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PubMed1989

Synthesis, antibacterial activity and structure-activity relationships of N-substituted 3-methyl-4-diazo-5-pyrazolecarboxamides.

A number of N-substituted 3-methyl-4-diazo-5-pyrazolecarboxamides (IVa-p) have been synthesized and tested for their in vitro antibacterial activity. All the compounds have been assayed against several representative Gram-negative and Gram-positive bacteria, as well as against some intestinal bacterial species. Some of the 4-diazopyrazoles IVa-c have shown a quite interesting broad-spectrum activity, while they are ineffective against the "protective" intestinal flora. The structure-activity relationships of the series have been studied quantitatively, via both univariate and multivariate methods: the results are consistent and permit some rationalization of the behaviour of the compounds investigated.

Anti-Bacterial Agents↗
PubMed2006

Structural analysis of ionic organotin(IV) compounds using electrospray tandem mass spectrometry.

A novel electrospray ionization (ESI) mass spectrometric approach for the structure elucidation of ionic organotin(IV) compounds or complexes with weakly bonded ligands as for example monodentate carboxylates or sulfonates is proposed using both positive-ion and negative-ion ESI tandem mass spectra. The ionization mechanism of organotin(IV) compounds involves the cleavage of the most labile bond with an ionic character yielding two complementary ions, [Cat]+ and [An]-. Positively charged species containing tin atom, [Cat]+, are analyzed in the positive-ion mode and negatively charged species without the tin atom, [An]-, in the negative-ion mode. Fragmentation patterns of [C24H29N2Sn]+, [C21H22NSn]+, and [C17H30NSn]+ ions are proposed based on the detailed interpretation of MSn spectra, which is simplified by an easy recognition of characteristic tin isotopic clusters in particular fragment ions. Proposed fragmentation mechanisms are supported by comparison with MSn spectra of deuterium-labeled analogues. The applicability of this method is illustrated on two sets of organotin(IV) compounds, including seven [2,6-bis(dimethylaminomethyl)phenyl]diphenyltin(IV) derivatives with small inorganic counteranions X (Br, NO3, SCN, BF4, SeCN, CN, PF6), six organotin(IV) complexes containing two C,N-chelating ligands with azo dyes, and the identification of unknown hydrolysis products.

Anions↗
PubMed1961

Anti-trypanosomal activity of certain phenyldiazoamino- and phenylazoamino-phenanthridinium compounds.

Red phenyldiazoaminophenanthridinium and purple phenylazoaminophenanthridinium compounds, most of which were obtained as isomeric pairs, were tested in mice for curative and prophylactic action against Trypanosoma congolense. Several of the individual compounds showed a high degree of activity, the red isomer of each pair usually being more active therapeutically and prophylactically than the purple one, although high prophylactic effect was not always associated with high therapeutic potency. The most interesting isomeric pair was that consisting of metamidium, 7-(m-amidinophenyldiazoamino)-2-amino-10-ethyl-9-phenylphenanthridinium chloride hydrochloride (red isomer) and x-(m-amidinophenylazo)-2,7-diamino-10-ethyl-9-phenylphenanthridinium chloride hydrochloride (purple isomer). Among the individual compounds, the one with the greatest curative action was the red isomer of metamidium, now known as isometamidium. Its 10-methyl homologue was slightly less active and its p-amidino-isomer was considerably less active. The compounds with the greatest prophylactic action were 2,7-di(m-amidinophenyldiazoamino)-10-ethyl-9-phenylphenanthridinium chloride dihydrochloride trihydrate, its 10-methyl homologue, and the red m-amidino-isomers mentioned above. The only other compounds to show appreciable prophylactic action were three guanidino-substituted phenyldiazoaminophenanthridines, although they were less active than metamidium at low doses. One of these, 2-amino-10-ethyl-7-(m-guanidinophenyldiazoamino)-9-phenylphenanthridinium chloride hydrochloride, was also very active therapeutically.

Animals↗
PubMed1984

Excretion and distribution of two occupational toxicants, tetrachloroazobenzene and tetrachloroazoxybenzene in the rat.

The clearance profile and tissue distribution of 2 occupational toxicants, 3,3',4,4'-tetrachloroazobenzene (TCAB) and 3,3',4,4'-tetrachloroazoxybenzene (TCAOB), were examined in male Sprague-Dawley rats. TCAB was found to be cleared from the body more rapidly than TCAOB when a single dose of 14C-labeled TCAB or TCAOB was administered orally. While 66% of the administered TCAB dose was excreted via the urine and feces within the first 24 h, TCAOB-treated animals were only able to clear 37% of the administered dose by the same elimination route. The half-lives for elimination of TCAB and TCAOB were estimated to be 18 h and 34 h, respectively. Examination of the tissue distribution of the remaining radioactivity indicated that, for both compounds, the adipose tissue contained the highest level of radioactivity. The rapid elimination of TCAB and TCAOB by rats may explain in part the reduced toxicity of these 2 compounds to whole animals in comparison to the isosteric 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Animals↗
PubMed1988

Effect of D,L-alpha-difluoromethyl ornithine on cleft palate induced by the TCDD congener, 3,3',4,4'-tetrachloroazoxybenzene, in the fetuses of mice.

The importance of inhibition of ornithine decarboxylase (ODC) activity in murine embryonic tissues for the teratogenic action of the TCDD congener 3,3',4,4'-tetrachloroazoxybenzene (TCAOB), has been studied. When D,L-alpha-difluoromethyl ornithine (DFMO), an inhibitor of ODC activity, was coadministered with TCAOB, it decreased the frequency of cleft palate compared with TCAOB alone. Fetal death induced by TCAOB was not affected by DFMO treatment. It is suggested that the mechanism of cleft palate induced by TCAOB may involve ODC stimulation. However fetal death induced by the latter compound may involve another mechanism, that may not be related to the mechanism of cleft palate induction.

Animals↗
PubMed1992

Microbiological research on soft drinks: discolouring of natural-flavoured products.

The results of experiments testing the effects of yeasts, sunlight, and temperature on the food dyes tartrazine, ponceau 4R, indigotin and azorubin (used for colouring ginger soft drink) are reported. Light was found to exert a greater influence than heat, and yeasts growth hastened colour degradation. Yeasts assimilated to varying extent the colouring compounds and, when failing to do it, showed a certain power of adsorption by the no longer viable cells.

Azo Compounds↗
PubMed2001

Principles for microscale separations based on redox-active surfactants and electrochemical methods.

We report principles for microscale separations based on selective solubilization and deposition of sparingly water-soluble compounds by an aqueous solution of a redox-active surfactant. The surfactant, (11-ferrocenylundecyl)trimethylammonium bromide, undergoes a reversible change in micellization upon oxidation or reduction. This change in aggregation is exploited in a general scheme in which micelles of reduced surfactant are formed and then put in contact with a mixture of hydrophobic compounds leading to selective solubilization of the compounds. The micelles are then electrochemically disrupted, leading to the selective deposition of their contents. We measured the selectivity of the solubilization and deposition processes using mixtures of two model drug-like compounds, o-tolueneazo-beta-naphthol (I) and 1-phenylazo-2-naphthylamine (II). By repeatedly solubilizing and depositing a mixture that initially contained equal mole fractions of each compound, we demonstrate formation of a product that contains 98.4% of I after six cycles. Because the aggregation states of redox-active surfactants are easily controlled within simple microfabricated structures, including structures that define small stationary volumes (e.g., wells of a microtiter plate) or flowing volumes of liquids (e.g., microfabricated channels), we believe these principles may be useful for the purification or analysis of compounds in microscale chemical process systems. When used for purification, these principles provide separation of surfactant and product.

Azo Compounds↗
PubMedDate not supplied

Cytotoxic activity of aryl and heteroaroxylazoxy derivatives.

Synthesis of aryl and heteroarylazocyanides, azoxyesters and azoxysulphones, was carried out by the action of appropriate reagents on the corresponding nitroso derivatives and arylazoxyamides were obtained by hydrolysis of the corresponding azoxycyanides. Cytotoxic activity was assessed utilizing cultured P388 leukemia cells. Most of the compounds tested showed a marked cytotoxicity at concentrations below 1 micrograms/ml.

Animals↗
PubMed1995

Antimicrotubular effect of calvatic acid and of some related compounds.

A structure-activity relationship has been established between calvatic acid and some related synthetic compounds, and their ability to inhibit GTP-induced microtubular protein polymerization in vitro. These compounds were effective in a dose- and a time-dependent manner. The most active drug was the p-chloro substituted compound, which showed its inhibitory activity without any preincubation period, which the others needed. Since if cysteine was present, polymerization was no longer affected, an involvement of titratable -SH groups of tubulin could be suggested. In contrast, taxol-induced polymerization was only slightly inhibited by these compounds, and colchicine-binding activity was not generally impaired.

Animals↗
PubMedDate not supplied

Efficient photoaffinity labeling of human beta-hexosaminidase A. Synthesis and application of 3-azi-1-[(2-acetamido-2-deoxy-1-beta- D-glucopyranosyl)thio]- and -galactopyranosyl)thio]butane.

Two photolabile thioglycosides (8 and 9) were synthesized by Koenigs-Knorr type glycosylation. These compounds, being enzyme-resistant analogues of N-acetylhexosaminides, were shown to be good competitive inhibitors of lysosomal beta-hexosaminidase (2-acetamido-2-deoxy- beta-D-hexoside acetamidodeoxyhexohydrolase, EC 3.2.1.52) action. For photoaffinity labeling 3H-labeled 8a was prepared by enzymatic oxidation with galactose oxidase followed by reduction with sodium [3H]borohydride. Compound 8a, when photolyzed in the presence of hexosaminidase, specifically labeled both subunits of the enzyme.

Affinity Labels↗
PubMed2005

Aromatic and aliphatic mono- and bis-nitroxides: a study on their radical scavenging abilities.

Nitroxide radicals are an emerging class of interesting compounds with versatile antioxidant and radioprotective properties. All literature studies have so far concentrated on compounds bearing only one nitroxide function. Here, we now investigate and compare the radical scavenging behaviour and antioxidant activity of aromatic indolinonic and aliphatic piperidine bis-nitroxides, i.e compounds bearing two nitroxide functions. Their corresponding mono-derivatives were also studied for comparison. Radical scavenging activity was investigated using EPR and UV-Vis spectroscopy by following spectral changes in acetonitrile of the nitroxides in the presence of alkyl and peroxyl radicals generated, respectively, under anoxic or aerobic conditions from thermal decomposition of AMVN [2,2'-azobis(2,4-di-methylvaleronitrile)]. Antioxidant activity of the nitroxides was evaluated by monitoring conjugated dienes (CD) formation during methyl linoleate micelles peroxidation and by measuring carbonyl content in oxidized bovine serum albumin (BSA). The results show that: (a) each nitroxide moiety in bis-nitroxides scavenges radicals independent of each other; (b) aliphatic nitroxides do not scavenge peroxyl radicals, at least under the experimental conditions used here, whereas indolinonic aromatic ones do: their stoichiometric number is 1.14 and 2.17, respectively, for mono- and bis-derivatives; (c) bis-nitroxides are roughly twice more efficient at inhibiting lipid peroxidation compared to their corresponding mono-derivatives. Although this study provides only comparative information on the relative radical-scavenging abilities of mono- and bis-nitroxides, it helps in understanding further the interesting reactivity of these compounds especially with regards to peroxyl radicals where many controversies in the literature exist.

Acetonitriles↗
PubMed1979

Preventive effect of diethyldithiocarbamate on experimental diabetes produced by dithisone and 8-oxychinoline.

Diethyldithiocarbamate sodium (DDC)--a compound forming complexes with metal ions-did not change the structure of endocrine pancreas and did not affect the glycemia after the repeated administration of a dose of 250 mg kg-1 while a single dose of 500 or 1000 mg kg-1 increased the glycemia for 2 to 4 h in most of rabbits tested. DDC injected in similar doses prevented a diabetogenic action of dithisone and of a number of 8-oxichinoline derivatives. This effect appeared very rapidly and persisted for several hours being dependent on a dose of DDC and on the interval between its administration and the injection of diabetogenic compounds. It was concluded that DDC forms stable complexes with zinc ions in pancreatic beta-cells which appear to be resistant towards the action of diabetogenic compounds directed selectively to the blocking of zinc ions too and thus to the development of experimental diabetes.

Animals↗
PubMed2001

Structure-based inhibitor screening: a family of sulfonated dye inhibitors for malaria parasite triosephosphate isomerase.

The crystal structure of malaria triosephosphate isomerase (TIM) was screened against the National Cancer Institute database of three-dimensional molecular structures. Ten top-scoring commercially available compounds were analyzed for inhibition of recombinant TIM. Two anionic dyes showed inhibition of TIM at concentrations of <100 mM. Four related sulfonated dyes were identified from the literature, docked, and screened in vitro. All showed inhibition of malaria TIM. Models indicate that these compounds bind in two suggested conformations to the active site region of the TIM enzyme. These compounds may be used in rational modification procedures for the synthesis of lead anti-TIM drugs.

Animals↗
PubMed1992

Antioxidant properties of nitecapone (OR-462).

Nitecapone [3-(3,4-dihydroxy-5-nitrophenyl)methylene-2,4-pentanedione] [OR-462] is a catechol-O-methyltransferase inhibitor with gastroprotective properties. Recently, its antioxidant properties have been discovered: It scavenges peroxyl radicals (ROO.) and thus spares glutathione. Further examination of the properties of nitecapone demonstrated a remarkable ability of this compound to act as an antioxidant: (1) to scavenge ROO. in solution with a stoichiometry factor of 2; (2) to scavenge ROO. in membranes; (3) to inhibit lipid peroxidation; (4) to act as a competitive inhibitor for xanthine oxidase with Ki of 8.8 microM; (5) to scavenge O2- with a second order kinetic rate constant of 1.0 x 10(4) M-1 s-1; and (6) to scavenge HO.. Nitecapone also interacts with oxidation product of ascorbate to participate in recycling of vitamin E. Thus, nitecapone potentially is an effective therapeutic antioxidant, and the use of this compound in a combination with other antioxidants may be beneficial.

Animals↗
PubMed2006

Synthesis and reactivity of nonstabilized diazo sugars.

1,6-Anhydro-4-deoxy-4-diazo-2,3-O-isopropylidene-beta-D-lyxo-hexopyranose (4) is a stable crystalline compound readily accessible by an improved synthetic procedure. It has been used as a model for evaluating the reactivity of the diazo group, when not stabilized by an adjacent carbonyl function, in a rigid chiral matrix. A range of carbene-type, electrophile-promoted, and 1,3-dipolar reactions were evaluated, leading to 4,4'-alkene dimers, 4-deoxy-3-enose and related derivatives, 4,4-dihalo compounds, 4-spirocyclopropane derivatives, 4-spiropyrazole structures, and by skeletal rearrangement, branched-chain anhydropentose structures having a bicyclo[2.2.2] skeleton.

Azo Compounds↗
PubMed1976

Tetrazolium salts and formazans.

The history of the tetrazolium salts and formazans goes back 100 years, to when Friese (1875) reacted benzene diazonium nitrate with nitromethane, to produce a cherry-red "Neue Verbindung". This was the first formazan. 19 years later, Von Pechmann and Runge (1894) oxidised a formazan to produce the first tetrazolium salt. Many hundreds of tetrazolium salts and formazans were prepared in the following years, but only a handful have found applications in biological research. This article has attempted to describe the properties of these compounds, and to illustrate how the tetrazolium salt-formazan reaction has been exploited to serve an extremely wide variety of functions.

Animals↗