bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Mechanism of the Oxidation of Toluenes in Artificial P450 Model Systems: Formation of Benzyl Alcohols, Benzaldehydes, and Phenols
Authors: Nakano Taku , Kawabata Sally , Sugihara Tamami , Agatsuma Noriko , Kakuda Hiroko , Mori Yoshihiro 
Published: December 2003

Abstract
Systems with pentafluoroiodosylbenzene (PFIB) and hemin (FeTPPCl8Cl) in dichloromethane were adopted to study the activities of the model system using toluenes as substrates for P450 enzymes. The oxidation products were mainly corresponding benzyl alcohols and benzaldehydes. Previously reported suspension systems were extended to homogeneous mixed solution systems of CH2Cl2/CH3OH/H2O to study the oxidation of benzyl alcohols to the corresponding benzaldehydes: the Hammett relation with ρ = −0.86 against σ+. As benzaldehydes were scarcely observed in natural P450 systems, the formation of benzaldehyde seemed characteristic only of the “open” model systems. In suspension systems, the product ratios between corresponding benzaldehydes and benzyl alcohols (ald/alc) were about 0.1–0.4, specific to the substituents and conditions applied. Curiously, the ratios (ald/alc) increased with the electronegativity of the substituents on the phenyl rings of the toluene derivatives. Time course experiments in suspension systems indicated that benzyl alcohols and benzaldehydes were formed not stepwise, but simultaneously from toluene. Separate experiments indicated that the reaction of benzyl alcohol to benzaldehyde was four-fold faster than that of toluene to benzyl alcohol. The rate was not enough to elucidate the amount of benzaldehyde. We suggest that the benzyl radical is formed by hydrogen abstraction and is attacked by the second oxidant, PFIB. Rebounding of the hydroxyl radical and the reaction with the oxidant were competitive depending on the conditions. Additionally, small amounts of phenols were formed from toluenes with electron-donating substituents. This was a minor reaction on which the aromatic hydroxylation occurred via epoxidation under the present conditions.
Fundamental Studies on the Structures and Spectroscopic Properties of Imidazo[1,2-a]pyrazin-3(7H)-one Derivatives
Authors: Nakai Shunichiro , Yasui Masanori , Nakazato Masaki , Iwasaki Fujiko , Maki Shojiro , Niwa Haruki , Ohashi Mamoru , Hirano Takashi 
Published: December 2003

Abstract
The fundamental physical properties of 2-methyl and 2-phenylimidazo[1,2-a]pyrazin-3(7H)-one 1 and 2, and their N- and O-alkylated derivatives 3–6 have been investigated by X-ray crystallography, UV/vis absorption spectroscopy, NMR, and AM1-COSMO calculations. The crystal structures of 3 and 4 showed that the imidazo[1,2-a]pyrazin-3(7H)-one (imidazopyrazinone) π-system has a planar ring structure and a weakened carbonyl character of the C3–O10 bond, suggesting that the imidazopyrazinone π-system has the character of a zwitter-ionic resonance structure to increase the aromaticity. The data concerning the bond length alternations and the NMR chemical shifts of 1–4 also support that their imidazopyrazinone rings have small portions of aromatic character. In addition, imidazopyrazinone derivatives 1–4 showed solvatochromism originating by hydrogen-bonding interactions with hydrogen-bond donor solvent molecules; derivatives 1 and 2 prefer to be the NH form isomers in their tautomeric equilibriums. These observations were consistently evaluated by MO calculations. The physical properties of protonated species of 1–6 and anion species of 1 and 2 were also established. The fundamental properties of the imidazopyrazinone π-system explain the several problems of the chemi- and bioluminescence reactivities of imidazopyrazinone derivatives and of the construction of a bioluminescent supramolecule.
Syntheses and Structural Characterizations of a Novel Bowl-Type Germanol and Its Derivatives
Authors: Goto Kei , Shimo Isao , Kawashima Takayuki 
Published: December 2003

Abstract
A novel bowl-type triarylgermyl group, tris(2,2″,6,6″-tetramethyl[1,1′:3′,1″-terphenyl]-5′-yl)germyl (denoted as TRMG), was designed, and a germanol and its derivatives bearing this framework were synthesized. X-ray crystallographic analysis of TRMG–OH (5) revealed that there is no OH···O hydrogen bonding between adjacent molecules, although the possible presence of a weak intermolecular OH···π interaction was suggested. In sharp contrast to organogermanols known so far, 5 is extremely resistant to self-condensation; no digermoxane was obtained when 5 was subjected to the conditions under which Ph3GeOH (8) affords the corresponding digermoxane. On the other hand, germanol 5 was readily converted to various derivatives. The crystal structure of TRMG–SH (12) was also determined.
Enzymatic Synthesis of (R)-Flurbiprofen
Authors: Terao Yosuke , Ijima Yoichiro , Kakidani Hitoshi , Ohta Hiromichi 
Published: December 2003

Abstract
α-Methyl-α-(2-fluoro-4-biphenylyl)propionic acid (flurbiprofen) was prepared from the corresponding malonic acid derivative via asymmetric decarboxylation catalyzed by an enzyme, arylmalonate decarboxylase (EC 4.1.1.76), in high chemical and optical yields.
Copper-Catalyzed Oxidation of Amines with Molecular Oxygen
Authors: Maeda Yasunari , Nishimura Takahiro , Uemura Sakae 
Published: December 2003

Abstract
An improved system for selective aerobic oxidation of amines to imines or nitriles is presented. It involves commercially available and inexpensive copper(I) or (II) chloride as catalyst, toluene as solvent, and MS3A as dehydrating agent under an atmospheric pressure of oxygen. A variety of amines can be used as substrates for this oxidation system to give the corresponding nitriles from primary amines (up to 97% yield; TON, up to 60) and the imines from secondary amines (up to 90% yield; TON, up to 45).
Factors Affecting the Conformational Preference and Magnetic Shielding of Isobutenylene Chains in Macrocyclic Salicylideneaniline Derivatives
Authors: Houjou Hirohiko , Tsuzuki Seiji , Nagawa Yoshinobu , Kanesato Masatoshi , Hiratani Kazuhisa 
Published: December 2003

Abstract
The 1H NMR chemical shifts and X-ray crystal structures of various salicylideneaniline derivatives containing an isobutenylene (2-methylenepropane-1,3-diyl) chain were analyzed in detail. In solution, these compounds were present to some extent as syn–syn conformers with respect to the isobutenylene chain; the actual syn–syn population depended on the molecular structure, especially on the size of the macrocycle. Small substituents on the phenyl ring hardly affected the stability of the syn–syn form at all, whereas replacement of the phenyl group with a naphthalene moiety considerably destabilized the syn–syn form relative to the syn–skew form. The conformation–chemical shift relationship was validly maintained irrespective of the substituent, provided the conformational preference was correctly taken into account.
Charge-Transfer Quenching of Excited Ketones by Selenides
Authors: Yamazaki Yuko , Nakamura Takayuki , Hasegawa Tadashi 
Published: December 2003

Abstract
Diphenyl selenide (kq = 2.5 × 109 mol−1 dm3 s−1) and selenoxide (2.5 × 108) quenched the Type II reaction of butyrophenone through a charge-transfer process more efficiently than the corresponding sulfide (1.5 × 108) and sulfoxide. The irradiation of 2-(benzylseleno)ethyl benzoylacetate gave bis[2-(benzoylacetoxy)ethyl] diselenide and 1,2-diphenylethane.
Pore Size Distribution and Porosities of Nano-TiO2 Films Made by Using Cellulosic Thickener and Their Influence on Performance of Dye-Sensitized Solar Cells
Authors: Jiang Ke-Jian , Kitamura Takayuki , Wada Yuji , Yanagida Shozo 
Published: December 2003

Abstract
A series of mesoporous TiO2 films with different average pore sizes and distributions were prepared by changing the addition content of cellulosic thickener in the pastes. The BET surface area shows that, for the samples with 3, 5, 10 and 15 wt % cellulosic thickener, the average pore size remained centered at 14–15 nm, but the pore size distribution became narrower with the increase of cellulosic thickener addition. With further increase of cellulosic thickener to 21 and 30 wt %, the average pore size decreases to 13 and 11 nm, and the pore size distribution also became much narrower. The sample, prepared from the paste with 15 wt % cellulosic thickener, shows the best result: short-circuit photocurrent density 13 mA/cm2, open-circuit photovoltage 0.72 V, fill factor 0.68, and conversion efficiency 6.4%.
Immobilization of Aqueous Heavy Metal Cations with Phosphates and Sulfates
Authors: Sugiyama Shigeru , Fujisawa Masayoshi , Koizumi Tatsuya , Tanimoto Shinya , Kawashiro Katsuhiro , Tomida Tahei , Hayashi Hiromu 
Published: December 2003

Abstract
The dissolution–precipitation mechanism has been suggested for the immobilization of aqueous lead cation with calcium hydroxyapatite (Ca10(PO4)6(OH)2; CaHAp). Here Na2HPO4, K2HPO4, MgHPO4 and CaHPO4 were employed for CaHAp. These hydrogenphosphates could favorably remove Pb2+, Cd2+, Co2+ and Cu2+ from aqueous solution for 0.5 h at 293 K. The removability of those hydrogenphosphates was evidently greater than that of CaHAp and seemed to be dependent on solubility of those hydrogenphosphates and the hydration enthalpy of those heavy metal cations. The structures of phosphates recovered after immobilization of Pb2+, Cd2+, and Co2+ were strongly influenced by the pH in the aqueous solution, while the structures after immobilization of Cu2+ for 0.5 and 12 h were amorphous compound and Cu2(PO4)(OH), respectively. The employment of solid state 31P MAS NMR and XRD revealed that the amorphous compound was also Cu2(PO4)(OH). The removability found with those hydrogenphosphates was also observed in the immobilization of Pb2+ with MgSO4 and CaSO4.
Preparation and Photochromic Properties of Powder and Films of DNA–Dodecyltrimethylammonium Ion Complex Containing Spiropyran Derivatives
Authors: Saito Masako , Musha Kiyoshi , Yokoyama Yayoi , Yokoyama Yasushi 
Published: December 2003

Abstract
Two thermally reversible photochromic spiropyrans, 1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-indoline] 1 and 3′,3′-dimethyl-6-nitro-1-(3-sulfopropyl)spiro[2H-1-benzopyran-2,2′-indoline] triethylamine salt 2, were incorporated in powder and films of an organic-solvent-soluble DNA–dodecyltrimethylammonium ion complex. The powder and the films showed thermally reversible photochromism. The spiropyrans in the powder were considered to be intercalated into the DNA base pairs because: 1) they were thoroughly washed to remove weakly attaching molecules and 2) the color of the powder was different from either of the closed or open forms of the spiropyran, whereas spiropyrans doped in the films behaved as in the polar organic solvents, so that the film was a mixture of spiropyran and the DNA–dodecyltrimethylammonium ion complex.
Coupling Covalent and Noncovalent Electron Transfer in a Catenane-type Donor-Sensitizer-Acceptor Triad
Authors: Hu Yi-Zhen , Tsukiji Shinya , Shinkai Seiji , Oishi Shigero , Dürr Heinz , Hamachi Itaru 
Published: December 2003

Abstract
A catenane-type triad consisting of a donor (phenothiazine), a sensitizer (Ru(2,2′-bipyridine)3) and an acceptor (cyclobis(paraquat-p-phenylene)) was prepared by stepwise coordination. Multistep noncovalent and covalent electron transfer was successfully carried out in this triad.
The First Evidence Indicating Formation of Superoxide by Manganese-Dependent Peroxidase (MnP) in the Presence of Excess H2O2
Authors: Watanabe Takashi , Kamitsuji Hisatoshi , Enoki Makiko , Honda Yoichi , Kuwahara Masaaki 
Published: December 2003

Abstract
Production of O2− by manganese peroxidase (MnP) in the absence of free radical intermediates was analyzed by ESR spin trapping experiments with 4-POBN and DMPO. MnPs from Pleurotus ostreatus and Bjerkandera adusta produced O2− after addition of an excess of H2O2 independently of the presence of organic acid chelator for Mn(II) and Mn(III). This is the first report demonstrating direct production of O2− by MnP.
Low Temperature Synthesis of Ultrafine SnTe Powder in Ethanol Solvent
Authors: Zhang Weixin , Cheng Youwei , Hu Junqing , Zhan Jinhua , Yu Weichao , Yang Li , Qian Yitai 
Published: December 2003

Abstract
Reaction of a tellurium alkaline ethanol solution and tin(II) tartaric acid complex produced ultrafine SnTe powder with a cubic phase. The XRD pattern indicated that the tellurium alkaline ethanol solution as a tellurium source, made the product crystallize well at 140 °C on reflux. The TEM image showed that the particle size was in the range of 0.25-0.50 µm. The mechanism of the formation of tin(II) telluride was discussed.
A Practical Method for Optical Resolution of Racemic Alcohols or Esters via Lipase-Catalyzed Transformation and Sulfation
Authors: Yamano Toru , Kikumoto Fumio , Yamamoto Shozo , Miwa Katsuhiko , Kawada Mitsuru , Ito Tatsuya , Ikemoto Tomomi , Tomimatsu Kiminori , Mizuno Yukio 
Published: December 2003

Abstract
Optically active esters were conveniently obtained from the corresponding racemic alcohols or esters by lipase-catalyzed transformation, followed by sulfation. Sulfation by sulfurtrioxide pyridine complex enabled facile isolation of optically active esters by extraction instead of laborious column chromatography. The method would be especially advantageous on a large scale.
Synthesis of Wholly Alicyclic Polyimides from N-Silylated Alicyclic Diamines
Authors: Watanabe Yasufumi , Sakai Yoshimasa , Ueda Mitsuru , Oishi Yoshiyuki , Mori Kunio 
Published: December 2003

Abstract
A synthetic method to give wholly aliphatic polyimides with high molecular weights has been developed. The polymerization of cyclobutanetetracarboxylic dianhydride (CBDA) with 5-trimethylsilylamino-N-trimethylsilyl-1,3,3-trimethylcyclohexanemethylamine (NSD-1) or 2,5(2,6)-bis(N-trimethylsilylaminomethyl)bicyclo[2.2.1]heptane (NSD-2) was carried out in polar aprotic solvents at room temperature, giving poly(amic acid trimethylsilyl ester)s (PATSEs) as precursor polymers which were hydrolyzed to poly(amic acid)s (PAAs) with inherent viscosities up to 0.74 dL g−1. Both polyimide precursors were readily converted to the corresponding polyimides by thermal treatment.
Tetravalent Ion(Zr4+) Conduction in Solids
Authors: Imanaka Nobuhito , Ueda Tomohiro , Okazaki Yusuke , Tamura Shinji , Hiraiwa Masamichi , Adachi Gin-ya 
Published: December 2003

Abstract
Tetravalent Zr4+ ion was directly demonstrated to migrate in zirconium oxide phosphate(Zr2O(PO4)2) solid in which pentavalent phosphorus ion forms PO43− unit with bonding strongly to counter four oxygen ions, resulting in a released circumstance for the rest of the constituent tetravalent ion, Zr4+, to migrate.
Deamination of 1-Alkyl-9-aminomethyltriptycenes: Participation of the α-C-H Bond of the 1-Alkyl Group
Authors: Yamamoto Gaku , Mochida Hisashi 
Published: December 2003

Abstract
Diazotization of 1-alkyl-9-aminomethyltriptycenes (alkyl = methyl and ethyl) in AcOH or CHCl3 gives products derived from participation of an α-C-H bond of the 1-alkyl group. The product distributions strongly depend on the 1-alkyl group and the solvent.
Ultrafast Bimolecular Reaction Kinetics between S1 trans-Stilbene and Carbon Tetrachloride Studied by Sub-Picosecond Time-Resolved Visible Absorption Spectroscopy
Authors: Iwata Koichi , Hamaguchi Hiro-o 
Published: December 2003

Abstract
Ultrafast bimolecular reaction kinetics between S1 trans-stilbene and carbon tetrachloride is monitored by sub-picosecond time-resolved visible absorption spectroscopy. The observed kinetics is well explained either by Smoluchowski’s theory or by Collins-Kimball’s theory of diffusion-controlled reactions. These results suggest that the molecular motion in solution for a few picosecond time period is well described by diffusion.
Imaging of Diaphorase Micropatterned at Gold Arrays with Scanning Electrochemical Microscopy
Authors: Yasukawa Tomoyuki , Kanaya Norihiro , Mandler Daniel , Matsue Tomokazu 
Published: December 2003

Abstract
Diaphorase was hydrophobically immobilized onto a self-assembled monolayer of alkanethiol at an interdigitated Au microarray. The diaphorase activity at the array substrates was imaged with the scanning electrochemical microscopy (SECM) in the presence of NADH and ferrocenemethanol as a redox mediator. The images demonstrate that diaphorase was immobilized onto the SAM layer to form a line-and-space micropattern which reflected the pattern of the Au microarray.
Benzyltriphenylphosphonium Peroxymonosulfate: As a Novel and Efficient Reagent for Oxidation of Alcohols under Solvent-Free Conditions
Authors: Hajipour Abdol Reza , Mallakpour Shadpour E , Adibi Hadi 
Published: December 2003

Abstract
This paper describes the oxidation of alcohols under solvent-free conditions using benzyltriphenylphosphonium peroxymonosulfate, which has been prepared by mixing an aqueous solution of benzyltriphenylphosphonium chloride with oxone® at room temperature. This reagent is stable white powder, which may be stored for months without loss of its activity. This compound is readily soluble in organic solvents such as acetonitrile, chloroform, and dichloromethane and slightly soluble in carbon tetrachloride, ether, and hexane.
One-Dimensional Arsenic-Vanadium Cluster Chain Bridged by Two Co(en)2 Groups
Authors: Bu Wei-Ming , Yang Guo-Yu , Ye Ling , Xu Ji-Qing , Fan Yu-Guo 
Published: December 2003

Abstract
The hydrothermal reaction of As2O3, V2O5, Co(Ac)2, H3PO4, en and H2O produces [CoII(en)3][{CoII(en)2}2AsIII6VIV15O42]·4H2O, which consists of a one-dimensional arsenic-vanadium cluster chain bridged by two different geometries of Co(en)2 groups. The interactions, which are established through hydrogen-bonding involving water molecules, the amine nitrogens, and terminal oxygen atoms, result in three-dimensional hydrogen-bonding network. Magnetic measurement indicates that the overall magnetic behavior is weakly antiferromagnetic.
First Synthesis of Subelliptenone F, an Inhibitor of Topoisomerase II
Authors: Ohira Susumu , Fukamachi Norihiro , Nakagawa Osamu , Yamada Masashi , Nozaki Hiroshi , Iinuma Munekazu 
Published: December 2003

Abstract
Subelliptenone F, a potent inhibitor of topoisomerase II, was synthesized for the first time via coupling of A and C ring components and B ring formation, followed by Claisen rearrangement of the 3-methyl-2-butenyl ether.
Glucosylated Tris-bipyridine Ferrous Complexes: Construction of Hexavalent Saccharide Clusteres via Self-Assembly and Their Recognition by Lectin
Authors: Hasegawa Teruaki , Matsuura Kazunori , Kobayashi Kazukiyo 
Published: December 2003

Abstract
Hexavalent glycoconjugates were prepared via self-assembly of divalent glycosylated 2,2′-bipyridine derivatives with ferrous chloride. The Λ- and Δ-stereoisomeric complexes were preferentially formed from α- and β-glucoside derivatives, respectively. The α-glucoside cluster exhibited an enhanced affinity for concanavalin A.
Facile Synthesis of Optically Active Homocysteine from Methionine
Authors: Shiraiwa Tadashi , Nakagawa Kazuo , Kanemoto Norito 
Published: December 2003

Abstract
l-Methionine (l-Met) reacted with dichloroacetic acid in concentrated hydrochloric acid under refluxing to give (4S)-1,3-thiazane-2,4-dicarboxylic acid hydrochloride [(4S)-TDC·HCl]. l-Homocysteine (l-Hcy) was obtained in an optically pure form by treatment of (4S)-TDC·HCl with hydroxylamine hydrochloride. d-Hcy was also synthesized starting from d-Met via (4R)-TDC·HCl intermediate.
Mechanism of Skeletal Isomerization of n-Butane Using 1,4-13C2-n-Butane on Solid Strong Acids
Authors: Suzuki Tetsuo , Okuhara Toshio 
Published: December 2003

Abstract
Mechanism of skeletal isomerization of n-butane over Cs2.5H0.5PW12O40 as well as sulfated ZrO2 was revealed at a temperature range 393 - 523 K by using 1,4-13C2-n-butane. 13C-Distributions of isobutane at 393 K were close to binomial distribution, indicating a bimolecular pathway. On the other hand, an intramolecular (monomolecular) rearrangement became significant over Cs2.5H0.5PW12O40 at 523 K.
Nonlinear Optical Properties of [C6H5N-R][Ni(mnt)2] (R = p-nitrobenzyl)
Authors: Zhu Xuhui , You Xiaozeng , Ren Xiaoming , Tan Weilian , Ji Wei , Raj S S Sundara , Fun Hoongkun 
Published: December 2003

Abstract
Investigation of third-order optical nonlinearity of complex 1, [C6H5N-R][Ni(mnt)2] where R = p-nitrobenzyl, mnt = maleonitrile-1,2-dithiolate, with 7 ns laser pulses at 532 nm shows that it exhibits negligible nonlinear absorption, but considerable nonlinear refraction. In terms of two calculated figures of merit W and B resulting from one-photon and two-photon absorptions, complex 1 may be used for all-optical signal processing.
A New Reduction-Carburization Route to Nanocrystalline TiC
Authors: Hu Jun-Qing , Lu Qing-Yi , Tang Kai-Bin , Deng Bin , Jiang Rongrong , Qian Yi-Tai , Zhou Gui-En , Yang Li 
Published: December 2003

Abstract
Nanocrystalline TiC was synthesized through a new reduction-carburization route by using metallic Na as the reductant, and tetrachlorotitanium (TiCl4) and carbon as Ti and C sources at 650 °C. The present route allowed for the formation of nanocrystalline TiC with fine particle sizes, narrow size distribution (8-12 nm). A possible formation mechanism for nanocrystalline TiC was proposed.
Novel Method for Synthesizing Zirconium Oxide Thin Membrane on/into Polymer Membranes
Authors: Kakuta Yoshihisa , Atoguchi Takashi , Yao Shigeru 
Published: December 2003

Abstract
Polymer supported zirconium oxide thin layer was prepared by means of a simple sol-gel method using inorganic salt and methanol. This simplified method was effective for reducing steps of sol-gel procedure and was applicable to many kinds of polymer substrate not only hydrophilic but hydrophobic. This method was also applicable to porous membrane as substrate, and was effectively applied to fill the pore with zirconium oxide.
Enhancing Effect of SO2 on Selective Catalytic Reduction of NO by Methanol over Ag/Al2O3
Authors: Zhu Tianle , Hao Jiming , Li Weibin 
Published: December 2003

Abstract
The effect of SO2 on activity for NO reduction by methanol over Ag/Al2O3 in the presence of excess oxygen has been investigated. Selective catalytic reduction activity was not decreased but increased and most effective NO reduction temperature shifted from 200-250 °C to 300-350 °C by pre-sulfated Ag/Al2O3 or addition of SO2 to reaction mixture.
Synthesis of β-Substituted 21,23-Dithiaporphyrins
Authors: Ravikanth M 
Published: December 2003

Abstract
Synthesis and characterization of β-substituted 5,10,15,20-tetraphenyl-21,23-dithiaporphyrins are reported. The absorption and emission spectra exhibited large bathochromic shifts due to nonplanarity of porphyrin ring which is induced on β-substitution.
Optical Resolution of a Six-Coordinate Silicon(IV) Complex with a Tripodal Hexadentate Ligand
Authors: Kojima Masaaki , Azuma Shunryo , Hirotsu Masakazu , Nakajima Kiyohiko , Nonoyama Matsuo , Yoshikawa Yuzo 
Published: December 2003

Abstract
The reaction of silicon tetraacetate with a tripodal hexadentate ligand (H3L = 1,1,1-tris(N-salicylideneaminomethyl)ethane) afforded the colorless [Si(L)]+ complex. The X-ray analysis of the complex revealed that the Si–N bond distance, av. 1.926(2) Å, is much longer than the Si–O bond distance, av. 1.723(2) Å. The complex is stable toward hydrolysis and could be optically resolved by fractional crystallization of the diastereomeric salt with (−)-dibenzoyl-l-tartaric acid.
Selective Bridging of Calix[6]arene: Synthesis of 1,2-Calix[6]dioxocrowns
Authors: Chen Yuanyin , Yang Fafu 
Published: December 2003

Abstract
Treating p-tert-butylcalix[6]arene with oligoethylene glycol bischloroacetates, a series of ester-containing 1,2-bridged calix[6]crowns have been synthesized in reasonable yields for the first time. The longer the spacer in bischloroacetates, the higher the yield. The extraction ability towards alkali metal and ammonium cations of the obtained 1,2-calix[6]dioxocrowns are superior to that of 1,2-calix[6]crown-5.