Naphthalenedisulfonic Acid Research Articles

Intrinsically conducting polymer blends

Polyaniline (PANI) doped with different dopants (HCl, dodecyl benzene sulfonic acid, (+)-Camphor-10 sulfonic acid, dinonyl naphthalene disulfonic acid) was synthesized by chemical oxidation method. The FTIR studies indicated that the back bone structure of doped PANI was similar. Thermal stability was evaluated in nitrogen atmosphere by dynamic thermogravimetry and PANI-HCl sample showed minimum weight loss below 400°C. The electrical conductivity of PANI was not affected by the structure of dopants. The microwave absorption studies of several polymers blends containing PANI-HCl and/or carbon black were also carried out by using wave guide technique.

Synthesis of Potential Anti-AIDS Amphiphiles. A New Efficient Acylation of Amino-Naphthalene Disulfonic Acid Derivatives

Abstract We describe a new synthetic route to amphiphilic derivatives of naphthalene disulfonic acid which have been found to be active against HIV-1 and HIV-2. The compounds were obtained in good yield by a new efficient acylation of amino-naphthalene disulfonic acid using N-acyl-thiazolidine-2-thiones as acylating agents.

Selective inhibition of human cytomegalovirus replication by naphthalenedisulfonic acid derivatives

Several naphthalenedisulfonic acid derivatives were found to be selective inhibitors of human cytomegalovirus (CMV) replication in MRC-5 cells. Among the test compounds, the bis-naphthalenedisulfonic acid derivative having an hexamethylene spacer emerged as the most potent inhibitor of CMV replication. Its 50% antivirally effective concentration (EC 50) for AD-169 strain was 12 μM, whereas the compound did not affect the growth of mock-infected MRC-5 cells at concentrations up to 500 μM. The naphthalenedisulfonic acid derivatives were also inhibitory to CMV clinical isolates. Virus yield reduction assay revealed that the compounds significantly reduced virus growth in CMV-infected MRC-5 cells. The bis-naphthalenedisulfonic acid derivatives with an hexamethylene spacer suppressed the expression of CMV-induced immediate early, and early antigens at a concentration of 20 μM, whereas the anti-CMV nucleoside ganciclovir did not do so even at the concentration that was 10-fold higher than its EC 50 for CMV-induced plaque formation. Furthermore, naphthalenedisulfonic acid derivatives had to be present at the time of virus infection to exert their anti-CMV activity. These results suggest that the compounds are targeted at an early event in the virus replicative cycle, presumably, virus adsorption.

Identification of a subunit-specific antagonist of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/kainate receptor channels.

Excitatory synaptic transmission in the mammalian central nervous system is mediated predominantly by glutamate receptor (GluR) channels of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/kainate (AMPA/KA) receptor type. A major improvement in our understanding of glutamatergic synaptic transmission has been achieved after the identification of quinoxalinediones (e.g., 6-cyano-7-nitroquinoxaline-2,3-dione) as specific antagonists of AMPA/KA receptors. In addition to their effects on neurons, quinoxalinediones were also shown to block glutamate-induced responses mediated by recombinant AMPA/KA receptor channels expressed in heterologous systems, irrespective of their particular subunit composition. Here we report the identification of an AMPA/KA receptor antagonist that selectively blocks a subset of AMPA/KA receptors. We found that Evans blue, a biphenyl derivative of naphthalene disulfonic acid, blocks at low concentrations (IC50 = 355 nM for the subunit combination GluR1,2) KA-mediated responses of the subunits GluR1, GluR1,2, GluR1,3, and GluR2,3 expressed in Xenopus oocytes but not responses of GluR3 or GluR6. The blocking action of Evans blue was partially reversible and did not compete with KA for the agonist binding site. These findings suggest not only that Evans blue is a potent tool for elucidating the functional role of specific AMPA/KA receptor subtypes for excitatory synaptic transmission but also that it may also represent a powerful starting point for clinically useful drugs that are able to reduce the excitatory drive in specific neuronal populations of the central nervous system.

Potential anti-AIDS naphthalenesulfonic acid derivatives. Synthesis and inhibition of HIV-1 induced cytopathogenesis and HIV-1 and HIV-2 reverse transcriptase activities.

Several naphthalenedi- and trisulfonic acids have been synthesized and evaluated for inhibitory potential against cytopathogenesis and purified recombinant human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) reverse transcriptase (RT). The most potent derivative that emerged from the anti-RT study was a small molecule 6 (MW = 840), a dipalmitoylated derivative of 2,7-naphthalenedisulfonic acid. Analog 6 demonstrated 50% inhibitory concentration (IC50) values of 2.42 and 0.86 microM for HIV-1 and HIV-2 RT, respectively. The second most active compound was also a derivative of the same naphthalenedisulfonic acid but contained only one palmitoyl moiety. This compound 9 displayed IC50 values of 4.8 and 3.7 microM for HIV-1 and HIV-2 RT, respectively. Both analogs 6 and 9 are active at noncytotoxic doses, exhibit slightly higher potencies for the RT of HIV-2 over HIV-1, and demonstrate activities superior to the hexasulfonic acid derivative suramin (IC50 values of 9.4 and 15.5 microM for HIV-1 and HIV-2 RT, respectively). In the cytopathogenesis assay, the most active compound is a bis naphthalenedisulfonic acid derivative 17, containing a flexible octamethylene spacer and exhibiting an in vitro therapeutic index of 29.7. Most striking, however, is the influence of the palmitoyl functionality in the naphthalenedisulfonic acid series to confer activity against both HIV-1 and HIV-2 RT.

Structural design and anti-HIV-1 evaluation of novel naphthalenedisulfonic acid derivatives

Structural design and anti-HIV-1 evaluation of novel naphthalenedisulfonic acid derivatives

Anti-HIV-1 and HIV-2 activity of naphthalenedisulfonic acid derivatives. Inhibition of cytopathogenesis, giant cell formation, reverse transcriptase activity

Dans la quete de nouveaux agents antiviraux contre les virus HIV-1 et HIV-2, les derives de l'acide naphtalene-disulfonique ont ete testes sur la transcriptax reverse et la replication du virus dans les cellules MT-4 et sur la formation de cellules geantes MOLT-4

Potential anti-AIDS agents. Synthesis and antiviral activity of naphthalenesulfonic acid derivatives against HIV-1 and HIV-2

Certain naphthalenesulfonic acid analogues have been synthesized and evaluated for their inhibitory effects on HIV-1- and HIV-2-induced cytopathogenicity, HIV-1 giant cell formation, and HIV-1 reverse transcriptase (RT) activity. A bis(naphthalenedisulfonic acid) derivative having a biphenyl spacer emerged as the most potent and selective inhibitor of virus-induced cytopathogenicity in MT-4 cells. The ED50 values for this compound were 7.6 and 36 microM for HIV-1 and HIV-2, respectively. No toxicity to the host cells was detected at 98 microM. This compound also inhibited giant cell formation and was superseded in potency by a bis(naphthalenedisulfonic acid) derivative having a flexible decamethylene spacer. In the cell-free RT assay, a long-chain amide derivative exhibited the most inhibition of RT. All the compounds that achieved complete inhibition of virus-induced cytopathogenicity at concentrations not toxic to host cells were derivatives of 4-amino-5-hydroxy-2,7- naphthalenedisulfonic acid. These analogues represent new leads for the development of anti-HIV agents.

Inhibition of HIV replication by derivatives of naphthalenedisulfonic acids

Inhibition of HIV replication by derivatives of naphthalenedisulfonic acids

Inhibition of HIV replication by naphthalenemonosulfonic acid derivatives and a bis naphthalenedisulfonic acid compound

Several naphthalenemonosulfonic acid analogs and a bis naphthalenedisulfonic acid have been evaluated for anti-HIV activity in assays using H9 and MOLT-3 cells. Among the naphthalenemonosulfonic acids,a 4-amino-5-hydroxy compound and a 4,5-diamino compound showed low anti-HIV activity (upto 50% inhibition) at non-toxic doses. The bis naphthalenedisulfonic acid compound demonstrated significant suppression of HIV-1 antigen expression as measured by monoclonal antibodies to p17 (95%), p24 (94%) and syncytia inhibition (82%) at a dose of 20 μg/ml that was non-toxic to the host cells. The bis naphthalenedisulfonic acid analog represents a new class of compounds which may be effective in the treatment of HIV infected patients. The structure activity relationship and a probable mode of action of these compounds is discussed.

A Colorimetric Method for the Determination of Proteolytic Degradation of Feed Proteins by Rumen Microorganisms

A new colorimetric method for the determination of the degradation of soybean meal by rumen microorganisms in vitro is described. Proteins in soybean meal were diazotized with 7-amino-1,3,naphthalene disulfonic acid. The diazotized meal was incubated at 37 C with rumen microbial suspension (approximately equivalent to 2.0 ml of rumen fluid) in 2.0 ml of. 1M potassium phosphate buffer, pH 7.6. The undigested diazo-protein was precipitated by the addition of perchloric acid and the precipitated protein was solubilized by incubating with crystalline bacterial protease. A portion of the solubilized protein was treated with .15N NaOH and the color intensity was measured at 440 nanometers. Application of the diazo method for the determination of the degradation of soybean meal when present as part of ruminant feed mixture, for evaluating the effectiveness of the protective treatment of soybean meal with formaldehyde and for the determination of solubility of soybean meal in boiled rumen fluid are described.

Gravimetric determination of zirconium with a new azopyrazolone derivative

3-Methyl-5-oxo-1-phenyl-2-pyrazolin-4-ylazo-2'-(6',8'-naphthalenedisulfonic acid) (disodium salt) is proposed as a new reagent for the gravimetric determination of zirconium. The precipitate formed at pH 1–1.5 can be weighed directly and there are few interferences.

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Separation and determination of naphthalene-disulfonic acids by ion exchange resins

塩溶液中のナフタリンジスルホン酸の弱酸性陽イオン交換樹脂 Amberlite CG-50に対する分子吸着性を検討したところ,1価の塩溶液中では吸着されず,2価の塩溶液中では異性体の間に吸着性の差が生じることを見いだした.これを利用して,ナフタリンをスルホン化する場合に生じる-1,5-および-1,6-ジスルホン酸を,また-2,6-および-2,7-ジスルホン酸を,それぞれ濃度2Mおよび0.5M,pH2.0およびpH4.0の塩化カルシウム溶液で展開して,クロマトグラフ的に分離し,吸光光度法により定量を行なって良好な結果が得られた.酸性の塩化カルシウム中において弱酸性陽イオン交換樹脂に対するナフタリンジスルホン酸の分子吸着を利用すると,従来困難とされていたこれらの試料を定量的に分離することが可能となり,また展開剤の濃度およびpHが一定であれば,保持容量は変わらず再現性のよい結果が得られる.さらに用いる陽イオン交換樹脂は容易に再生することができる利点も有する.

Spectrophotometric Determination of Rare Earths

ArsenazoSTA3-(2-arsonophenylazo)-4,5-dihydroxy-2,7naphthalenedisulfonic acid! is used for the quantitative colorimetric determination of yttrium and rare earths. The method is applicable to the determination of very low concentrations of rare earth and is not highly pH dependent. Through the use of quick separations, good selectivity is achieved. Iron and other reducible metals are removed by electrolysis using a mercury cathode; aluminum interference is avoided by masking with sulfosalicylate, small amounts of uranium are removed by extraction as the diethyldithiocarbamate. Calcium and magnesium interference are avoided by pH control. (auth)

Chelometric Titrations Using Azoarsonic Acid Indicator

Arsenazo STA3-(2-arsonophenylazo)-4,5-dihydroxy-2,7naphthalenedisulfonic acid, trisodium salt! is an excellent indicator for the EDTA titration of rare earths and yttrium in weakly acid solution. In many cases, use of masking agents or a simple preliminary separation permits determination of rare earths in samples containing foreign metal ions. Aluminum is masked by sulfosalicylate, and interference from calcium and magnesium is avoided by proper pH control. Small amounts of uranium, iron, and most divalent metals are masked by diethyldithiocarbomate; larger amounts of these metals are removed by exraction of their diethyldithiocarbamate complexes. Thorium interferes with the titration of rare earths, but can be titrated at a more acidic pH. Titration of thorium in the presence of uranium is possible. (auth)