- Synthesis of chiral diaza 18-crown-6 ethers from chiral amines and molecular recognition of potassium and sodium salts of amino acids
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A practical synthesis of chiral amine precursors 3 and 4 and chiral diaza 18-crown-6 ethers 5, 6 and 7 starting from chiral amines are reported. The molecular recognition of these chiral crown ethers for amino acids potassium and sodium salts has been characterized by UV-vis. The selectivity order is Phe>Thr>Ala. In the case of 6 the cavity of the macrocycle plays an important role in recognition.
- Demirel,Bulut
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- Macrocyclic bis-urea receptor: Synthesis, crystal structure and phosphate binding properties
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A macrocyclic bis-urea receptor (L1) and two acyclic bis-urea analogues (L2 and L3) have been synthesized. The crystal structure of L1 was obtained. The experimental results show that the receptor L1 has high selectivity to H2PO4 ?. Meanwhile, compared with the acyclic receptors L2 and L3, L1 has higher binding ability to H2PO4 ?. The results of density functional theory (DFT) calculations deepened our understanding on L1 conformations stability and its anion-binding property.
- Shu, Xi,Wang, Ruyu,Fan, Yu,Li, Shoujian,Huang, Chao
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supporting information
p. 729 - 733
(2019/02/13)
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- Rapid and scalable synthesis of chiral porphyrin cage compounds
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An improved and scalable synthetic route to chiral porphyrin cage compounds, which will be used as catalytic machines for the encoding of information into polymers, has been developed. The porphyrin cage was made chiral by introducing one or two nitro gro
- Gilissen, Pieter J.,Swartjes, Anne,Spierenburg, Bram,Bruekers, Jeroen P.J.,Tinnemans, Paul,White, Paul B.,Rutjes, Floris P.J.T.,Nolte, Roeland J.M.,Elemans, Johannes A.A.W.
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p. 4640 - 4647
(2019/07/12)
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- Formation and uses of europium complexes
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The present invention provides a method of forming an oxidatively-stable aqueous Eu(II) complex by synthesizing ligands that coordinate to large, soft, electron rich metals like Eu(II). The invention also provides an oxidatively stable aqueous Eu(II) complex. The complex can be used for a variety of purposes some of which include, but are not limited to, in paramagnetic chemical exchange saturation transfer, as a medical diagnostic, as a semiconductor, and for use in forming materials.
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Page/Page column 11; 12
(2017/09/07)
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- Synthesis of enantiopure P-stereogenic diphosphacrowns using P-stereogenic secondary phosphines
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A new synthetic route to enantiopure P-stereogenic benzodiphosphacrowns using a P-stereogenic secondary bisphosphine as the key building block is reported. Syntheses of the enantiomer and P-stereogenic crowns with various ring structures, as well as debor
- Morisaki, Yasuhiro,Kato, Ryosuke,Chujo, Yoshiki
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p. 2769 - 2774
(2013/05/21)
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- Synthesis of monoazacrown ethers under phase-transfer catalysis
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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 4-10 equiv of LiCl, BaBr2, and CsCl, respectively, to the reaction mixture, which probably indicated template effect. Pleiades Publishing, Ltd., 2012.
- Luk'yanenko,Basok,Kulygina, E. Yu.,Bogashchenko, T. Yu.,Yakovenko
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p. 1345 - 1352
(2013/02/22)
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- Synthesis and extraction properties of some lariat ethers derived from the spontaneously resolved guaifenesin, 3-(2-methoxyphenoxy)propane-1,2-diol
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Capable of spontaneous resolution rac-3-(2-methoxyphenoxy)propane-1,2-diol, guaifenesin 1 has been proposed as a cheap and readily available enantiopure precursor for the synthesis of nonracemic crown ethers having ligating OAr and OMe arms (lariat ethers). The crowns studied failed to form stable host/guest complexes with amine hydrochloride salts; the effective complexation was achieved using hexafluorophosphate salts. Moderate enantiomeric recognition of R*NH2·HPF6 was achieved with the lariat ethers 11c. As a whole, the enantioselectivity of the extraction is inversely related to the extractive power of the lariat ether. ARKAT-USA, Inc.
- Bredikhina, Zemfira A.,Eliseenkova, Rimma M.,Fayzullin, Robert R.,Novikova, Viktorina G.,Kharlamov, Sergey V.,Sharafutdinova, Dilyara R.,Latypov, Shamil K.,Bredikhin, Alexander A.
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experimental part
p. 16 - 32
(2011/09/21)
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- Synthesis and evaluation of bis-thiazolium salts as potential antimalarial drugs
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An innovative therapeutic approach based on the use of dicationic derivatives was previously designed to inhibit the biosynthesis of phosphatidylcholine in Plasmodium spp. Among these, bis-thiazolium salts were shown to block proliferation of the malaria
- Caldarelli, Sergio A.,Duckert, Jean-Frederic,Wein, Sharon,Calas, Michele,Perigaud, Christian,Vial, Henri,Peyrottes, Suzanne
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experimental part
p. 1102 - 1109
(2011/02/22)
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- Oxidatively stable, aqueous europium(II) complexes through steric and electronic manipulation of cryptand coordination chemistry
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A series of cryptands has been prepared and they demonstrate the relationship between oxidative stability of aqueous EuII and ligand properties (see figure). One of these EuII complexes is more stable than FeII in hemoglobin and appears to be the most oxidatively-stable aqueous EuII species known. The high stability of EuII is expected to enable the use of the unique magnetic and optical properties of this ion in vivo.
- Gamage, Nipuni-Dhanesha H.,Mei, Yujiang,Garcia, Joel,Allen, Matthew J.
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supporting information; experimental part
p. 8923 - 8925
(2011/02/23)
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- Synthesis of new chiral diaza 18-crown-6-ethers from chiral amines
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Practical syntheses of versatile building blocks of crown ethers 1 and 2, chiral amine precursors 3-6 and chiral diaza 18-crown-6 ethers 7-12 are reported starting from chiral amines.
- Demirel, N.,Turgut, Y.,Hosgoeren, H.
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p. 1047 - 1055
(2007/10/03)
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- Substitution effect, absorption, and fluorescence behaviors of 11,12-benzo-1,7,10,13-tetraoxa-4-azacyclopentadec-11-ene (Benzoaza-15-crown-5) derivatives upon cation complexation in solvent extraction
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Substitution effect, absorption, and fluorescence behaviors of some benzoaza-15-crown-5 derivatives upon cation complexation in solvent extraction were studied. The introduction of a substituent on the nitrogen atom in benzoaza-15-crown-5 enhanced extractabilities in the solvent extraction of aqueous alkali metal picrates. The nondonating substituents raised the cation selectivity for Na+ over K+, but the donating substituents reduced the cation selectivity. The absorption and fluorescence spectral behavior was different with the alkali metal cations.
- Nakamura, Mitsunobu,Yokono, Hideaki,Tomita, Ken-Ichi,Ouchi, Mikio,Miki, Masamichi,Dohno, Reizo
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p. 3533 - 3536
(2007/10/03)
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- Facile synthesis of mono and dibenzo N,N-disubstituted diaza 18-crown-6 derivatives
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This study represents a facile synthesis of building blocks (1-3) of crown ethers and amine precoursers (4a-d). The study also involves synthesis of mono and dibenzo N,N-disubstituted diaza 18-crown-6 derivatives with high yield without chromatographic pu
- Topal,Demirel,Togrul,Turgut,Hosgoeren
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p. 281 - 284
(2007/10/03)
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- Studies on quinones. Part. 33. Synthetic approach to podands containing quinone fragments
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The preparation and oxidative demethylation attempts of podands 3-5, and 9 containing the 2,5-dimethoxyphenyl substituent are described. The reaction of alizarine 13 with chloroethanol afforded compounds 14 and 15. The pathway formation of heterocycle 15 from 14 is proposed. The synthesis of podand 16 containing the cytotoxic 1-hydroxy-9,10-anthraquinone fragment as the terminal groups is reported.
- Valderrama, Jaime A.,Leiva, Hilda,Tapia, Ricardo
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p. 737 - 749
(2007/10/03)
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- Porphyrin clips derived from diphenylglycoluril. Synthesis, conformational analysis, and binding properties
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With the aim to construct synthetic systems that function according to the principles of enzymes, molecular clips based on diphenylglycoluril were covalently attached to (metallo)porphyrins. Two different porphyrin clips, 1 and 2, were synthesized that differ in the length and position of the linker between the clip and the porphyrin. This resulted in a great difference in flexibility of the cavity molecules, which had remarkable consequences for their binding properties in organic solution. The physical properties of the free base and zinc porphyrin clips have been studied in detail with NMR techniques and by the host-guest binding of viologen, dihydroxybenzene, and pyridine derivatives.
- Elemans, Johannes A.A.W.,Claase, Menno B.,Aarts, Patrick P.M.,Rowan, Alan E.,Schenning, Albertus P.H.J.,Nolte, Roeland J.M.
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p. 7009 - 7016
(2007/10/03)
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- Concave Reagents, 15. New Concave 1,10-Phenanthrolines: Catalysts for the Alcohol Addition to Ketenes and Ligands in Transition Metal Complexes
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By bridging tetrahydroxy-1,10-phenanthrolines 9 by ditosylates 10 or diiodides 11 concave 1,10-phenanthrolines 1 were synthesized.Their concave shape was proven by X-ray analyses of 1a and 1c, their basicities were determined by photometric titrations.Compounds 1a-g are active in the base-catalyzed addition of alcohols to ketenes and form stable metal ion complexes with transition metal salts. - Key Words: Macrocycles / Broensted plot / Catalysis, base / Basicity / Transition metal complexes
- Luening, Ulrich,Mueller, Michael,Gelbert, Markus,Peters, Karl,Schnering, Hans Georg von,Keller, Manfred
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p. 2297 - 2306
(2007/10/02)
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- Synthesis of Odd-Numbered 13-Crown-4 Derivatives Possessing a Functional Group and Their Application in C-Lithiation of Acrylates
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The synthesis of symmetrically hydroxy-substituted 13-crown-4 derivatives 2 and 3 is reported.To this end, diol 7 is first deprotonated with potassium tert-butoxide and then treated with ditosylate 6 in the presence of lithium perchlorate as a template.Ba
- Jatzke, Harald,Schmidt, Richard R.
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p. 753 - 758
(2007/10/02)
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- Synthesis of Three Series of Diastereoisomeric Bicyclic Crown Ethers and their Stability Constants with Group 1A Cations
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The syntheses of a series of bridged crown ethers are described.Their binding strength to group 1A metals has been compared by determination of the stability constants: an explanation for the wide variation of the measured stability constants is given in terms of the influence of steric interactions on the conformation of the isomers and electrostatic effects occurring within the cavity.
- Parsons, David G.
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p. 1193 - 1198
(2007/10/02)
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- Circular Dichroism Studies on Three Isomeric Dimethylbenzo-15-crown-5 Ethers and Some of Their Complexes
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With ethyl lactate as an optically active precursor and with employment of Williamson reactions, three isomeric and axially symmetric dimethylbenzo-15-crown-5 ethers were prepared and characterized: (5R,15R)-5,15-dimethyl-5,6,8,9,11,12,14,15-octahydrobenzo-1,4,7,10,13-pentaoxacyclopentadecin and the (6S,14S)-6,14-dimethyl and (8S,12S)-8,12-dimethyl isomers, termed the α, β, and γ isomers, respectively.The circular dichroism spectra of the ethers and their complexes with Na+ in CH3OH have been determined and interpreted in terms of the gross overall orientationof the macrocycle in relation to the aromatic ring.The behavior of the γ-isomer with Ba2+ and with low ratios of K+ suggests dominance of 2:1 (sandwich) complexes.
- Mack, Mark P.,Hendrixson, Richard R.,Palmer, Richard A.,Ghirardelli, Robert G.
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p. 2029 - 2035
(2007/10/02)
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- Anticoccidial activity of crown polyethers
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Anticoccidial activity in vitro against Eimeria tenella is reported for crown polyethers with ring sizes from 14 to 30 atoms. The most potent compounds, 4 and 9, were found active at 0.33 ppm, but none were active in vivo. Test results are discussed in te
- Brown,Foubister
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p. 590 - 592
(2007/10/02)
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- NEW LIPOPHILIC IONIZABLE CROWN ETHERS
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Two new ionizable crown ethers which bear lipophilic groups are synthesized and found to exhibit selectivity for complexation of K(1+) in competitive solvent extractions of alkali metal cations.
- Czech, Bronislaw,Kang, Sang Ihn,Bartsch, Richard A.
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p. 457 - 460
(2007/10/02)
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- Macrocyclic hetero imine complexing agents
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Macrocyclic imines useful as complexing agents for ionic metal compounds characterized by a macrocyclic ring or rings of carbon and hetero-atoms totaling 14-60 ring atoms, at least one hetero-atom being nitrogen and the remainder being oxygen, each hetero-atom in the ring being separated from adjoining hetero-atoms by links of 2 or 3 carbon atoms. The macrocyclic ring or rings are fused to 1-4 carbocyclic rings. The macrocyclic rings or substituted derivatives of them can be monocyclic, bicyclic, or bridged by a carbon, or carbon-hetero-atom chain.
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