Aziridinium Salts Research Articles

Stereospecific Synthesis of Unprotected, α,β-Disubstituted Tryptamines and Phenethylamines from 1,2-Disubstituted Alkenes via a One-Pot Reaction Sequence.

Unprotected, α,β-disubstituted tryptamines and phenethylamines are obtained by a one-pot, metal-free sequence that proceeds by the in situ formation of aziridinium salts followed by Friedel-Crafts reaction with electron-rich (hetero)arenes. Both steps are facilitated by hexafluoroisopropanol as the solvent. The one-pot sequence was effective for diversely substituted indoles and 1,3,5-trimethoxybenzene, for cyclic and acyclic alkenes, and proceeded in a stereospecific fashion for both (E)- and (Z)-1,2-disubstituted alkenes. Moreover, one-pot morpholine addition to an aziridinium salt provided a diamine.

Regiodivergent Nucleophilic Fluorination under Hydrogen Bonding Catalysis: A Computational and Experimental Study

The controlled programming of regiochemical outcomes in nucleophilic fluorination reactions with alkali metal fluoride is a problem yet to be solved. Herein, two synergistic approaches exploiting hydrogen bonding catalysis are presented. First, we demonstrate that modulating the charge density of fluoride with a hydrogen-bond donor urea catalyst directly influences the kinetic regioselectivity in the fluorination of dissymmetric aziridinium salts with aryl and ester substituents. Moreover, we report a urea-catalyzed formal dyotropic rearrangement, a thermodynamically controlled regiochemical editing process consisting of C-F bond scission followed by fluoride rebound. These findings offer a route to access enantioenriched fluoroamine regioisomers from a single chloroamine precursor, and more generally, new opportunities in regiodivergent asymmetric (bis)urea-based organocatalysis.

Phase Transfer Synthesis of Novel Based Surfactants: Role of Biocorrosion Inhibition

Two types of corroded medium, acid and SRB, could be evaluate novel aziridinium, pyrrolium and azepanium quaternary ammonium salts as corrosion inhibitors at the concentration range of 500 - 100 ppm in 1M HCl. Quaternization of a series of heterocyclic amines with 4-nonyl phenol in the presence of aqueous sodium hydroxide under phase transfer conditions in chloroform as a solvent was performed (Scheme 1). Active ingredients of those inhibitors included long chain hydrocarbon heterocyclic amines were confirmed using FTIR, 1H NMR, and elemental analyses. The results, which include the corrosion and electrochemical testing data, showed that tested corrosion inhibitors In1 - In4 are effective in studied range of concentration and the corrosion effectiveness of tested quats increases toward In1- In3 with increase the number of member rings. The galvanostatic polarization curves showed that, the inhibitor behaves as mixed type. The observed corrosion data indicate that, the inhibition of carbon steel corrosion is due to the adsorption of the inhibitor molecules on the surface, which follow Langmuir adsorption isotherm. By fitting the obtained experimental data with Langmuir adsorption model, some thermodynamic and kinetic parameters such as adsorption free energy, Gads, equilibrium constant, Kads, were estimated. Apparently, the polar group makes it possible to lengthen the hydrophobic fragment of the inhibitor without significantly disturbing its hydrophilic–lipophilic balance and thus make the inhibitor not only more hydrophobic but also more soluble in water, which enhances its technological properties. For evaluation of SRB inhibition efficacy, microbial activity was monitored and cell counts were determined. All inhibitors were able to reduce microbial activity. The growth of the reference SRB (Desulfomonas pigra) was shown to be completely inhibited by In1- In3. In contrast, In4 had only a slight effect as being due to the presence of pyrrolium cation which may also be achieved due to decreasing the protective effect process. In this work, the thermodynamic parameters for adsorption and activation processes were determined; the following formulation properties are considered: the surface tension at cmc (?cmc), critical micelle concentration (cmc) of the surfactants in aqueous solutions, saturated adsorption amount of the surfactant (G8) and the minimum average area per surfactant molecule (Amin) at the air–water interface. On the bases of the result of small saturated adsorption amount and the large minimum average area per surfactant molecule, it is indicated that the minimum average area of surfactant decreases with the enhanced hydrophilic character of the molecule. A direct relationship has found between the corrosion efficacy (% IE) and G8.

ChemInform Abstract: Reactivity of Aziridinium Salts in Different Solvents Unraveled by a Combined Theoretical and Experimental Approach

This chapter focuses on the importance of aziridinium ions as intermediates in organic chemistry. The principal aim is to gain insight into the factors to take into account for the selective synthesis of a variety of functionalized amines via aziridinium salts, such as the nature of the aziridinium ion (ring strain and N- and C-substituents of the aziridine ring), the nucleophile, and the solvent environment. Molecular modeling is used to investigate kinetics, electrostatics, and frontier molecular orbitals of reactions involving intermediate aziridinium ions, such as the nucleophilic ring opening of aziridines, the ring expansion of nitrogen heterocycles, and the ene reactions with triazolinedione. Open image in new window

ChemInform Abstract: Nucleophile‐Dependent Regio‐ and Stereoselective Ring Opening of 1‐Azoniabicyclo[3.1.0]hexane Tosylate.

AbstractThe title tosylate (III), a stable bicyclic aziridinium salt, is synthesized and subjected to ring‐opening reactions with various nucleophiles including halides, azide, acetate, and cyanide.

Nucleophile‐Dependent Regio‐ and Stereoselective Ring Opening of 1‐Azoniabicyclo[3.1.0]hexane Tosylate

1-[(1R)-(1-Phenylethyl)]-1-azoniabicyclo[3.1.0]hexane tosylate was generated as a stable bicyclic aziridinium salt from the corresponding 2-(3-hydroxypropyl)aziridine upon reaction with p-toluenesulfonyl anhydride. This bicyclic aziridinium ion was then treated with various nucleophiles including halides, azide, acetate, and cyanide in CH3CN to afford either piperidines or pyrrolidines through regio- and stereoselective ring opening, mediated by the characteristics of the applied nucleophile. On the basis of DFT calculations, ring-opening reactions under thermodynamic control yield piperidines, whereas reactions under kinetic control can yield both piperidines and pyrrolidines depending on the activation energies for both pathways.

ChemInform Abstract: Synthesis and Characterization of Novel Ionic Liquids: N‐Substituted Aziridinium Salts.

AbstractSome representative compounds of a new family of room‐temperature ionic liquids built from aziridinium cations are prepared.

Synthesis and Characterization of Novel Ionic Liquids: N‐Substituted Aziridinium Salts

Ionic liquids based on three‐membered ring aziridinium cations have been synthesized for the first time using a straightforward synthetic route. N‐butyl‐N‐methylaziridinium bis(trifluoromethanesulfonyl)imide, N‐propyl‐N‐ethylaziridinium bis(trifluoromethanesulfonyl)imide, N‐butyl‐N‐[2‐(2‐methoxyethoxy)ethyl]aziridinium bis(trifluoromethanesulfonyl)imide, N‐butyl‐N‐methylaziridinium dicyanamide, and N‐butyl‐N‐ethylaziridinium dicyanamide were thus obtained in good yields and satisfactory purity and fully characterized.

ChemInform Abstract: Regioselectivity in the Ring Opening of Non‐Activated Aziridines

AbstractReview: 81 refs.

Regioselectivity in the ring opening of non-activated aziridines

In this critical review, the ring opening of non-activated 2-substituted aziridines via intermediate aziridinium salts will be dealt with. Emphasis will be put on the relationship between the observed regioselectivity and inherent structural features such as the nature of the C2 aziridine substituent and the nature of the electrophile and the nucleophile. This overview should allow chemists to gain insight into the factors governing the regioselectivity in aziridinium ring openings (81 references).

Phosphorylated aziridinium salts: synthesis and ring opening with nucleophiles

Treatment of 1- tert -butyl-2-dimethoxyphosphoryl-3,3-dimethylaziridine with picric, perchloric or fluoboric acid affords the stable corresponding aziridinium salts, which are prone to undergo ring opening on reaction with alcohols, carboxylate and thiocyanate ions.

Some Differential Effects of 4-Diphenylacetoxy-N-(2-chloroethyl)-piperidine Hydrochloride on Guinea-pig Atria and Ileum

4-Diphenylacetoxy-N-(2-chloroethyl)-piperidine hydrochloride (I) cyclizes at neutral pH to form an aziridinium salt. The formation and breakdown of the salt depend on the temperature (in the range 25 to 37 degrees C). In solution at 30 degrees C, peak levels, corresponding to 60-80% conversion, are reached after around 60 min and the half-life exceeds 100 min. In the presence of 0.9% NaCl conversion was reduced to 45-60%. I blocks muscarinic receptors in guinea-pig ileum and atria irreversibly and it is possible to produce dose-ratios on ileum with 10 nM I which are about 100 times those on atria. After about 30 min exposure to solutions of I (prepared 15-20 min previously so that formation of aziridinium ions is well-established) the graph of log (dose-ratio) against time is linear and similar plots were obtained with two different agonists, carbachol and ethoxyethyltrimethylammonium. With results for the ileum, extrapolation of the line suggests that it does not start from zero (dose-ratio = 1): this is because of an initial relatively rapid reversible block. This early phase is similar to that seen on ileum with 10 nM 4DAMP methobromide, which is a competitive antagonist, so is probably caused by competitive block by the aziridinium ion, which closely resembles 4DAMP metho-salts. The subsequent irreversible phase should be caused by alkylation of the receptors. I is easy to make and should be a valuable tool for the study of muscarinic receptors.

ChemInform Abstract: Efficient Synthesis of Functionalized Aziridinium Salts.

AbstractThe authors revise the results reported in a previous paper [J.

Zurückziehung: Stable Aziridinium Salts as Versatile Intermediates: Isolation and Regio‐ and Stereoselective Ring‐Opening and Rearrangement

Der Artikel Stable Aziridinium Salts as Versatile Intermediates: Isolation and Regio and Stereoselective Ring-Opening and Rearrangement, online veröffentlicht am 13. Januar 2009 in der Wiley Online Library (www.onlinelibrary.wiley.com, DOI: 10.1002/ange.200805244) und gedruckt in der Angewandten Chemie (Angew. Chem. 2009, 121, 1354--1356), wird nach Übereinkunft des Korrespondenzautors mit dem Chefredakteur Dr. Peter Gölitz und Wiley-VCH zurückgezogen. Diese Zurückziehung wurde vereinbart, weil die Autoren durch zusätzliche NMR-spektroskopische Analysen und die Herstellung authentischer Bezugsverbindungen entdeckten, dass die Strukturen der Aziridinium-Ionen 3 falsch zugeordnet wurden.

Retraction: Stable Aziridinium Salts as Versatile Intermediates: Isolation and Regio‐ and Stereoselective Ring‐Opening and Rearrangement

The following article from Angewandte Chemie International Edition, “Stable Aziridinium Salts as Versatile Intermediates: Isolation and Regio- and Stereoselective Ring-Opening and Rearrangement”, published online on January 13, 2009 in Wiley Online Library (www.onlinelibrary.wiley.com, DOI: 10.1002/anie.200805244) and in print (Angew. Chem. Int. Ed. 2009, 48, 1328–1330), has been retracted by agreement between the corresponding author, the journal Editor, Dr. Peter Gölitz, and Wiley-VCH. The retraction has been agreed upon because by performing additional NMR analyses and preparing authentic reference compounds, the authors discovered that the structures of the aziridinium ions 3 were incorrectly assigned.

Efficient Synthesis of Functionalized Aziridinium Salts

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionEfficient Synthesis of Functionalized Aziridinium SaltsHyun-Soon Chong*, Hyun A. Song, Mamta Dadwal, Xiang Sun, Inseok Sin, and Yunwei ChenCite this: J. Org. Chem. 2010, 75, 22, 7966Publication Date (Web):September 28, 2010Publication History Received2 September 2010Published online28 September 2010Published inissue 19 November 2010https://doi.org/10.1021/jo101732rCopyright © 2010 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views6619Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (596 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Anions,Chemical structure,Functionalization,Ions Get e-Alerts

Systematic Study of Halide‐Induced Ring Opening of 2‐Substituted Aziridinium Salts and Theoretical Rationalization of the Reaction Pathways

AbstractThe ring‐opening reactions of 2‐alkyl‐substituted 1,1‐bis(arylmethyl)‐ and 1‐methyl‐1‐(1‐phenylethyl)aziridinium salts with fluoride, chloride, bromide and iodide in acetonitrile have been evaluated for the first time in a systematic way. The reactions with fluoride afforded regioisomeric mixtures of primary and secondary fluorides, whereas secondary β‐chloro, β‐bromo and β‐iodo amines were obtained as the sole reaction products from the corresponding halides by regiospecific ring opening at the substituted position. Both experimental and computational results revealed that the reaction outcomes in the cases of chloride, bromide and iodide were dictated by product stability through thermodynamic control involving rearrangement of the initially formed primary halides to the more stable secondary halides. The ring opening of the same aziridinium salts with fluoride, however, was shown to be mediated by steric interactions (kinetic control), with the corresponding primary β‐fluoro amines being obtained as the main reaction products. Only for 2‐acylaziridinium ions was the reaction outcome shown to be under full substrate control, affording secondary β‐fluoro, β‐chloro, β‐bromo and β‐iodo amines through exclusive attack at the activated α‐carbonyl carbon atom.

ChemInform Abstract: Ring Opening Reactions of 2-Trialkylsilylaziridines.

2-Trialkylsilylaziridines do not readily undergo nucleophilic ring opening without electrophilic assistance. In the presence of strong acids protonation at the nitrogen is followed by nucleophilic attack α to the silicon. With non-nucleophilic counterions, the protonated aziridine can be obtained. N-Alkylation gives the aziridinium salt, which also undergoes α-cleavage. However, the presence of a 3-phenyl substituent gives a stable aziridinium salt that undergoes nucleophilic attack β to the silicon. Reaction of 2-trialkylsilylaziridines with trialkylsilyl halides usually leads to α-cleavage, however, desilylation to give the enamine is also observed. Fluorodesilylation of the 2-trialkylsilylaziridine is not straightforward and only occurred readily when a 2-ethoxycarbonyl group was present. Fluorodesilylation followed by attack on a carbonyl was only observed when very dry samples of fluoride ions were employed.

ChemInform Abstract: Efficient Synthesis of Functionalized Aziridinium Salts.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Stable Aziridinium Salts as Versatile Intermediates: Isolation and Regio- and Stereoselective Ring-Opening and Rearrangement

In dieser Zuschrift wurde den Verbindungen 8 fälschlicherweise die Struktur von α,β-ungesättigten Aminen zugeordnet. Eine Überprüfung der NMR-Spektren spricht dafür, dass es sich bei 8 um Allylamine handelt. 1 Die Korrektur betrifft das Inhaltsverzeichnis, Schema 1 und Tabelle 3 in der Zuschrift sowie die Hintergrundinformationen. Außerdem sind Textpassagen, in denen 8 als α,β-ungesättigtes Amin bezeichnet wird, entsprechend abzuwandeln. Die Autoren entschuldigen sich für dieses Versehen.