Behavior of dialkylallyl(4-hydroxybut-2-ynyl)ammonium bromides toward powdered sodium hydroxide and aqueous alkali

Under the influence of a twofold molar quantity of powdered sodium hydroxide in the presence of a few drops of methanol at room temperature dialkylallyl(4-hydroxybut-2-ynyl)ammonium bromides undergo a Stevens rearrangement with transfer of the reaction center, forming substituted amino alcohols with an allene group. Intramolecular cyclization of the products and concurrent hydration lead to the formation of a mixture of dialkyl(4-allyl-2,5-dihydrofuran-2-yl)amines and dialkylamino-3-allyl-4-hydroxybutanones with overall yields of 37-41%. During the aqueous-alkali cleavage of dialkylallyl(4-hydroxybut-2-ynyl)ammonium bromides the products from intramolecular cyclization were obtained with yields of 38-41%. Under the conditions both of Stevens rearrangement and of aqueous-alkali cleavage the secondary amines are also formed with yields of 15-17%. As nonamine products mixtures of compounds, which according to the IR spectra contain unconjugated and conjugated carbonyl groups, were obtained. The presence of an aldehyde group was established by a silver mirror reaction. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 354-360, March, 2009.     

Interaction of acridine orange and sodium poly-α, L-glutamate

Summary The interaction of acridine orange and sodium poly-, L-glutamate in the pH range of 3.8–6.8 was studied by a spectral method and viscosity measurement. From the binding data, the molar change in entropy, enthalpy and the number of binding sites on polymer were calculated. The values of S° were positive. S° for binding decreasing extensively in pH range of 5.0. These results are explained by the transition of helix coil of the polymer. The intrinsic viscosity reduction in the presence of the dye, in pH 3.8 is due to the formation of dye bridges between the polymer helix.

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Zusammenfassung Die Wechselwirkung zwischen Natriumsalz-, L-Glutamin-Säure wurde mit den Methoden der Spektroskopie und der Viskositätsmessung untersucht. Aus den Bindungsdaten wurde die molare Änderung von Entropie und Enthalpie und die Zahl der Brückenstellen des Polymeren berechnet. Die Werte von S° sind positiv. Für die Binding ergibt sich für S° eine starke Verminderung im Bereich pH 5.0. Diese ist durch die Änderung der Konformation der Polymerketten (Helix Knäuel-Umwandlung) zu erklären.

     

Binding mechanisms of nano-baskets toward alkali metals

Thirty-four nano-basket derivatives of di-ionizable calix[4]arene conformers in nine scaffolds bearing two pendant groups of N-(R)-sulfonyl carboxamides were synthesized and examined using isothermal titration calorimetry. The binding mechanisms of synthesized conformers toward alkali metal cations were evaluated and two main interactions were assessed including cation?C?? interaction between alkali metal and the aromatic unit of conformer as well as the strong binding ion?Cdipole interaction between nitrogen atoms in the pendant groups and alkali cation. The ITC data revealed that the bindings of cone and partial-cone conformers toward alkali metal cations exhibited one-step mechanism, while both 1,2 alternate conformer bounds the alkali metal cations in a two-step mechanism.     

Reaction of sodium amide with 1-chloromethylsilatrane

The reaction of 1-chloromethylsilatrane with sodium amide in benzene is accompanied by ring expansion with formation of 1-amino-2-carba-3-oxahomosilatrane.     

Fluorescence quenching method for the determination of sodium carboxymethyl cellulose with acridine yellow or acridine orange

In near neutral to weak basic media, sodium carboxymethyl cellulose (NaCMC) will dissociate to become a macro polymeric anion, which can react with acridine yellow (AY) or acridine orange (AO) to form an ion-association complex resulting in fluorescence quenching of the acridine dyes. The maximum fluorescence quenching wavelength is 505 nm (lambda(ex)=440 nm) for AY system and 530 nm (lambda(ex)=493 nm) for AO system, respectively. The fluorescence quenching values (DeltaF) are directly proportional to the concentrations of NaCMC and the linear ranges are 20.0-4000 microg/L for AY system and 20.0-7000 microg/L for AO system, separately. This method has high sensitivity and the detection limits for NaCMC are 58.0 microg/L (AY system) and 157.2 microg/L (AO system). The effects of coexistent substance have been investigated, and the results show that this method has a relatively good selectivity. A fluorescence quenching method for the determination of NaCMC based on the ion-association reactions of CMC polymeric anion with a basic acridine dye was developed. The method is sensitive, simple and fast.     

2,4,6-Trichloropyrimidine. Reaction with sodium amide

The first reaction between 2,4,6-trichloropyrimidine 1 and anionic nitrogen nucleophiles is described. Treatment of 1 with one equivalent of sodium amide gave mixtures of 4-amino-2,6-dichloropyrimidine 2 and 2-amino-4,6-dichloropyrimidine 3 . Additional quantities of sodium amide failed to provide either diamino- or triaminopyrimidines. Instead, the strongly basic nature of sodium amide led to higher molecular products that were not characterized.     

Trimagnesium-bridged trinuclear ferrocenophanes cocomplexed with solvated mononuclear alkali metal amide molecules

Three prototypes of the remarkable new class of compound referred to in the title have been synthesised by treating ferrocene with the same mixed lithium (or sodium)-magnesium amide recipes as those used previously to make s-block metal inverse crowns.     

Lanthanum and alkali metal coordination chemistry of the bis(dimethylphenylsilyl)amide ligand

The coordination chemistry of the bis(dimethylphenylsilyl)amide ligand, [N(SiMe2Ph)2]1-, with sodium, potassium, and lanthanum has been investigated for comparison with the more commonly used [N(SiMe3)2]1- and [N(SiHMe2)2]1- ligands. HN(SiMe2Ph)2 reacts with KH to produce KN(SiMe2Ph)2, 1, which crystallizes from toluene as the dimer [KN(SiMe2Ph)2(C7H8)]2, 2. The structure of 2 shows that the [N(SiMe2Ph)2]1- ligand can function as a polyhapto ligand with coordination from each phenyl group as well as the normal nitrogen ligation and agostic methyl interactions common in methylsilylamides. Each potassium in 2 is ligated by an eta4-toluene, two bridging nitrogen atoms, and an eta2-phenyl, an eta1-phenyl, and an eta1-methyl group. KN(SiMe2Ph)2 crystallizes from toluene in the presence of 18-crown-6 to make the monometallic complex (18-crown-6)KN(SiMe2Ph)2, 3, in which [N(SiMe2Ph)2]1- functions as a simple monodentate ligand through nitrogen. The reaction of HN(SiMe2Ph)2 with NaH in THF at reflux for 2 days generates Na[N(SiMe2Ph)2], 4, which crystallizes as the solvated dimer {(THF)Na[mu-eta1:eta1-N(SiMe2Ph)2]}2, 5. A lanthanide metallocene derivative of [N(SiMe2Ph)2]1- was obtained by reaction of K[N(SiMe2Ph)2] with [(C5Me5)2La][(mu-Ph)2BPh2]. Crystals of (C5Me5)2La[N(SiMe2Ph)2], 6, show agostic interactions between lanthanum and methyl groups of each silyl substituent. The [N(SiMe3)2]1- analogue of 3, (18-crown-6)KN(SiMe3)2, 7, was also structurally characterized for comparison.     

Synthetic studies toward the pyran core and the amide side chain of psymberin

A synthetic approach to the polysubstituted pyran core and amide side chain of psymberin (irciniastatin A) using stereoselective organoboron methodology is described. An advanced oxyranyl pyran intermediate was prepared using a catalytic enantioselective and diastereoselective three-component reaction involving first an inverse electron-demand hetero [4+2] cycloaddition between 3-boronoacrolein pinacolate and 1-ethoxy-2-methylpropene, followed by an allylboration of ethyl glyoxylate. The amide side chain was prepared highly efficiently using the first example of a doubly diastereoselective allylboration of a chiral α-alkoxy aldehyde under the Lewis acid-catalyzed reaction manifold.     

钠碱法烟气脱硫膜电解再生研究

通过中试实验,研究了钠碱法吸收SO2的过程及其不同条件下膜电解循环再生脱硫废液。结果表明,电流密度和吸收液浓度对再生效果影响较大,高电流密度时的中间室硫转化率高、电导率下降速率快,而低电流密度时的中间室电流效率则稍大;高电流密度时的阴极室pH值和电导率上升速率大于低电流密度时的上升速率,并在电解一定时间后上升速率突然加大。低浓度时中间室电流效率高、硫转化率大且电导率下降速率快;低浓度时阴极室pH值和电导率上升速率要大于高浓度时的上升速率,且在电解一定时间后上升速率突然加大。     

吖啶染料共振瑞利散射法测定藻酸钠

在pH8.5和6.0的BR缓冲溶液中,吖啶橙(AO)和吖啶黄(AY)等碱性吖啶染料能与藻酸钠(SA)反应形成复合物,而使其共振瑞利散射RRS急剧增强并产生新的RRS光谱,其最大散射波长位于523nm(AO体系)和485nm (AY体系),藻酸钠浓度在0.075mg/L～5.0mg/L (AO体系)、0.25mg/L～3.0mg/ L(AY体系)时与散射强度(ΔI)呈直线关系,方法具有较高的灵敏度,其检出限分别为23.8ng/mL(AO体系),6.5ng/mL (AY体系).以吖啶橙体系为例研究了共存物质的影响,表明方法选择性好.用于海带提取液中藻酸钠的测定,结果满意.     

Behavior of triethyloxonium fluoborate toward hydride-ion donors

Summary Triethyloxonium fluoborate reacts with sodium borohydride and with lithium aluminum hydride to give ethane, and does not react with dioxane, ethyl alcohol, benzyl alcohol or tropilidene.     

Interaction between p-tetraphenyl tetrahomodioxacalix[4]arene amide derivatives and alkali and alkaline-earth metal cations

The binding properties of four amido derivatives of p-tetraphenyl tetrahomodioxacalix[4]arene towards alkali and alkaline-earth metal cations using UV-absorption spectrophotometry, ¹H NMR and ESI-mass spectrometry techniques are reported.