bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen Redistribution of Acetone on ZnO Catalysts
Authors: Nagai Ken-ichi , Tanaka Ken-ichi , Miyahara Koshiro 
Published: July 2006

Abstract
The hydrogen redistribution reaction between d0-acetone and d6-acetone was carried out at −10–60 °C over ZnO catalysts subjected to various modes of pretreatment. The activity of ZnO was several times larger than that of Zn metal, being hardly affected by the conditions of pretreatment below 350 °C and illumination with a mercury lamp. The rate of hydrogen redistribution was proportional to the amount of chemisorbed acetone which obeys the Langmuir adsorption isotherm. The activation heat of redistribution and the heat of acetone chemisorption were estimated to be 14±2 and 10±1 kcal/mol, respectively. The time course of the relative amounts of dn-acetones, independent of the catalyst or its activity, was reproducible by a calculation based on the stepwise exchange model for the hydrogen exchange of acetone. About half of the chemisorbed acetone was found to be active for the redistribution or exchange of hydrogen. From the results and IR spectrometric study of acetone adsorbed on ZnO, the hydrogen redistribution of acetone was concluded to proceed via a chemisorbed acetone with an enol type configuration on a pair of sites, Zn2+–O2−, of ZnO surface.
A Solvated Electron Formed from the Water by the Irradiation of the Recoil Particles of 10B(n,α)7Li and 6Li(n,α)T
Authors: Yokohata Akira , Tsuda Satoru 
Published: July 2006

Abstract
The G values of a solvated electron produced by ionizing radiation from the (n,α) activation of boron and lithium were estimated to be 0.36 (±0.06) and 0.50 (±0.05) in neutral aqueous solutions (ClCH2COOH–N2O), and 0.24 (±0.05) and 0.46 (±0.05) in alkaline aqueous solutions (K3Fe(CN)6–NaOH), respectively.
A Mössbauer Study of the Valence States of 119Sn after the EC Decay of 119Sb in Antimony and Tellurium Iodides
Authors: Ambe Fumitoshi , Ambe Shizuko 
Published: July 2006

Abstract
The 119Sn-Mössbauer emission spectra of 119SbI3 and 119mTeI4 sources showed the formation of Sn(II) and Sn(IV) species after the EG decay of 119Sb in the matrices.
The Reaction of Biguanides and Related Compounds. XI. The Interaction of Ethylene Carbonates with Aryl-biguanides and Related Compounds.
Authors: Furukawa Mitsuru , Yoshida Takatoshi , Hayashi Seigoro 
Published: July 2006

Abstract
The treatment of arylbiguanides with ethylene carbonates afforded 1-aryl-4,6-diimino-2-oxo-hexahydro-s-triazines, which were then readily converted into 1-arylisocyanuric acid by hydrolysis with concentrated hydrochloric acid.
The Syntheses of Acronycidine and 4,5,8-Trimethoxyfuro[2,3-b]quinoline
Authors: Sekiba Tetsuya 
Published: July 2006

Abstract
2,3-Dihydroacronycidine (VIa) was obtained from 2,3,5-trimethoxyaniline by condensation with diethyl β-benzyloxyethylmalonate, methylation, debenzylation, and then cyclodehydration. The dehydrogenation of Via gave acronycidine in relatively high yields.
Synthetic Photochemistry. V. Azulene Derivatives from the Photo-adducts of Methyl Acetopyruvate with Cycloheptatriene
Authors: Takeshita Hitoshi , Mori Akira 
Published: July 2006

Abstract
Two azulene derivatives, 1-methoxycarbonyl-3-methylazulene (III) and 1-methoxycarbonyl-2-methylazulene (IV), were obtained by the pyrolysis of the photoproducts of methyl acetopyruvate-cycloheptatriene. IV was understood to be derived from a subsequent photo-pinacolization of an unisolable [2+2]π photoadduct (VIII).
The Reaction of Ethyl Azidoformate with Electron Deficient Olefins and the Thermal Ring Opening of the Resulting Aziridines.
Authors: Hiyama Tamejiro , Taguchi Hiroaki , Nozaki Hitosi 
Published: July 2006

Abstract
Thermal or photochemical decomposition of ethyl azidoformate in mesityl oxide or in methyl crotonate afforded the corresponding aziridines. Thermal C–C bond cleavage of aziridine-1-carboxylates thus obtained is described.
Optical Resolution and Configuration of cis-β-Phenylglycidic Acid
Authors: Harada Kaoru , Nakajima Yousuke 
Published: July 2006

Abstract
Dl-cis-β-phenylglycidic acid was resolved using (−)-ephedrine. The configurations of α- and β-carbons of the resolved cis-(+)-glycidic acid were determined by oxydative and hydrogenolytic reactions.
Group Interactions in Polyelectrolytes. VIII. The Animation of Chloromethylated Polystyrene with Secondary Amines and the Quaternization of the Aminated Polymer
Authors: Kawabe Hiroshi 
Published: July 2006

Abstract
The animation of chloromethylated polystyrene (CMPS) and benzyl chloride with diethyl amine, diethanolamine, and di-n-butylamine was investigated kinetically in N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or dioxane. The apparent second-order rate constant decreased as the amination proceeded in the amination of CMPS with diethylamine and di-n-butylamine in DMF as well as in dioxane. Although a similar deceleration was also observed in the amination of CMPS with diethanolamine in DMF and DMSO, acceleration was observed during the course of the amination in dioxane. It is assumed that the deceleration and the acceleration are due to the steric obstruction and to the formation of a hydrogen bond by the neighboring groups in the transition state respectively. The intrinsic rate constants of the amination of CMPS were almost the same as those of benzyl chloride. The rate of the amination with diethanolamine was lower than that of the amination with diethylamine because of the inductive effect of the hydroxyl group. The rate constants in different solvents were in this order; DMSO&gt;DMF&gt;&gt;dioxane. The aminated CMPS with diethanolamine (pK0=7.37) was quaternized with methyl iodide or bromoacetic acid in 50% aq. DMF. The deceleration due to the electrostatic effect of the neighboring groups was observed in the quaternization.
Effects of Pressure on Organic Reactions. VI. The Acid-catalyzed Rearrangement of Benzopinacol in Acetic Acid
Authors: Tamura Katsuhiro , Moriyoshi Takashi 
Published: July 2006

Abstract
The rates of the acid-catalyzed rearrangements of benzopinacol and of tetraphenylethylene oxide in acetic acid have been measured in the range of 35–45°C at pressures up to 983 kg/cm2. It was proved under pressures that the rearrangement of pinacol proceeds through two routes, with three processes. The probable mechanism for each process has been discussed in the light of the activation parameters, particularly the volume parameters (ΔV\eweq and ΔV). Consequently, it may be probably inferred that the classical carbonium ion is an intermediate in the rearrangement of oxide, but not in the other two processes, i.e., the conversion of pinacol to oxide and the direct rearrangement to pinacolone, and that the transition states in the two processes of rearrangement must be clearly distinguished.
The Adsorption of the Aminoethyl Derivatives of Poly(vinyl alcohol) onto Bemberg Rayon Fibers
Authors: Higuchi Mitsuo , Koyakumaru Takatoshi , Senju Ryoichi 
Published: July 2006

Abstract
A series of aminoethyl derivatives of poly (vinyl alcohol) was synthesized, and their adsorption behavior onto a cellulosic fiber was investigated. The results indicate that the primary factor causing adsorption is the charge interaction at the solid-liquid interface; the adsorption was suppressed as the concentration of a foreign salt (NaCl) exceeded 0.02 M, and polymers bearing no cationic group poly(vinyl alcohol) and its aminoethyi derivatives in the un-ionized state) exhibited no appreciable adsorption. The results also demonstrate that the primary variable controlling the amount of adsorption is the charge density on the polymer; the amount of adsorption increases steeply with an increase in the charge density up to a maximum, and then decreases with the increase in the charge density.
A Polarographic Investigation of the Reactions between Nitrate Ions and Chromium(II)–Cyclohexanediaminetetraacetate, Chromium(II)–Trimethylenediaminetetraacetate, and Chromium(II)–N-(2-Hydroxyethyl)ethylenediaminetriacetate Complexes
Authors: Tanaka Nobuyuki , Kano Taisaku , Ogino Hiroshi , Yamada Akifumi 
Published: July 2006

Abstract
Kinetic studies of the reactions between nitrate ions and Cr(II)–Y complexes, where Y represents cyclohexanediaminetetraacetic acid (CyDTA), trimethylenediaminetetraacetic acid (TRDTA), and N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), have been carried out. The reaction mechanisms of these complexes at the dropping mercury electrode were found to be expressed by the following equations:
(Remark: Graphics omitted.)
The formation constant, K, and the rate constants, k1 and k2, were determined in 0.1 M acetate buffer solutions of μ=0.5 by procedures including a curve-fitting method; the results were K=2.0×104 M−1, k1=0.55 M−1 s−1 and k2=2.8 M−1 s−1 for Cr(II)–CyDTA, K=2.4×10−5 M−1, k1=1.0×102 M−1 s−1, and k2&lt;3 M−1 s−1 for Cr(II)–TRDTA and k1∼2×103 M−1 s−1 for Cr(II)–HEDTA.
Oxidation Activity and Acidity of V2O5–P2O5 Catalyst
Authors: Ai Mamoru , Suzuki Sadao 
Published: July 2006

Abstract
The oxidations of 1-butene, butadiene, and hydrogen in a large excess of air were carried out over various V–P oxide catalysts with different P2O5 contents. The oxidation activities were compared with the dehydration activity for isopropyl alcohol, which was used as a measure of the acidity of the catalysts. The surface area and the acidity per unit of surface area sharply decrease with an increase in the P2O5 content up to about 20 mol% P2O5, while with a further increase in the P2O5 they remain almost unchanged. The activity per unit of surface area for the oxidation of butene and butadiene, as well as that for the isomerization of butene, changes in the same direction as the acidity per unit of surface area. The equilibrium constant for the adsorption of olefin changes analogously. The activity per unit of surface area for the oxidation of hydrogen is not affected by the P2O5 content. The effects of the P2O5 introduced into V2O5 on the activity and selectivity are discussed from the viewpoint of the acidic nature of the catalysts.
The Radiophoto-luminescence of γ-Irradiated Hydrocarbon Glasses at 77 K
Authors: Yamazaki Hideo , Oka Koichi , Sato Masabumi , Shida Shoji 
Published: July 2006

Abstract
The radiophoto-luminescence (RPL) from γ-irradiated hydrocarbon glasses, i.e., 3-methylhexane, methylcyclohexane, and ethylcyclohexane, containing small amounts of various aromatics (1,3,5-trimethylbenzene, biphenyl, naphthalene, and 1,4-diazine) is investigated at 77 K by infrared-light irradiation. The spectra of the R PL consist of the fluorescence and phosphorescence of the guest aromatic molecule, and the ratio of the phosphorescence to the fluorescence intensity is larger than that in the photoexcitation, indicating the existence of another path to the triplet state. The RPL is quenched by the addition of N2O, but it is not much affected by that of NH3. A possible mechanism for the RPL is considered, and its analysis is given.
Synthesis of 1-N-[(S)-4-Amino-2-hydroxybutyryl]-3′,4′-dideoxyneamine
Authors: Takagi Yasushi , Ikeda Daishiro , Tsuchiya Tsutomu , Umezawa Sumio , Umezawa Hamao 
Published: July 2006

Abstract
The titled compound (5) has been prepared from 3′,4′-dideoxyneamine or ribostamycin via 1,6-cyclic carbamate intermediates (2 and 12). 3′,4′-Dideoxygenation, which is the key step in the synthesis from ribostamycin, was accomplished by the hydrogenation of 3′,4′-unsaturated derivative which was prepared from the corresponding 3′,4′-di-O-mesyl derivative by the action of sodium iodide and zinc dust in DMF. The title compound was found to have an improved antibacterial spectrum broader than 3′,4′-dideoxyneamine.
Synthesis and Photochemical Reaction of 1,5,5,9-Tetramethyl-2-decalone
Authors: Tatee Tochiro , Tsuyuki Takahiko , Aoyagi Reiko , Takahashi Takeyoshi 
Published: July 2006

Abstract
1,5,5,9-Tetramethyl-2-decalone (6) was synthesized from 5,5,9-trimethyl-1-decalone (7) and irradiated in n-hexane under a nitrogen atmosphere using a high pressure mercury lamp. Oxygen was passed through the reaction mixture in the dark to give a seco-nor acid, 1-carboxymethyl-2-ethyl-2,6,6-trimethylcyclohexane (8a) and a seco acid, 1-(2-carboxyethyl)-2-ethyl-2,6,6-trimethylcyclohexane (9a).
Absolute Configuration of Some Chiral Cyclopropanes
Authors: Nishiyama Kazuyoshi , Oda Jun’ichi , Inouye Yuzo 
Published: July 2006

Abstract
The absolute configurations of (1S : 2R)-(−)-cis-, and (1S : 2S)-(+)-trans-1-phenylcyclopropane-1,2-dicarboxylic acids, and (1S : 2R)-(−)-cis-, and (1S : 2S)-(+)-trans-1-phenyl-1,2-bis(acetoxymethyl)cyclopropanes were established by correlation to (R)-(−)-2,2-diphenylcyclopropane-1-carboxylic acid.
Phenanthro[4,5-bcd]furan Derivatives. II. A Synthesis of 3-Hydroxyphenanthro[4,5-bcd]furan (Morphenol)
Authors: Horaguchi Takaaki , Shimizu Takahachi 
Published: July 2006

Abstract
3-Hydroxyphenanthro[4,5-bcd]furan (I) was synthesized by the dehydrogenation, with 20% palladium on charcoal, of 3-oxo-1,2,3,8,9,9a-hexahydronaphtho[4,5-bcd]furan (XII), which had itself been prepared via a naphtho[1,8-bc]furan derivative (IX) starting from 8-hydroxy-1-tetralone (IV).
A New Technique Using the Polynomials Approximation and Trapezoidal Average Method for Estimating Kinetic Rate Constants in Systems of Linear or Nonlinear Differential Equations
Authors: Ohkubo Katsutoshi , Tsuchihashi Kohji , Sakamoto Hiroyuki 
Published: July 2006

Abstract
A new technique using the polynomials approximation and the trapezoidal average method, has been proposed for estimating kinetic rate constants. It is implemented by minimizing the error of the concentration (of a product) obtained from the polynomial-approximated least square-error analysis of the observed concentrations during the initial reaction stage relative to that obtained theoretically from the trapezoidal average of the calculated concentration (of a product) on the basis of the law of mass action. The technique is useful for easily and exactly estimating the rate constants in systems of linear or nonlinear differential equations. A kinetic model, A→ B\ightleftarrowsC, was used to illustrate and develop the present technique.
Reactions of Bis(acetylacetonato)palladium(II) with Triphenylphosphine and Nitrogen Bases
Authors: Baba Shigeru , Ogura Tetsuya , Kawaguchi Shinichi 
Published: July 2006

Abstract
Bis (acetylacetonato)palladium (II) reacts with triphenylphosphine and nitrogen bases such as pyridine, diethylamine, and N-methylbenzylamine to transform one of the chelating ligands into the carbon-bonded state. The product complexes of the type Pd(acac)2L have been isolated in high yields and characterized by IR and NMR spectra. Several reactions of Pd(acac)2PPh3 and Pd(acac)2py were also examined.
The Crystal Structure of Sodium Molybdate Dihydrate, Na2MoO4·2H2O
Authors: Matsumoto Kazuko , Kobayashi Akiko , Sasaki Yukiyoshi 
Published: July 2006

Abstract
Na2MoO4·2H2O is orthorhombic, with the space group of Pbca and with cell constants of a=8.463(3), b=10.552(3), and c=13.827(6) Å; U=1234.8 Å3; Z=8. The crystals are composed of alternate layers of MoO42− tetrahedra and water molecules. The layers are connected by interlinking sodium cations and hydrogen bonds. The MoO42− tetrahedron is slightly elongated in the direction of the hydrogen bonds.
The Dimerization of the Phenoselenazine and Benzo[c]-phenoselenazine Cation-radicals
Authors: Matsunaga Yoshio , Tanaka Tomio 
Published: July 2006

Abstract
The equilibrium constants and the heats of dimerization and the monomer and dimer spectra were determined for the phenoselenazine and benzo[c]phenoselenazine cation-radicals in aqueous sulfuric acid (1:1 by volume).
A Novel Method for the Synthesis of Cytidine Diphosphate-Choline
Authors: Kurihara Takashi , Yamamoto Isamu , Hata Tsujiaki 
Published: July 2006

Abstract
Cytidine diphosphate choline was synthesized by the reaction of cytidine 5′-phosphate with 2-bromoethyl 2′-(chloromethyl)-4′-nitrophenyl phosphate in the presence of trimethylamine.
Synthesis of α,β-Ethylenic Sulfones
Authors: Seshapathi M , Naidu Rao , Reddy D Bhaskar 
Published: July 2006

Abstract
A series of new α,β-ethylenic sulfones were prepared by the condensation of p-chlorophenylsulfonylacetic acid with various aryl aldehydes. The UV and IR spectra of all these compounds were recorded. Their IR spectra exhibited medium to strong bands in the region 1000–975 cm−1, characteristic of trans ethylenic compounds.
The Carbon-13 Nuclear Magnetic Resonance Spectra of Isomers of the Tris(l-propylenediamine)cobalt(III) Ion
Authors: Kojima Masaaki , Yamasaki Kazuo 
Published: July 2006

Abstract
The proton-decoupled carbon-13 NMR spectra were measured for the mer-Λ(ob), facial-Λ(ob), and facial-Δ(lel)[Co(l-pn)3]3+ ions using the Fourier transform technique. There was a clear difference between the Λ and Δ configurations. However, no appreciable difference was observed between the mer and facial isomers of Λ(ob)-[Co(l-Pn)3]3+.
The Crystal and Molecular Structure of Nagilactone A Diacetate
Authors: Hirotsu Ken , Higuchi Taiichi , Shimada Akira , Hayashi Yuji , Sakan Takeo 
Published: July 2006

Abstract
The title compound crystallizes in the orthorhombic space group P212121, with cell dimensions of a=10.43, b=15.45, c=13.65 Å, and Z=4. The structure was determined by direct methods from photographic data, and was refined by the least-squares method to a final R of 0.098 for 2581 reflections. Rings A and B are subject to steric strains resulting from the formation of a lactone ring. This is reflected in the abnormal values for some bond lengths, angles, and dihedral angles.
X-Ray Photoelectron Spectroscopic Studies of Catalysts — Supported Cobalt Catalysts —
Authors: Okamoto Yasuaki , Nakano Hajime , Imanaka Toshinobu , Teranishi Shiichiro 
Published: July 2006

Abstract
XPS techniques were used to clarify the state of supported cobalt catalysts. In order to characterize Co2+ and Co3+, the spin-orbit splitting of the 2p level, which is considered to be affected by the exchange interaction between the unpaired 3d electrons and 2p electrons, was found to be very useful. The interaction between catalyst and support was investigated. The state of supported cobalt was determined: Co2O3 on SiO2, Co2O3+ CoAl2O4 on γ-Al2O3, and LaCoO3 on La2O3. The order of the strength of the chemical interaction between cobalt and support is as follows:
La_2O_3&gt;γ-Al_2O_3&gt;SiO_2.
This fact was also confirmed by reduction experiments.
The Quenching of the Cadmium Resonance Radiation at 326.1 nm by Ammonia and the Emission from the Complex between Excited Cadmium Atoms and Ammonia in the Presence of Argon
Authors: Yamamoto Shunzo , Tsunashima Shigeru , Sato Shin 
Published: July 2006

Abstract
The pressure dependences of the emission intensities at 326.1 and 432 nm in the cadmium-photosensitized reaction of ammonia have been measured. In order to interpret the nonlinear Stern-Volmer plots for the quenching of the 326.1 nm resonance line, the following reactions have to be taken into account in the reaction scheme: Cd*+NH3\ightleftharpoonsCdNH3*V, CdNH3*V+M→CdNH3*+M. The pressure dependence of the emission from the CdNH3* complex (at 432 nm) was also well explained in terms of a reaction scheme involving the above reactions.
Kinetics and Steric Course of the Substitution of Various Olefins for the Asymmetric Olefin in trans(N,olefin)-Chloro-l-prolinato-trans-2-buteneplatinum(II)
Authors: Terai Yoshiro , Kido Hiroaki , Fujita Junnosuke , Saito Kazuo 
Published: July 2006

Abstract
Replacement of the coordinated trans-2-butene in trans(N,olefin)[PtCl(l-pro)(S,S-trans-2-butene)] (l-pro=l-prolinate anion) by various olefins in acetone has been studied at −20 to +23 °C. The rate is proportional to concentrations of the complex and the olefin nucleophile. No solvent path is observed. The second order rate constant k2 (10−4 to 10−1 M−1 s−1 at 8.0 °C) can be the measure of each substitution. The ΔH\eweq is around 10 kcal/mol, and ΔS\eweq ranges from −25 to −46 cal/mol K. Substitution of cis-2-butene for the asymmetrically coordinated trans-2-butene-3H gives equal k2’s on the measurement of CD strength and on that of isotopic exchange. Similar substitution of trans-2-butene gives significantly larger k2 on isotopic exchange than that on CD measurement, indicating sterically selective substitution with retention of configuration. Substitution of ethylene derivatives with various groups on the carbon atoms gives different k2’s depending on the kind of substituents. The steric interaction between the olefin nucleophile and the coordinated ligands seems to be a very important factor in determining the ease of substitution.
Sugars Containing a Carbon-phosphorus Bond. VI. 5-(Alkylphosphinyl)-5-deoxy-d-xylopyranose
Authors: Seo Kuniaki , Inokawa Saburo 
Published: July 2006

Abstract
The reactions of diethyl ethylphosphonite with 3-O-acetyl-5-deoxy-5-iodo-1,2-O-isorpopylidine-α-d-xylofuranose (Ia) or 3-O-benzoyl-5-deoxy-5-iodo-1,2-O-isopropylidene-α-d-xylofuranose(Ib) afforded IIa or IIc, respectively. Similarly, using diethyl butylphosphonite in place of diethyl ethylphosphonite, IIb and IId were obtained. Treatment of IIb with methanolic sodium methoxide gave 5-deoxy-1,2-O-isopropylidene-5-(methoxybutylphosphinyl)-α-d-xylofuranose together with a small amount of 5-(3-O-cyclo-butylphosphinate)-5-deoxy-1,2-O-isopropylidene-α-d-xylofuranose(VII). Compound VII was also obtained from the reaction of 5-deoxy-5-iodo-1,2-O-isopropylidene-α-d-xylofuranose(VIII) and diethyl butylphosphonite. The reaction of IIa or IIc with sodium dihydrobis(2-methoxyethoxy)aluminate gave 5-deoxy-5-(ethylphosphinyl)-1,2-O-isopropylidene-α-d-xylofuranose(IIIa). Similarly, 5-(butylphosphinyl)-5-deoxy-1,2-O-isopropylidene-α-d-xylofuranose(IIIb) was obtained from IIb, IId, VI, and VII. Hydrolysis of IIIa and IIIb with sulfuric acid gave 5-deoxy-5-(ethyl-phosphinyl)-(IVa) and 5-(butylphosphinyl)-5-deoxy-d-xylopyranose(IVb), respectively. Acetylation of IVa and IVb with acetic anhydride in pyridine gave the corresponding O-acetates Va and Vb.
Stereospecific Synthesis of Natural (+)Blastmycinone and Its Three (2R)-Diastereomers
Authors: Aburaki Shinpei , Konishi Norio , Kinoshita Mitsuhiro 
Published: July 2006

Abstract
Natural (+)blastmycinone [(+)1a] and its three (2R)-diastereomers [(+)1b, (−)1c, and (−)1d] were synthesized through stereospecific routes via the corresponding (−)blastmycinolactol [(−)2a] and its diastereomeric hydroxylactones [(+)2b, (−)2c, and (−)2d] from methyl 4,6-O-benzylidene-3-C-butyl-3-deoxy-α-d-altropyranoside (4) prepared by the Grignard reaction of methyl 2,3-anhydro-4,6-O-benzylidene-α-d-mannopyranoside (3) with butylmagnesium chloride. By the synthesis the relative configurations of natural type of racemic blastmycinone and its all diastereomers were completely established.
Infrared Spectra and Structure of Substituted Unsaturated Carbonyl Compounds. XIX. Four Component Conformational Equilibria in β-Ketoaldehyde Trans Enol Ethers
Authors: Dabrowski Janusz , Tencer Michal 
Published: July 2006

Abstract
Acylic aliphatic trans β-alkoxy-α,β-unsaturated ketones, R1COCR2=CHOR3, have been shown to exhibit restricted rotation around both the Csp2–Csp2 and Csp2–O single bonds. The conformational equilibria between the EZZ, EEZ, EZE and EEE rotamers, estimated from comparison of the IR band intensities, are dependent on the steric requirements of the alkyl substituents. The sequence of the νC=O and νC=C vibrational frequences is νC=O(s-cis/O-s-trans)&gt;νC=O(s-cis/O-s-cis)&gt;νC=O(s-trans/O-s-trans)&gt;νC=O(s-trans/O-s-cis)&gt;νc=C(s-trans/O-s-trans)&gt;νC=O(s-trans/O-s-cis)&gt;νC=C(s-cis/O-s-trans)&gt;νC=C(s-cis/O-s-cis). The wave number differences ΔνC=CC=O(s-cis/O-s-trans)=75–85 cm−1, ΔνC=CC=O(s-cis/O-s-cis)=80—100 cm−1, ΔνC=CC=O(s-trans/O-s-trans)=20—30 cm−1 and ΔνC=CC=O(s-trans/O-s-cis)=35–50 cm−1.