Supramolecular catalytic systems based on 1, 4-diazabicyclo[2.2.2]octane,its alkylated quaternary derivatives,and lanthanum nitrate

Spectrophotometry was used to study the catalytic effects of the systems composed of N-monoand N, N-dialkylated 1, 4-diazabicyclo[2.2.2]octanes and lanthanum nitrate on the hydrolysis rate of O-alkyl O-4-nitrophenyl chloromethylphosphonates (Alk = Et, Buⁿ, and n-hexyl). The mechanism of action and efficiency of the catalytic system depend on the structure of the heterocycle, its propensity to aggregation and complexation with the lanthanum cation, and the relative content of the components in solution. The maximum catalytic effect (a ～115-fold increase in the hydrolysis rate constant) was achieved in micellar solutions of the cationic monoalkylated derivative of 1, 4-diazabicyclo[2.2.2]octane and lanthanum nitrate.

     

Synthesis of 1,4-diazabicyclo[2.2.2]octane

Double intramolecular cyclization of N,N-bis(2-chloroethyl)-N-N-bis(2-cyanoethyl)ethylenediamine leads to 1,4-bis(2-cyanoethyl)-1,4-diazoniabicyclo[2.2.2]octane dichloride, which undergoes decyanoethylation to 1,4-diazabicyclo[2.2.2]octane when it is heated. The structures of the compounds were confirmed by their IR and PMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 548–550, April, 1978.     

Design and synthesis of artificial ribonucleases based on 1,4-diazabicyclo[2.2.2]octane and imidazole

The review surveys the results of our studies devoted to the design of highly efficient catalysts of hydrolysis of the phosphodiester bonds in RNA. These catalysts contain the imidazole residue in the catalytic domain, one or several bis-quaternized rings of 1,4-diazabicyclo[2.2.2]octane as a polycationic RNA-binding domain, and a lipophilic radical. A versatile approach to artificial ribonucleases of this type was proposed, which allows one to vary not only the number of positive charges in the RNA-binding domain, the structure of the catalytic site, and their mutual arrangement but also the domain structure of the molecule as a whole. Analysis of the catalytic properties of the synthesized constructs makes it possible to optimize the domain structure and the geometry of the molecule ensuring its maximum ribonuclease activity.     

DABCO-directed self-assembly of bisporphyrins (DABCO=1,4-diazabicyclo[2.2.2]octane)

Three isomeric zinc bisporphyrins have been prepared by covalently linking together two aminoporphyrins with an isophthalic acid derivative. The porphyrins differ in the substitution pattern on the meso phenyl groups, that is, ortho, meta, or para. Titrations carried out by UV-visible and 1H NMR spectroscopy have been used to map out the stabilities and the stoichiometries of the complexes formed with 1,4-diazabicyclo[2.2.2]octane (DABCO) in chloroform. The ortho- and meta-substituted bisporphyrins form 1:1 intramolecular sandwich complexes. The para-substituted bisporphyrin cannot adopt the cofacial conformation required for this type of complex and forms a higher order 2:2 intermolecular assembly, which is stable over a wide range of DABCO concentrations.     

Conformation perturbation of p-sulfonatocalix[5]arene via complexation of 1,4-diazabicyclo[2.2.2]octane

A novel conformation of p-sulfonatocalix[5]arene has been established in the solid state with two calixarenes organised in a 'bis-molecular capsule' shrouding two di-protonated DABCO molecules and two water molecules within.     

Tetracationic compounds based on 1,4-diazabicyclo[2.2.2]octane: antibacterial activity and reactions with N-containing nucleophiles

Antibacterial activity of tetracationic compounds based on 1,4-diazabicyclo[2.2.2]octane (DABCO) bis-quaternary salts with dodecyl substituents bound by linker groups containing four carbon atoms was studied. All the compounds exhibited activity against the test-strains under study. The gram-positive culture S. aureus was found to be the most sensitive to the influence of compounds in question. The highest activity against S. aureus was exhibited by the compounds containing a but-2-yne or a butane linker; their efficiency exceeded that of the reference compound, antibiotic Ciprofloxacin. For the gram-negative culture P. aeruginosa, the highest activity was exhibited by the compound containing a but-2-yne linker. The compounds with a but-2-yne or a butane linker are stable in the presence of nitrogen-containing nucleophiles, which makes them promising for further studies.     

Supramolecular systems based on 1-alkyl-4-aza-1-azoniabicyclo[2.2.2]octane bromides

The aggregation in aqueous solutions of alkylated 1,4-diazabicyclo[2.2.2]octanes of various hydrophobicity and their adsorption at the water-air interface were studied by tensiometry, conductometry, potentiometry, viscosimetry, and ESR spectroscopy. The parameters of adsorption, critical micelle concentrations, concentrations of free counterions (bromide ions), and degree of binding of the counterions with micelles were determined. The intensification of the micelle formation ability of the surfactants with an elongation of the alkyl fragment was shown. The effective radii of ensembles of the hexadecyl and octadecyl derivatives were determined by the dynamic light scattering method. A relationship between the concentration dependences of the size of micelles and their shape was established.     

Complex of alkylated derivative of 1,4-diazabicyclo[2.2.2]octane with palladium dichloride: synthesis,self-association,and biological activity

Russian Chemical Bulletin - A new complex of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide (cationic surfactant with a bicyclic head group) with palladium dichloride (1:1) was synthesized....     

Synthesis of 5,6-benzo-1,2-diazabicyclo [2.2.2]octane

5,6-Benzo-1,2-diazabicyclo[2.2.2]octane was synthesized by nitrosation of 1,2,3,4-tetrahydrocinchoninic acid, reduction of the 1-nitroso derivative to 1-amino-1,2,3,4-tetrahydrocinchoninic acid, cyclodehydration of it to 3-oxo-5,6-benzo-1,2-diazabycyclo[2.2.2]octane, and reduction of the oxo group to a methylene group with lithium aluminum hydride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1369–1371, October, 1970.     

Chemical nuclear polarization effects in photoreactions of 1,4-diazabicyclo[2.2.2]octane with carbonyl-containing compounds

Elementary acts of the photoreaction of diamine with 2,6-diphenyl-p-benzoquinone are determined from the effects of chemical nuclear polarization effects. Hydrogen atom transfer is shown to occur in two stages with the participation of a radical ion pair.     

Synthesis of 1, 2-diazabicyclo [2.2.2] octane, 1, 2-diazabicyclo [3.2.1]-octane,and their derivatives

1, 2-Diazabicyclo [2.2.2] octane, its 6-methyl homolog, and 1, 2-diazabicyclo [3.2.1] octane are synthesized by a general method involving nitrosation of piperidine carboxylic acids, subsequent reduction to 1-aminopiperidine carboxylic acids, cyclization to 3-keto-1, 2-diazabicycloalkanes, reduction of the latter to 1, 2-diazabicycloalkanes. A number of 2-substituted 1, 2-diazabicyclo [2.2.2] octanes are synthesized.     

Catalytic properties of polymer-colloid complexes based on polyethyleneimines and mono- and diquaternized 1,4-diazabicyclo[2.2.2]octane derivatives in the hydrolysis of phosphorus acids esters

Russian Chemical Bulletin - It is established by spectrophotometry that polyethyleneimines, mono- (MQD) and diquaternized (DQD) hexadecyl derivatives of 1,4-diazabicyclo[2.2.2]octane, and mixed...     

Alkylated 1,4-diazabicyclo[2.2.2]octanes: self-association, catalytic properties, and biological activity

Aggregation of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide in the presence of diethyl 4-nitrophenyl phosphate was studied using ¹H NMR spectroscopy. The quantitative characteristics of the aggregation were determined. The data obtained were used to explain the catalytic effect of micelles on the hydrolysis of the phosphate. It was found that the aggregation properties and biological activity of alkylated mono- and dicationic 1,4-diazabicyclo-[2.2.2]octanes are correlated.     

Synthesis of bridgehead hydroxy bicyclo[2.2.2]octane derivatives

Two independent synthetic routes, starting from 1,3-cyclohexadione, toward the 4-hydroxy bicyclo[2.2.2]octane-2,6-dione derivative 3 are described.     

Thermal behaviour of some dibenzobicyclo[2.2.2]octane derivatives

A number of dibenzobicyclo[2.2.2]octane derivatives have been studied due to the interest of such compounds as ligands for coordination compounds with potential biological activity. Their thermal behaviour has been analyzed in order to find out more information about their fragmentation. A connection between the bridge substituents and the fragmentation process has been observed.     

A facile synthesis of highly functionalized dihydrofurans based on 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyzed reaction of halides with enones

Treatment of halides 5 with electrophilic alkenes 2 afforded the corresponding dihydrofurans 3 and 4 in the presence of 1, 4-diazabicyclo[2.2.2]octane (DABCO) with good to excellent yields and in a stereoselective manner in most cases. Moreover, the stereoisomers 3 and 4 could be easily transformed each other in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).     

1,4-diazabicyclo[2.2.2]octanes. I. Method for the synthesis of 1,4-diazabicyclo[2.2.2]octanes with functional substituents or condensed with benzene rings

The reaction of substituted 1,4-dimethylpiperazines and tetrahydroquinoxaline with dibromoethane gives the corresponding 1,4-diazabicyclo[2.2.2]octanes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 272–275, February, 1976.     

Synthesis of novel spiro-cyclohexene bicyclo[2.2.2]octane derivatives

A methodology for the synthesis of novel spiro-cyclohexene bicyclo[2.2.2]octane derivatives, including Claisen rearrangement and ring-closing metathesis (RCM) as key synthetic steps, is described.