- Preparation and application of cholesteryl-benzo-15-crown-5/cholesteryl mixed liquid crystals
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Various mixed liquid crystals containing crown ether-cholesteryl liquid crystal, benzo-15-crown-5-COO-C27H45 (B15C5-COOCh), with various common cholesteric liquid crystals, e.g., cholesteryl chloride, cholesteryl benzoate and cholesteryl palmitate, were prepared and studied using polarizing microscopy and differential scanning calorimetry. Investigating the concentration effect of B15C5-COOCh in mixed liquid crystals revealed that the addition of B15C5-COOCh resulted in wider phase transition temperature ranges of these cholesteryl liquid crystals. The stability of these B15C5-COOCh/ cholesteryl mixed liquid crystals was studied using comprehensive graphic molecular modeling computer programs (Insight II and Discover) to calculate their molecular energy and stability energy. The effect of salts, e.g. Na +, Co3+, Y3+ and La3+, on the transition temperature range of the mixed liquid crystals was also investigated. The crown ether cholesteric liquid crystal B15C5-COOCh was applied both as a surfactant and an ion transport carrier to transport metal ions through liquid membranes. Cholesteryl benzo-15-crown-5 exhibited distinctive characteristics of a surfactant and the critical micellar concentration (CMC) of the surfactant was investigated by the pyrene fluorescence probe method. Cholesteryl benzo-15-crown-5 was successfully applied as a good ion transport carrier (Ionophore) to transport various metal ions, e.g. Li+, Na +, La3+, Fe3+ and Co3+, through organic liquid membranes. The transport ability of the cholesteryl benzo-15-crown-5 surfactant for these metal ions was in the order: Co 3+ ≥ Li+ > Fe3+ > Na+ > La3+.
- Shen, Ya-Chi,Shih, Jeng-Shong
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- Synthesis and properties of macroheterocyclic azomethines based on 4-aminobenzo-15-crown-5
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A number of new stable azomethine crown ether derivatives have been synthesized by condensation of 4-aminobenzo-15-crown-5 with aromatic aldehydes. Complexation of the products with transition metal cations (Cu2+, Zn2+, Fe3+, Co3+, Ni3+) has been studied by spectrophotometry.
- Sadovskaya, N. Yu.,Glushko,Retivov,Belus',Grokhovskii
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- Establishment of an efficient synthetic route to 3,4:3′,4′-bis(3,6,9-trioxaundecane-1,11-dioxy)benzil
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3,4:3′,4′-Bis(3,6,9-trioxaundecane-1,11-dioxy)benzil (1) [bis(crown ether)benzil] was prepared by three different routes in which the third route C, including the method of Sonogashira-coupling, was the most efficient method with the overall yield of 50%. Further, the method of synthesizing the novel compound 3,4:3′,4′-bis[3,4-(3,6,9-trioxaundecane-1,11-dioxy)]benzoin (6) [bis(crown ether)benzoin], which has not yet been prepared appropriately, was also provided.
- Kimura, Masaru,Shi, Kun,Hashimoto, Koji,Hu, Zhi Zhi
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- Template Effects. 6. The Effect of Alkali Metal Ions on the Formation of Benzo-3x-crown-x Ethers over a Wide Range of Ring Sizes
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The rate formation of benzo-3x-crown-x ethers with x = 4,5,7,10 and 16 via intramolecular alkylation of o--OC6H4(OCH2CH2)x-1Br in 99percent aqueous Me2SO was found to be markedly affected by added alkali metal bromides.Catalysis or inhibition was observed, depending on the cation-substrate pair.Combination of the present results with those previously reported for the formation of B18C6 offers a large variety of patterns.The magnitude of the observed effects ranges over four powers of ten.The dependence of the observed rates (kobsd) on metal ion concentration was expessed in terms of independent contributions from free and cation-paired aryl oxide ions, whose relative weights are ruled by the rate constants ki and kip, respectively, and by the ion-pairing association constants KArO-.A self-consistent analysis was used to derive numerical values of the above parameters.A definite contribution from an additional reaction path involving two metal ions was detected in the case of the K+-catalyzed formation of B30C10.The equilibrium constants KC for associations between many cation-crown pairs were also determined under the same conditions.A comparative analysis of structure and metal ion effects on the extent of interaction of the alkali metal ions with the reactants, transition states, and reaction products shows that the cation interaction in the transition state is strongly reminiscent of the host-guest interactions found in the cation-B3XCx complexes.The catalytic efficiency of the alkali metal ioms (log kip/ki) shows a definite tendency to parallel the strength of interaction with the reaction products (log KC), thus indicating that a metal ion capable of binding strongly with a crown ether is also a good catalyst for the formation of the crown ether itself.
- Mandolini, Luigi,Masci, Bernardo
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- Production of macrocyclic polyether benzo-15-crown-5 and its functional derivatives
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Study of interaction between catechol and tetraethylene glycol dichloride in the n-butanol media, resulting with benzo-15-crown-5 production. Production of nitro- and amino-derivatives of benzo-15-crown-5. Determination of their thermogravimetric characteristics.
- Glushko, Valentina N.,Sadovskaya, Natalya Yu.,Kozhuhov, Vadim I.,Blokhina, Lidiya I.,Antropova, Irina A.,Petina, Ekaterina S.,Retiviov, Vasiliy M.,Melnikova, Ekaterina Yu.
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- Complete charge separation provoked by full cation encapsulation in the radical mono- and di-anions of 5,6:11,12-di-: O -phenylene-tetracene
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Herein, we report the synthesis and molecular structure of the mono- and dianionic aromatic molecules [(B15C5-κ5O)2K+](LDOPT-) (1) and [(B15C5-κ5O)2K+]2(LDOPT2-)THFsolv (2) derived from the parent aromatic polyhydrocarbon 5,6:11,12-di-o-phenylenetetracene (DOPT, LDOPT) by a controlled stepwise one and two electron chemical reduction. The effect of single and double electron charge transfer to a polycondensed aromatic hydrocarbon (PAH) without any disturbing influence of an associated metal cation has been demonstrated. This was achieved by fully sandwiching the cationic K+ counterions between two benzo-15-crown-5-ether (B15C5) ligands resulting in a fully encapsulating (κ10O) geometry which ensures a complete separation of the K+ counterions and the bare anionic PAH species [LDOPT-] and [LDOPT2-]. The structural changes accompanied by the stepwise reduction from LDOPT to [LDOPT-] to [LDOPT2-] are discussed and compared to earlier predictions based on density functional theory (DFT) as well as the results of previous studies of alkaline metal cationic PAH anion interactions of DOPT in which only a partial metal cation encapsulation has been achieved so far.
- Wombacher, Tobias,Goddard, Richard,Lehmann, Christian W.,Schneider, J?rg J.
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- Acetylation of B15C5 crown ether on Cu modified clay catalysts
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With different copper-clay based catalysts, in the presence of AcCl as acetylation agent, B15C5 crown ether is acetylated in a convenient heterogeneous catalytic procedure. We show here the first heterogeneous catalytic method for crown ether acylation, where the Cu exchanged clay gives the best results using really catalytic amount of catalyst.
- Cseri, Tivadar,Bekassy, Sandor,Bodas, Zoltan,Agai, Bela,Figueras, Francois
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- Structure and Reactivity of Lithium and Sodium Aryloxides in Dimethylformamide. Ions, Ion Pairs, and Ion Triplets
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Reactivity and u.v. spectra of aryloxide ions in dimethylformamide are affected by the addition of either Li(1+) and Na(1+) ions in a way that suggests the occurrence of ion triplets M(1+)A(1-)M(1+) in addition to free ions and ion pairs.
- Crescenzi, Manuela,Galli, Carlo,Mandolini, Luigi
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- A benzo-15-crown-5-modifying ratiometric-absorption and fluorescent OFF-ON chemosensor for Cu2 +
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One new benzo-15-crown-5-modifying fluorene Schiff base (FBC), together with the C=N-linked fluorene-3,4-dimethoxybenzene (FBDMO) and fluorene-benzene (FB) references, has been designed and facilely synthesized. The binding of Cu2 + with nitrogen atom of C=N moiety in these three compounds can inhibit the photo-induced electronic transition process and induce the ratiometric-absorption and fluorescent OFF-ON response to Cu2 +. Whereas the employment of benzo-15-crown-5 moiety in FBC as additional binding platform for Cu2 + not only amplifies the fluorescent enhancement of FBC via preventing the isomerization of C=N moiety, but also endows this compound high selectivity and rapid response towards Cu2 + over the references FB and FBDMO. These results render FBC highly sensitive ratiometric-absorption and fluorescent OFF-ON detecting potential for Cu2 + with the detection limit of 3.91 × 10- 6 M.
- Chen, Yuting,Wang, Xinxin,Wang, Kaili,Zhang, Xiuling
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p. 144 - 149
(2016/04/04)
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- Novel crown ether functionalized imidazolium-based acidic ionic liquid catalyzed synthesis of pyrazole derivatives under solvent-free conditions
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Abstract An innovatively designed novel crown ether functionalized imidazolium-based reusable acidic ionic liquid [crown ether MIm] [HSO4] has been efficiently implemented for the synthesis of pyrazole derivatives using various substituted enaminones, hydrazine hydrate and phenyl hydrazine under solvent-free conditions. Structural novelty and task efficiency of the catalyst, high yields of desired products, greener approach attributing high atom economy and solvent-free conditions render this protocol suitable to cope with the current demand in contemporary organic chemistry. The inventive idea of utilizing crown ether functionalized ionic liquid as a catalyst was for the first time demonstrated in this protocol.
- Patil, Dayanand,Chandam, Dattatraya,Mulik, Abhijeet,Jagdale, Suryabala,Patil, Prasad,Deshmukh, Madhukar
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p. 6843 - 6858
(2015/08/18)
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- Studies on the photochemical behavior of N-salicylidenaniline in chloroform
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An N-salicylidenaniline (SA), compound 1 with 15-crown-5 moiety, was synthesized. The time-dependent NMR was used to track its photochromic process. The experimental results showed that ultraviolet irradiation would lead compound 1 to decompose into the corresponding salicylaldehyde and amine in chloroform solution, instead of experiencing a photochromic process. By the same method, the reported photochromic results of other SAs were also corrected.
- Zhao, Liyan,Xia, Wujiong,Gou, Baoquan,Lu, Yu,Yang, Chao,Li, Dazhi
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p. 199 - 203
(2012/08/08)
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- Preparation of benzo- and polybenzocrown ethers by macrocyclization reactions
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Macrocyclization of crown ethers and their methods of preparation were explored. We present a robust, scalable method for the preparation of these macrocycles. Additionally, the effect of changing the structures of the precursors was explored to determine whether the 'cut' of bisphenol and dimesylate influenced the course of the reaction as measured by the yield. Further, using catechol derivatives, the method was used for the preparation of monobenzocrown ethers. Interestingly, for the preparation of monobenzocrown ethers, [2+2] adducts were discovered to be significantly contaminating the products. Dimesylates were chosen as the leaving group due to their ease or preparation and the ability to use the unpurified products with no apparent impact on the macrocyclization.
- Hanes, Robert E.,Lee, Jong Chan,Ivy, Sheryl N.,Palka, Anna,Bartsch, Richard A.
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p. 238 - 248
(2012/11/07)
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- N-Methylbenzoazacrown ethers with the nitrogen atom conjugated with the benzene ring: The improved synthesis and the reasons for the high stability of complexes with metal and ammonium cations
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An improved method for the synthesis of formyl derivatives of N - Methylbenzoazacrown ethers is proposed. They are prepared in up to 68% yields over fewer steps and with a much shorter time required for the last step. The stability constants of complexes formed by N-methylbenzoazacrown ethers and their structural analogs with alkali metal, alkaline - Earth metal and ammonium cations were determined by 1H NMR titration in CD3CN. High stability of complexes of N-methyl derivatives of benzoazacrown ethers is demonstrated, comparable with or even exceeding the stability of benzocrown-ether complexes and markedly exceeding the stability of complexes of phenylazacrown ethers with the same macrocycle size. The structures of azacrown ethers and their complexes with Ba(ClO4)2 were studied by X-ray diffraction. A high degree of pre-organization of N - Methylbenzoazacrown ethers toward the formation of complexes with metal and ammonium cations was noted, which is due to the clear-cut pyramidal geometry of the nitrogen atom and the orientation of the lone electron pairs (LEPs) of most heteroatoms towards the centre of the macroheterocycle. Copyright
- Gromov, Sergey P.,Dmitrieva, Svetlana N.,Vedernikov, Artem I.,Kurchavov, Nikolay A.,Kuz'Mina, Lyudmila G.,Strelenko, Yuri A.,Alfimov, Michael V.,Howard, Judith A. K.
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scheme or table
p. 823 - 833
(2010/06/16)
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- Electrogenerated chemiluminescence of benzo 15-crown-5 derivatives
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Novel electrogenerated chemiluminescence (ECL) reagents C1, C2, and C3 with high fluorescence quantum yields bearing 15-crown-5 moiety have been synthesized and characterized. The photophysical, electrochemical, and ECL characters of these compounds have been studied in a 1:1 (v/v) PhH/MeCN mixed solvent. The ECL intensity is enhanced distinctly with the increase in the fluorescence quantum yield. Their ECL behaviors have been studied using annihilation and co-reactant methods (tri-n-propylamine (TPrA) was used as a co-reactant), respectively. The stable ECL emissions of compounds C1-C3 can be ascribed to the typical and simple monomer ECL emission via S-route. Copyright
- Jiang, Xiao,Yang, Xichuan,Zhao, Changzhi,Sun, Licheng
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experimental part
p. 1 - 8
(2009/07/26)
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- Bimodal fluorescence signaling based on control of the excited-state conformational twisting and the ground-state protonation processes
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Amino-based fluoroionophores 1 and 2 can selectively sense alkaline earth metal ions in MeCN under both neutral and acidic conditions by different signaling mechanisms. The fluoroionophoric behavior for the neutral probes is characterized by an 'off-on' photoinduced electron transfer (PET)-like fluorescence intensity response due to a switching from a twisted internal charge transfer (TICT) to a planar internal charge transfer (PICT) state. For the protonated probes (i.e., 1/H+ and 2/H+), the fluorescing species is the localized stilbene fluorophores, but dual fluorescence is induced upon metal-ion recognition through a deprotonation process.
- Yang, Jye-Shane,Hwang, Chung-Yu,Chen, Mon-Yao
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p. 3097 - 3102
(2008/02/02)
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- A practical synthesis of benzocrown ethers under phase-transfer catalysis conditions
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Convenient and effective procedures for the synthesis of benzo-12-crown-4, benzo-15-crown-5, benzo-18-crown-6, benzo-21-crown-7 and benzo-24-crown-8 under phase-transfer catalysis conditions have been developed.
- Bogaschenko, Tatyana,Basok, Stepan,Kulygina, Catherine,Lyapunov, Alexander,Lukyanenko, Nikolay
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p. 2266 - 2270
(2007/10/03)
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- An Improved Method for Preparing Dibenzo Crown Ethers
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In synthesis of symmetrical and unsymmetrical dibenzo crown ethers, the use of dimethyl sulfoxide as a solvent in cyclization allows an increase in the yields, a significant reduction in the reaction time, and simplification of refining.
- Kotlyar,Gorodnyuk,Grigorash,Chuprin
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p. 1135 - 1138
(2007/10/03)
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- Synthesis of formyl derivatives of benzocrown ethers containing N, S, and O heteroatoms in the macrocycle
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A method for the synthesis of 4'-bromobenzodithia-15(18)-crown-5(6) and 4'-bromobenzodiaza-15(18)-crown-5(6) by condensation of 3,4-di(2'-haloethoxy)bromobenzene with polyoxaalkanes containing terminal SH or NHMe groups was suggested.The method for the synthesis of formyl derivatives of benzocrowns containing N, S, and O heteroatoms in the macrocycle based on the metallation of appropriate bromo derivatives with BunLi followed by treatment of the resulting organolithium intermediates with DMF was developed.Oximes and semicarbazones of benzaldehydes containing a crown ether fragment were obtained, and their transformation into the original aldehydes by treatment with KNO2 in an acid medium was studied. - Key words: 4'-bromobenzocrowns, synthesis, metallation; 4'-formylbenzocrown ethers; semicarbazones and oximes of 4'-formylbenzocrown ethers.
- Gromov, S. P.,Fedorova, O. A.,Vedernikov, A. I.,Samoshin, V. V.,Zefirov, N. S.,Alfimov, M. V.
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p. 116 - 123
(2007/10/02)
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- Thermodynamics of Solvent Extraction of Metal Picrates with Crown Ethers: Enthalpy-Entropy Compensation. Part 1. Stoicheiometric 1:1 Complexation
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Quantitative solvent extractions were performed in the water-dichloromethane system at 10-25 deg C to give the extraction equilibrium constants (Kex) and the thermodynamic quantities (ΔH0 and ΔS0) for the ion-pair extraction of aqueous alkali (Li(1+)-Cs(1+)), alkaline earth (Ca(2+)-Ba(2+)), and some heavy metal (Ag(1+), Tl(1+)) picrates with 15-crown-5, benzo-15-crown-5, cis-cyclohexano-15-crown-5, 16-crown-5, 15-(2-methoxyethoxy)methyl-15-methyl-16-crown-5, 18-crown-6, dibenzo-18-crown-6, and dibenzo-24-crown-8.The cation-binding abilities and relative cation selectivities of the ligands are discussed from the thermodynamic point of view.Global treatment of the thermodynamic data obtained in the present and previous works reveals not only that, as is the case with the complexation in the homogeneous phase, the enthalpy-entropy compensation effect holds in the solvent extraction system, but also the ΔH0 vs.TΔS0 plot affords the characteristic slope (α) and intercept (TΔS0) which are comparable to the corresponding values obtained for the homogeneous-phase complexation.This indicates that the conformational change and the extent of desolvation upon cation binding by crown ethers are quite analogous both in the homogeneous phase and in the solvent extraction beyond the apparent differences in the phase and the complexed species involved.
- Inoue, Yoshihisa,Amano, Fumie,Okada, Naoko,Inada, Hiroshi,Ouchi, Mikio,et al.
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p. 1239 - 1246
(2007/10/02)
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- Synthesis of 4'-Vinylbenzo-3n-crown-n Ethers (4<=n<=10)
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4'-Vinylbenzo-3n-crown-n ethers (4=n=10) are prepared by a "Cs-templated" cyclization reaction of catechol with dimesylates of oligoethylene glycols, acetylation of the resultant benzo-3n-crown-n ethers (4=n=10), reduction of the acyl group, and dehydration of the resultant alcohols with pyridinium tosylate.
- Talma, Auke G.,Vossen, Huib van,Sudhoelter, Ernst J. R.,Eerden, Johan van,Reinhoudt, David N.
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p. 680 - 683
(2007/10/02)
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- Application of the Okahara Cyclization to the Preparation of Crown Ethers with Aromatic Units
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A series of crown ethers with single benzene, naphthalene, biphenyl and binaphthyl units are prepared by the intramolecular Okahara cyclization of appropriate symmetrical diols.The method is used to synthesize new crown ether compounds and to prepare previously-reported crown ethers in improved yields.
- Czech, B.,Czech, A.,Bartsch, R. A.
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p. 341 - 343
(2007/10/02)
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- Ring-Closure Reactions. 19. Kinetics of Formation of Benzo-Crown Ethers by Intramolecular Nucleophilic Substitution. A Comparison between Poly(oxyethylene) and Polymethylene Chains
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Kinetic data have been obtained for the formation of 9-, 12-, 15-, 21-, 30-, and 48-membered benzo-crown ethers by intramolecular Williamson synthesis in Me2SO-water (99:1, v/v).Comparison with earlier data for the formation of catechol polymethylene ethers provides an insight into the influence on the ease of ring closure of the replacement of methylene groups by oxygen atoms.Little or no effect occurs at ring size 9.In the next higher homologues the ease of cyclization of the poly(oxyethylene) chains is some 3 times as great as that of the polymethylene chains of similar length, but in the limit of the very long chains the two series behave much in the same way.Interestingly, literature data related to the fast, encounter-controlled reactions between end groups linked by poly(oxyethylene) and polymethylene chains reveal much the same features of the slow, activation-controlled reactions.The general picture fits in with well-established conformational arguments based on the expected strain relief due to replacement of trasannular CH...HC interactions with CH...O or O...O interactions.The oxygen atom effect turns out to be a sensitive tool for the detection of even weak strain energies in ring compounds.
- Illuminati, Gabriello,Mandolini, Luigi,Masci, Bernardo
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p. 4142 - 4145
(2007/10/02)
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