bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and Properties of Nickel–Phosphine Complexes Coordinated with α,β-Unsaturated Ester
Authors: Ishizu Junichi , Yamamoto Takakazu , Yamamoto Akio 
Published: July 2006

Abstract
Reactions of bis(1,5-cyclooctadiene)nickel, Ni(cod)2, with α,β-unsaturated esters in the presence of tertiary phosphine give a series of nickel-phosphine complexes formulated as Ni(tertiary phosphine)nL(L=alkyl methacrylates, methyl acrylate, or methyl cinnamate; n=2 for P(C6H5)3, P(C2H5)(C6H5)2, P(CH3)2(C6H5), P(C2H5)3, n=1 for P(cyclo-C6H11)3). Elemental analyses, IR and NMR spectra, and chemical properties of the complexes confirm the molecular formula. The olefinic proton signals of methyl acrylate and alkyl methacrylates coordinated to nickel shift to upfield by 2.6–4.9 ppm from those of free olefins in the 1H-NMR spectra, indicating that the α,β-unsaturated esters coordinate to nickel through the double bond. The IR spectra show only small low frequency shifts of the ν(C=O) bands of the α,β-unsaturated esters on complex formation. The reactions of Ni(P-(C6H5)3)2 (ethyl methacrylate) and Ni(P(cyclo-C6H11)3) (ethyl methacrylate) with vinyl acetate at room temperature cause the scission of the C–O bond in vinyl acetate to yield ethylene and nickel acetate.
Molecular Conformations of γ-Aminobutyric Acid and γ-Amino-β-hydroxybutyric Acid in Aqueous Solution
Authors: Tanaka Kaori , Akutsu Hideo , Ozaki Yukihiro , Kyogoku Yoshimasa , Tomita Ken-ichi 
Published: July 2006

Abstract
Proton magnetic resonance and Raman spectra indicate that the backbone of γ-aminobutyric acid is fairly flexible and rotational isomers are almost equally populated in aqueous solution. The population is not much affected by change of pH. On the other hand, in γ-amino-β-Hydroxybutyric acid the trans-trans and gauche-trans conformations of the backbone are equally populated in neutral solution, trans-trans conformation being predominant in non-zwitterionic forms. The conformation in solution is discussed in relation to the structure of these molecules in crystal.
Layered Compounds. LIII. Unique Skeletal Rearrangement of Multilayered [2.2]Paracyclophanes
Authors: Horita Hisanori , Koizumi Yosuke , Otsubo Tetsuo , Sakata Yoshiteru , Misumi Soichi 
Published: July 2006

Abstract
Skeletal rearrangements of multilayered [2.2]paracyclophanes to [2.2]metaparacyclophanes with several Friedel-Crafts acids have been studied. Two types of rearrangements depending on the catalyst were observed. Treatment of triple-layered paracyclophane(8) with AlCl3–HCl gave mainly triple-layered metaparacyclophane(9), which was derived by migration of one of the ethylene bridges attached to the outer benzene rings. Treatment of 8 with mild protonic acids such as SnCl4–HCl, TiCl4–HCl, etc. afforded two kinds of metaparacyclophanes 10 and 11 in high yields, which arose from double migration of the two ethylene bridges attached to the inner benzene ring. Such a double migration of substitutents was also observed in the case of tertamethyl[2.2]paracyclophane and quadruple-layered one. The structures of products were determined by means of NMR spectra, alternative syntheses, and X-ray analyses. The mechanism of the rearrangements is discussed in view of protonation experiment.
Macrocyclic Enzyme Model Systems. Catalytic Activity of Cyclic Peptides Involving Hydrophobic Segments
Authors: Murakami Yukito , Nakano Akio , Matsumoto Kiyoshi , Iwamoto Kiyoshi 
Published: July 2006

Abstract
In order to develop an effective hydrolase model, BCP-1 was synthesized and its kinetic behavior investigated. The corresponding linear hexapeptide was prepared by the solid phase method and subjected to cyclization by the azide method. BCP-1 enhanced the hydrolysis of p-nitrophenyl carboxylates bearing a long alkyl chain. The pH-rate profile for the hydrolysis of p-nitrophenyl hexadecanoate (PNPP) as effected by BCP-1 was not of a bell-shaped type but a sigmoid, from which the kinetic pKa value was estimated as 12.3. The initial reaction rate was found to level off beyond a certain range of substrate concentration (saturation-type kinetics), the kinetic data being analyzed on the basis of Michaelis-Menten scheme. The large hydrophobic binding ability of BCP-1 toward PNPP (Km(app) \simeq10−6M) was attributed to its double-layered bicyclic structure. The Hammett plot for the hydrolysis of substituted phenyl hexadecanoates gave a satisfactory linear correlation. Consequently, the acyl transfer from the bound substrate to the imidazole anion of the histidyl residue of BCP-1 was referred to the rate-determining step. The large negative entropy change for the acyl transfer step seems to indicate that the Michaelis complex does not have a conformation favorable for such acyl transfer process. The catalytic effectiveness (kcat⁄Km(app)) for the BCP-1 catalysis in PNPP hydrolysis is comparable to that for enzymatic hydrolysis.
Kinetics and Mechanism of the Oxidation of Alcohols by Pyridinium Chlorochromate
Authors: Banerji Kalyan K 
Published: July 2006

Abstract
The kinetics of the oxidation of ten primary alcohols by pyridinium chlorochromate has been studied. The main product of the oxidation is the corresponding aldehyde. The reaction is of first order with respect to the concentration of the alcohol and oxidant. The reaction is catalysed by acid, the catalysed reaction being nearly first order in acidity. The kinetic isotope effect, kH⁄kD is 5.71 at 303 K for ethanol. The reaction does not induce polymerisation of acrylonitrile. The reaction constant ρ* for the uncatalysed and acid-catalysed oxidations have the values −1.93 and −1.75 at 303 K respectively. Probable mechanisms are discussed.
Polarization Dispersion in the Resonance Raman Spectra of EDA Complexes with TCNE and TCNB
Authors: Tahara Masao , Matsuzaki Susumu , Maeda Shiro 
Published: July 2006

Abstract
Synopsis. Polarization dispersion of the νC≡N Raman line of the N,N-dimethylaniline-TCNB complex indicated that the two CT absorption bands are assignable to different acceptor orbitals, in contrast with those of TCNE complexes.
The Phosphorescence Spectra of 1,4-Naphthoquinone and Its Alkyl Derivatives in Solutions at 77 K
Authors: Kuboyama Akira 
Published: July 2006

Abstract
The phosphorescence spectra of 1,4-naphthoquinone (NQ), 2-methyl-, 2,6-dimethyl-, 2,6-diisopropyl-, and 2,6-di-t-butyl-NQ’s in various kinds of solutions at 77 K were studied. The phosphorescence bands of NQ and 2,6-di-t-butyl-NQ in all the solutions and those of the other NQ’s in saturated hydrocarbon solutions are assigned to the n,π* band. In the ethanol solution, 2-methyl-NQ shows a dual phosphorescence, the lifetimes of which are different and which depends on the excitation wavelength. In the Daifloil solutions, 2-methyl- and 2,6-dimethyl-NQ’s also show a dual phosphorescence. In the toluene solutions, these two NQ’s show remarkably broad phosphorescence bands. These facts are discussed on the basis of the electronic structures at the excited states of these NQ’s.
Studies on the Syntheses of Sesquiterpene Lactones. I. Chemical Transformation of α-Santonin into Vulgarin, C4-Epivulgarin, and Arglanine
Authors: Ando Masayoshi , Akahane Atsushi , Takase Kahei 
Published: July 2006

Abstract
Syntheses of vulgarin, C4-epivulgarin, and arglanine are reported. An efficient conversion of 3-oxo-5αH, 4β,6β,11βH-eudesm-1-en-6,13-olide into 1-oxo-5αH,4β,6β,11βH-eudesm-2-en-6,13-olide, a key intermediate of these syntheses, was achieved by the Meerwein-Ponndorf reaction and the allylic rearrangement of the resultant 3-hydroxyl derivative followed by the Collins oxidation. Acetalization of 1-oxo-5αH,4β,6β,11βH-eudesm-2-en-6,13-olide and successive isomerization of the double bond gave 1,1-ethylenedioxy-5αH,6β,11βH-eudesm-3-en-6,13-olide regioselectevity. Oxidation of this compound with OsO4 gave 3α,4α-dihydroxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesman-6,13-olide, 3α,4α-dihydroxy-1-oxo-5αH,6β,11β-eudesman-6,13-olide and 3β,4β-dihydroxy-1,1-ethylene-dioxy-5αH,6β,11βH-eudesman-6,13-olide. Oxidation of 1,1-ethylenedioxy-5αH,6β,11βH-eudesm-3-en-6,13-olide with m-chloroperoxybenzoic acid gave 3α,4α-epoxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesm-6,l3-olide stereoselectively in a quantitative yield. Treatment of 3α,4α-dihydroxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesman-6,13-olide,3α,4α-dihydroxy-1-oxo-5αH,6β,11βH-eudesman-6,13-olide, and 3α,4α-epoxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesm-6,13-olide with boiling 50% AcOH gave vulgarin. The same treatment of 3β,4β-dihydroxy-1,1-ethylene-dioxy-5αH,6β,11βH-eudesman-6,l3-olide gave C4-epivulgarin. Phenylselenenylation of 3α,4α-dihydroxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesman-6,13-olide and successive syn-elimination of the resultant phenylseleno lactone gave 3α,4α-dihydroxy-1,1-ethylenedioxy-5αH,6βH-eudesm-11-en-6,13-olide, which was transformed into arglanine by treatment with boiling 50% AcOH.
Standard Redox Potentials of R−/R+ Reference Redox Couples and Solvent Activity Coefficients
Authors: Kakutani Tadaaki , Morihiro Yoshikazu , Senda Mitsugi , Takahashi Reiji , Matsumoto Koichi 
Published: July 2006

Abstract
The standard redox potentials of five R−/R+ redox couples that can be considered as candidates for the reference redox couple, i.e., the anion/cation couples of tris(2,2′-bipyridine)iron(II), tris(2,2′-bipyridine)ruthenium(II), cobaltocene, perylene, and 9,10-diphenylanthracene, have been determined in acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and propylene carbonate by means of polarography and voltammetry. The results confirmed that the standard potentials of these redox couples are independent of the solvents studied so that they can be used as solvent-independent reference points for potential comparisons. The solvent activity coefficients of the silver ion have been estimated on the basis of these reference redox couples.
Reduction by a Model of NAD(P)H. XVI. Effect of Magnesium Ion for the Reduction of Thiopivalophenone
Authors: Ohno Atsuyoshi , Yasui Shinro , Nakamura Kaoru , Oka Shinzaburo 
Published: July 2006

Abstract
Magnesium ion retards the reduction of thiopivalophenone with 1-benzyl-1,4-dihydronicotinamide (BNAH) in acetonitrile. Kinetics and other investigation have revealed that the retardation is due to the formation of non-reactive complexes, thiopivalophenone·Mg2+ and BNAH·Mg2+.
An ESR Study of N-Benzoyl- and N-Pivaloyl-N-(arylthio)aminyls
Authors: Miura Yozo , Katsura Yosuke , Kinoshita Masayoshi 
Published: July 2006

Abstract
N-Benzoyl-N-(arylthio)aminyls, ArCO\dotNSAr′, and N-pivaloyl-N-(arylthio)aminyls, t-BuCO\dotNSAr, were generated in benzene by hydrogen-abstraction from N-benzoyl- and N-pivaloylbenzenesulfenamides. The hyperfine coupling constants (hfcc) for the radicals are in the range of 6.80–7.57 G for the nitrogen nucleus and 1.68–1.97 G for the S-phenyl ring protons. However, hfcc due to the benzoyl and pivaloyl protons were not detected. The g-values lie in the range of 2.0081–2.0084. On the basis of these ESR parameters, it is suggested that the acylaminyls exist in a π-electronic ground state and that the unpaired electron is located predominantly on the nitrogen atom (2pz orbital) and the phenylthio group. From the decay kinetic study of the radicals, it was found that N-benzoyl-N-(4-cnlorophenylthio)aminyl persisted for more than 3 h in benzene at 24 °C, and N-pivaloyl-N-(4-chlorophenylthio)aminyl decayed only a little, even after 20 h.
The Binding and Catalytic Properties of a Positively Charged Cyclodextrin
Authors: Matsui Yoshihisa , Okimoto Akihiko 
Published: July 2006

Abstract
In order to learn the significance of electrostatic interactions between charged groups in an enzymatic process, a positively charged cyclodextrin, mono-(6-trimethylammonio-6-deoxy)-β-cyclodextrin hydrogencarbonate (βCDtma), was prepared as a simple enzyme model, and its binding and catalytic properties were examined. The dissociation constant for an inclusion complex of βCDtma with an azo dye, sodium 4-(4-hydroxy-1-naphthylazo)-1-naphthalenesulfonate (1), was found to be 5.4×10−5 mol/dm3 in an alkaline solution (pH 10.5, Ic=0.0 mol/dm3) at 25 °C, the value being smaller than that for an inclusion complex of the parent β-cyclodextrin (βCD) with 1 by a factor of ca. 4. The catalytic effect of βCDtma on the alkaline hydrolyses of o-, m-, and p-acetoxybenzoic acids was significantly different from that of βCD. These observations were explained in terms of electrostatic and hydrophobic interactions between βCDtma and a guest molecule.
Macrocyclic Formals. IV. Macrocyclic Formals as Compiexing Agents
Authors: Kawakami Yuhsuke , Sugiura Tomiya , Yamashita Yuya 
Published: July 2006

Abstract
Eleven to twenty membered macrocyclic formals have been synthesized from the corresponding polyethylene glycols and paraformaldehyde. Their activating efficiency has been measured in nucleophilic substitution reactions with alkali metal ions as counter ions. These macrocyclic formals were not as good compiexing agents as crown ethers, but were much better than open chain polyethers which had the same number of oxygen atoms. In the reaction of butyl bromide with alkali metal acetate, 1,3,6,9,12,15-hexaoxacycloheptadecane was several times more effective than pentaethylene glycol dimethyl ether.
Pyrolytic Sulfurization Gas Chromatography. IV. Removal of Trace Amounts of Organic Compounds in Sulfur by Refluxing with Oxides
Authors: Hara Tadashi , Fujinaga Kaoru , Tsuji Katsuya , Okui Fujio 
Published: July 2006

Abstract
Oxides of aluminium, silicon, and titanium, instead of the magnesium oxide used in the Bacon-Fanelli method, were found to be effective for the elimination of trace amounts of organic compounds in sulfur. Prolonged refluxing in an inert gas atmosphere were especially favorable for the removal of organic compounds
Reaction of α-Keto Sulfoxides with Hydrogen Chloride and Trichloroacetic Acid
Authors: Wakui Toshimitsu , Nakamura Yoshio , Motoki Shinichi 
Published: July 2006

Abstract
α-Keto sulfoxides (1) reacted with hydrogen chloride to afford chloroformates, disulfides, and thiosulfonates. 1 also reacted with trichloroacetic acid to give methyl trichloroacetate, disulfide and thiosulfonate.
A Molecular Orbital Study of the Conformation and g-Factors of the HSSH− Radical Anion
Authors: Kikuchi Osamu 
Published: July 2006

Abstract
The electronic structure and g-factors of the HSSH− radical anion were calculated by means of a restricted open-shell SCF MO method with the MINDO/3 approximation, and the dependence of the g-factors upon the conformation was clarified. The most stable conformation predicted agreed well with the experimentally estimated –S–S– geometry of dialkyl disulfide anions, and its g-factors agreed well with the observed values.
Absolute Configurations of Asperlin, a Metabolite of Aspergillus nidulans, and Its Related Compounds
Authors: Fukuyama Keiichi , Katsube Yukiteru , Noda Akihiro , Hamasaki Takashi , Hatsuda Yuichi 
Published: July 2006

Abstract
The structures of asperlin (1) C10H12O5 and asperlinol (2) C10H14O6, isolated from Aspergillus nidulans, and a chloro derivative of asperlin (3) C10H13O5Cl have been studied by the X-ray diffraction method. The absolute configuration of 3 has been determined by the Bijvoet method by utilizing the anomalous scattering of chlorine atom for Cu Kα radiation. The present analysis has verified the configurations of the atoms in an αβ-unsaturated δ-lactone ring as suggested by spectroscopy. In each compound, the acetoxyl group occupies a quasi-axial and the three-carbon side chain a quasi-equatorial position on the lactone ring. All the crystals are orthorhombic, space group P212121with Z=4. The cell dimensions are a=26.536, b=5.955, c=6.973 Å for 1, a=25.496, b=7.097, c=6.329 Å for 2, and a=26.050, b=5.899, c=7.548 Å for 3. The structures of 1, 2, and 3 were refined by the block-diagonal least-squares method to R=0.068 for 1084 reflections, R=0.056 for 1127 reflections, and R=0.051 for 831 reflections, respectively.
Metachromasy. IV. The Simultaneous Determination of the Bound Dye Spectra and the Equilibrium Constants between Metachromatic Dyes and Various Polyelectrolytes by the Extended Principal Component Analysis Method
Authors: Yamaoka Kiwamu , Takatsuki Mineo 
Published: July 2006

Abstract
Fourteen sets of visible absorption spectra of two metachromatic dyes, Crystal Violet (CV) and Trypaflavine (TF), were measured in the presence of seven widely different polyelectrolytes—sodium polyphosphate, polyacrylate, and poly(ethylenesulfonate), sodium and potassium poly(p-styrenesulfonate)s, and native and denatured calf thymus DNA–in polymer residue-to-dye ratios between 0 : 1 and about 1 : 1. The optical titration curves of these dye-polyanion systems showed either of two changes, sigmoidal or monotonous. The method of principal component analysis was applied to the observed spectra of each dye-polyanion system in order to determine both the equilibrium constant of the binding reaction and the pure spectrum of the bound dye. An empirical parameter a was introduced into the expression for the equilibrium constant in such a way that K=[complex]/[free dye][unoccupied binding site]α, by which the sigmoidal titration curves could be reproduced only with α&gt;1 and the monotonous ones, with α≤1. The spectra of bound CV and TF showed metachromasy bands, which depend on the functional group and the conformation of the polyanions, in wavelength regions both shorter and longer than the peak wavelength of the free dyes.
Resonance Raman Spectra of p-Benzosemiquinone Anion Dimer
Authors: Yamaguchi Satoshi , Yokoyama Kenji , Maeda Shiro 
Published: July 2006

Abstract
Resonance Raman specta have been observed for the dimer of p-benzosemiquinone anion. When the exciting-light frequency was exactly resonant with the absorption band characteristic of this dimer, a new polarized Raman line appeared at 177 cm−1 with a striking resonance enhancement. The resonant behavior and the frequency value both indicate that it can reasonably be assigned to the interradical stretching vibration of the parallel D2h dimer molecule, much as in the case of the previous Würster’s cation dimers.
Structural Study of Optical Resolution. VI. The Crystal Structure of (+)589-cis-Chloroamminebis(ethylenediamine)cobalt(III) d-3-Bromocamphor-9-sulfonate Monohydrate
Authors: Kuramoto Masahiro , Kushi Yoshihiko , Yoneda Hayami 
Published: July 2006

Abstract
The crystal structure of cis-chloroamminebis(ethylenediamine)cobalt(III) d-3-bromocamphor-9-sulfonate monohydrate, (+)589-[CoClNH3(en)2](d-BCS)2·H2O, has been determined by three-dimensional X-ray analysis. The deep red crystals are orthorhombic, space group P212121, with four formula units in the unit cell of dimensions a=34.97(2), b=14.25(1), and c=7.08(1) Å. The calculated density of 1.64 g·cm−3 compares well with the observed density 1.65 g·cm−3. The structure has been refined by the block -diagonal least-squares method to an R-factor of 0.096 for 2662 reflection data points. In the complex cation, one of the two ethylenediamine chelate rings has a “50% ob, 50% lel” type disordered character in its conformation and the other ring is in a “lel” type. The absolute configuration of the complex cation is denoted as Λ[(50%λ, 50%δ)δ], which was determined by comparison with that of the d-BCS anion. There are notable differences between the two crystallographically independent d-BCS anions with respect to their local packing modes.
Solution Equilibria of Ternary α-Amino Acid-Copper(II) Complexes with Electrostatic Ligand-Ligand Interactions
Authors: Sakurai Takeshi , Yamauchi Osamu , Nakahara Akitsugu 
Published: July 2006

Abstract
The stability constants for the parent and mixed copper (II) complexes involving an acidic α-amino acid (aspartic acid or glutamic acid, abbreviated as A) and/or a basic α-amino acid (arginine, lysine, or ornithine, abbreviated as B) have been determined by potentiometric titration at 25 °C in 0.1 and 0.03 M KNO3 (M=mol dm−3). The protonated ternary species Cu(l-A)(l-B)(H) and Cu(d-A)(l-B)(H) (species 1111) have essentially the same stability constants, the log β1111 values being in the range 25.0–27.5. The species distribution curves for the systems Cu(II)-l- or d-glutamic acid-l-lysine at the ionic strength I=0.1 and 0.03 reveal that species 1111 is more predominant at I=0.03 than at I=0.1, suggesting that electrostatic ligand-ligand interactions between the carboxylate group in the side chain of A and the ammonium or the guanidinium group in the side chain of B are reinforced in solution at lower ionic strength to favor the ternary complex formation. The constants for deprotonation from species 1111 to form 1110, e.g. Cu(l-A)(l-B), are given by the difference log β1111−log β1110, which is higher for the Cu(II)–A–B systems than for the systems containing alanine in place of A. The results indicate that intramolecular electrostatic interactions are present in the ternary species 1111, stabilizing them under favorable conditions.
Photochemical Reactions of Aromatic Compounds. XXIX. Photochemical and Thermal Cycloreversions of 1,2,2a,8b-Tetrahydrocyclobuta[a]naphthalenes
Authors: Pac Chyongjin , Mizuno Kazuhiko , Sakurai Hiroshi 
Published: July 2006

Abstract
Photochemical and thermal cycloreversions of 1,2,2a,8b-tetrahydrocyclobuta[a]naphthalenes were investigated. The cycloreversion in the excited singlet state was completely stereospecific; a concerted mechanism was assigned. The benzophenone-sensitized and thermal decomposition gave a mixture of cis- and trans-olefins, but favored stereoretention. The mechanisms are discussed in terms of singlet and triplet 1,4-biradicals.
Reactive Troponoids and o-Aminophenol. II. The Formation of Cyclohepta[b][1,4]benzoxazine and 11H-Cyclohepta[b][1,4]benzoxazin-10-one Derivatives from Isomeric Isopropyl-2-chlorotropones
Authors: Nozoe Tetsuo , Someya Taichi 
Published: July 2006

Abstract
The reactions of three isomeric isopropyl-2-chlorotropones with o-aminophenol were investigated. 8-Isopropylcyclohepta[b][1,4]benzoxazine was obtained from 5-isopropyl-2-chlorotropone, while 4- and 6-isopropylderivatives gave the same mixture of 7- and 9-isopropylcyclohepta[b][1,4]benzoxazine. These facts showed that the amino group of o-aminophenol attacked both the C-1 and C-2 positions of 2-chlorotropones. Also 6-, 7-, and 8-isopropyl-11H-cyclohepta[b][1,4]benzoxazin-10-ones were obtained as the minor products of these reactions.
The Acetoxylation of p-Substituted Acetophenones and β-Diketones with (Diacetoxyiodo)benzene
Authors: Mizukami Fujio , Ando Moriyasu , Tanaka Tatsuo , Imamura Juichi 
Published: July 2006

Abstract
The methyl groups of p-substituted acetophenones and the methylene groups of β-diketones were acetoxylated with (diacetoxyiodo)benzene. When the substrates were p-chloroacetophenone, p-nitroacetophenone and 4,4,4-trifluoro-1-phenyl-1,3-butanedione, the corresponding acetoxylated compounds were obtained in high yields.
Dehydroannulenes. X. Synthesis and Properties of 3,9,12,18-Tetra-substituted-1,10-bisdehydro[18]annulenes
Authors: Iyoda Masahiko , Akiyama Shuzo , Nakagawa Masazumi 
Published: July 2006

Abstract
The cyclic dimerization of 1,7-disubstituted-1-oxo-2,4,6-nonatrien-8-ynes on treatment with a suspension of potassium hydroxide in liquid ammonia to give tetrasubstituted 18-membered cyclic glycols has been achieved. The cyclic glycols could be converted into 3,9,12,18-tetrasubstituted 1,10-bisdehydro[18]annulenes which were found to be conformationally stable and strongly diatropic.
Dehydroannulenes. XI. Synthesis and Properties of 3,11,14,22-Tetra-t-butyl-1,12-bisdehydro[22]annulene
Authors: Iyoda Masahiko , Nakagawa Masazumi 
Published: July 2006

Abstract
7-t-Butyl-9-trimethylsilyl-2,4,6-nonatrien-8-ynal prepared from 5-t-butyl-7-trimethylsilyl-2,4-heptadien-6-ynal diethyl acetal was converted into 8-t-butyl-1,3,5,7-decatetraen-7-ynyl t-butyl ketone. Treatment of the tetraenyne ketone with potassium hydroxide in liquid ammonia gave 22-membered cyclic glycol in a high yield. Reductive dehydroxylation of the cyclic glycol by tin(II) chloride and hydrogen chloride yielded tetra-t-butylbisdehydro[22]annulene in good yield. The [22]annulene was found to be strongly diatropic and conformationally stable.