bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Syntheses of Several N,N′-Bis(hydroxymethyl)parabanic Acid Derivatives
Authors: Tanimoto Shigeo , Taniyasu Ryozo , Okano Masaya 
Published: July 2006

Abstract
Starting from N,N′-bis(hydroxymethyl)-parabanic acid, the following new compounds have been synthesized: N,N′-bis(aiylaminomethyl)parabanic acids, N,N′-bis(bromomethyl)parabanic acid, and N,N′-bis(alkoxymethyl)parabanic acids.
Multidentate Ligand Kinetics. I. The Ligand Substitution Reaction between Ethylenediaminetetraacetatocuprate(II) and Triethylenetetraminezinc(II)
Authors: Katsuyama Tetsuo , Kumai Toshihiko 
Published: July 2006

Abstract
The kinetics and the mechanism of the ligand substitution reaction between ethylenediaminetetraacetatocuprate-(II)(CuY2−) and triethylenetetraminezinc(II)(ZnT2+) were studied spectrophotometrically in the pH range 7.0–10.5 at I=0.2(NaClO4) and 25.0 °C. The exchange reaction was accelerated by traces of either EDTA or triethylenetetramine(Trien). The exchange reaction was shown to proceed by the chain reaction mechanism where the chain-propagating steps are the reaction of CuY2− with Trien and the reaction of ZnT2+ with EDTA. Each chain-propagating step was investigated. The apparent rate constant of the reaction of CuY2− with Trien increases with pH, while that of ZnT2+ with EDTA decreases with pH.
The Amperometric Titration of Metal(II) Ions with trans-1,2-Cyclohexanediamine-N,N,N′,N′-tetraacetate (CyDTA)
Authors: Kodama Mutsuo 
Published: July 2006

Abstract
The use of CyDTA in the amperometric determination of metal-ion mixtures was studied systematically. Because of the sluggishness of the nickel(II)-EDMA∼CyDTA substitution reaction, the nickel(II) ion in the EDMA solution could be masked completely in respect to the CyDTA. Therefore, even in the presence of an excess of nickel(II)ions, the copper(II), lead(II), cobalt(II), cadmium(II), and zinc(II) ions in the EDMA solution at about pH=6.50 could be determined accurately with CyDTA. In the amperometric titration of binary mixture of copper(II) and zinc(II), lead(II), cadmium(II), or cobalt(II) ions in the EDMA solution, titration curves with two sharp breaks could be obtained by following the change in the diffusion current due to the reduction of the copper(II)–EDMA complex. The first and second breaks correspond, respectively, to the equivalence point of zinc(II), lead(II), cadmium(II), or cobalt(II) and to that of copper(II).
Mixed Complexes with Bulky Ligands. I. Cobalt(II) Complexes Containing N,N-Bis[2-(dimethylamino)ethyl]methylamine
Authors: Utsuno Shunji 
Published: July 2006

Abstract
Nine new cobalt(II) complexes were prepared which contained N,N-bis[2-(dimethylamino)ethyl]methylamine (dienMe) and some unidentate or bidentate ligands, such as acetonitrile, ammonia, ethylenediamine (en), trimethylenediamine (tn), the acetylacetonate ion (acac), or the oxalate ion. The solid-reflectance spectra revealed that six complexes of the [Co(XX)dienMe](ClO4)n formula (XX=2CH3CN, 2NH3, en, tn, acac, or 1/2C2O4; n=1 or 2) are five-coordinated, whereas three complexes, [Co(C2O4)(H2O)dienMe] and Co(C2O4)1⁄2 (solv)(dienMe)ClO4 (solv=CH3CN or CH3OH), are six-coordinated. On the basis of their electronic spectra, most of the five-coordinated complexes were supposed to have a trigonal-bipyramidal structure in the solid state and in solution. The IR spectra of three hemioxalato complexes revealed the presence of quadridentate oxalateion bridging between two cobalt ions, regardless of their coordination number.
The Bromination of 1- and 2-Methylthiophenazine Derivatives
Authors: Tada Masao 
Published: July 2006

Abstract
The bromination of 1-methylthiophenazine has been investigated and found to occur in Position 4. 2-Methylthiophenazine and its 5-oxide have been found to be brominated in Position 1. The bromination of these compounds in acetic acid gave both a ring-substituted product and its oxidised product.
The Retardation of the Benzidine Rearrangement of Hydrazobenzene by Cyclodextrins
Authors: Matsui Yoshihisa , Mochida Kazuo , Fukumoto Osamu , Date Yoshio 
Published: July 2006

Abstract
The benzidine rearrangement of hydrazobenzene is retarded by the addition of α-, β-, and γ-cyclodextrins. The effects on the rate of the cyclodextrins are decreased by the addition of cyclohexanol. The deceleration of the reaction by the cyclodextrins was attributed to the equilibrium complexation of the substrate in the cavities of the cyclodextrins, which may either restrict the large conformational change of the substrate necessary for reaching a sandwich-type transition state or lower the concentration of the diprotonated hydrazobenzene by means of the space alkalinity of cyclodextrins.
Hydrogenation and Hydrogenolysis. XV. Hydrogenation of Isomeric Anisidines with Platinum Metal Catalysts in Acetic Acid
Authors: Nishimura Shigeo , Takaoka Takeaki , Maekawa Yoshihiro 
Published: July 2006

Abstract
m-Anisidine was hydrogenolyzed to an extent of 92.5% in hydrogenation with a palladium catalyst in acetic acid at 60 °C and 90 kg/cm2. The amount of hydrogenolysis in o- and p-anisidine was only 2.1 and 2.5%, respectively. This great difference in hydrogenolysis between the isomers was not observed with rhodium and platinum catalysts. With m- and p-anisidines, selectivity at the initiation of hydrogenation was studied for the formation of N-cyclohexylanisidine intermediates and for other products by an extrapolation method. Extensive hydrogenolysis of m-anisidine and slight hydrogenolysis of o- and p-anisidines over palladium result from a high selectivity in the formation of the enamine or imine intermediates. The hydrogenation pathways leading to hydrogenolysis and secondary amine formation over the three platinum metals are discussed.
Über die Feststellung der Wanderung des Äthoxycarbonyl-Restes bei der Dienon-Phenol-Umlagerung
Authors: Suehiro Tadashi , Yamazaki Shozo 
Published: July 2006

Abstract
3,4-Dimethyl-4-äthoxycarbonyl-cyclohexa-2,5-dienon-4-14C (9) lagert sich bei 60–70 °C in 60% Schwefelsäure zu 2,3-Dimethyl-5-hydroxybenzoesäure-äthylester-2-14C (10, 99.8%) und -1-14C (10b, 0.2%) insgesammt in ca. 50% Ausbeute um, unter Nebenbildung von 3,4-Xylenol (11, 12%) und 2,3-Dimethyl-5-hydroxybenzoesäure (12, 5%). Dass 10 die Struktur von 2,3-Dimethylbenzoesäure-Derivat hat, wurde durch Mischprobe mit der authentischen Verbindung festgestellt.
Photochemical cis-trans Isomerization of 2,4,5-Triphenylimidazolines
Authors: Matsuura Teruo , Ito Yoshikatsu 
Published: July 2006

Abstract
Irradiation of cis- (amarine; I) and trans- (isoamarine; II) 2,4,5-triphenylimidazolines in acetonitrile or benzene gave a photostationary mixture of cis- and trans-isomers, the latter predominating over the former. On irradiation in a dilute acetone solution under the conditions that acetone absorbed most of the incident light, cis-trans isomerization occurred only with isoamarine but not with amarine. In acetone, 2,4,5-triphenylimidazole (III) was also formed. Two kinds of intermediate species for the cis-trans isomerization were proposed; imidazolinyl radicals IV and/or V formed by hydrogen abstraction with the excited state of acetone (in acetone) and a biradical or a zwitterionic species VIa formed by cleavage from the excited state of I or II (in acetonitrile or benzene). Evidences for the intermediacy of VIa are presented.
Solvent Effects under High Pressure. II. Determination and Applications to Kinetic Studies of the ET-Value at High Pressures
Authors: Tamura Katsuhiro , Imoto Tatsuya 
Published: July 2006

Abstract
The ET-value was determined for eight solvents at 25 °C over the pressure range 1–1,960 kg/cm2. They increase with pressure; the pressure dependence is affected by the nature of the solvents. It was also found that there is a linear relationship between the pressure coefficient of ET and that of the logarithm of the rate constant of a Menschutkin reaction: In k=a+bET On the basis of this relationship, an equation was derived in which the volume of activation ΔV\eweq is represented by the pressure coefficient of ET; the effect of solvents on ΔV\eweq is discussed by making use of this equation.
(−)-(1S,4R,5R)-Guaia-6,9-diene from Geranium Bourbon
Authors: Nagahama Yoko , Naoki Hideo , Naya Yoko 
Published: July 2006

Abstract
A sesquiterpene from Geranium Bourbon has been found to be guaia-6,9-diene in accordance with the report of Pesnelle et al.; it had previously been erroneously assigned as 3,7-diene by Herout et al. The details of the evidence on the structure, along with its stereochemistry, are described.
Absolute Configuration of 3-Amino-1-phenylbutane
Authors: Yamamoto Yukio , Oda Jun’ichi , Inouye Yuzo 
Published: July 2006

Abstract
The absolute configuration of (−)-3-amino-1-phenylbutane was established by the correlation to (R)-(−)-N-benzoylalanine methylester via (+)-trans-3-amino-1-phenylbut-1-ene.
Solvent Extraction Equilibria of Thallium(III) from Weakly Acidic Chloride Solutions into 4-Methyl-2-pentanone
Authors: Hasegawa Yuko , Kurihara Shinji , Masui Naohito , Sekine Tatsuya 
Published: July 2006

Abstract
From the distribution data of thallium (III) between 4-methyl-2-pentanone and 4 mol dm−3 sodium per chlorate solutions containing chloride ions at pH 2, the Na+TlCl4− species in the organic phase and the TlCl2+, TlCl3, and TlCl4− species in the aqueous phase were recognized. The equilibrium constants for the formation and extraction of these complexes were determined.
Reaction of N-Aroyl-N-arylhydroxylamines with o-Nitrobenzenesulfenyl Chloride
Authors: Oae Shigeru , Sakurai Tadamitsu 
Published: July 2006

Abstract
Reactions of N-aroyl-N-arylhydroxylamines with o-nitrobenzenesulfenyl chloride were found to afford the corresponding N-aroylarylamines and S-(o-nitrophenyl) o-nitrobenzenethiosulfonate in good yields, respectively. Both the product distributions and the effect of substituents on the amount of reduction product suggest these reactions to proceed via homolytic cleavage of the N–O bond.
Synthesis of (2-Chloroethyl)-nitrosourea Derivatives of Carbohydrate
Authors: Machinami Tomoya , Nishiyama Shigeru , Kikuchi Kazuo , Suami Tetsuo 
Published: July 2006

Abstract
Six antileukemic carbohydrate derivatives which have a (2-chloroethyl)-nitrosoureido group have been prepared by a reaction between amino sugars and 2-chloroethyl isocyanate, followed by nitrosation.
Reaction of a Stable Free Nitrogen-Centered Radical, 3,4-Dihydro-2,4,6-triphenyl-2H-1,2,4,5-tetrazin-1-yl, with Orgranoaluminum Compounds
Authors: Miura Yozo , Morimoto Yuzo , Kinoshita Masayoshi 
Published: July 2006

Abstract
Reactions of 3,4-dihydro-2,4,6-triphenyl-2H-1,2,4,5-tetrazin-1-yl (1) with triethylaluminum, triisobutylaluminum, and diethylaluminum chloride were examined, and from the product analysis, these reactions are proposed to proceed by means of a homolytic substitution process.
The Convenient Syntheses of Biopterin and Its Three Opitical Isomers
Authors: Sugimoto Takashi , Matsuura Sadao 
Published: July 2006

Abstract
Simple syntheses of biopterin (4a) and its three optical isomers (4b, c, d) are described. The condensation of 2,4,5-triaminopyrimidin-6(1H)-one (1) with each of the 5-deoxypentose phenylhydrazones (2a, b, c, d), followed by oxidation with K3[Fe(CN)6] and H2O2 in the presence of KI, gives biopterin (4a) and the isomers (4b, c, d) respectively.
Detection of Hydrophobic Stain on Cotton Surface by Fluorescent Probe
Authors: Seimiya Toshiko , Purchase Mary E 
Published: July 2006

Abstract
The minute amount of hydrophobic substances 10−8∼10−7 mol/cm2 (geometric area) on cotton fabric surface can effectively be detected by fluorescent probe using magnesium-8-anilino-1-naphthalenesulfonate (ANS). The cotton fabrics were dyed in aqueous ANS solution (1×10−4 mol/1), before and after the staining with stearic acid, palmitic acid, tristearin, oleic acid, and squalene, and the intensities of fluorescence from the cotton surface was measured by reflectance spectrophotometer under the varying wavelength of ultra-violet (200–300 mμ). The intensity of fluorescence increased with the increase of fatty stain on the surface, but showed the tendency of saturation by exceeding the closest packing of the fatty acid monolayers. Correlation was also found between the fluorescent intensity and the yellowness (b-value) of naturally soiled cotton fabrics. The bleaching of the yellowed fabrics by sodium hypochlorite effectively reduced the b- value but did not change the fluorescence appreciably, and suggested that the hydrophobic substances still remained on the fabric surfaces in spite of their white appearance.
Use of the Copper(II)-Selective Electrode for the Determination of the Stability Constants of Copper(II) Complexes
Authors: Nakagawa Genkichi , Wada Hiroko , Hayakawa Tomohiko 
Published: July 2006

Abstract
In the determination of stability constants of metal complexes, usually the measurements of the activities of free metal ions at very low levels are required. The electrode response of an Orion Model 94–29 copper(II) ion selective electrode at very low activity levels was studied in the various metal buffers composed of copper(II) ions and an excess of ligand. Usually the linear calibration range of the copper(II) ion selective electrode was extended to very low activity levels in the presence of a strong complexing agent. The stability constants of copper(II) complexes with acetate, ammonia, ethylenediamine, glycine, iminodiacetic acid, 1,10-phenanthroline, etc. were determined successfully. In the cases of EDTA and NTA, however, the lower limit of the linear calibration range was abnormally high and the stability constant of copper–EDTA or –NTA chelate could not be obtained. Some experimental results on the potentiometric titration of copper(II) ion with EDTA were also presented.
The Effect of the Pressure on the Micellization of the Surfactant in Aqueous Urea Solutions
Authors: Tanaka Mitsuru , Kaneshina Shoji , Kuramoto Seiji , Matuura Ryohei 
Published: July 2006

Abstract
The critical micelle concentrations (CMC) of dodecyltrimethylammonium bromide (DTAB) in aqueous urea solutions have been determined over a range of pressures up to 2500 atm at 25 and 35 °C. The partial molal volumes of DTAB in micellar (\barVm) and singly-dispersed states (\barVs) have also been determined in aqueous urea solutions at 25 °C. \barVs increases with the addition of urea, while \barVm remains approximately constant. The partial molal entropy change of micellization (Δ\barSm) in water increases with an increase in the pressure up to about 1500 atm, while Δ\barSm in 3-m urea solution remains virtually unaltered in the low-pressure region. The results suggest that the “iceberg” structure of water around the hydrocarbon chain of the monomeric surfactant is effectively broken down by urea.
The Polarographic Behavior and Determination of Orotic Acid (Vitamin B13) in Milk
Authors: Yao Toshio , Musha S\={o}ichir\={o} 
Published: July 2006

Abstract
The polarographic behavior of orotic acid at the dropping mercury electrode was studied in the Britton-Robinson buffer solution; it was found to be a complex function of the pH. Three polarographic waves were observed over the pH range from 2 to 12. In the 1M HClO4 electrolyte, orotic acid showed a very well-defined, diffusion-controlled, two-electron polarographic reduction wave which enabled us to determine orotic acid polarographically. A polarographic method for the determination of orotic acid in milk was proposed, and the effect of the presence of surface-active substances like proteins was investigated. The proposed method is very simple and rapid, and permits the accurate determination of 4–1000 μg/g of orotic acid in milk.
Magnetic Circular Dichroism of [Cr(CN)5NO]3−
Authors: Kobayashi Hiroshi , Eguchi Ken , Kaizu Youkoh 
Published: July 2006

Abstract
Magnetic circular dichroism (MCD) was observed in the region of the 22000 cm−1 band of [Cr(CN)5NO]3−. The absorption band was assigned to a charge-transfer transition linearly polarized in the direction of Cr–NO, while the MCD observed in the same region was assigned to B term extrema of the (d, d*) transitions hidden beneath the charge-transfer band. The charge-transfer transition gives rise to an absorption peak but no MCD, since the transition is polarized in the direction of the orbital angular momentum, even in the case where a degenerate excited state is involved.
Polarized Reflection and Absorption Spectra of the [2.2]-Paracyclophane Crystal
Authors: Fuke Kiyokazu , Nagakura Saburo 
Published: July 2006

Abstract
The reflection spectra of a [2.2]-paracyclophane crystal were measured in the 17000–62000 cm−1 region with incident light polarized parallel and perpendicular to the a-axis. From analysis of the reflection spectra by the Kramers-Kronig method, the a-axis and c-axis polarized absorption spectra in the 38000–60000 cm−1region were obtained. The c-axis polarized spectrum was obtained for the first time. The 43000 cm−1 band in the c-axis spectrum was assigned to the transitions to the 1B1u(p) and 1B1u (CT) states. The band around 48000 cm−1 was assigned to the transition to the 1B3u-state, corresponding to the transition to the 1E2g -state in benzene.
Magnetic Circular Dichroism of Dicyanobis(2,2′-bipyridine)iron(II)
Authors: Kobayashi Hiroshi , Agarwala Badri Vishal , Kaizu Youkoh 
Published: July 2006

Abstract
Magnetic circular dichroism (MCD) of cis-dicyanobis(2,2′-bipyridine) iron(II) was measured for a variety of solvents. The visible absorption band is assigned to the lowest “iron(II) to bipyridine” charge-transfer transition. The complex exhibits a significant MCD in its lowest charge-transfer absorption band. The transition shows a shift to higher wave number with an increase in the proton-donating power of solvent. This spectral shift is attributed to hydrogen-bonding interactions of protolytic solvent molecules. In H2SO4 this dibasic complex is subjected to stepwise protonations. The complex is diamagnetic in protolytic solvents, and even in cone H2SO4 the diprotonated complex formed is mostly present in the diamagnetic state.
Reaction of Cupric Ion Fixed on the Ion Exchange Resin with Acetylacetone
Authors: Okamura Takashi , Ohzeki Kunio , Kambara Tomihito 
Published: July 2006

Abstract
It was found that the cupric ions fixed on the resin are removed by acetylacetone(Hacac) to form bisacetylacetonatocopper(II), Cu(acac)2. By the addition of a small amount of pyridine-water mixture to the copper-(II) form resin in acetylacetone milieu, the cupric ions are quantitatively removed from the resin in the form of pyridine adduct, and the pyridinium ions are adsorbed on to the resin in place of the cupric ions. The reaction was successfully applied to the synthesis of Cu(acac)2.
Metal Complexes Containing Six-membered Chelate Rings V. Preparation and Structure of Oxalato Complexes of Cobalt(III) with Substituted 3,7-Diaza- 1,9-nonanediamine Derived from 2,4-Pentanediamine
Authors: Mizukami Fujio 
Published: July 2006

Abstract
The syntheses, resolution and structure of three oxalato complexes of cobalt(III) with tetramine ligand, R(4), R(6)- and R(4), S(6)-4,6-dimethyl-1,9-nonanediamine (RR- and RS-2,3″, 2-tet), and R(6), S(8)-6,8-dimethyl-2,5,9,12-tetraazatridecane (N,N′-Me2-RS-2,3″,2-tet) are reported. Only one geometrical isomer (cisβ) was isolated for each complex, [Co(ox)(N,N′-Me2-RS-2,3,″,2-tet)]+, [Co(ox)RS-2,3″,2-tet]+ and [Co(ox)RR-2,3″,2-tet]+· The central six-membered chelate rings of (−)546-cis β-[Co(ox)(N,N′-Me2-RS-2,3″,2-tet]+ and (−)546-cis β-[Co(ox)(RS-2,3″,2-tet)]+ take a chair conformation with two equatorial methyl groups, and that of (−)546-cis β-[Co-(ox)(RR-2,3″,2-tet)]+ a chair conformation with an axial and equatorial methyl group.
Reactions of Sulfenes with Schiff Bases. The Stereochemistry and Thermal Fragmentation of Thiazetidine 1,1-Dioxide
Authors: Hiraoka Tetsuo , Kobayashi Takeo 
Published: July 2006

Abstract
Phenylsulfene (II) generated from benzylsulfonyl chloride (I) and triethylamine, reacted with N-(p-Substituted)-benzylidene-methylamine to give 2-methyl-4-phenyl-3-(p-substituted-phenyl)-1,2-thiazetidine 1,1-dioxide whose cis and trans isomers were separated. Both cis and trans 3,4-diphenyl-2-methyl-1,2-thiazetidine 1,1-dioxide (IV and V) afforded trans stilbene and benzaldehyde on pyrolysis. This new fragmentation reaction could be explained by a stepwise decomposition because of its non-stereospecificity.
Formation of Phosphate Derivatives by the Reaction of Propyl and Allyl Halides with Phosphorus Trichloride and Oxygen
Authors: Okamoto Yoshiki , Okada Toshihiro , Sakurai Hiroshi 
Published: July 2006

Abstract
In addition to phosphonyl dichlorides, a significant amount of phosphoryl dichlorides was obtained by the reaction of propyl and allyl halides with phosphorus trichloride in oxygen atmosphere. Formation of the P–O–C bond can be explained by a scheme involving a preferential reaction of the bridged intermediate radical with oxygen.
The Convenient Synthesis of Anhydronucleosides via the 2′,3′-O-Sulfinate of Pyrimidine Nucleosides as the Active Intermediates
Authors: Sowa Tsuneo , Tsunoda Kozo 
Published: July 2006

Abstract
The synthesis of 2,2′-O-anhydro(1-β-d-arabinofuranosyl) cytosine (3a) and 2,2′-O-anhydro(1-β-d-arabinofuranosyl) uracil (3b) is described. The active intermediates, 2′,3′-O-sulfinyl cytidine (2a) and 2′,3′-O-sulfinyl uridine (2b), were prepared from the corresponding nucleosides (1a or 1b) by successive treatment with thionyl chloride in acetonitrile and with water. The 2,2′-O-anhydropyrimidine nucleosides were formed quantitatively by heating the intermediates in an acidic aqueous solution or in N,N-dimethylformamide in the presence of sodium acetate. The treatment of the anhydronucleosides with alkali gave the corresponding arabinonucleosides.
Studies of Reaction Mechanisms with All-valence Electron Semi-empirical SCF MO Theories. IX. The Role of Tetracyclo[4.2.0.02,805,7]oct-3-ene on the Ground State Potential Energy Hypersurfaces of (CH)8 Isomers
Authors: Iwamura Hiizu , Kihara Hiroshi 
Published: July 2006

Abstract
Tetracyclo[4.2.0.02,805,7]oct-3-ene (1) is estimated by a MINDO MO calculation to be moderately strained. Interaction between the ethylenic π orbital and the Walsh orbitals of the two cyclopropane rings is extensive in the ground state structure of 1. The third highest occupied MO is an out-of-phase combination of the ethylenic 2pπ AO’s on C3 and C4, while the corresponding in-phase combination appears in the lower unoccupied MO’s. The interconversion between 1 and bicyclo[4.2.0]octa-2,4,7-triene (2) is a typical symmetryallowed reaction as revealed by a smooth change in bond indices along the reaction coordinates. The isomerization of substituted cyclooctatetraenes via 1 and 2 (Eq. (2)) is predicted to be possible at elevated temperatures. The symmetry-allowed degenerate valence isomerization of 1 (Eq. (3)) is energetically less favorable due to skeletal constraint.
The Stereochemistry of Autoxidation of 2-Bromo-1-methylcyclohexane
Authors: Miyajima Shingo , Simamura Osamu 
Published: July 2006

Abstract
Autoxidation of cis-2-bromo-1-methylcyclohexane and subsequent reduction of the resulting hydroperoxide with lithium aluminium hydride gave only t-2-bromo-1-methyl-r-1-cyclohexanol to the exclusion of the c-2-bromoisomer. The reactivity ratio of the C–1 hydrogen in cis-2-bromo-1-methylcyclohexane to that in 1, c-3, c-5-trimethylcyclohexane towards abstraction was estimated to be about 4 by competitive oxidation experiments. An explanation for the acceleration of hydrogen abstraction and the stereospecific oxygen attack on the intermediate radical is given in terms of a bromine bridged radical. Autoxidation of a sample of 2-bromo-1-methylcyclohexane, containing about 90% of the trans isomer, took place very slowly as compared with the cis isomer.