The generality of the nitroso-glyoxylate reaction: Conversion ofp-nitronitrosobenzene to the hydroxamic acid

Summary The reaction of glyoxylic acid withp-nitronitrosobenzene (1b) in dilute aqueous solution gave the hydroxamic acid (2b) as the major detectable product. The significance of this observation with respect to the title reaction is discussed.This study was supported by grant No. CA 32395 from the National Cancer Institute, and by Research Career Development Award ES 00120 from the National Institute of Environmental Health Sciences, DHHS.     

Addition of sulphydryl groups to biliverdin

Summary Sulphydryl groups add to the central methine bridge of biliverdin in organic solvents as well as in aqueous solution (pH 7.4). The addition reaction is favoured by albumin but reversed in acid media.     

Role of the conserved glutamine 291 in the rat γ-aminobutyric acid transporter rGAT-1

We investigated the role of the Q291 glutamine residue in the functioning of the rat γ-aminobutyric acid (GABA) transporter GAT-1. Q291 mutants cannot transport GABA or give rise to transient, leak and transport-coupled currents even though they are targeted to the plasma membrane. Coexpression experiments of wild-type and Q291 mutants suggest that GAT-1 is a functional monomer though it requires oligomeric assembly for membrane insertion. We determined the accessibility of Q291 by investigating the impact of impermeant sulfhydryl reagents on cysteine residues engineered in close proximity to Q291. The effect of these reagents indicates that Q291 faces the external aqueous milieu. The introduction of a steric hindrance close to Q291 by means of [2-(trimethylammonium)ethyl] methanethiosulfonate bromide modification of C74A/T290C altered the affinity of the mutant for cations. Taken together, these results suggest that this irreplaceable residue is involved in the interaction with sodium or in maintaining the cation accessibility to the transporter. Received 24 October 2005; accepted 11 November 2005     

Novel rearrangement of purines

6-Trichloromethyl-9-methylpurine (1) rearranges to 6-dichloromethyl-9-methyl-8-oxopurine (2) in aqueous mild acidic solution. The rearrangement is rationalized in terms of a reaction involving protonation, covalent hydration, prototropic equilibrium and/or a hydride transfer. An alternative mechanism involving a "positive' halogen compound and hypochlorous acid as an intermediary is also proposed. Compound 1 condenses with 4,5-diaminopyrimidine to give the purine-pyrimidine Schiff base pair 4.     

Acid rain affects egg-laying behavior of apple maggot flies

Summary The tephritid fruit fly,Rhagoletis pomonella, is less likely to attempt oviposition in host fruit that have been exposed to acid rain or to a simulated acid rain solution (pH<3.8). Electrophysiological data suggest that acid rain residue on the fruit surface may interfere with the sensory mechanisms that the fly uses during recognition and acceptance of host fruit.9 December 1986     

微弧氧化法制备TiO2／Ti电极及其光催化性能研究

采用微弧氧化的方法,分别在2,4,8,12和16g／l的NaH2PO4溶液中制备了不同的TiO2／Ti电极,并在主波长为365nm的250W高压汞灯照射下,对所制备的TiO2／Ti电极的光催化性能进行了测试。结果表明：在NaH2PO4电解质溶液浓度为4mg／l时制备的TiO2／Ti电极效果最好。辐照浓度为5mg／1的若丹明B溶液120min时,若丹明B降解速率达到85％。试验结果模拟证实,在该实验条件下,TiO2／Ti电极降解若丹明B溶液反应符合准一级反应。     

合成对乙酰氨基苯磺酰氯的新工艺

为了减少氯磺酸的用量,提高对乙酰氨基苯磺酰氯(P ASC)的收率,提出一种新的 P ASC合成工艺,即溶剂法 ClSO3H/PCl5联合氯磺化生产工艺.以乙酰苯胺为原料,通过氯磺酸磺化、五氯化磷氯化,合成 P ASC.在氯磺化过程中引入溶剂,并在反应后期加入助剂,用正交实验确定了最佳的反应条件及原料配比:n(乙酰苯胺)∶n(氯磺酸)∶n(五氯化磷)∶n(助剂)=1.0∶2.0~2.3∶1.0~1.3∶0.1.实验结果表明:新工艺降低了氯磺酸的用量58%,且相同成本条件下的收率比传统工艺提高10~12%     

Photooxidation,reduction of the ferric ion-glucose complex

Summary Ferric ions in an acid solution of glucose are reduced by irradiation with light of wavelengths less than 400 nm. The action spectrum for this reaction and the oxidation products of glucose have been determined.     

Kinetische Isotopeneffekte bei elektrophilen aromatischen Substitutionen

Summary In an aqueous buffer solution (pH 6...64) p-diazochlorbenzene reacts with 2-naphthol-6,8-disulphonic acid four times faster than with the deuterated compound 1-d-2-naphthol-6, 8-disulphonic acid. This shows that the proton loss is rate determining. Other diazo coupling reactions do not give such a kinetic isotope effect.     

离子液体双水相萃取红霉素的研究

建立了由亲水性离子液体[Emim] BF4和NaH2PO4形成的双水相体系萃取红霉素的新方法.考察了磷酸盐浓度、离子液体用量、萃取温度、震荡时间、pH值、萃取次数等因素对红霉素萃取率的影响;分析了离子液体的可再生性.结果表明,在红霉素溶液中加入3.5g离子液体,调节体系pH到7～8,温度在303.15 K下,萃取时间2～3h,红霉素的萃取率为87.2％;萃取3次后,萃取率可达98.32％;离子液体重复利用可达到5次.研究表明,离子液体双水相体系可成功用于红霉素的富集分离中,为食品中微痕量红霉素的测定提供新方法.     

Le potassium et le sodium de l'humeur aqueuse du lapin et leurs variations sous l'effet de l'acétazolamide (Diamox)

Summary In 21 rabbits, the average concentration of sodium and potassium in the aqueous humor was found to be respectively 149±4.3 mEq/l and 5.34±mEq/l.Eleven of these animals were injected with Diamox (100 mg/kg of body weight); a significant drop of potassium concentration in the aqueous humor was observed three hours later, as compared with the ten control animals. No change in sodium concentration occurred.Our findings are considered in correlation with the fall of intraocular pressure produced by the carbonic anhydrase inhibitor, and the role of this enzyme is discussed.     

Phtalocyanine in wässriger Lösung. Zum Mechanismus der Metallkomplexbildung

Summary The mechanism of incorporation of different mental ions into phthalocyaninetetrasulfonic acid in aqueous solution has been investigated. It was found that the rate of the reacion with Cu²⁺ depends on the dissociation rate of the N-H-bond of this porphyrin-like chelating agent, whereas the reaction rate with other metal ions, like Zn²⁺, does not.

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II. Mitt. Siehe I. Mitt.:K. Bernauer undS. Fallab, Helv.44, 1287 (1961).

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Herrn Prof. Dr.H. Erlenmeyer sind wir für sein reges Interesse an dieser Arbeit zu bestem Dank verpflichtet.     

Inhibition of nitrosamine formation by ascorbic acid: participation of free radicals in its anaerobic reaction with nitrite

Summary The participation of semiquinone free radicals during the reaction of ascorbic acid with acidified sodium nitrite has been demonstrated by ESR spectroscopy unambiguously for the first time. Scavenging of the nitrosating agent, reflected by the observed free radical concentration, unexpectedly occurs with scarcely varying efficiency over the pH range 0.1–4.5.     

Paper chromatographic separation of some phloroglucinal derivatives fromDryopteris filix mas

Résumé L'acide filicique, l'acide flavaspidique, l'albaspidine et l'acide filicinique ont pu être isolés par chromatographie sur papier, suivant la méthode ascendante, avec comme phase mobile une solution de carbonate de sodium 2N, dans laquelle on a dissous 2 g de sulfite de sodium par litre. Les spots étaient rendus visibles en pulvérisant une solution de sulfanilamide diazotée. En même temps se manifestait aussi une différence de couleur pour les dites substances phlorogluciniques.     

泛昔洛韦与十二烷基苯磺酸钠对盐水中黄铜的协同缓蚀效应研究

采用失重法、极化曲线法、交流阻抗法研究泛昔洛韦与十二烷基苯磺酸钠（SDBS）对黄铜在3．0％NaCl介质中的缓蚀作用。结果表明：当泛昔洛韦浓度为0．40g／L、SDBS浓度为0．35g／L时,其复配缓蚀效率达到93．5％。泛昔洛韦和SDBS对黄铜的缓蚀机理分析表明,泛昔洛韦在铜舍金表面通过物理与化学吸附共同作用形成保护膜,与SDBS发挥了极好的协同作用,阻碍Cl^-对铜的侵蚀,实现了对铜的高效保护。     

Cytosine deaminase: structural modifications studies

Structural modification studies have been shown that a cysteine, a histidine and possibly an arginine residue are involved in the catalytic process. The enzyme gave a single band on polyacrylamide gel electrophoresis, and the amino acid analysis showed it to contain a high proportion of hydrophobic residues, which was in agreement with the chemical modification results.     

Spermatogenesis is extraordinarily accelerated in metamorphosis-arrested larvae of a salamander,Hynobius retardatus

Laboratory experiments were conducted to induce neoteny inHynobius retardatus, which had been reported to propagate in larval forms like axolotl. A large number of newly hatched larvae were reared in an aqueous solution of thiourea (TU) and sodium perchlorate (SPC) in order to arrest the metamorphosis. Gonadal development in the metamophosis-arrested larvae was compared with that in normally metamorphosing and metamorphosed controls. Metamorphosis-arrested male larvae produced morphologically mature spermatozoa approximately 4 months after hatching, when the gonads in the controls began to differentiate into testes, or to show the premeiotic proliferation of germ cells. Possible endocrine controls of these phenomena are discussed.     

Evaluation of cement degradation induced by the metabolic products of two fungal strains

Summary During their metabolism, microorganisms can produce acids able to bring about the degradation of cement. Two acid-producing alkalophilic fungal strains have been isolated from soil, a strain ofAspergillus niger which produces gluconic and oxalic acid and ofMycelia sterila which produces gluconic and malic acid. After eleven months of contact the acids produced byAspergillus dissolved portlandite with a low leaching of calcium, increased the cement porosity by 11.4%, and reduced the bending strength by 78%. The second strain is responsible for a significant dissolution of portlandite with a leaching of calcium of 4.2% of the initial content, an increase of the porosity of 11%, and a loss of the bending strength of 62%. Direct contact of mycelia with the cement surface is not necessary for effective dissolution to take place. Low pH and a high temperature favor the the production of acids.     

三方硼镁石合成方法研究

采用液-固转化法,研究了室温下水溶液中三方硼镁石的合成方法,并初步探讨了三方硼镁石的结晶机理.合成的三方硼镁石晶体,经化学分析法、X-ray粉晶衍射法、红外光谱法和热分析方法物相鉴定,发现合成晶体纯度高,可满足应用于该矿物的溶液化学性质研究.     

Novel rearrangement of purines

Summary 6-Trichloromethyl-9-methylpurine (1) rearranges to 6-dichloromethyl-9-methyl-8-oxopurine (2) in aqueous mild acidic solution. The rearrangement is rationalized in terms of a reaction involving protonation, covalent hydration, prototropic equilibrium and/or a hydride transfer. An alternative mechanism involving a positive halogen compound and hypochlorous acid as an intermediary is also proposed. Compound1 condenses with 4,5-diaminopyrimidine to give the purine-pyrimidine Schiff base pair4.Acknowledgments. We are deeply indebted to Professor S. Cohen of the Sackler School of Medicine, Tel Aviv University (Ramat Aviv, Isreal) for his advice and encouragement. Support of this research by the Israel Cancer Association, the Ber-Lamsdorf Foundation Switzerland Israel and by the Advancement of Mankind Foundation, is gratefully acknowledged. We thank Proff. D. Arigoni and A. Eschenmoser, ETH Zürich, for their valuable proposals and comments on the mechanism of the rearrangement.