Synthesis and Properties of First Bis(fluoreno)crownophanes

Alkylation of 2,7-dihydroxy-9H-fluoren-9-one with 2-(2-chloroethoxy)ethanol, 2-[2-(2-chloroethoxy)-ethoxy]ethanol, and 2-{2-[2-(2-chloroethoxy)ethoxy]ethoxy}ethanol in dimethylformamide in the presence of potassium carbonate gave 78–80% of the corresponding diols which were treated with p-toluenesulfonyl chloride in a dioxanechloroform mixture in the presence of triethylamine at 0– 5°C (30 h). The resulting bis(p-toluene-sulfonates) were brought into condensation with 2,7-dihydroxy-9H-fluoren-9-one in a very dilute solution in dimethylformamide containing anhydrous potassium carbonate at 80–85°C. Appropriate treatment of the reaction mixture, followed by chromatographic purification afforded 53–27% of the first representatives of a new class of cyclophanes, bis(oxofluoreno)crownophanes. Raising the temperature to 95–105°C resulted in an appreciable decrease of the product yield. The yield of the target products did not increase on replacement of potassium carbonate by cesium carbonate.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 144–149.Original Russian Text Copyright © 2005 by Lyapunov, Kirichenko, Kulygina, Luk’yanenko.     

Facile Synthesis of Bis(crown ether)benzils: Prospective Building Blocks for Metal Ion Sensors

A new facile synthetic route to benzils containing fragments of 12-crown-4, 15-crown-5, and 18-crown-6 by oxidation of corresponding stilbenes was developed. The first representative of a new family of fluorescent sensors was obtained by reaction of bis(15-crown-5)benzil with o-phenylenediamine. The latter exhibits great fluorescence enhancement upon association with K⁺ and Rb⁺ compared to Na⁺ and Cs⁺.     

Synthesis and Complex-Forming Properties of N-Substituted Diazacrown Ethers

N-Substituted mono- and diazacrown ether with ethoxycarbonylmethyl, 7-phenyl-3,6-dioxaheptyl, p-methoxy, and p-nitrobenzyl groups in the side chain have been synthesized. Their reactions with alkali and alkaline-earth metals have been studied. Substituents affect the complex-forming ability of the base macrocycle by changing the basicity of the nitrogen atoms and coordinating with the complexing ion.     

Synthesis and Complexing Properties of <Emphasis Type="Italic">N,N</Emphasis>′-Bis(2-hydroxyethyl) Diaza Crown Ethers

The stability constants of complexes of 12-, 15-, and 18-membered diaza crown ethers, N,N′-dimethyl diaza crown ethers, and N,N′-bis(2-hydroxyethyl) diaza crown ethers with alkali and alkaline-earth metal ions in 95% aqueous methanol at 25°C were determined. The stability of the complexes of unsubstituted diaza crown ethers with alkali metal cations is low, probably because of stabilization of the exo,exo conformation of the ligands due to interaction of the nitrogen lone electron pairs with the solvent. The complexes with the double-charged cations are appreciably more stable. N,N′-Dimethyl diaza crown ethers form stable complexes with all the ions studied. As compared to the dimethyl derivatives, N,N′-bis(2-hydroxyethyl) diaza crown ethers form more stable complexes with the Na⁺, K⁺, Ca²⁺, Sr²⁺, and Ba²⁺ ions, which is due to participation of the side hydroxyethyl groups in the coordination.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 4, 2005, pp. 665–669.Original Russian Text Copyright © 2005 by Kulygina, Vetrogon, Basok, Luk’yanenko.     

Synthesis,properties, and interaction with paraquat of new fluorenonocrownophanes containing a hydroquinone fragment

New crownophane family was synthesized containing fragments of 2,7-dioxyfluorenone and hydroquinone connected with residues of tri- and tetraethylene glycols. The formation of inclusion complexes of these ligands with paraquat was established by means of mass spectrometry (fast-atom bombardment), ¹H NMR and electronic spectroscopy. The crownophane with a larger ring formed the more stable complex.

     

Synthesis and Structure of Bis-crown-Containing Stilbenes

An improved procedure was proposed for the synthesis of stilbenes fused to two crown ether fragments at both benzene rings. The structure of new homologous symmetric bis-crown-containing stilbenes was determined by X-ray analysis. Relations were revealed between the size of the crown ether moiety and stilbene conformation in crystal and the mode of crystal packing. Conformational analysis of the prepared stilbenes in solution and in the solid state was performed by ¹H and ¹³C NMR spectroscopy and by DFT quantum-chemical calculations.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 864–875.Original Russian Text Copyright © 2005 by Vedernikov, Basok, Gromov, Kuz’mina, Avakyan, Lobova, Kulygina, Titkov, Strelenko, Ivanov, Howard, Alfimov.     

Synthesis of monoazacrown ethers under phase-transfer catalysis

A procedure has been proposed for the synthesis of monoazacrown ethers by reaction of N-benzyldiethanolamine with oligo(ethylene glycol) bis-p-toluenesulfonates in a two-phase system aromatic hydrocarbon-50% aqueous alkali, followed by removal of the benzyl group by catalytic hydrogenolysis. The maximal yields of N-benzylaza-12-crown-4, -18-crown-6, and -21-crown-7 were achieved by adding 4?C10 equiv of LiCl, BaBr₂, and CsCl, respectively, to the reaction mixture, which probably indicated template effect.     

Synthesis and properties of new fluorenonocrownophanes having a stilbene fragment and their reaction with paraquat

New crownophanes containing 2,7-dioxyfluorenone and 4,4??-dioxystilbene fragments linked through di-, three, tetra-, and pentaethylene glycol linkers were synthesized. The formation of pseudorotaxanetype host-guest complexes in reactions of these crownophanes with 1,1??-dimethyl-4,4??-bipyridinium dication was detected by fast atom bombardment mass spectrometry, ¹H NMR, and electron spectroscopy.     

Macroheterocycles. 7. Synthesis and extraction capacity of some dibenzo-18-crown-6-derivatives

Derivatives that contain vinyl, formyl, acetyl, carboxy, carbethoxy, -carboxyvinyl, or -carbethoxyvinyl groups in the benzene rings were synthesized from dibenzo-18-crown-6. The ability of the synthesized crown ethers to extract picrates of alkali metals from the aqueous phase to the chloroform phase was investigated.See [1] for Communication 6.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 599–603, May, 1981.     

Synthesis, crystal structure and complexation with dibenzylammonium ion of a novel class of crownophanes containing bridged fragments of fluorenone and stilbene

Two representatives of a novel class of crownophanes containing fragments of fluorenone and stilbene bridged by units of diethylene glycol and triethylene glycol, respectively, have been synthesized. The crystal structure and complexation behavior of these crownophanes were studied. They form much stronger complexes with dibenzylammonium hexafluorophosphate (logK_a value in CH₃CN is equal to 3.92 ± 0.06 and 4.40 ± 0.05, respectively) than benzocrown ethers. This makes them an attractive alternative for benzocrown ethers as components in supramolecular synthesis.