bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spin Label Investigation of the Crown Ether. Complex Formation between the Veratrole Analogue of Phenoxyl-labeled Benzo-15-crown-5 and Alkali and Alkaline Earth Metal Salts in Frozen Solution
Authors: Mukai Kazuo , Tanii Michiyo , Yurugi Yohko , Tajima Kunihiko , Ishizu Kazuhiko 
Published: July 2006

Abstract
A stable “phenoxyl-veratrole” (2), a veratrole analogue of “phenoxyl-benzo-15-crown-5” (1), was prepared and the complex formation between 2 and the alkali and alkaline earth metal salts has been studied by the ESR technique. Existence of the 2:1 complex of 2 with K+, Rb+, and Cs+ salts was confirmed by the observation of the triplet ESR spectra in ethanol rigid matrix at 77 K. Essentially the same g- and D-tensor values were observed for all the 2:1 complexes, indicating similar conformation of the ligand molecule 2. By comparing the observed D and E parameters with those of the 2:1 complexes reported for the alkali and alkaline earth metal complexes of 1 in a previous paper (Ref. 10), the structure of the 2:1 complex in ethanol rigid matrix was discussed. On the other hand, the results of the ESR measurements of the Li+, Na+, and alkaline earth metal complexes suggested a 1:1 complex formation between 2 and the metal salts.
Thermal Reactions of the Nickel(II) Complexes Containing 1-Phenyl-1,2-ethanediamine in the Solid Phase
Authors: Ihara Yoshinori 
Published: July 2006

Abstract
Nickel(II) complexes [Ni(phenen)2](ClO4)2 and [Ni(H2O)2(phenen)2]X2 (phenen=1-phenyl-1,2-ethanediamine, X=Cl, Br, or NO3) were prepared, and their thermal behavior was investigated in the solid phase. The nitrate showed a thermochromism consisting of two steps, violet→yellow→violet, which corresponds to a structural change from an octahedral diaqua complex to a square planar anhydride, and then to the octahedral dinitrato complex, respectively. Both the chloride and bromide were converted into the octahedral dianiono complexes by thermal deaquation-anation, retaining their octahedral configuration. However, no change was observed in the perchlorate, which is invariably square planar.
A Synthesis of a Versatile Intermediate Leading to Thienamycin Analogs
Authors: Maruyama Hiroshi , Shiozaki Masao , Hiraoka Tetsuo 
Published: July 2006

Abstract
l-Threonine was converted to a versatile azetidinone derivative stereospecifically in 3 steps. This azetidinone was further transformed to (3S,4R)-3-[(R)-1-hydroxyethyl]-1-(4-methoxybenzyl)-4-[(phenylthio)-carbonylmethyl]-2-azetidinone (S-Phenyl thioester), a key intermediate for the synthesis of thienamycin and it’s biologically active analogs. Since the thiol part of this S-phenyl thioester can be exchanged easily with other complex or useful thiols under mild conditions, important S-thioester precursors for the production of carbapenem analogs were obtained in high yield.
Stereoselective Oxylactonization. Preparation of 2-Deoxy-Dl-ribono-1,4-lactone Derivatives from 3-Silyloxy-4-alkenamides
Authors: Ichikawa Yuh-ichiro , Miwa Tetsuo , Narasaka Koichi 
Published: July 2006

Abstract
The oxylactonization of 3-silyloxy-4-alkenamides proceeds stereoselectively by treatment with m-chloroperbenzoic acid to give the corresponding 2-deoxy-Dl-ribono-1,4-lactone derivatives.
Diene-transmissive Diels-Alder Reaction Using 2-Ethoxy-3-methylene-1,4-pentadiene and 2-(2-Bromo-1-ethoxyethyl)1,3-butadiene
Authors: Kanemasa Shuji , Sakoh Hirohiko , Wada Eiji , Tsuge Otohiko 
Published: July 2006

Abstract
A new cross-conjugated triene, 2-ethoxy-3-methylene-1,4-pentadiene, and a triene equivalent, 2-(2-bromo-1-ethoxyethyl)-1,3-butadiene, have been synthesized and their diene-transmissive Diels-Alder cycloadditions are investigated. The initial Diels-Alder reaction selectively occurs not across the diene part substituted with the alkoxyl moiety but the monosubstituted diene. Some cross types of diene-transmissive Diels-Alder reaction are demonstrated using the triene equivalent and two different dienophiles.
Total Synthesis of (−)-Deoxocassine and Its Diastereomers
Authors: Kurihara Kazuo , Sugimoto Takashi , Saitoh Yutaka , Igarashi Yukinobu , Hirota Hiroshi , Moriyama Yoshihiko , Tsuyuki Takahiko , Takahashi Takeyoshi , Khuong-Huu Qui 
Published: July 2006

Abstract
(−)-Deoxocassine [(2R,3R,6S)-6-dodecyl-2-methyl-3-piperidinol] and its diastereomers with 2R-configuration were synthesized starting from d-alanine by a route involving the intramolecular aminomercuration of an ε,ζ-unsaturated amine.
Viscosity B Coefficients for Polymethylenebis(trimethylammonium) Dibromides in Aqueous Solutions
Authors: Tamaki Kunio , Fujiwara Akifumi 
Published: July 2006

Abstract
The viscosity B coefficients of the Jones-Dole equation for N,N′-polymethylenebis(trimethylammonium) dibromides [(CH3)3N(CH2)nN(CH3)3]Br2 (n=3–8, 10, and 12) and for comparison for alkyltrimethylammonium bromides CnH2n+1N(CH3)3Br (n=2–6) in aqueous solutions at 25 and 35 ° have been determined, and the effect of structural changes in the solvent water upon the dissolution of both series of electrolytes is discussed.
Substituent Effect on Stereoselectivity for Cobalt(III), Chromium(III), and Manganese(III) Complexes of Ring-substituted 1-l-Menthyloxy-3-benzoylacetones
Authors: Nakamura Michio , Okawa Hisashi , Kida Sigeo 
Published: July 2006

Abstract
Stereoselectivities of tris(1-l-menthyloxy-3-benzoylacetonato)M(III) ([M(l-moba)3] (M=CoIII, CrIII, MnIII)) and its homologs [M(l-moba-Br)3] and [M(l-moba-Me)3] (possessing bromo and methyl substituents at the 4-position of the aromatic ring, respectively) were examined by CD spectra. The stereoselectivity increased in the order [Co(l-moba-Br)3]&lt;[Co(l-moba)3]&lt;[Co(l-moba-Me)3], and this trend was explained in terms of the electronic effect of the substituents on the interligand CH/π-interaction.
Peterson Olefination of (α-Methoxybenzyl)silane with Aldehydes and Ketones Leading to Vinyl Ethers
Authors: Kanemasa Shuji , Tanaka Junji , Nagahama Hideki , Tsuge Otohiko 
Published: July 2006

Abstract
(α-Methoxybenzyl)trimethylsilane is deprotonated with butyllithium and then allowed to react with a variety of carbonyl compounds giving vinyl ethers which are convertible into methyl ketones under mild conditions.
A Molecular Mechanical Calculation along the Intrinsic Reaction Coordinate
Authors: Cho Seikichi 
Published: July 2006

Abstract
A normal coordinate analysis was applied to nonequilibrium states composed of atoms. A normal coordinate, Qk, can be the intrinsic reaction coordinate if, and only if, all the first-order differentials have vanished except the k-th one. The HNC-to-HCN isomerization reaction was treated with the ab initio STO-3G potential surface: we thus observed several interesting features.
15N NMR Spectra of Cobalt(III) Complexes Containing 15NO2−
Authors: Odaka Yoshio , Yamasaki Akira , Watabe Masatoshi 
Published: July 2006

Abstract
The nitrogen-15 nuclear magnetic resonance spectra of the cobalt(III) complexes containing 15NO2− were first measured; the coordination chemical shifts, Δδ (=δcomplex–δfree), were found to be from 135.0 to 161.5 ppm. The relationship between Δδ and the geometrical configuration was discussed in terms of the paramagnetic anisotropy of the cobalt(III) ion.
Induced Circular Dichroism of Bis(tropolonato)copper(II) with Optically Active Amines
Authors: Murakami Tasuku 
Published: July 2006

Abstract
Bis(tropolonato)copper(II) forms adducts with chiral aromatic amines and exhibits circular dichroism(CD) induced for d-d and intra-ligand transitions. The applicability of the dispersion-induced CD theory to this complex system is discussed.
The Total Synthesis of (±)-Megaphyllone Acetate, A Cytotoxic Neolignan
Authors: Matsumoto Takashi , Imai Sachihiko , Yamaguchi Tadashi , Morihira Masakazu , Murakami Masao 
Published: July 2006

Abstract
Conversion of 3-methoxy-4,5-methylenedioxybenzaldehyde into (2RS,3SR,4RS)-2-methoxycarbonyl-4-(3-methoxy-4,5-methylenedioxyphenyl)-3-methyl-4-butanolide (11) was carried out in seven steps via 1-acetoxy-1-(3-methoxy-4,5-methylenedioxyphenyl)propanone. The butanolide 11 was further converted into (2RS,3SR,3aRS,5RS)-3,3a,4,5-tetrahydro-5-methoxy-2-(3-methoxy-4,5-methylenedioxyphenyl)-3-methyl-3a-(2-propenyl)6(2H)-benzofuranone (22) in eight steps. Reduction of 22 with lithium aluminium hydride followed by acetylation with acetic anhydride in pyridine afforded (±)-megaphyllone acetate.
Photoredox Chemistry of Chloro and Bromo Complexes of Copper(II) in Methanolic Medium
Authors: David Pazhayirayyathu Geeverghese , da Silva Paulo Augusto Correa 
Published: July 2006

Abstract
Investigation of the photoreduction of copper(II) to copper(I) in methanolic solutions of copper(II) chloride and copper(II) bromide indicates the halide-to-copper(II) charge-transfer (CT) responsible for the photoreduction. Quantum yields for the formation of copper(I) as a function of irradiating wavelength and copper(II) halide concentration show that [Cu(CH3OH)5Cl]+ and [Cu(CH3OH)4Cl2] have identical photoreaction efficiency, while [Cu(CH3OH)4Br2] is more photoreactive than [Cu(CH3OH)5Br]+. In the copper(II) chloride system the chloride-to-copper(II) CT band centered around 272 nm appears to be responsible for the photoreaction, while the bromide-to-copper(II) CT band centered around 245 nm effects the photoreaction in copper(II) bromide system.
New Amino-protective Reagents for t-Butoxycarbonylation and Benzyloxycarbonylation of Amines and Amino Acids
Authors: Kim Sunggak , Lee Jae In , Yi Kyu Yang 
Published: July 2006

Abstract
New amino-protective reagents for t-butoxycarbonylation and benzyloxycarbonylation of amines and amino acids have been developed. t-Butyl 2-pyridyl carbonate and t-butyl S-(2-pyridyl) thiocarbonate react cleanly with various amines and amino acids to afford N-Boc amines and N-Boc amino acids in high yields. Benzyl 2-pyridyl carbonate and O-benzyl S-(2-pyridyl) thiocarbonate are also found to be very effective in the benzyloxycarbonylation of amino acids.
Refractive Indices, Dielectric Constants, and Order Parameter of Four Alkyl/Alkoxyphenylcyclohexanecarboxylate Liquid Crystals in the Nematic Phase
Authors: Kali Krishnakali , Sen Sushmita , Roy Subir Kumar 
Published: July 2006

Abstract
The extraordinary and ordinary refractive indices, ne and no and the densities of four liquid crystals 4-pentylphenyl trans-4′-pentylcyclohexanecarboxylate, 4-ethoxyphenyl trans-4′-propylcyclohexanecarboxylate, 4-ethoxyphenyl trans-4′-butylcyclohexanecarboxylate, and 4-methoxyphenyl trans-4′-pentylcyclohexanecarboxylate have been reported at different temperatures. The effective polarizabilities αe and αo in the nematic phase have been calculated using 1) Neugebauer and 2) Vuks methods. The order parameter S calculated from the two methods were comparable. The dielectric constants ε|| and ε⊥, parallel and perpendicular to the long axis of the molecules have been measured at 1 kHz at different temperatures. The order parameters for the liquid crystals were then evaluated from dielectric anisotropy Δε(=ε||−ε⊥), polarizability anisotropy Δα(=αe−αo) and dipole moment μ, using Maier and Meier equation and were found only slightly less than those obtained from refractive indices method. It was concluded that Maier and Meier equation also could be used to evaluate the order parameter of liquid crystals of molecules having dipole moments 2 Debye or less.
Synthesis and Characterization of a Chloro-bridged Binuclear Iron(III) Complex
Authors: Matsumoto Naohide , Yoshimura Chikako , Maeda Yonezo , Okawa Hisashi , Ohyoshi Akira 
Published: July 2006

Abstract
A chloro-bridged binuclear iron(III)complex [Fe2ClL](BPh4), where [H4L] and BPh4− denote N,N,N′,N′-tetrakis(3-salicylideneaminopropyl)ethylenediamine and tetraphenylborate, respectively, was prepared and characterized by elemental analysis, electrical conductivity, Mössbauer spectrum, and cryomagnetic data. The magnetic susceptibility data of the complex was analyzed by the Heisenberg model on the basis of a binuclear structure \hatH=−2J\hatS1·\hatS2 (S1=S2=5⁄2), leading to an antiferromagnetic interaction parameter of J=−3.9 cm−1.
Preparation and Characterization of (Iminodiacetato)cobalt(III) Complexes with l-Methioninate and S-Methyl-l-cysteinate
Authors: Umehara Hideki , Isago Takashi , Okamoto Ken-ichi , Hidaka Jinsai 
Published: July 2006

Abstract
The (iminodiacetato)(l-methioninato or S-methyl-l-cysteinato)cobalt(III) complex was prepared and separated into three geometrical isomers by ion-exchange chromatography. The isomers were characterized from the electronic absorption, 1H NMR and CD spectra.
A New Gas Sampler for Pyrolytic Sulfurization Gas Chromatography
Authors: Kawai Itsuro , Hara Tadashi 
Published: July 2006

Abstract
A new gas sampler was designed and constructed by the use of a commercially available pyrolytic apparatus. This sampler made easier heating and crushing an ampoule, and introducing a liberated gas into a gas chromatograph than those by the conventional gas sampler.
Absolute Configurations of Novel Axially Dissymmetric 10,10′-Dihydroxy-9,9′-biphenanthryl and Its Related Compounds
Authors: Yamamoto Koji , Fukushima Hitoshi , Yumioka Hiroya , Nakazaki Masao 
Published: July 2006

Abstract
Stereoselective oxidative coupling of 10-hydroxy-1,2,3,4-tetrahydrophenanthrene derived from methyl 3-methoxy-2-naphthoate gave (−)-(S)-10,10′-dihydroxy-1,1′,2,2′,3,3′,4,4′-octahydro-9,9′-biphenanthryl which was converted into (+)-(S)-10,10′-dimethoxy-9,9′-biphenanthryl assigning the S configuration to (−)-10,10′-dihydroxy-9,9′-biphenanthryl.
A HPLC Study of Adsorption of Organic Solutes on Cellulose Acetate
Authors: Kiso Yoshiaki 
Published: July 2006

Abstract
The liquid chromatographic technique was useful for the measurement of adsorption of some nonionic organic solutes on cellulose acetate. It was recognized that there were linear correlations between logarithmic capacity factors measured by HPLC, logk′, and logarithmic 1-octanol: water partition coefficients, logP.
Extractability of Copper(II) and Zinc(II) with Crown Ethers as Picrates
Authors: Hasegawa Yuko , Tanabe Hiroaki , Yoshida Satoshi 
Published: July 2006

Abstract
The extraction of copper(II) and zinc(II) with picrate ion and 12-crown-4(1,4,7,10-tetraoxacyclododecane) or 15-crown-5(1,4,7,10,13-pentaoxacyclopentadecane) into benzene or chloroform has been measured. The extraction of copper(II) is better than that of zinc(II), in spite of the similar ionic size, although the difference is much smaller than that in the extraction of these metal ions with β-diketones.
A Novel Synthesis of Dihydropyranoflavonols
Authors: Takkellapati Sudhakar Rao , Mathur Hari Har , Trivedi Girish Kumar 
Published: July 2006

Abstract
Condensation of 6-formyl-7-hydroxy-2,2-dimethylchroman with ω-nitrostyrene in the presence of triethylamine yields 3-nitro-8,8-dimethyl-2-phenyl-7,8-dihydro-2H,6H-benzo[1,2-b:5,4-b′]dipyran which on treatment with hydrogen peroxide gives 3-hydroxy-8,8-dimethyl-2-phenyl-7,8-dihydro-4H,6H-benzo[1,2-6:5,4-b′]dipyran-4-one.
Spectrophotometric Determination of Cobalt(II) with Thiocyanate. A Modification for Increasing Sensitivity and Selectivity
Authors: Singh Ajai Kumar , Kumar Dinesh , Katyal Mohan 
Published: July 2006

Abstract
The ion association complex formed between [Co(SCN)4]2− and 3,3′-(1,1′-biphenyl-4,4′-diyl)bis[2,5-diphenyl-2H-tetrazolium] dichloride, commercially known as neotetrazolium chloride, has been extracted into isobutyl methyl ketone and used for the photometric determination of 2.5–9.8 μg cm−3 cobalt at pH 3.5–5.0 (acetate buffer). Sandell’s sensitivity of the method (0.02 μg cm−2) is better than most of the other thiocyanate methods known so far. Interference of diverse ions has been studied. Using the higher tolerances of anions, many cations interfering in the other thiocyanate methods have been masked, thus making the present procedure more selective. The method has been applied to wire alloys.
The Preparation of a Highly Active Raney Nickel Catalyst with Formation of a Recoverable Bayerite
Authors: Nishimura Shigeo , Ikeda Satoshi , Kinoshita Makoto , Kawashima Masaaki 
Published: July 2006

Abstract
In the presence of a properly prepared bayerite and a small amount of sodium hydroxide, Raney nickel–aluminium alloy is developed with water to give a highly active catalyst with formation of a recoverable bayerite. In hydrogenation of typical organic compounds the catalyst is even more active than the T-4 Raney nickel.
Characterization of Catalyst for Coal Liquefaction. Exchange of Hydrogen Attached to Condensed Aromatics with Deuterium in Heavy Water over Catalyst
Authors: Yokono Tetsuro , Kohno Taro , Sanada Yuzo 
Published: July 2006

Abstract
The H–D exchange reaction of hydrogen atoms attached to condensed aromatics with deuterium atoms in D2O over catalyst for coal liquefaction was studied by means of D-NMR. MoO3/ZrO2, MoO3/SiO2, Fe2O3–SO42−, SbCl3 and ZnCl2 showed a significant catalytic activity for the exchange reaction. The H–D exchange ability was discussed in terms of the acidic properties and concentration of Mo5+ over supports for coal liquefaction catalysts.
Formation Constants of Lanthanoid(III) Complexes with 4-(2-Thiazolylazo)resorcinol
Authors: Ohyoshi Emiko 
Published: July 2006

Abstract
The formation constants of the protonated (MHR) and normal (MR) complexes (1 : 1) of lanthanoids(III) with 4-(2-thiazolylazo)resorcinol (TAR, H2R) have been determined spectrophotometrically by estimation of the free ligand. The MR complexes of TAR were less stable than the corresponding 4-(2-pyridylazo)resorcinol (PAR) complexes, but the relative stabilities were reversed for the MHR complexes.
Structural Studies of Cyclo(l-histidyl-l-histidyl) and Its Metal Complexes
Authors: Kojima Yoshitane , Yamashita Tetsushi , Nishide Shinya , Hirotsu Ken , Higuchi Taiichi 
Published: July 2006

Abstract
The crystal structure of cyclo(l-histidyl-l-histidyl) was determined by X-ray diffraction techniques, and was refined to a final R index of 0.066 for 680 reflections. This showed that one imidazolyl group of this compound faces the piperazine ring(folded) whereas the other is kept away from the ring(unfolded). A calculation using the α-β coupling-constant data of this peptide obtained by an 1H NMR measurement shows that the ratio of a folded conformation to an unfolded one is 49:51 in D2O. Also, NMR investigations of zinc(II) and silver(I) complexes with this peptide were carried out in D2O.
The Effects of the pH and the Temperature on the Oxidation-reduction Properties of Adriamycin Adsorbed on a Mercury Electrode Surface
Authors: Kano Kenji , Konse Tomonori , Kubota Tanekazu 
Published: July 2006

Abstract
The effects of the pH and the temperature on the oxidation-reduction properties of the quinone moiety in adriamycin adsorbed on a mercury electrode surface have been investigated by means of cyclic d.c. voltammetry. The quinone waves have been fundamentally interpreted in terms of a two-step one-electron surface-redox reaction, even in a neutral or an alkaline solution, where the reduced product is liable to cause the following chemical reaction. The pH dependences of the standard surface-redox potential of the adsorbed adriamycin are −60 mV/pH (pH 2–6), −30 mV/pH (pH 7–8), and −60 mV/pH (pH 9–12). The semiquinone formation constant is 0.15 at pH 2–6 and 5 at pH 9–12. These results can be well explained by considering the protolytic equilibria of the phenolic hydroxyl groups among the oxidized, semiquinone, and reduced forms of adriamycin, the pKa’s of which are 8.53, 6.93, and 6.83 respectively. The thermodynamic constants of the semiquinone formation reaction at pH 4.5 have been determined to be ΔH=−24.6 kJ mol−1 and ΔS=−99.7 J K−1 mol−1.
The Near Infrared Emission Band Observed in Electron Irradiated Xe and Xe in Other Rare Gases
Authors: Tanaka Masako , Sasaki Susumu , Katayama Meiseki 
Published: July 2006

Abstract
The near-infrared emission spectra were studied for xenon diluted with krypton, argon, and neon, respectively, in order to estimate the origin of an emission band at 1260 nm which was previously observed at several hundred Torr(1 Torr=133.2 Pa) of pure Xe irradiated with pulses of high-energy electrons. A continuous band around 1260 nm was observed only in Xe-Ar mixtures. This band appeared at Xe pressures above 20 Torr(diluted in 600 Torr of Ar) while it was detected above 190 Torr in pure Xe. In Xe–Ar mixtures, three emission lines due to Xe 5d(3/2)1 were also observed at 1700, 2020, and 2650 nm. On the basis of the reported kinetic data for the reactions of rare gas mixtures, the present results led to the conclusion that the band at 1260 nm was due to emission from highly excited excimer states, of which the dissociation limits were higher Rydberg states above the energy level of the Xe2+ ion.
Asymmetric Transformation of Dl-p-Hydroxyphenylglycine by a Combination of Preferential Crystallization and Simultaneous Racemization of the o-Toluenesulfonate
Authors: Hongo Chikara , Tohyama Masanori , Yoshioka Ryuzo , Yamada Shigeki , Chibata Ichiro 
Published: July 2006

Abstract
The asymmetric transformation of Dl-p-hydroxyphenylglycine was achieved between two enantiomers by a combination of preferential crystallization of a desired enantiomer of p-hydroxyphenylglycine o-toluenesulfonate (HPG·o-TS) and the simultaneous racemization of the antipode. l-HPG·o-TS was easily racemized by heating at 100 °C in aqueous 95% (v/v) acetic acid in the presence of small amounts of salicylaldehyde and free Dl-HPG. A supersaturated solution of Dl-HPG·o-TS placed under such conditions for racemization was seeded with the crystals of d-HPG·o-TS, and added with Dl-HPG and o-toluenesulfonic acid in order to provide continuously the supersaturated state of Dl-HPG·o-TS as a driving force. As a result, 77.2% of Dl-HPG added was transformed to d-isomer.
Mössbauer Spectroscopic Studies of the Correlation between Molecular Structure and Sign of Quadrupole Splitting in Tris(β-diketonato)iron(III) Complexes Utilizing Paramagnetic Relaxation Effects
Authors: Yamauchi Shigeru , Sakai Yoichi , Tominaga Takeshi 
Published: July 2006

Abstract
The change of the Mössbauer line shape with the paramagnetic relaxation time was studied in several tris(β-diketonato)iron(III) complexes to determine the sign of the quadrupole splitting. The correlation observed between the molecular structure and the sign of the quadrupole splitting demonstrates that the sign should depend on the bond angle (∠O–Fe–O) in iron(III) complexes.
SH2 Reactions of Triethylgermyl Radical with Thiosulfonic S-Esters and Selenosulfonic Se-Ester
Authors: Kobayashi Michio , Kobayashi Masanori , Yoshida Masato 
Published: July 2006

Abstract
The triethylgermyl radical was found to react with thiosulfonic S-esters to generate sulfonyl radicals. The SH2 character of this new reaction was confirmed by a C-13 CIDNP study and products analysis. Selenosulfonic Se-ester reacts with germyl radical in a similar way.
A Comparative Study of Photoinduced Isomerizations between 1-exo- and 1-endo-Cyano-1a,7b-dihydro-1H-cyclopropa[a]naphthalenes
Authors: Kobayashi Hisako , Kato Masahiko , Miwa Toshio 
Published: July 2006

Abstract
The titled compunds 1-exo-Cyano-1a,7b-dihydro-1H-cyclopropa[a]naphthalenes(8a), 1-endo-Cyano-1a,7b-dihydro-1H-cyclopropa[a]naphthalenes(8b), were photolyzed in several solvents. The results were: (1) The isomerization proceeded faster in aprotic nonpolar solvents than in polar ones. (2) The 1-endo derivative (8b) rearranged faster than the 1-exo-isomer (8a). (3) 8b was isomerized through Berson-Willcott rearrangement by the fission of bonds C1–C7b and C1–C1a, while 8a gave 1-cyanomethylnaphthalene (5b) as a main product. (4) Examination with an optically active 1-exo derivative (8a) showed that the exo-endo interconversion occured by the simultaneous two centered (30%) and one centered (70%) epimerization.