- Synthesis of a new enantiopure chiral aza crown ether and its application in enantiomeric separation
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A new enantiopure chiral aza crown ether (S,S)-1,7-bis(4-phenyl-5-hydroxy- 2-oxo-3-zapentyl)-1,7-diaza-12-crown-4 ligand (1) has been synthesized and used as a chiral selector in the enantiomeric separation of D/L-carnitine by capillary electrophoresis.
- Wang, Cheng-Yun,Wang, Da-Hui,Leng, Tao-Hua,Yu, Qing-Sen
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Read Online
- · Uniform catalyst by using alcohol aminosilicone di-, tri-and a method of manufacturing a polyphenylenepolyamine
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The invention relates to a method for producing primary amines, which contain at least one functional group of the formula (-CH2-NH2) and at least one further primary amino group, by the alcohol amination of reactants, which contain at least one functional group of the formula (-CH2-OH) and at least one further functional group (-X), wherein (-X) is selected from hydroxyl groups and primary amino groups, using ammonia with removal of water, wherein the reaction is carried out in a homogeneously catalyzed manner in the presence of at least one complex catalyst containing at least one element selected from groups 8, 9 and 10 of the periodic table and at least one donor ligand.
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Paragraph 0099; 0114
(2016/10/09)
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- PROCESS FOR PREPARING DI-, TRI- AND POLYAMINES BY HOMOGENEOUSLY CATALYZED ALCOHOL AMINATION
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Process for preparing primary amines which have at least one functional group of the formula (—CH2—NH2) and at least one further primary amino group by alcohol amination of starting materials having at least one functional group of the formula (—CH2—OH) and at least one further functional group (—X), where (—X) is selected from among hydroxyl groups and primary amino groups, by means of ammonia with elimination of water, wherein the reaction is carried out homogeneously catalyzed in the presence of at least one complex catalyst comprising at least one element selected from groups 8, 9 and 10 of the Periodic Table and also at least one donor ligand.
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Page/Page column 12; 17
(2012/09/22)
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- Synthesis and photophysical properties of polyazacrown ethers with appended naphthyl or anthracenyl units
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Polyazacrown ethers containing one, two, and four appended naphthyl or anthracenyl units have been synthesized. The absorption spectra and photophysical properties of the novel compounds have been investigated in CH2Cl2 solution. Acid titration of the amine nitrogens of the polyazacrown ethers causes strong changes in the absorption and fluorescence spectra. In the unprotonated compounds of the naphthalene family, the naphthalene-type emission is completely quenched and a weak, unstructured, and broad fluorescence band with maximum at 440 nm is observed. Upon addition of trifluoroacetic acid, the absorption maximum is displaced to the red by a few nanometers, and a revival of the strong naphthalene-type emission at 340 nm is observed. These results are accounted for by the change in the nature of the lowest excited state (CT to π-π(*)) upon protonation. In the compounds of the anthracene family, the deprotonated forms of the species containing the polyazacrown groups show an absorption around 300 nm and a long wavelength tail at lower energies, neither of which are present in the 9- [(methylamino)methyl]anthracene. In all cases a weak, anthracene-type fluorescence is present, increasing in intensity on protonation. Furthermore, the emission spectra of the compounds with two or four anthracene moieties show an excitation-dependent, broad emission band at lower energies, which almost disappears upon protonation. This behaviour can be accounted for by the quenching of the anthracene-type emission caused by lower lying charge- transfer levels and in the case of the compounds containing two and four anthracene moieties, of conformers where an anthracene-anthracene interaction is present. In all cases, each equivalent of added acid causes protonation of one equivalent of crown nitrogen. However, in the azacrown with four appended naphthyl units the revival of the naphthalene-type fluorescence does not parallel the number of added protons. This shows that the higher energy π- π(*) levels of the protonated units are quenched by the lower energy CT levels of the units involving the not yet protonated crown nitrogens.
- Quici, Silvio,Manfredi, Amedea,Maestri, Mauro,Manet, Ilse,Passaniti, Paolo,Balzani, Vincenzo
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p. 2041 - 2046
(2007/10/03)
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- Synthesis and Properties of New Lipophilic Macrotricyclic Cylindrical Cryptands
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Cylindrical cryptands 2a-c, in which two 1,7-dioxa-4,10-diazacyclododecane rings are connected by two equally substituted propylene bridges, have been obtained in appreciable yields by a ''one-pot'' synthesis.The assembling of the macrotricyclic structure is likely driven by the template effect of metal cations.These compounds, both as free receptors or as complexes, exist as cis and trans diastereoisomers, which do not interconvert and have been separated and characterized by X-ray analysis.The extraction constants (Ke) of cryptands 2 for alkali picrates under CHCl3/H2O and solid/liquid two-phase conditions have been measured by UV-vis spectrophotometry.The complexation behavior of cryptands 2 has been rationalized analyzing the preorganization of binding sites in the minimum energy conformations obtained by molecular mechanics calculations.Minimum energy conformations have been calculated also for the previously reported cryptands 1 and have been compared with those of 2.Results fit reasonably well with those of X-ray structures.
- Quici, Silvio,Manfredi, Amedea,Raimondi, Laura,Sironi, Angelo
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p. 6379 - 6388
(2007/10/03)
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- An Alternative Synthesis of Cyclic Aza Compounds
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A series of cyclic mono-, di- and poly-aza compounds has been synthesised in moderate to good yields by reaction of p-toluenesulfonamide and either α,ω-ditosylates or α,ω-dichlorides.
- Boerjesson, L.,Welch, C. J.
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p. 621 - 626
(2007/10/02)
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- A General Method for the Synthesis of Diazacoronands
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α,ω-Diamino aliphatic ethers react under ambient conditions with dimethyl α,ω-dicarboxylates, in methanol as a solvent, to give the cyclic diamides in good yields, and their subsequent reduction with lithium aluminium hydride affords the respective diazacoronands.
- Jurczak, Janusz,Kasprzyk, Stanislaw,Salanski, Piotr,Stankiewicz, Tomasz
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p. 956 - 957
(2007/10/02)
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- MACROHETEROCYCLES. PART 44. FACILE SYNTHESIS OF AZACROWN ETHERS AND CRYPTANDS IN A TWO-PHASE SYSTEM
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A facile procedure is proposed for the preparation of azacrown ethers and cryptands by condensation of dibromides or ethylene glycol bis(toluene-p-sulphonate)s with acyclic bis(sulphonamide)s or with bisdiazacrown ethers, respectively.The reaction was carried out in a two-phase system of aqueous alkali-toluene (benzene)in the presence of quaternary ammonium salts as phase transfer catalysts.The catalytic activity decreased in the sequence: Bu4NI ca.Bu4NBr > Bu4NCl > Bu4NHSO4 > Et3NCH2C6H5NCl.Maximum yields of twelve-membered azacrown ethers are obtained when lithium hydroxide is used, while crown ethers of larger size are observed in the presence of sodium or potassium hydroxides; this may be due to a template effect.
- Lukyanenko, Nikolai G.,Basok, Stepan S.,Filonova, Lyubov K.
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p. 3141 - 3148
(2007/10/02)
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- MACROHETEROCYCES. XXXVI. A CONVENIENT METHOD FOR SYNTHESIS OF DI- AND POLYAZACROWN ETHERS
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A method is proposed for the production of di- and polyazacrown ethers by the condensation of bissulfonamides with dibromides or ditosyloxy derivatives in a two-phase aqueous alkali-toluene (benzene) system.The optimum concentration range for the substrate and the alkylating agent is 0.017-0.1 M.The catalytic activity of the quaternary ammonium salts decreases in the order (Bu)4NI > (Bu4)NBr > (Bu4)NCl > (Bu4)NHSO4 > (C2H5)3C6H5CH2NCl >> (Et)4NI > (Et)4NBr.The highest yields of te 12-membered azacrown ethers are obtained in the presence of lithium hyroxide, and the largest yields of the crown ethers with larger ring sizes are obtained in the presence of sodium or potassium hydroxide, and this is probably due to the matrix effects of the cation.
- Luk'yanenko, N.G.,Basok, S.S.,Filonova, L.K.
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p. 1562 - 1571
(2007/10/02)
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- Host-Guest Complexation. 38. Cryptahemispherands and Their Complexes
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Syntheses and crystal structures are reported for a new class of hosts, their complexes, and their precursors.The cryptahemispherands 5-8 are composed of molecular modules that are half spherand 1 and half cryptand 3.They were synthesized by the reactions of diacid chloride 20 with cyclic diamines 21-23 to produce diamides 13-16, reduction of which gave the desired hosts 5-8.These diamines were best purified, stored, and handled through their respective hydroborane complexes, 9-12.Hosts 6 and 7 are diastereomeric, as are diamides 14 and 15 and hydroborane complexes 10 and 11.Diamines 6 and 7 equilibrate rapidly at 25 deg C probably by ring inversion of the methoxyl groups to give a 5:1 ratio of 6 over 7.Diamides 14 and 15 equilibrate readily at 90 deg C to give only 14 in detectable amounts.Hydroborane complexes 10 and 11 do not equilibrate at 90 deg C.Cryptahemispherands 5, 6 and 8 formed a variety of complexes with the alkali metal cations, diamides 14 and 16 exhibited a low level of binding power, and hydroborane complexes 10 and 12 had no detectable affinity for the alkali metal cations.Hemispherand 17 was synthesized for comparison purposes.Crystal structures were determined for the isomeric diamides 14 and 15, for hydroborane complex 9, and for alkali cation complexes 5.NaB(Ph)4, 6.KSCN, 8.NaSCN, 8.KSCN, and 8.CsClO4.The trisanisyl modules of all eight compounds possess the same preorganized conformation, with the unshared electron pairs of the three methoxyl groups turned inward and the methyl groups outward.The potential cavities of 9, 14, and 15 are filled inward-turned hydrogens of the ethylene bridges.In the alkali metal ion complexes, the unshared electron pairs of the heteroatoms are all turned inward toward the quest metal ion.The use of CPK molecular models in predicting the structures of complexes is evaluated.
- Cram, Donald J.,Ho, Siew Peng,Knobler, Carolyn B.,Maverick, Emily,Trueblood, Kenneth N.
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p. 2989 - 2998
(2007/10/02)
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- Complexes of macrocyclic compounds
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Novel macrocyclic (monocyclic and bicyclic) compounds having nitrogen bridgehead atoms and having in the hydrocarbon bridging chains at least two additional hetero atoms selected from the group consisting of sulfur, oxygen, and nitrogen, when admixed with a compatible cation-donor compound form stable cation-containing macrocyclic complexes which, in turn, can be conveniently dissociated by addition of acid or a quaternizing agent. The novel macrocyclics are valuable for use in the same way and for the same purposes as chelating agents.
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