- Anion-free bambus[6]uril and its supramolecular properties
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Methods for the preparation of anion-free bambus[6]uril (BU6) are presented. They are based on the oxidation of iodide anion, which is bound inside the macrocycle, utilizing dark oxidation by hydrogen peroxide or photooxidation in the presence of titanium dioxide. Anion-free BU6 was found to be insoluble in any of the investigated solvents; however, it dissolves in methanol/chloroform (1:1) or acetonitrile/water (1:1) mixtures in the presence of the tetrabutylammonium salt of a suitable anion. The association constants with halide ions, BF4-, NO3-, and CN-, were measured by 1H NMR spectroscopy. The highest association constant (8.9×105 M-1) was found for the 1:1 complex of BU6 with I- in acetonitrile/water mixture. A number of crystal structures of BU6 complexes with various anions were obtained. The influence of the anion size on the macrocycle diameter is discussed together with an unusual arrangement of the macrocycles into separate layers.
- Svec, Jan,Dusek, Michal,Fejfarova, Karla,Stacko, Peter,Klan, Petr,Kaifer, Angel E.,Li, Wei,Hudeckova, Edita,Sindelar, Vladimir
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- Enthalpies and heat capacities of solution of racemic N-methyl-substituted glycolurils in water at T = (278.15 to 313.15) K
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The molar enthalpies of solution of racemic (with enantiomer ratio of 1:1) 2-monomethyl-, 2,6-dimethyl-, and 2,4,6-trimethylglycolurils (2-MMGU, 2,6-DMGU and 2,4,6-TMGU, respectively) in water were measured calorimetrically in the temperature range between (278.15 and 313.15) K and at p = 99.6 kPa. Derived from experimental data, the standard (at infinite dilution) molar enthalpic characteristics of the dissolution process are positive by sign and increase with rising temperature as well as in a sequence of 2,4,6-TMGU 2,6-DMGU 2-MMGU. In the same way, the standard heat capacity of solution decreases distinctly, leading to the conclusion that the effect of hydrophobic hydration is more pronounced for the more N-methylated solute. It was suggested that, despite the presence of hydrophobic moieties (N-sited methyl groups) in the molecules considered, a hydrophilic constituent (via H-bonding) seems to be the predominant one in the total enthalpy effect of a solute hydration.
- Ivanov, Evgeniy V.,Batov, Dmitriy V.
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- Dihydroxy methyl dihydroxy ethene carbamide improved preparation method
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The invention provides a preparation method of dimethylol dihydroxy ethylene urea. The method comprises the following steps: 1, reacting urea with glyoxal in the presence of sulfonic acid and sulfonic acid alkali metal salt at 30-60DEG C for 3-6h to prepare a dihydroxy ethylene urea intermediate; and 2, reacting the dihydroxy ethylene urea intermediate obtained in step 1 with a formaldehyde and optional organic alcohol amine mixture in the presence of dialkali metal hydrogen phosphate and alkali metal dihydrogen phosphate at 40-60DEG C for 2-4h to obtain a target product. The preparation method has the advantages of stable reaction and high conversion rate, and the product has the advantages of high content of active groups, and strong responsivity.
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Paragraph 0051; 0052; 0056; 0060
(2017/08/25)
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- Easy Synthesis of trans -4,5-Dihydroxy-2-imidazolidinone and 2,4-Dimethylglycoluril
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A simple and efficient synthesis of 2,4-dimethylglycoluril involving the formation of trans-4,5-dihydroxy-2-imidazolidinone is presented as well as a reproducible protocol to reduce contamination with its decomposition products, identified as urea and 1,3-dimethylimidazolidine-2,4-dione.
- Correia, Henrique D.,Cicolani, Renato S.,Moral, Raphael F.,Demets, Grégoire J. F.
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supporting information
p. 210 - 212
(2016/01/12)
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- FORMALDEHYDE FREE BINDER COMPOSITIONS WITH UREA-ALDEHYDE REACTION PRODUCTS
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Fiber-containing composites are described that contain woven or non-woven fibers, and a cured binder formed from a binder composition that includes (1) a reducing sugar and (2) a crosslinking agent that includes a reaction product of a urea compound and a polycarbonyl compound. Exemplary reaction products for the crosslinking agent may include the reaction product of urea and an α,β-bicarbonyl compound or an α,γ-bicarbonyl compound. Exemplary fiber-containing composites may include fiberglass insulation.
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Paragraph 0135; 0136
(2016/10/27)
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- New access to thioglycolurils by condensation of 4,5-dihydroxyimidazolidin-2-ones(thiones) with HSCN
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A general and highly effective protocol for the direct synthesis of mono- and dithioglycolurils containing various substituents at the 1,3-nitrogen atoms has been developed based on the condensation of easily accessible dihydroxyimidazolidin-2-ones with HSCN under mild reactions conditions.
- Baranov, Vladimir V.,Nelyubina, Yulia V.,Kravchenko, Angelina N.,Kolotyrkina, Natalya G.,Biriukova, Ksenia A.
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p. 6085 - 6088
(2015/10/28)
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- UREA-DERIVED PRODUCTS AND METHODS FOR MAKING SAME
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Urea-derived products, for example liquid compositions containing urea-derived compounds, such as dihydroxyethyleneurea (“DHEU”), and methods for making same are provided.
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Paragraph 0070
(2014/05/08)
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- UREA-DERIVED PRODUCTS AND METHODS FOR MAKING SAME
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A liquid composition comprising DHEU and greater than 0 to less than 4000 ppm of glycoluril, and methods for making same are provided:
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Page/Page column 12; 13
(2014/05/24)
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- Diastereoselective synthesis of 4,5-dihydroxyimidazolidin-2-ones (-thiones) and their structure
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Studies on the synthesis of 4,5-dihydroxyimidazolidin-2-ones (-thiones) based on the condensation of ureas or thioureas with glyoxal or 1,2-dioxo-1,2-diphenylethane showed high diastereoselectivity in the formation of racemates (trans-diastereomers) of 4,5-dihydroxyimid- azolidin-2-ones (-thiones) and meso-forms (cis-diastereomers) of 4,5-dihydroxy-4,5-diphenyl-1,3- dialkylimidazolidine-2-thiones; plausible mechanisms of their formation were suggested. X-ray diffraction studies confirmed structures of diastereomers for separate examples of race-mates and meso-forms of 4,5-dihydroxyimidazolidin-2- ones (-thiones).
- Kravchenko,Baranov,Nelyubina,Gazieva,Svitanko
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Synthesis of 5-nitroiminoperhydroimidazo[4,5-d]imidazol-2-ones and 6-nitroimino-5,6,7,8-tetrahydro-4himidazo[4,5-e]furazano[3,4-b]pyrazines
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4,5-Dihydroxy-2-oxo-, -2-cyanoimino-, and -2-nitroiminoimidazolidines were synthesized by reactions of glyoxal with ureas and cyano- and nitroguanidines in aqueous solution at pH 8-9. Cross condensations of these products with ureas, nitroguanidine, and diaminofurazan in acid aqueous solution gave 5-nitroiminoperhydroimidazo[4,5-d]imidazol-2-ones and 6-nitroimino-5,6,7,8-tetrahydro-4H-imidazo[4,5-e]-furazano[3,4-b]pyrazines. The main factors influencing the process are the basicity and structure of the diamino compounds and acidity of the medium. 1998 MAHK Hayka/Interperiodica Publishing.
- Terpigorev,Rudakova
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p. 1026 - 1031
(2007/10/03)
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- Isolation and X-ray structure of the intermediate dihydroxyimidazolidine(DHI) in the synthesis of glycoluril from glyoxal and urea.
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The X ray structure of DHI, an intermediate in the synthesis of glycoluril from urea and glyoxal is reported; it gives 1- and 1,3-substituted glycolurils not available from unsubstituted glycoluril.
- Grillon, E.,Gallo, R.,Pierrot, M.,Boileau, J.,Wimmer, E.
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p. 1015 - 1016
(2007/10/02)
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