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PubMed1976

[On the chloranilic acid reaction (RAC) proposed by Closs (author's transl)].

On the serum of 3790 patients (2131 women and 1659 male), aged from 3 days to 84 years, the RAC has been performed at the same time with the Mc Lagan's Kunkel's and Takata's reactions. The test of sulfobromophthalein's excretion has been performed in 246 of these patients. Between RAC and T.D., disagreement has been observed in 111 cases (- 2,9%). RAC positive and T.D. negative occurred in 68 cases; T.D. positive and RAC negative in the other 43. Repetition of the RAC on 100 sera (after complement inactivation at 56 degrees C for 30 min; after permanence at 4 degrees C for 7 days; after congealment at -18 degrees C) has always given the same results obtained on fresh sera. The complement, therefore, has no way influence on the RAC. The study of disagreeing cases has shown the RAC become positive for: 1) an apperance in serum of abnormal lipoproteins (chloestasis, cholangitis, some dislipemias), 2) a rise in gamma-M (biliary cirrhosis, macroglobulinaemia, lymphatic chronic leukema); 3) 1 and 2. It is always necessary to perform T.D. and RAC on the same serum, because these two test express different modification of the serum-proteins picture. Their agreement, or their disagreement, is very important in every single case, particularly in the diagnostic of jaundice and of bilary ducts pathology.

Adult↗
PubMed1969

Reactions of vitamin A with acceptors of electrons. Formation of radical anions from 7,7,8,8-tetracyanoquinodimethane and tetrachloro-1,4-benzoquinone.

1. The interactions of retinol and retinoic acid with two electron acceptors, 7,7,8,8-tetracyanoquinodimethane (TCNQ) and tetrachloro-1,4-benzoquinone (chloranil), were studied in an investigation on the ability of vitamin A to behave as a donor of electrons. 2. Retinol reacts with TCNQ in polar organic solvents with the formation, as judged by spectral studies, of the radical anion of TCNQ. 3. Addition of the products of this reaction to water is accompanied by a rapid consumption of OH(-) ions. 4. Consumption of OH(-) ions is also a feature of the reactions between retinol and chloranil, but the spectrum of the radical anion of chloranil is observed only when retinol and chloranil are suspended in aqueous salt solutions. 5. Retinoic acid behaves similarly to retinol in its reactions with TCNQ and chloranil, but it appears to be a weaker electron donor than retinol. 6. The reaction products that may be formed from retinol in its reactions with TCNQ and chloranil are discussed. 7. It is suggested that the ability of vitamin A to behave as a donor of electrons may be an important aspect of its biochemical mode of action.

Chemical Phenomena↗
PubMed1983

In vitro binding of 3,4,5,6-tetrachloro-1,2-benzoquinone by rat liver glutathione S-transferases.

The in vitro interaction of 3,4,5,6-tetrachloro-1,2-benzoquinone (o-chloranil) with rat liver glutathione S-transferases (GST) was studied, using reduced glutathione (GSH) and 1-chloro-2,4-dinitrobenzene (CDNB) as substrates. o-Chloranil inhibited the GST activity in crude extracts in a dose dependent manner, while 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone did not. Each of the GST isoenzymes was inhibited, albeit at different degrees. Kinetic studies never revealed competitive inhibition kinetics, with GSH nor CDNB as the variable substrate. Titration of remaining GSH in appropriate incubation mixtures indicated a minor spontaneous conjugation of o-chloranil with GSH, which was not enzymatically activated. It is concluded that o-chloranil interact with GST by direct binding to these proteins. This binding could have a protective function against o-chloranil.

Animals↗
PubMed2005

Distribution patterns of PCDD/Fs in chlorinated chemicals.

The purpose of this research was to determine polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in five chlorinated chemicals (phthalocyanine copper, phthalocyanine green, chloranil-1 and 2, and triclosan), and to compare their 2,3,7,8-tetrachlordibenzo-IpI-dioxin equivalents (TEQ). The distribution patterns of total PCDD/Fs and 2,3,7,8-substituted PCDD/Fs were elucidated in detail. The TEQ values of toxic PCDD/Fs in all chemicals were in the range of 5.03-1379.55 ng I-TEQ/kg. The contribution of OCDD and OCDF in phthalocyanine green was 75% of the total TEQ. For chloranils, the maximum contribution of toxic PCDD/Fs was from 2,3,7,8-substituted HxCDF and 2,3,7,8-substituted HpCDF. The TEQ of HxCDF and HpCDF in chloranil-1 was 90% and in chloranil-2 was 71%. And the toxic contribution increased with the degree of chlorination for PCDFs.

Anti-Infective Agents, Local↗
PubMed2000

Quinones as co-catalysts and models for the surface of active carbon in the phosphovanadomolybdate-catalyzed aerobic oxidation of benzylic and allylic alcohols: synthetic, kinetic, and mechanistic aspects

Quinones have been considered as reactive compounds present on the surface of active carbon. Thus, the co-catalytic use of quinones combined with the phosphovanadomolybdate polyoxometalate, PV2Mo10O40(5-), has been studied as an analogue of the known PV2Mo10O405-/C catalyst in oxidative dehydrogenation reactions. From the synthetic point of view both biphasic the quinone (org)-Na5PV2Mo10O40- (aq) and monophasic quinone (org)- 4Q5PV2Mo10O40-(org) [4Q = (nC4H9)4-N+] systems are effective for the selective oxidation of benzylic and allylic alcohols to their corresponding aldehydes. Kinetic measurements carried out on the model oxidative dehydrogenation of 4-methylbenzyl alcohol in the presence of p-chloranil, 4Q5PV2Mo10O40, and molecular oxygen showed that the reaction was non-elementary, although the 4-methylbenzyl alcohol oxydehydrogenation was the rate-determining step. ESR measurements showed the presence of the semiquinone of p-chloranil, probably as a complex with the polyoxometalate. This proposed complex was shown to be a more potent oxidant than p-chloranil. Thus, for the oxidation of 4-methoxytoluene the semiquinone complex was active, whereas p-chloranil alone was inactive. Beyond the importance of understanding quinone-phosphovanadomolybdate polyoxometalate-catalyzed reactions, insight gained from the formation of semiquinone active species can be applied for heterogeneous and aerobic oxidative transformations catalyzed by PV2Mo10O405- with carbon matrices as active supports.

Journal Article↗
PubMed1972

Studies on Effect of Certain Quinones: I. Electron Transport, Photophosphorylation, and CO(2) Fixation in Isolated Chloroplasts.

The effect of quinone herbicides and fungicides on photosynthetic reactions in isolated spinach (Spinacia oleracea) chloroplasts was investigated. 2,3-Dichloro-1,4-naphthoquinone (dichlone), 2-amino-3-chloro-1,4-naphthoquinone (06K-quinone), and 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) inhibited ferricyanide reduction as well as ATP formation. Benzoquinone had little or no effect on these reactions. The two reactions showed a differential sensitivity to these inhibitors. Dichlone was a strong inhibitor of both photosystems I and II; photosystem I was more sensitive to 06K-quinone than was photosystem II, whereas the reverse was true of chloranil. Chloranil and 06K-quinone inhibited ferricyanide reduction and the coupled photophosphorylation to the same extent, whereas dichlone affected photophosphorylation to a greater extent than the ferricyanide reduction.CO(2) fixation was inhibited by all the quinones to varying degrees. In chloroplasts treated with 06K-quinone or benzoquinone, CO(2) fixation was inhibited to a greater extent than the photoreduction of ferricyanide or ATP formation, indicating the possibility that the two quinones may also inhibit certain reactions in the carbon reduction cycle. The effect of dichlone and chloranil, but not of 06K-quinone, was overcome by the addition of reduced glutathione. The quinones caused an increase in the proportion of (14)C incorporated into 3-phosphoglyceric acid and a reduction in the amount of glycolic acid.

Journal Article↗
PubMed1969

Utilization of electron spin resonance spectroscopy for observation of in vivo response to fungicides.

Electron spin resonance studies of the in vivo response to fungicides (chloranil and thiram) by Aspergillus niger of different ages are described. The spores possessed a natural free radical signal which grew rapidly upon application of chloranil. Thiram, on the other hand, produced weak changes in the free radical region but easily detectable changes at lower fields, indicating involvement of copper and iron. In addition, flow experiments are described in which the production and decay of the chloranil semiquinone radical produced in the reaction of solutions of chloranil with extracts of bakers' yeast were monitored, both in the absence and in the presence of several buffers and respiratory chain inhibitors.

Antifungal Agents↗
PubMed1977

Schistosoma mansoni: localization of calcium-detecting reagents in electron-lucent areas of specific preacetabular gland granules.

In an attempt to establish the exact location of calcium within the preacetabular glands of cercariae of Schistosoma mansoni, these larvae were exposed to reagents (potassium oxalate, potassium pyroantimonate, chloranilic acid, and silver nitrate) useful in the detection of calcium, and were subsequently observed with the aid of light and electron microscopes. Cercariae incubated in potassium oxalate and viewed in polarized light showed birefringence only in the preacetabular gland funduses. At the ultrastructural level, the preacetabular glands of potassium oxalate-treated cercariae had no electron-dense precipitate, but instead had translucent, irregularly shaped inclusions, similar to spaces left by volatilized calcium oxalate as described by others. Pyroantimonate treatment, on the other hand, localized the reaction in the electron-lucent areas of the light-spotted granules. The von Kossa silver nitrate procedure destroyed the secretory granules; therefore, an electron-dense precipitate was distributed throughout the gland. However, pretreatment with chloranilic acid before fixation preserved the granules, and subsequent exposure to the von Kossa silver nitrate gave a reaction identical to that obtained with the pyroantimonate alone. When viewed in polarized light, chloranilic acid-incubated cercariae showed birefringence in the fundus and duct areas.

Animals↗
PubMed1986

The microsomal metabolism of hexachlorobenzene. Origin of the covalent binding to protein.

The microsomal metabolism of hexachlorobenzene is studied, with special attention to the covalent binding to protein. The metabolites formed are pentachlorophenol and tetrachlorohydroquinone. In addition, a considerable amount of covalent binding to protein is detected (250 pmoles pentachlorophenol, 17 pmoles tetrachlorohydroquinone and 11 pmoles covalent binding in an incubation containing 50 mumoles of hexachlorobenzene). In order to establish the potential role of reductive dechlorination in the covalent binding, the anaerobic metabolism of hexachlorobenzene was investigated. At low oxygen concentrations no pentachlorobenzene was detected, and only very small amounts of pentachlorophenol as well as covalent binding, indicating a relationship between covalent binding and the microsomal oxidation of hexachlorobenzene. Incubations with 14C-pentachlorophenol at low concentrations showed that a conversion-dependent covalent binding occurs to the extent of 75 pmole binding per nmole pentachlorophenol. This is almost enough to account for the amount of label bound to protein observed in hexachlorobenzene incubations. This indicates that less than 10% of the covalent binding occurs during conversion of hexachlorobenzene to pentachlorophenol, and the remainder is produced during conversion of hexachlorobenzene to pentachlorophenol, and the remainder is produced during conversion of pentachlorophenol. The major product of microsomal oxidation of pentachlorophenol is tetrachlorohydroquinone, which is in redox-equilibrium with the corresponding semiquinone and quinone (chloranil). The covalent binding is inhibited by addition of ascorbic acid or glutathione to the hexachlorobenzene incubations. Ascorbic acid decreases the covalent binding with a simultaneous increase in formation of tetrachlorohydroquinone, probably due to a shift in the redox-equilibrium to the reduced side. Glutathione does not act as a reducing agent, since the inhibition of covalent binding is not accompanied by an increase in tetrachlorohydroquinone formation. Instead, glutathione reacts with chloranil, producing at least three stable products, probably in a Michael-type reaction. These results strongly indicate the involvement of chloranil or the semiquinone radical in the covalent binding during microsomal hexachlorobenzene metabolism.

Animals↗
PubMedDate not supplied

Detection of alpha-methyldopa on thin-layer plates using pi-acceptors in 1,4-dioxane.

pi-Acceptors (P-chloranil and chloranilic acid) in 1,4-dioxane were used to detect alpha-methyldopa on thin layer plates. Thin layer plates coated to a thickness of 0.25 mm with silica gel G60 were spotted with solution of alpha-methyldopa from drug formulations and pure alpha-methyldopa solution. The plates were developed in a solvent system of methanol: glacial acetic acid: water (14:5:3). The developed plates were dried and sprayed with pi-acceptors, and further were counter-sprayed with dimethylformamide (DMF). P-Chloranil gave an immediate blue green complex with alpha-methyldopa which intensified on counter-sprayed with DMF. alpha-methyldopa (reference sample and those from drug formulations) gave Rf of 0.85 and excipients from the drug formulations did not interfere with the result.

Benzoquinones↗
PubMed1980

The production of heterotopic calcification by certain chemical salts.

The subcutaneous injection of small quantities of LaCl3 and CeCl3 was followed by calcification of the dorsal fascia in mice. The calcification reaction was shown by separate positive histochemical tests for calcium ions (the chloranilic acid reaction) and phosphate (the von Kossa reaction). The injection of cadmium chloride and stannous salts caused damage to and a positive von Kossa reaction in the fibres of the panniculus carnosus muscle. The significance and specificity of the histochemical tests was determined by X-ray microprobe analysis of tissues injected with the above salts and other salts known to cause either combined chloranilic acid and von Kossa positive reactions or isolated von Kossa positive reactions in mouse skin. The pathogenesis of the reactions produced by LaCl3, CeCl3 and KMnO4 was studied by applying histochemical tests to tissues recovered at timed intervals after injection. The reactions produced by LaCl3 and CeCl3 were similar and occurred in the dorsal fascia with positive VK reactions occurring first after 18 followed by positive CA reactions after 24 hr. The distribution of these reactions suggested a haematogenous origin for the constituent ions. The injection of KMnO4 in a much higher dose caused damage to the skin and particularly the fibres of the panniculus carnosus muscle. In contrast to the other salts, the calcific reaction occurred in association with these fibres, showing equally positive von Kossa and chloranilic acid reactions from the early stages.

Animals↗
PubMed2004

Spectrophotometric determination of nizatidine and ranitidine through charge transfer complex formation.

Two Spectrophotometric procedures are presented for the determination of two commonly used H2-receptor antagonists, nizatidine (I) and ranitidine hydrochloride (II). The methods are based mainly on charge transfer complexation reaction of these drugs with either p-chloranilic acid (rho-CA) or 2, 3 dichloro-5, 6-dicyanoquinone (DDQ). The produced colored products are quantified spectrophotometrically at 515 and 467 nm in chloranilic acid and DDQ methods, respectively. The molar ratios for the reaction products and the optimum assay conditions were studied. The methods determine the cited drugs in concentration ranges of 20-200 and 20-160 microg/mL for nizatidine and ranges of 20-240 and 20-140 microg/mL for ranitidine with chloranilic acid and DDQ methods, respectively. A more detailed investigation of the complexes formed was made with respect to their composition, association constant, molar absorptivity and free energy change. The proposed procedures were successfully utilized in the determination of the drugs in pharmaceutical preparations. The standard addition method was applied by adding nizatidine and ranitidine to the previously analyzed tablets or capsules. The recovery of each drug was calculated by comparing the concentration obtained from the spiked mixtures with those of the pure drug. The results of analysis of commercial tablets and the recovery study (standard addition method) of the cited drugs suggested that there is no interference from any excipients, which are present in tablets or capsules. Statistical comparison of the results was performed with regard to accuracy and precision using student's t-test and F-ratio at 95% confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.

Anti-Ulcer Agents↗
PubMed2005

Spectrophotometric and electrical studies of charge transfer complexes of 2-amino-1,3,4-thiadiazole with pi-acceptors.

Charge transfer (CT) complexes formed between 2-amino-1,3,4-thiadiazole as donor and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), p-chloranil (p-CHL), o-chloranil (o-CHL), p-bromanil (BRL) and chloranilic acid (CHA) as acceptors, have been studied spectrophotometrically. Benesi-Hildebrand and Job continuous variation methods were applied to the determination of association constant (K), molar extinction coefficients (epsilon), dipole moment and stoichiometric ratio, respectively. The solid CT complexes have been synthesized and characterized by different spectral methods. The spectral changes reveal that the CT interaction depends on the type of the acceptors. The magnetic properties of the various complexes were also investigated. The electrical properties for the solid CT complexes are measured from which the activation energies are calculated.

Electrochemistry↗
PubMedDate not supplied

Use of charge-transfer complex formation for the spectrophotometric determination of nortriptyline.

Three simple and selective methods are proposed for the determination of nortriptyline hydrochloride in bulk form and in tablets. The first two methods are based on the formation of charge-transfer complexes between the drug base as a n-donor and quinhydrone or p-chloranil as pi-acceptor. The products exhibit absorption maxima at 497 and 560 nm in acetonitrile for quinhydrone and p-chloranil, respectively. The third method is based on the interaction of N-alkylvinylamine formed from the condensation of the free secondary amine group and acetaldehyde with p-chloranil to give a vinylamino substituted quinone. The coloured product exhibits an absorption maximum at 650 nm in dioxane. All variables were studied to optimize reaction conditions. Beer's law was obeyed and the relative standard deviations were found to be less than 1.5%. The methods have been applied to the analysis of nortriptyline hydrochloride in the bulk drug and in tablets.

Antidepressive Agents, Tricyclic↗
PubMed1997

Spectrophotometric determination of moclobemide by charge-transfer complexation.

A simple and sensitive spectrophotometric method is described for the assay for the moclobemide. The method is based on the molecular interaction between the drug and chloranilic acid, to form a charge-transfer complex in which the drug acts as n-donor and chloranilic acid as pi-acceptor. Chloranilic acid was found to form a charge-transfer complex in a 1:1 stoichiometry with a maximum absorption band at 526 nm. Conformity with Beer's law was evident over the concentration range 4-36 mg 100 ml-1. A complete, detailed investigation of the complex formed was made with respect to its composition, association constant, molar absorptivity and free energy change. The method has been applied successfully to the analysis of commercially available moclobemide tablets with good recovery and reproducibility.

Benzamides↗
PubMed2001

Non-aqueous capillary electrophoresis of p-quinone anion radicals.

The electrophoretic detection of two kinds of p-quinone anion radicals arising from the electrolysis of benzoquinone and chloranil was achieved by employing an acetonitrile medium. Sufficient dehydration of a running solution was necessary for the detection of the benzoquinone anion radical. Oxygen in the running solution also caused a serious decrease in the amount of the benzoquinone anion radical during electrophoresis. The addition of methanol as a hydrogen-donor decreased the electrophoretic mobility of the benzoquinone anion radical significantly, while that of the chloranil anion radical was little changed. This result is interpreted in terms of hydrogen-bonding interaction between the p-quinone anion radicals and methanol, reflecting the magnitude of their proton-accepting ability (benzoquinone anion radical > chloranil anion radical).

Anions↗
PubMed1976

The deleterious effects of fungicides and herbicides on Xenopus laevis embryos.

Groups of 30 Xenopus laevis embryos, at "tail-bud" stage (Nieukoop-Faber stages 22-24) were exposed to 0.1-2 ppm concentrations of various pesticides for 1 to 10 days. The pesticides used were chloranil and dichlone (both are fungicidal and herbicidal); diquat (herbicide); and nabam (fungicide). The parameters examined were mortality, gross morphology, histology, and behavior. Chloranil (1.25 to 1.75 ppm) treated embryos showed abnormalities of the otolith, optic cup, and general pigmentation. Their movement was sporadically convulsive and they were unable to maintain proper balance. Dichlone (0.1 to 0.15 ppm) disrupted the development of the cephalic end of the embryo. Many of these embryos developed a slightly retarded trunk and tail only. These headless embryos lived for a time and were relatively lethargic. Diquat (0.75 to 2.0 ppm) administration reduced body size and pigmentation, and altered body shape. When embryos were treated with both 1.0 ppm of diquat and 2.0 ppm of nabam the integrity of myomeres and myocommata of the musculature was disrupted. The histological bases of these morphological and behavioral changes are discussed.

Animals↗
PubMed1998

Utility of certain pi-acceptors for the spectrophotometric determination of perindopril.

Simple, rapid, accurate and sensitive spectrophotometric methods are described for the determination of perindopril. The methods are based on the reaction of this drug as n-electron donor with 2,3-dichloro-5,6-dicyano-p-benzoquinone(DDQ)-7,7,8,8- tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE), chloranil (CL) and p-chloranilic acid (p-CA) as pi-acceptors to give highly coloured complex species. The coloured products are measured spectrophotometrically at 588, 843, 419, 550 and 520 nm for DDQ, TCNQ, TCNE, CL and p-CA, respectively, optimization of different experimental conditions is described. Beer's law is obeyed in the range of 20-200 micrograms ml-1 and colours were produced in non-aqueous media and were stable for at least 1 h. Application of the suggested methods to perindopril tablets are presented.

Antihypertensive Agents↗