Synthesis and hydrolysis of substituted imidazolinium salts. Behaviour of the degradation products on varying pH

Reaction of l-alkyl-2,3-diarylimidazolinium iodides 1a-i with alkaline solutions afforded N'-alkyl-N-aroyl-N-arylethylenediamines 2a-i. Compounds 2 are stable under acid conditions but in neutral or alkaline media rearrange giving N-alkyl-N-aroyl-N-arylethylenediamines 3a-i. Treating compounds 3 with concentrated acids reverse reaction 3 → 2 takes place. Kinetic studies were performed on this intramolecular N → N' aroyl transfer over the H_o-pH range ?0.9 to 2.30. Compounds 3 undergo acyl transfer to give 2 by a mechanism which involves a change in the rate determining step from formation to catalysed decomposition of a heterocyclic intermediate I ²⁺ on going from H_o to pH values. The existence of maxima in the pH rate profile allowed to determine apparent pK_a values of the imidazolidine intermediates which gave good correlation with Hammett sigma values. Stability of these heterocycles was also predicted by determination of thermodynamic parameters.     

Azulene‐substituted pyranylium salts. Syntheses and products characterization

The synthesis of 4‐azulene‐substituted 2,6‐diphenyl‐ and 2,6‐dimethyl‐pyranylium salts and 2‐azulenesubstituted 4,6‐dimethyl‐pyranylium salts by nucleophilic substitution at pyranylium moiety with various azulenes was studied. The starting materials for 2,6‐diphenyl derivatives were 4 chlorinated pyranylium salts. They were obtained by the halogenation with PCl₅ of corresponding pyranones and were used either in situ or after separation. For the synthesis of dimethyl derivatives the corresponding pyranones were treated with POCl₃ and the resulted intermediate was reacted in situ with azulene. In the aim to study the influence of dihedral angle between azulene and pyranylium planes on the recorded spectra, both moieties were adequately substituted. The obtained results were in accord with the calculated values.     

Azulene‐substituted pyridines and pyridinium salts. Synthesis and structure. 2. Azulene‐substituted pyridinium salts

4‐Azulen‐1‐yl substituted 2,6‐dimethyl‐and 2,6‐diphenyl‐pyridinium salts are obtained in yields between 50 % and 100 % in the reaction of corresponding 4‐azulen‐1‐yl‐pyranylim salts and various amines. The effects of amine structure and of substitution in the heterocycle or at azulene moieties on the synthesis have been investigated. The uv‐vis and NMR spectra of reaction products are examined and discussed in correlation with their structure.     

Stevens rearrangement of unsaturated ammonium salts. Synthesis of substituted furans

Ammonium salts bearing but-2-ynyl and phenacyl or 2-(naphth-2-yl)-2-oxoethyl moieties at the nitrogen atom underwent Stevens rearrangement to form substituted furan-3-amines. Quaternization of the latter afforded appropriate iodomethylates.     

Synthesis of substituted 2- and 4-carboxypyrylium salts

Modified methods for the synthesis of substituted 2- and 4-carboxypyrylium perchlorates and the necessary diphenacylacetic acids are proposed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 162–166, February, 1981.     

Synthesis of oxazolyl‐substituted morpholinium salts

Morpholinium salts coupled to oxazolyl moieties have been synthesized via nucleophilic substitution of a series of oxazolyl chlorides with morpholine. The oxazole moieties were first synthesized and then coupled with morpholine. The corresponding hydrochloride and methyl iodide salts were obtained, purified, characterized and then tested for muscarinic receptor binding affinity. Biological test results from MDS Pharma Services revealed no significant muscarinic receptor affinity.     

Azulene‐substituted pyridines and pyridinium salts. Synthesis and structure. 1. Azulene‐substituted pyridines

4‐Azulen‐1‐yl substituted 2,6‐dimethyl‐and 2,6‐diphenyl‐pyridines are obtained in good yields from the reaction of corresponding 4‐azulen‐1‐yl‐pyranylium salts and ammonium acetate in ethanol or starting from 4‐chloro‐2,6‐diphenyl‐pyranylium salts in two steps: reaction with azulenes followed by in situ treatment with ammonium acetate. The effect of substitution at the 3‐position of the heterocycle was taken into account. The structure assignment was accomplished with NMR and uv‐vis spectra.     

Photochemical reactions of substituted cyclopropenium salts.

Photochemical reactions of triphenylcyclopropenium tetrakis(pentafluorophenyl)gallate (TPCPGa) and diphenyl-(2-methoxy-1-naphthyl)-cyclopropenium tetrakis(pentafluorophenyl)gallate (DPMNCPGa) (Chart 1) have been investigated in acetonitrile. Traces of water were required for the photochemical reactions to proceed. The disappearance of both TPCPGa and DPMNCPGa obeys zero-order kinetics with rate constants (k) having a linear dependence on the concentration of water. Electron-transfer from water to the cyclopropenium cation is proposed as the primary process in the formation of the cyclopropenyl radical. The latter dimerizes leading to the photoproducts.     

Ion chromatographic determination of hydrolysis products of hexafluorophosphate salts in aqueous solution

In this work, hydrolysis of three different hexafluorophosphate salts in purified water was investigated. Aqueous samples of lithium hexafluorophosphate (LiPF₆), sodium hexafluorophosphate (NaPF₆) and potassium hexafluorophosphate (KPF₆) were prepared and stored for different times. Ion chromatography (IC) with UV as well as non-suppressed and suppressed conductivity detection was used for the analysis of the reaction products. For the detection and identification of the formed decomposition products, an IC method using IonPac AS14A 250 mm × 4.0 mm i.d. column and 2.5 mM KHCO₃–2.5 mM K₂CO₃ eluent was established. Besides hexafluorophosphate, four other anionic species were detected in fresh and matured aqueous solutions. The hydrolysis products fluoride (F⁻), monofluorophosphate (HPO₃F⁻), phosphate (HPO₄²⁻) and difluorophosphate (PO₂F₂⁻) were found and were unambiguously identified by means of standards or electrospray ionization mass spectrometry (ESI-MS). It was shown that stability of hexafluorophosphate solutions depends on the nature of the counter ion and decreases in the order potassium > sodium > lithium.     

Synthesis of functionally substituted benzo[c]pyrylium salts

Benzo[c]pyrylium salts that contain an acetyl, cyano, or ethoxycarbonyl group in the 4 position of the pyrylium ring were synthesized by the reaction of 3-(3,4-dimethoxyphenyl)pentane-2,4-dione and -(3,4-dimethoxyphenyl)acetoacetonitrile and ethyl -(3,4-dimethoxyphenyl)acetoacetate, as well as ethyl -(3,4-dimethoxyphenyl)benzoylacetate, with acyl perchlorates. It is shown that -(3,4-dimethoxyphenyl)acetoacetonitrile ethyleneketal is converted to 3-amino-4-acetylbenzo(c)pyrylium salts under these conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 465–470, April, 1990.     

Synthesis of highly phenylene substituted p-phenylene oligomers from pyrylium salts

A transition metal free route to phenyl substituted oligophenylenes that tolerates halogens is described.     

溴化苄基取代吡啶类季铵盐的制备和抗菌性能

抗菌材料和抗菌制品的研究与应用一直是世界各国研究的重要课题~([1-3]),其中有机抗菌剂占据主要地位.季铵盐是研究比较多的一类有机抗菌剂,它们表现出良好的物理性质,如胶束浓度低,黏弹性好和溶解性强~([4]),同时此类抗菌剂具有强效的抗菌作用~([5]),引起了人们的极大兴趣.季铵盐广泛应用于医药、卫生、食品、饲料工业、农业、纺织、塑料、橡胶、造纸、水处理、油田开采、涂料、日常生活等多种领域~([6-10]).     

Use of tetrahydropyrimidinium salts for highly efficient palladium-catalyzed cross-coupling reactions of aryl bromides and chlorides

New, sterically demanding 1,3-dialkyl-3,4,5,6-tetrahydropyrimidinium salts (2) as NHC precursors have been synthesized and characterized. These salts, in combination with palladium acetate, provided active catalysts for the cross-coupling of aryl chlorides and bromides under mild conditions. The catalytic system was applied to the Heck, Suzuki and benzaldehyde (Kumada) coupling reactions. Catalyst activity was found to be influenced by the presence of a methoxy group on the ring of the p-position of benzyl substituent of the ligand precursor.     

Effect of pH on the aluminum salts hydrolysis during coagulation process: formation and decomposition of polymeric aluminum species

Effect of pH on the aluminum chloride hydrolysis at low concentration was investigated in detail by electrospray ionization (ESI) mass spectrometry. In particular, formation and decomposition processes of polymeric aluminum species were discussed. When coagulant AlCl(3) was diluted to normal coagulant dose (1.5 x 10(-4) mol/L), hydrolysis occurred immediately. Monomeric and dimeric aluminum species were the main products at pH 4.0. With pH increasing, hydrolysis and polymerization processes were accelerated. Monomeric and dimeric aluminum species hydrolyzed and polymerized into small polymeric aluminum species (Al(3)-Al(5) species) at pH 4.8. Through aggregation and self-assembly, the small polymeric aluminum species polymerized into median polymeric species (Al(6)-Al(10) species) at pH 5.0. In the same way, small and median polymeric aluminum species further aggregated into large polymeric species (Al(11)-Al(21) species). When pH was up to 5.8, metastable median and large polymers species decomposed into small aluminum species, then further disaggregated into dimeric species. With pH increased to 6.4, majority of aluminum species formed to Al(OH)(3) amorphous flocs. Accordingly, coagulant hydrolysis mechanism from polymerization toward decomposition was proposed. Furthermore, formation and decomposition of polymeric aluminum species in AlCl(3) solution followed the "Core-links" model, while those of Keggin-Al(13) species in polyaluminum solution was based on the "Cage-like" model.     

Synthesis of deuterium labeled compounds by KCN-assisted hydrolysis of phosphonium salts

We developed a facile deuterium labeling method for benzylic or allylic halides or acetates systems. Conversion of the halides or acetates to the corresponding phosphonium salts and the following mild hydrolysis with KCN afforded the deuterium labeled compounds in good yields.     

Synthesis of cyclopentanoid natural products via vinyl phosphonium salts

Cyclopentenones obtained from cyclisations involving phosphonium salts are converted to dihydrojasmone, dihydrojasmolone and known precursors of methylenomycins A and B.     

Investigation of hydrolysis products from uranium trioxide and uranyl salts by derivatography and infrared spectroscopy

Summary It can be established from the data obtained by derivatography and infrared spectroscopy that the hydrolysis of- and amorphous UO₃ at room temperature, and that of uranyl salts in the presence of anion exchange resins, leads to compounds of UO₃ · 2H₂O composition with identical properties. This type of compound is of complex structure containing in addition to water molecules in two kinds of bonds, hydroxyl groups as well. The relative quantities of the components with different bond strengths show that the molecular structure can be described only by a trimeric formula, or by a formula corresponding to an integral multiple of a trimeric form. One kind of water has diffuse bond strength and is probably water between individual layers, while the other is a structural water of definite bond strength which may form various hydrogen bridge bonds.

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Zusammenfassung Aus derivatographischen und IR-spektroskopischen Untersuchungen ergab sich, daß die Hydrolyse von-UO₃ und amorphem UO₃ bei Zimmertemperatur sowie die Hydrolyse von Uranylsalzen in Gegenwart von Anionenaustauschharzen zu Verbindungen der Zusammensetzung UO₃ · 2H₂O führt, die identische Eigenschaften haben. Dieser Verbindungstypus hat komplexe Struktur und enthält außer Wassermolekülen mit zwei verschiedenen Bindungsarten auch Hydroxylgruppen. Die relativen Mengen der verschieden fest gebundenen Komponenten zeigen, daß die Molekülstruktur nur durch eine trimere Formel wiedergegeben werden kann. Ein Teil der Wassermoleküle ist diffus gebunden. Dabei handelt es sich wahrscheinlich um solche zwischen einzelnen Schichten. Die anderen sind strukturell gebunden und dürften verschiedene Wasserstoffbrücken ausbilden.

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Résumé On a pu établir, à partir de données obtenues par dérivatographie et spectroscopie infrarouge, que l'hydrolyse de UO₃ et amorphe à température ambiante, ainsi que celle des sels d'uranyle en présence de résines échangeuses d'anions, conduisait à des composés de composition UO₃ · 2H₂O aux propriétés identiques. Ce type de composé est de structure complexe, contenant en plus de molécules d'eau correspondant à deux sortes de liaisons, également des groupes hydroxyles. Les quantités relatives de composants possédant des forces de liaison différentes montrent que la structure moléculaire ne peut être représentée que par une formule trimère, ou par une formule correspondant à un multiple entier d'une forme trimère. L'une des sortes d'eau possède une force de liaison diffuse et il s'agit probablement d'eau placée entre des couches individuelles, tandis que l'autre est de l'eau structurale, avec une force de liaison définie, pouvant former diverses liaisons par pont d'hydrogène.

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This paper was presented at the Symposium on Analytical Chemistry held in Graz, 29th September–1st October 1965.