- Understanding behaviour of vitamin-C guest binding with the cucurbit[6]uril host
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The present study describes non-covalent interaction and complexation behaviour of sodium ascorbate (SA) with cucurbit[6]uril (CB[6]) at neutral pH in aqueous Na2SO4 solution. The interaction behaviour is investigated using various analytical techniques like NMR, UV–Vis, fluorescence, TGA and DRS. The substantial increase in the intensity of emission and absorption spectra of sodium ascorbate is observed. The Benesi–Hildebrand evaluation method is used to determine the stoichiometry and equilibrium constant of the cucurbit[6]uril–sodium ascorbate complex, which suggested the 1:1 complex. Time-dependent 1H NMR, 13C CP MAS and CD studies also echoed non-covalent interaction between SA with CB[6].
- Pandey, Shubham,Soni, Vineet Kumar,Choudhary, Ganpat,Sharma, Pragati R.,Sharma, Rakesh K.
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Read Online
- Effect of glycoluril and its derivatives on the flame resistance and physico-mechanical properties of rubber
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The effect of bicyclic bisureas (glycolurils) and their derivatives functionalized with hydroxymethyl, halomethyl, and dimethoxyphoshorylmethyl groups on the flame resistance and physico-chemical properties of synthetic isoprene and divinyl rubbers was studied, and the procedures for preparing these agents were suggested. The rubbers with the addition of the synthesized bicyclic bisureas demonstrated satisfactory levels of flame resistance and physico-mechanical parameters.
- Sal’keeva,Bakibaev,Khasenova,Taishibekova, Ye. K.,Sugralina,Minaeva, Ye. V.,Sal’keeva
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Read Online
- Efficient method for the cycloaminomethylation of glycoluril
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The efficient method for the cycloaminomethylation of glycoluril to yield 2,6-ditert-butylhexahydro-1H,5H-2,3a,4a,6,7a,8a-hexaazacyclopenta[def]fluorene-4,8-dione is described. The material is synthesized employing water as the solvent, and is isolated by filtration. This is an improvement over the previous reported synthetic method, which relied on the use of samarium trichloride catalysis, as well as silica gel column chromatographic purification to obtain the target product.
- Wingard, Leah A.,Johnson, Eric C.,Sabatini, Jesse J.
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Read Online
- Modulation of Bambusuril Anion Affinity in Water
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Neutral and negatively charged anion receptors functioning in pure water are rare in supramolecular chemistry. Moreover, studies on adjusting the affinity of such receptors toward anions in water are absent from the literature. Two new bambusurils, 1 a and 2 a, were prepared to demonstrate that the affinity of bambusurils towards anions can be altered by the length of carboxyalkyl groups attached to the macrocycles. The stability of the bambusuril complexes was further controlled by the pH value. The crystal structure of bambusuril 1 a was described, in which two carboxyalkyl arms fold into the macrocycle cavity, thus forming the intramolecular self-inclusion complex.
- Havel, Vaclav,Babiak, Michal,Sindelar, Vladimir
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Read Online
- Critical Parameters for Green Glycoluril Synthesis
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Abstract: We have studied the critical parameters of Micheletti’s glycoluril synthesisstarting from urea and glyoxal on a statistical and multivariate analysis basis[12]. The process ispotentially highly useful for scaling-up glycoluril production, and needs to beoptimized. We have come to a conclusion thatH3PO4 could be used as well asP4O10 giving high yields attemperature around 95°C, using glyoxal without prior purification. All reactionshave been completed in less than 25 min with the yield as high as 80% under theoptimized conditions.
- Araki, K.,Bertolucci, M. M.,Demets, G. J. F.,Oliveira, A. de,Soares, R. S. B.,Souza, L. R. R.
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p. 739 - 742
(2021/06/02)
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- Ring-opening hydrolysis of spiro-epoxyoxindoles using a reusable sulfonic acid functionalized nitrogen rich carbon catalyst
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Controlling the product selectivity of a ring-opening hydrolysis reaction remains a great challenge with mineral acids and to an extent with homogeneous catalysts. In addition, even trace amounts of metal impurities in a bioactive product hinder the reaction progress. This has necessitated the development of robust and metal-free catalysts to offer an alternative sustainable route. We report a nitrogen-rich sulfonated carbon as a catalyst derived from an inexpensive precursor for the synthesis of bioactive vicinal diols of spiro-oxindole derivatives. The well-characterized catalyst shows wide generality with different electronic and steric substituents in the substrates under mild reaction conditions. Hot filtration test confirms no leaching of the acid moiety and the catalyst could be reused for four cycles with retention of activities.
- Patel, Parth,Tak, Raj Kumar,Parmar, Bhavesh,Dabas, Shilpa,Patel, Brijesh,Suresh, Eringathodi,Khan, Noor-Ul H.,Subramanian, Saravanan
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p. 12808 - 12814
(2021/04/14)
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- Synthesis of Glycoluril using Urea Phosphate
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Abstract: Glycolurils are building blocks for the synthesis of cucurbiturils that are important host materials for several applications. Glycolurils are prepared conveniently by the condensation of 1,2-diketones with urea using an acid as catalyst. Herein, we report a facile method of synthesis of various glycolurils using urea phosphate and 1,2-diketones.
- Karpagalakshmi, K.,Lakshminarayanan, P.,Prakash, R.,Ramalakshmi, S.,Selvapalam, N.,Usha, G.,Yang, C.
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p. 1988 - 1992
(2022/01/24)
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- D - galactose bonded ring-opening cucurbituril and application thereof
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The invention belongs to the field of supermolecular drug carriers and discloses D-galactose-bonded open-ringed cucurbituril with a structural formula shown in the specification, wherein R is a groupshown in the specification or a halogen, and at least one R is the group shown in the specification. The open-ringed cucurbituril containing a D-galactose group is a macrocyclic cryptand with an innercavity, and the open-ringed structure makes the ring rigidity of the macrocycle of the D-galactose-bonded open-ringed cucurbituril reduced and the D-galactose-bonded open-ringed cucurbituril has extremely strong host-guest bonding capacity; and the galactose-containing open-ringed cucurbituril disclosed by the invention has good water solubility, can be used as a drug carrier to be widely appliedto drug transportation, can also be used for greatly improving the bioavailability and stability of a drug and has potential tumor cell targeting property.
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Paragraph 0032
(2021/06/22)
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- Dual-Stimuli Responsive 2D Supramolecular Organic Framework for the Detection of Azoreductase Activity
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A 2D supramolecular organic framework (SOF) based on synthetic macrocycles has been constructed in water by a self-assembly strategy. Two new organic monomers of this SOF, possessing viologen and azobenzene functional groups, form a stimuli-responsive host–guest system upon cooperatively binding with cucurbit[8]uril rings. The reversible formation and dissociation of 2D SOF can be realized by the isomerization of azobenzene under ultraviolet and visible light. The light-responsive property of the SOF is highly reversible and stable for up to four cycles. Moreover, azoreductase produced by Escherichia coli can reduce the N=N double bond of azobenzene entities, resulting in fluorescence recovery of the system. As an excellent and effective fluorescent probe, the SOF can detect azoreductase activity for real-time monitoring of the growth process of Escherichia coli. The dual-stimuli responsive 2D SOF is envisioned to drive the development of responsive devices with complex functions.
- Zhang, Hao,Liang, Feng,Yang, Ying-Wei
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supporting information
p. 198 - 205
(2019/12/12)
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- Synthesis of glycolurils and hydantoins by reaction of urea and 1, 2-dicarbonyl compounds using etidronic acid as a “green catalyst”
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Most of the known methods for the synthesis of heterocyclic compounds have disadvantages, such as a long reaction time and aggressive conditions. We have developed a new, rather simple and efficient method for the synthesis of a number of glycoluryls and hydantoins in water using a etidronic acid (HEDP) as “Green catalyst.” So, for the first time, the condensation reaction of ureas with 1, 2-dicarbonyl compounds was carried out in the presence of HEDP. Also based on NMR studies, a chemism of these reactions, which is stepwise, is proposed. It has been established that the optimal conditions for the synthesis of glycoluryls and hydantoins using HEDP are: temperature 80°C-90°C, 40-20 minutes, and the ratio of urea and HEDP is 1:1. In all cases, the remaining aqueous filtrate containing HEDP after the reaction can be reused for other cycles synthesis of glycoluril and other compounds, because HEDP is not converted during the reaction.
- Bakibaev, Abdigali A.,Uhov, Artur,S. Malkov, Victor,Yu. Panshina, Svetlana
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p. 4262 - 4270
(2020/10/02)
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- Supramolecular assembly of poly(ionic liquid) nanogel driven by host-stabilized charge transfer interaction
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Poly(ionic liquid) (PIL)-based nanogels, functionalized by naphthyl (Np), are fabricated via a facile one-step ternary crosslinking copolymerization in selective solvent. The size of PIL nanogels can be conveniently regulated through the feed ratio of IL monomer to crosslinker. The presence of Np groups in PIL nanogel is confirmed by using ultraviolet–visible (UV–vis), Fourier transform infrared, and X-ray photoelectron spectroscopy measurements. Through introducing cucurbit[8]uril (CB[8]) and bisviologen compound (DEDV) as the host molecule and electron acceptor, respectively, host-stabilized charge transfer (HSCT) interaction is achieved through utilizing Np containing PIL nanogel as the building block. The studies reveal that PIL nanogels can form schistose aggregates in the scale of micrometer via HSCT interaction. The aggregates will be broken in the presence a competitive guest molecule (amantadine) and can recover by adding another host molecule (CB[7]). HSCT interaction among CB[8], DEDV and PIL nanogel is investigated by dynamic light scattering, UV–vis, and Proton nuclear magnetic resonance. Our studies thus provided an applicable strategy for constructing dynamic polymer nanoparticles through noncovalent interaction.
- Tang, Yuntao,Wang, Ke,Zuo, Yong,Chen, Xi,Xiong, Yubing,Yuan, Yumin
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p. 2251 - 2259
(2019/11/13)
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- Oxidation of Thioamides to Amides with Tetrachloro- and Tetrabromoglycolurils
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Tetrabromo- and tetrachloroglycolurils have been shown to act as good oxidants capable of converting thioamides to the corresponding amides. This approach offers such advantages as good yields (81–99%), short reaction times (10–25 min), simple workup procedure, and environmental safety.
- Arrous, S.,Boudebouz, I.,Parunov, I. V.
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p. 1874 - 1877
(2020/02/03)
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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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- CLOMAZONE COMPOSITION, ITS PREPARATION AND USE THEREOF
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A composition comprising an active ingredient, in particular Clomazone, contained within a microcapsule is provided, the microcapsules having a shell comprising a urea-formaldehyde resin. A method of preparing a microencapsulated composition comprising an encapsulated active ingredient, in particular Clomazone, is also provided, the method comprising: a) preparing a urea-formaldehyde prepolymer by the reaction of urea and formaldehyde; b) dispersing the active ingredient and a water insoluble liquid carrier in an aqueous phase to form an emulsion; and c) adding the urea-formaldehyde prepolymer to the emulsion and allowing the components thereof to react to form microcapsule walls at the interface of the dispersed organic phase and the aqueous phase, so as to encapsulate the organic phase.
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Page/Page column 15
(2016/01/21)
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- Palladium complexes with 3-phenylpropylamine ligands: Synthesis, structures, theoretical studies and application in the aerobic oxidation of alcohols as heterogeneous catalysts
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The reaction of 3-phenylpropylamine with Pd(OAc)2 by heating in toluene resulted in the nearly square-planar complex trans-[Pd(C6H5(CH2)3NH2)2(OAc)2] (1). Complex 1 reacted with NaCl in methanol to obtain the corresponding product trans-[Pd(C6H5(CH2)3NH2)2Cl2] (2). Treatment of 2 with triphenylphosphine in dichloromethane afforded trans-[Pd(C6H5(CH2)3NH2)2(PPh3)2]2Cl- (3). All the palladium(ii) complexes (1-3) were fully characterized by IR and NMR spectroscopy. In addition, the crystal structures of 1 and 2 were determined by single-crystal X-ray diffraction analysis. In these structures, the acetate and chloride ligands are in trans geometry. Density functional theory (DFT) calculations gave bond lengths and angles that were noted as experimental values. Palladium nanoparticles that were derived from complexes (1-3) were supported on cucurbit[6]uril (CB[6]) and identified by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma analysis (ICP) and high-resolution X-ray powder spectroscopy (HR-XPS). CB[6]-supported palladium nanoparticles (NPs) were used as heterogeneous catalysts for the aerobic oxidation of alcohols to the corresponding aldehydes or ketones without over-oxidation. CB[6]-Pd NPs (3) (prepared from complex 3) show better catalytic activity than CB[6]-Pd NPs (1), (2), as a higher yield was observed with them in a relatively short time. Factors such as the amount of catalyst, solvent, temperature and reaction time were all systematically investigated to determine their effects on the yield of catalytic alcohol oxidation reactions. This catalytic system displayed high activity and selectivity toward alcohols in mild conditions. The catalyst was reused five times without any significant loss of catalytic activity.
- Karami, Kazem,Naeini, Nasrin Haghighat,Eigner, Vaclav,Dusek, Michal,Lipkowski, Janusz,Hervés, Pablo,Tavakol, Hossein
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p. 102424 - 102435
(2015/12/11)
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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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- HERBICIDE COMPOSITION COMPRISING CLOMAZONE AND USE
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There is provided a composition comprising clomazone encapsulated within microcapsules having a polymer wall comprising a cross-linked polyacetylene carbamide-polyurea. A preferred composition is prepared by providing a water imiscible organic phase comprising clomazone, one or more polyfunctional isocyanates and a cross-linking resin; providing an aqueous phase comprising one or more polyfunctional amines; dispersing the organic phase in the aqueous phase to form a dispersion of droplets of the organic phase in the aqueous; and allowing the formation of a polyacetylene carbamide-polyurea polymer at the interface of the dispersed organic phase and the aqueous phase. The composition is useful in the control of plant growth.
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Page/Page column 13
(2014/10/29)
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- A facile synthesis of imidazolidine-2,4,5-trione
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When glycoluril was oxidised with potassium persulfate, the main product was imidazolidine-2,4,5-trione. The structure of product was confirmed by IR, ESI, 1H NMR and X.ray crystal structure determination.
- Yang, De-Li,Li, Jia-Rong,Lu, Hong-Yan,Zhang, Pan,Shi, Da-Xin
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p. 625 - 626
(2015/01/09)
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- A new and efficient method for the preparation of 2,4,6,8- Tetraazabicyclo[3.3.0]octane-3,7-diones (Glycolurils) catalyzed by keggin, wells-dawson, and preyssler heteropolyoxometalates, effect of structure on the reactivity
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Some important cis- and trans-alkyl substituted glycolurils were prepared via condensation of vicinal dicarbonyl compounds with urea and/or methylurea catalyzed by 0.95 mol% of Keggin- type H3PW12O 40 under environmentally benign and simple condition. Proficiency of structurally different heteropolyoxometalates, including Keggin, Wells-Dawson, and Preyssler, was investigated in the reaction of urea with 2, 3-butanedione. A common method was introduced for the isolation of cis- and trans-isomers, role of different solvents was studied, and effect of catalyst mol% was also investigated in this reported.
- Tayebee, Reza,Esmaei, Rezaei-Seresht,Behrooz, Maleki
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experimental part
p. 183 - 191
(2012/08/14)
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- Facile synthesis of hydantoins and thiohydantoins in aqueous solution
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A series of hydantoins and thiohydantoins have been synthesized in water at room temperature from urea (or N-methylurea, or thiourea) and simple aldehydes (as glyoxal, and its simple derivatives) in the presence of phosphoric anhydride. The reaction time is 10 min using an equimolar amount of P 4O10 with respect to the other reagents, but the reaction occurs also, even if with longer reaction times, with very small amounts of P4O10. In addition, this method provides a clean and 'green' approach to hydantoins, compounds of great interest in biological and pharmacological fields.
- Baccolini, Graziano,Boga, Carla,Delpivo, Camilla,Micheletti, Gabriele
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experimental part
p. 1713 - 1717
(2011/05/05)
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- PROCESSES OF PREPARING GLYCOLURILS AND CUCURBITURILS USING MICROWAVE
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Provided are processes of preparing glycolurils and cucurbiturils using the glycolurils by microwave irradiation. Therefore, condensation and cyclization reactions for preparation of industrially widely applied cucurbituril derivatives, oxidation reaction for preparation of hydroxy-cucurbiturils, and condensation and cyclization reactions between glycolurils and paraformaldehyde or a formaldehyde solution can be efficiently performed in a short time.
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(2008/06/13)
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- Process for the continous preparation of Acetylenediureine
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Continuous production of acetylene urea is effected in a mixing reactor with glyoxal, urea and mineral acid being introduced continuously and a suspension of the product being withdrawn and mechanically separated to give a mother liquor residue which is recycled wholly or in part to the reactor.
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(2008/06/13)
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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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