroanthraquinone by treatment with N-methylformamide. Treatment of 5-chloro-1-N-methylaminoanthraquinone with potassamide in liquid ammonia or with potassium t-butoxide i n t-butylbenzene gave N-methylacridone-1-carboxylic acid. This pleasing result, t he outcome of r i ng opening and alter native ring closure, is being extended to related ring systems.

Aromatic nitro substitution reaction between 4-nitro-N-n-butyl-1,8-naphthalimide and n-heptanethiol in water-methanol binary mixtures

The second-order rate constants of thiolysis by n-heptanethiol on 4-nitro-N-n-butyl-1,8-naphthalimide (4NBN) are strongly affected by the water-methanol binary mixture composition reaching its maximum at around 50% mole fraction. In parallel solvent effects on 4NBN absorption molar extinction coefficient also shows a maximum at this composition region. From the spectroscopic study of reactant and product and the known H-bond capacity of the mixture a rationalization that involves specific solvent H-donor interaction with the nitro group is proposed to explain the kinetic data. Present findings also show a convenient methodology to obtain strongly fluorescent imides, valuable for peptide and analogs labeling as well as for thio-naphthalimide derivatives preparations. Copyright (C) 2008 John Wiley & Sons, Ltd.

The in vitro antiviral activity of an aliphatic nitro compound from Heteropteris aphrodisiaca

We investigated the antiviral activity of an aliphatic nitro compound (NC) isolated from Heteropteris aphrodisiaca O. Mach. (Malpighiaceae), a Brazilian medicinal ptant. The NC was tested for its antiviral activity against poliovirus type 1 (PV-1) and bovine herpes virus type 1 (BHV-1) by plaque reduction assay in cell culture. The NC showed a moderate antiviral activity against PV-1 and BHV-1 in HEp-2 celts, and the 50% inhibitory concentration (IC50) were 22.01 mu g/ml (selectivity index (SI) = 2.83) and 21.10 mu g/mi (SI = 2.95), respectivety. At the highest concentration of the drug (40 mu g/ml) a reduction of approximately 80% in plaque assay was observed for both viruses. The treatment of cells or virus prior to infection did not inhibit the replication of virus strains. (C) 2006 Elsevier GmbH. All rights reserved.

Avaliação da atividade mutagênica do resíduo sólido de uma fábrica de confecções de meias e lingerie em ensaios com Salmonella typhimurium

Cancer is one of the most hazardous effects to human health caused by the exposition to chemical agents. The search for new technological solutions in the industrial field led to a rapid increase in the productive sector, causing the workers to be exposed to millions of potentially toxic agents, substances potentially harmful to health. This study presents the mutagenic activity of sweepings from a sock and lingerie factory in Araraquara-Brazil, assayed with Salmonella typhimurium. All the extracts from the factory had mutagenic on activity the YG1024 strain, which is extremely sensitive to detect the mutagenic activity of the arilhydroxilamines, nitroarenes and aromatic amines. The extracts were non-mutagenics for the strains TA100 and TA98. The analysis of the mutagenicity of industrial residues is highly important because employees that participate in the production are directly exposed to those agents, as well as to the environment where the garbage is deposited.

Métodos "verdes" de produção de nanomateriais que promovem nanotecnologias sustentáveis

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química

The suppression of the Haller-Bauer scission for synthetic purposes /|nby S. M. Vines. -- 260 St. Catharines, Ont. : [s. n.],

A number of 2-chlorobenzophenones, containing electron releasing groups (e.g. hydroxy, thiomethoxy and methoxy) in the 4' - position, were prepared by the Friess rearrangement, or the Friedel-Crafts reaction. These ketones, when treated with potassamide in liquid ammonia, underwent partial Haller-Bauer scission, unlike 2-chlorobenzophenone which is known to undergo complete scission. Under similar conditions 4-nitrobenzophenone also underwent partial scission, but the main reaction in this case was nucleophilic amination of the nitro containing ring. This amination reaction was shown not to be a useful general reaction for aromatic nitro compounds. 3-Methylxanthone was then prepared by treatment of 2- and 3- chloro-2'-hydroxy-5'-methylbenzophenone with . little, if any, attendant scission. The corresponding 2fluoro- compound also gave the xanthone, but as the 3-fluoro compound did not, it was concluded that the 2-fluoro compound reacted through a nucleophilic substitution mechanism, rather than the benzyne mechanism invoked for the chloro and bromo compounds. 3-Methylthioxanthone was synthesised by treatment of methyl 4-tolyl sulphide and 2-chlorobenzoyl chloride with aluminum chloride in carbon disu1phide, followed.by heating. This compound was also prepared by treatment of 3-chloro-2'thiomethoxy- 5'-methylbenzophenone with potassamide in liquid ammonia.

Induction of tachyzoite egress from cells infected with the protozoan Neospora caninum by nitro- and bromo-thiazolides, a class of broad-spectrum anti-parasitic drugs

Neospora caninum represents an important pathogen causing stillbirth and abortion in cattle and neuromuscular disease in dogs. Nitazoxanide (NTZ) and its deacetylated metabolite tizoxanide (TIZ) are nitro-thiazolyl-salicylamide drugs with a broad-spectrum anti-parasitic activity in vitro and in vivo. In order to generate compounds potentially applicable in food and breeding animals, the nitro group was removed, and the thiazole-moiety was modified by other functional groups. We had shown earlier that replacement of the nitro-group by a bromo-moiety did not notably affect in vitro efficacy of the drugs against N. caninum. In this study we report on the characterization of two bromo-derivatives, namely Rm4822 and its de-acetylated putative metabolite Rm4847 in relation to the nitro-compounds NTZ and TIZ. IC(50) values for proliferation inhibition were 4.23 and 4.14 microM for NTZ and TIZ, and 14.75 and 13.68 microM for Rm4822 and Rm4847, respectively. Complete inhibition (IC(99)) was achieved at 19.52 and 22.38 microM for NTZ and TIZ, and 18.21 and 17.66 microM for Rm4822 and Rm4847, respectively. However, in order to exert a true parasiticidal effect in vitro, continuous culture of infected fibroblasts in the presence of the bromo-thiazolide Rm4847 was required for a period of 3 days, while the nitro-compound TIZ required 5 days continuous drug exposure. Both thiazolides induced rapid egress of N. caninum tachyzoites from their host cells, and egress was inhibited by the cell membrane permeable Ca(2+)-chelator BAPTA-AM. Host cell entry by N. caninum tachyzoites was inhibited by Rm4847 but not by TIZ. Upon release from their host cells, TIZ-treated parasites remained associated with the fibroblast monolayer, re-invaded neighboring host cells and resumed proliferation in the absence of the drug. In contrast, Rm4847 inhibited host cell invasion and respective treated tachyzoites did not proliferate further. This demonstrated that bromo- and nitro-thiazolides exhibit differential effects against the intracellular protozoan N. caninum and bromo-thiazolides could represent a valuable alternative to the nitro-thiazolyl-salicylamide drugs.

Synthesis, spectral and structural studies of transition metal complexes of N(4)-substituted semicarbazones

The thesis is an introduction to our attempts to evaluate the coordination behaviour of a few compounds of our interest. Semicarbazones and their metal complexes have been an active area of research during the past years because of the beneficial biological activities of these substances. Tridentate NNO semicarbazone systems formed from heterocyclic and aromatic carbonyl compounds and their transition metal complexes are well-authenticated compounds in this field and their synthesis and characterization are well desirable. Hence, we decided to develop a research program aimed at the synthesis and characterization of novel semicarbazones derived from 2-benzoylpyridine and 2-acetylpyridine and their transition metal complexes. In addition to various physicochemical methods of analysis, single crystal X—Ray diffraction studies were also used for the characterization of the complexes.

Complexos triazólicos de Pd(II): síntese, caracterização e atividade biológica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anise Myrtle (Syzygium anisatum) Oils

Syzygium anisatum (formerly Backhousia anisata and Anetholea anisata) is an Australian rainforest tree with leaves that produce an essential oil (EO) that has the characteristic aroma of aniseed. It is referred to as aniseed myrtle or anise myrtle in the trade and the fresh and dried leaves of this plant are used as a herb in culinary applications. The EO is extracted by steam distillation of the leaves and the major aromatic volatile compound is anethole. The EO has broad spectrum antimicrobial activity but is more effective against bacteria than fungi. Indigenous Australians have used anise myrtle for its medicinal values and in recent times it has been used as a flavoring agent by the food and beverage industry. This chapter covers the use of anise myrtle EO in food and agricultural applications, botanical aspects, and chemical composition.

Crystal Structure Of (3e)-3-[(4-nitro-phen-oxy)-meth-yl]-4-phenyl-but-3-en-2-one.

In the title compound, C17H15NO4, the conformation about the C=C double bond [1.348 (2) Å] is E with the ketone group almost co-planar [C-C-C-C torsion angle = 7.2 (2)°] but the phenyl group twisted away [C-C-C-C = 160.93 (17)°]. The terminal aromatic rings are almost perpendicular to each other [dihedral angle = 81.61 (9)°] giving the mol-ecule an overall U-shape. The crystal packing feature benzene-C-H⋯O(ketone) contacts that lead to supra-molecular helical chains along the b axis. These are connected by π-π inter-actions between benzene and phenyl rings [inter-centroid distance = 3.6648 (14) Å], resulting in the formation of a supra-molecular layer in the bc plane.

Crystal Structure Of (3e)-3-(2,4-di-nitro-phen-oxy-meth-yl)-4-phenyl-but-3-en-2-one.

In the title compound, C17H14N2O6, the conformation about the C=C double bond [1.345 (2) Å] is E, with the ketone moiety almost coplanar [C-C-C-C torsion angle = 9.5 (2)°] along with the phenyl ring [C-C-C-C = 5.9 (2)°]. The aromatic rings are almost perpendicular to each other [dihedral angle = 86.66 (7)°]. The 4-nitro moiety is approximately coplanar with the benzene ring to which it is attached [O-N-C-C = 4.2 (2)°], whereas the one in the ortho position is twisted [O-N-C-C = 138.28 (13)°]. The mol-ecules associate via C-H⋯O inter-actions, involving both O atoms from the 2-nitro group, to form a helical supra-molecular chain along [010]. Nitro-nitro N⋯O inter-actions [2.8461 (19) Å] connect the chains into layers that stack along [001].

2-Methoxy-6-methyl-3-nitro-4-(2-nitroprop-1-enyl)phenyl acetate

In the title compound, C13H14N2O7, steric crowding around the aromatic ring results in significant out-of-plane twisting of the nitro, methoxy, acetoxy and 2-nitropropenyl functional groups. These distortions are explained by comparison with less congested substituted benzene analogues.

Effects of surface chemistry on aromatic compound adsorption from dilute aqueous solutions by activated carbon

Adsorption of one nondissociating and four dissociating aromatic compounds onto three untreated activated carbons from dilute aqueous solutions were investigated. All adsorption experiments were preformed in pH-controlled solutions. The experimental isotherms were analyzed using the homogeneous Langmuir model. The surface chemical properties of the activated carbons were characterized using a combination of water adsorption, X-ray photoemission spectroscopy, and mass titration. These data give rise to a new insight into the adsorption mechanism of aromatic solutes, in their molecular and ionic forms, onto untreated activated carbons. It was found that, for the hydrophilic activated carbons, the dominant adsorption forces were observed to be dipolar interactions when the solutes were in their molecular form whereas dispersive forces, such as pi-pi interactions, were most likely dominant in the case of the basic hydrophobic carbons. However, when the solutes were in their ionic form adsorption occurs in all cases through dispersive forces.

The use of forensic polycyclic aromatic hydrocarbon signatures and Compound Ratio Analysis Techniques (CORAT) for the source characterisation of petrogenic/pyrogenic environmental releases.

This study utilised recent developments in forensic aromatic hydrocarbon fingerprint analysis to characterise and identify specific biogenic, pyrogenic and petrogenic contamination. The fingerprinting and data interpretation techniques discussed include the recognition of: The distribution patterns of hydrocarbons (alkylated naphthalene, phenanthrene, dibenzothiophene, fluorene, chrysene and phenol isomers), • Analysis of “source-specific marker” compounds (individual saturated hydrocarbons, including n-alkanes (n-C5 through 0-C40) • Selected benzene, toluene, ethylbenzene and xylene isomers (BTEX), • The recalcitrant isoprenoids; pristane and phytane and • The determination of diagnostic ratios of specific petroleum / non-petroleum constituents, and the application of various statistical and numerical analysis tools. An unknown sample from the Irish Environmental Protection Agency (EPA) for origin characterisation was subjected to analysis by gas chromatography utilising both flame ionisation and mass spectral detection techniques in comparison to known reference materials. The percentage of the individual Polycyclic Aromatic Hydrocarbons (PAIIs) and biomarker concentrations in the unknown sample were normalised to the sum of the analytes and the results were compared with the corresponding results with a range of reference materials. In addition, to the determination of conventional diagnostic PAH and biomarker ratios, a number of “source-specific markers” isomeric PAHs within the same alkylation levels were determined, and their relative abundance ratios were computed in order to definitively identify and differentiate the various sources. Statistical logarithmic star plots were generated from both sets of data to give a pictorial representation of the comparison between the unknown sample and reference products. The study successfully characterised the unknown sample as being contaminated with a “coal tar” and clearly demonstrates the future role of compound ratio analysis (CORAT) in the identification of possible source contaminants.