Tag: M.W:300-400

The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.14187-32-7, Name is Dibenzo-18-crown-6, molecular formula is C20H24O6. In a Article£¬once mentioned of 14187-32-7, Quality Control of: Dibenzo-18-crown-6

Synthesis of Azo Dyes from Mesoionic Carbenes and Nitrous Oxide

Covalent adducts of imidazole-based mesoionic carbenes and nitrous oxide (N2O, ?laughing gas?) can be converted into azo dyes by reaction with arenes in the presence of AlCl3 or HCl. The azo coupling can be achieved with electron-rich aromatic compounds such as mesitylene, trimethoxybenzene, azulene, or dibenzo-18-crown-6. The latter coupling reaction allows for the easy preparation of a colorimetric sensor for potassium or sodium ions. As a putative intermediate of the reaction with acid, we were able to isolate and structurally characterize a rare diazohydroxide. Using imidazolium compounds with two N2O groups, it was possible to prepare amine-substituted azo dyes or dyes with two azoarene groups attached to the heterocycle. A triazole-based mesoionic carbene was also found to form a stable covalent adduct with N2O. The adduct could be used to prepare novel azo triazolium dyes in good yields.

The reactant in an enzyme-catalyzed reaction is called a substrate. Enzyme inhibitors cause a decrease in the reaction rate of an enzyme-catalyzed reaction.I hope my blog about 14187-32-7 is helpful to your research., Quality Control of: Dibenzo-18-crown-6

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Electric Literature of 345967-22-8, Catalysts are substances that increase the reaction rate of a chemical reaction without being consumed in the process. 345967-22-8, Name is N,N-Dimethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine, molecular formula is C22H18NO2P. In a Patent£¬once mentioned of 345967-22-8

PHOSPHORAMIDITE LIGAND AND PRODUCTION METHOD OF ALLYLIC AMINE USING THE SAME

The present invention provides a production method of an allylic amine represented by the formula (III): wherein R3 is as defined in the specification, which comprises reacting by an allylic alcohol represented by the formula (II): wherein R3 is as defined in the specification, with sulfamic acid, in the presence of a phosphoramidite ligand represented by the formula (I): wherein each symbol is as defined in the specification, and an iridium complex. According to the present invention, a primary allylic amine can be produced directly from an allylic alcohol, without use of an activator for an allylic alcohol and conversion of an allylic alcohol into an activated compound thereof.

The proportionality constant is the rate constant for the particular unimolecular reaction. the reaction rate is directly proportional to the concentration of the reactant. I hope my blog about 345967-22-8 is helpful to your research., Electric Literature of 345967-22-8

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The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.14187-32-7, Name is Dibenzo-18-crown-6, molecular formula is C20H24O6. In a Article£¬once mentioned of 14187-32-7, Recommanded Product: Dibenzo-18-crown-6

The influence of structural effects on the complexing ability of crown ethers. III. Rubidium complexes formed by the ligands of the 18C6 type

A combined AM1 and molecular mechanics study of the complexation of the rubidium cation by nine substituted crown ethers, L, containing 18 atoms of macroring is presented. The role of microsolvation was incorporated into the models by studying the complexes surrounded by six methanol molecules. The substituent effect is related to the interaction energy, Eint, which was computed for the clusters LRb+(CH3OH)6 in their lowest energy conformations. This is demonstrated by the linear correlation found by plotting log Ks vs. Eint, where K2 stands for stability constant of a complex. The appropriate Ks values were calculated on the basis of cyclic voltammetric measurements.

The reactant in an enzyme-catalyzed reaction is called a substrate. Enzyme inhibitors cause a decrease in the reaction rate of an enzyme-catalyzed reaction.I hope my blog about 14187-32-7 is helpful to your research., Recommanded Product: Dibenzo-18-crown-6

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A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 39648-67-4, Name is (R)-4-Hydroxydinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, molecular formula is C20H13O4P. In a Article£¬once mentioned of 39648-67-4, SDS of cas: 39648-67-4

One-pot biomimetic total synthesis of yuehchukene via the organocatalytic alkylation-cyclization process of a sterically encumbered alpha-alkyl enal

A concise synthesis of yuehchukene has been achieved using organocatalytic Friedel-Crafts alkylation of indole to a sterically encumbered alpha-alkyl enal as the key step. A racemization process during the subsequent cyclization steps of the conjugate adduct to yuehchukene was observed.

Balanced chemical reaction does not necessarily reveal either the individual elementary reactions by which a reaction occurs or its rate law.SDS of cas: 39648-67-4. In my other articles, you can also check out more blogs about 39648-67-4

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Let¡¯s face it, organic chemistry can seem difficult to learn. Especially from a beginner¡¯s point of view. Like 14187-32-7, Name is Dibenzo-18-crown-6. In a document type is Article, introducing its new discovery., 14187-32-7

Structure of hydrated clusters of dibenzo-18-crown-6-ether in a supersonic jet – Encapsulation of water molecules in the crown cavity

The structure of dibenzo-18-crown-6-ether (DB18C6) and its hydrated clusters has been investigated in a supersonic jet. Two conformers of bare DB18C6 and six hydrated clusters (DB18C6-(H2O)n) were identified by laser-induced fluorescence, fluorescence-detected UV-UV hole-burning and IR-UV double-resonance spectroscopy. The IR-UV double resonance spectra were compared with the IR spectra obtained by quantum chemical calculations at the B3LYP/6-31+G* level. The two conformers of bare DB18C6 are assigned to “boat” and “chair I” forms, respectively, among which the boat form is dominant. All the six DB18C6-(H2O) n clusters with n = 1-4 have a boat conformation in the DB18C6 part. The water molecules form a variety of hydration networks in the boat-DB18C6 cavity. In DB18C6-(H2O)1, a water molecule forms the bidentate hydrogen bond with the O atoms adjacent to the benzene rings. In this cluster, the water molecule is preferentially hydrogen bonded from the bottom of boat-DB18C6. In the larger clusters, the hydration networks are developed on the basis of the DB18C6-(H2O)1 cluster. the Owner Societies.

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14187-32-7. Let¡¯s face it, organic chemistry can seem difficult to learn. Especially from a beginner¡¯s point of view. Like 14187-32-7, Name is Dibenzo-18-crown-6. In a document type is Article, introducing its new discovery.

Pairwise H2/D2 Exchange and H2 Substitution at a Bimetallic Dinickel(II) Complex Featuring Two Terminal Hydrides

A compartmental ligand scaffold HL with two beta-diketiminato binding sites spanned by a pyrazolate bridge gave a series of dinuclear nickel(II) dihydride complexes M[LNi2(H)2], M = Na (Na¡¤2) and K (K¡¤2), which were isolated after reacting the precursor complex [LNi2(mu-Br)] (1) with MHBEt3 (M = Na and K). Crystallographic characterization showed the two hydride ligands to be directed into the bimetallic pocket, closely interacting with the alkali metal cation. Treatment of K¡¤2 with dibenzo(18-crown-6) led to the separated ion pair [LNi2(H)2][K(DB18C6)] (2[K(DB18C6)]). Reaction of Na¡¤2 or K¡¤2 with D2 was investigated by a suite of 1H and 2H NMR experiments, revealing an unusual pairwise H2/D2 exchange process that synchronously involves both Ni-H moieties without H/D scrambling. A mechanistic picture was provided by DFT calculations which suggested facile recombination of the two terminal hydrides within the bimetallic cleft, with a moderate enthalpic barrier of ?62 kJ/mol, to give H2 and an antiferromagnetically coupled [LNiI2]- species. This was confirmed by SQUID monitoring during H2 release from solid 2[K(DB18C6)]. Interaction with the Lewis acid cation (Na+ or K+) significantly stabilizes the dihydride core. Kinetic data for the M[L(Ni-H)2] ? H2 transition derived from 2D 1H EXSY spectra confirmed first-order dependence of H2 release on M¡¤2 concentration and a strong effect of the alkali metal cation M+. Treating [LNi2(D)2]- with phenylacetylene led to D2 and dinickel(II) complex 3- with a twice reduced styrene-1,2-diyl bridging unit in the bimetallic pocket. Complexes [LNiII2(H)2]- having two adjacent terminal hydrides thus represent a masked version of a highly reactive dinickel(I) core. Storing two reducing equivalents in adjacent metal hydrides that evolve H2 upon substrate binding is reminiscent of the proposed N2 binding step at the FeMo cofactor of nitrogenase, suggesting the use of the present bimetallic scaffold for reductive bioinspired activation of a range of inert small molecules.

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14187-32-7, Name is Dibenzo-18-crown-6, belongs to chiral-catalyst compound, is a common compound. In an article, authors is Akutagawa, Tomoyuki, once mentioned the new application about 14187-32-7.14187-32-7

Solid-state molecular rotators of anilinium and adamantylammonium in [Ni(dmit)2]- salts with diverse magnetic properties

Supramolecular rotators of hydrogen-bonding assemblies between anilinium (Ph-NH3+) or adamantylammonium (AD-NH3 +) and dibenzo[18]crown-6 (DB[18]crown-6) or meso-dicyclohexano[18] crown-6 (DCH[18]crown-6) were introduced into [Ni(dmit)2] salts (dmit2- is 2-thioxo-1,3-dithiole-4,5-dithiolate). The ammonium moieties of Ph-NH3+ and AD-NH3+ cations were interacted through N-H+?O hydrogen bonding with the six oxygen atoms of crown ethers, forming 1:1 supramolecular rotator-stator structures. X-ray crystal-structure analyses revealed a jackknife-shaped conformation of DB[18]crown-6, in which two benzene rings were twisted along the same direction, in (Ph-NH3+)(DB[18]crown-6)[Ni(dmit) 2]- (1) and (AD-NH3+)(DB[18]crown-6) [Ni(dmit)2]- (3), whereas the conformational flexibility of two dicyclohexyl rings was observed in (Ph-NH3+)(DCH[18]crown-6) [Ni(dmit)2]- (2) and (AD-NH3 +)(DCH[18]crown-6)[Ni(dmit)2]_ (4). Sufficient space for the molecular rotation of the adamantyl group was achieved in the crystals of salts 3 and 4, whereas the rotation of the phenyl group in salts 1 and 2 was rather restricted by the nearest neighboring molecules. The rotation of the adamantyl group in salts 3 and 4 was evidenced from the temperature-dependent wide-line 1H NMR spectra, dielectric properties, and X-ray crystal structure analysis, ab initio calculations showed that the potential energy barriers for the rotations of adamantyl groups in salts 3 (DeltaE ? 18 kJmol-1) and 4 (DeltaE ? 15 kJmol -1) were similar to those of ethane (?12 kJmol-1) and butane (17-25 kuJmol-1) around the C-C single bond, which were 1 order of magnitude smaller than those of phenyl groups in salts 1 (DeltaE ? 180 kJmol-1) and 2 (DeltaE ? 340 kJmol-1). 1D or 2D [Ni(dmit)2]- anion arrangements were observed in the crystals according to the shape of crown ether derivatives. The 2D weak intermolecular interactions between [Ni(dmit)2]- anions in salts 1 and 3 led to Curie-Weiss behavior with weak antiferromagnetic interaction, whereas 1D interactions through lateral sulfur-sulfur atomic contacts between [Ni(dmit)2]- anions were observed in salts 2 and 4, whose magnetic behaviors were dictated by ferromagnetic (salt 2) and singlet-triplet (salt 4) intermolecular magnetic interactions, respectively.

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Chemistry is the experimental science by definition. We want to make observations to prove hypothesis. For this purpose, we perform experiments in the lab. 14187-32-7, Name is Dibenzo-18-crown-614187-32-7, introducing its new discovery.

The photochemical substitution of benzene in [Cb*Co(C 6H6)]+ (Cb* = C4Me 4) with benzo-15-crown-5 (1) gives the corresponding pi-complex [Cb*Co(eta6-C6H4(OCH2CH 2C)CH2CH2)2O)]+ (2). A similar reaction with dibenzo-18-crown-6 (3) produces cation [Cb*Co(eta6-C6H4(OCH2CH 2OCH2CH2O)2C6H 4)]+ (4). Arene exchange is reversible, and both 1 and 3 can be regenerated by irradiation of 2 and 4 with excess benzene. The reaction of [Cb*Co(C6H6)]+ with 0.5 equiv of 3 gives dinuclear complex [trans-Cb*Co(mu-eta6, eta6-C6H4(OCH2CH 2OCH2CH2O)2C6H 4)CoCb*]2+ (5). The structures of cations 4 and 5 were confirmed by X-ray diffraction. The electrochemical behavior of complexes prepared was studied. The sodium-binding ability of cobalt complexes 2,4, and 5 (determined by NMR titration; Ka = 2500, 800, and 50, respectively) was found to be much smaller than that of the free crown ethers 1 and 3 (K a, -200 000 and 5 000 000). DFT calculations suggest that this decrease is mainly due to electrostatic repulsion of Co+ and Na + centers.

Sometimes chemists are able to propose two or more mechanisms that are consistent with the available data.14187-32-7, If a proposed mechanism predicts the wrong experimental rate law, however, the mechanism must be incorrect.Welcome to check out more blogs about 14187-32-7, in my other articles.

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14187-32-7, An article , which mentions 14187-32-7, molecular formula is C20H24O6. The compound – Dibenzo-18-crown-6 played an important role in people’s production and life.

The effect of crown ethers, tetraalkylammonium salts, and polyoxyethylene amphiphiles on pirarubicin incorporation in K562 resistant cells

The basic distinguishing feature of all cells expressing functional P-glycoprotein-multidrug resistance (P-gp-MDR) is a decrease in steady-state accumulation drug levels as compared to drug-sensitive controls. In an attempt to identify mechanism(s) by which MDP can be circumvented, we examined the cellular accumulation, in resistant cells, of 4′-O-tetrahydropyranyl-doxorubicin (pirarubicin) alone and in conjunction with various molecules belonging to three different classes: the crown ethers, the tetraalkylammonium salts, and the polyoxyethylene amphiphiles. The present study was performed using a spectrofluorometric method which enabled us to follow the uptake and release of fluorescent molecules by living cells while the cells were being incubated with the drug. Erythroleukemia K562 cell lines were used. Our data show that the compounds of these three completely different classes were able to increase the incorporation of pirarubicin provided they had a minimum degree of lipophilicity. Study of the growth inhibitory activity of these compounds revealed that cross-resistance to the tetraalkyl ammonium salt increased with the lipophilicity and was equal to 58 for tetraoctylammonium salt, the most lipophilic compound of this series. This demonstrates that neither the presence of a positive charge nor an aromatic moiety is required for MDR recognition.

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Chemistry is the science of change. But why do chemical reactions take place? Why do chemicals react with each other? The answer is in thermodynamics and kinetics.In a document type is Article, the author is Dubberley, Stuart R. and a compound is mentioned, 14187-32-7, Dibenzo-18-crown-6, introducing its new discovery. 14187-32-7

Group 1 and mixed Group 1 and 2 metal complexes of dianionic p-tert-butylcalix[4]arenes

Group 1 and related complexes of 1,3-O,O?-disubstituted p-tert-butylcalix[4]arene dianions [tBu-calix[4](OR) 2(O)2]2- are reported. Reaction of tBu-calix[4](OMe)2(OH)2 with NaH, K, Rb or Cs gave dimeric [M2{tBu-calix[4](OMe)2-(O) 2}]2 (M = Na 1, K 2, Rb 3 or Cs 4). The X-ray structure of 1 shows that two Na+ ions are exo-bound between the two calix[4]arene ligands while the other two are endo-bound within the calix[4]arene cavities. Reaction of tBu-calix[4](OMe) 2(OH)2 with nBuLi (2 equiv.) gave a mixture of dimeric and monomeric compounds. Complex 1 is cleaved by 15-crown-5 forming [Na2{tBu-calix[4](OMe)2(O) 2}(15-crown-5)]. The complexes 2-4 are cleaved by dibenzo-18-crown-6 forming [M2{tBu-calix[4](OMe)2(O) 2}(dibenzo-18-crown-6)]. Reactions of tBu-calix[4](OR)2-(OH)2 (R = CH2Ph or SiMe3) with Li or Na reagents gave monomeric [M2{ tBu-calix[4](OR)2(O)2}]. The reaction of 1 with CsCl gave [NaCs{tBu-calix[4](OMe)2(O) 2}]2 13 in which the two Cs+ ions are endo-bound. Reaction of 1 with CaCl2 formed [Na2Ca{ tBu-calix[4](OMe)2(O)2}2]. The Royal Society of Chemistry 2003.

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