bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of Hydrous Tin(IV) Oxide Ion-exchangers. I. A Method for Synthesis and Some Properties
Authors: Inoue Yasushi , Yamazaki Hiromichi 
Published: July 2006

Abstract
A comprehensive study of the preparation of hydrous tin(IV) oxide ion-exchangers was made by using eight systems: (1)Na2[Sn(OH)6]–H2SO4, (2)Na2[Sn(OH)6]–H2SO4(boiling), (3)Na2[Sn(OH)6]–HCl, (4)Na2[Sn(OH)6]–CH3COOH, (5)SnCl4–NaOH, (6)SnCl4–NH3aq, (7)SnCl4–NH3aq(boiling), and (8)SnCl4-pyrohydrolysis. From a detailed examination of the dependency of the yield, the ion-exchange behavior toward Na+ and Cl− ions, the composition, and some other properties on the conditions for precipitation, it was found that the ion-exchange characteristics are similar among materials produced from the systems from (1) through (7) if we neglect some aging effect of boiling, while the difficulty of synthesis differs according to the systems. The materials obtained from the (8) system, however, showed titration curves different from those for the exchanges obtained from the other systems and had less cation-exchange capacity for Na+ by 20 per cent. From these results, it is concluded that the simplicity of the synthetic procedures in the most important criterion for choosing the best conditions for preparing the exchanger.
The Structure of the Cyclodextrin Complex. XV. Crystal Structure of Hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin–p-Nitrophenol (1 : 1) Complex Monohydrate
Authors: Harata Kazuaki , Uekama Kaneto , Otagiri Masaki , Hirayama Fumitoshi 
Published: July 2006

Abstract
The crystal structure of the hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin (abbreviated to methyl-α-CDx) complex with p-nitrophenol, C54H96O30·C6H5NO2·H2O, was investigated by the X-ray method. The crystal is monoclinic, the space group being P21 with Z=2; the cell dimensions are a=11.307(1), b=14.578(1), c=22.118(2) Å, and β=93.62(1)°. The structure was determined by means of the Patterson map and the trial-and-error method combined with the rigid-body least-squares technique, and refined by the block-diagonal least-squares method to the final R-value of 0.048 for 4976 reflections (sinθ⁄λ&lt;0.54). The methyl-α-CDx molecule has the shape of a truncated hexagonal cone, into which the p-nitrophenol molecule is inserted. The phenolic hydroxyl group is located at the center of the methyl-α-CDx cavity, while the nitro group protrudes outside from the base-side of the host cone and is in contact with the adjacent methyl-α-CDx molecule. The water molecule, which is also located within the cavity, links the methyl-α-CDx and p-nitrophenol molecules by hydrogen bonds. Methyl-α-CDx molecules are stacked along the crystallographic a axis in a heat-to-tail mode to form a channel-type structure.
Synthesis and Maganetic Susceptibility of Dimeric Copper(II) Acetate Adducts with Triphenylphosphine or Triphenylphosphine Oxide
Authors: Tokii Tadashi , Ikeda Toyoaki , Muto Yoneichiro 
Published: July 2006

Abstract
Two compounds of stoichiometry Cu(CH3COO)2·L (L=triphenylphosphine or triphenylphosphine oxide) were prepared. These compounds display the antiferromagnetic behavior typical of dimeric copper(II) carboxylates. The singlet-triplet splitting energy is 371 cm−1 for the phosphine adduct and 319 cm−1 for the phosphine oxide adduct.
Preparation and Characterization of Triammine Cobalt(III) Complexes with (R)-2-(Carboxymethylthio)propionate and Its Derivative
Authors: Suzuki Masutaro , Okamoto Ken-ichi , Einaga Hisahiko , Hidaka Jinsai 
Published: July 2006

Abstract
Two complexes of fac(NH3)-[Co(L)(NH3)3]+ type (where L denotes (R)-2-(carboxymethylthio)propionate and (R)-2-(2-carboxymethylthio)propionate) were newly prepared and separated into two isomers, R(S), R(C) and S(S), R(C), by column chromatography. The absolute configurations of the isomers are suggested on the basis of the 13C NMR spectra.
Synthesis of cis-Jasmone via the Retroaldol-aldol Condensation of 3-(cis-3-Hexenyl)-2-cyclopentenone in an Autoclave
Authors: Yoshida Takashi , Saito Shojiro 
Published: July 2006

Abstract
cis-Jasmone was efficiently synthesized from 2-cyclopentenone. The treatment of 2-cyclopentenone with sodium p-toluenesulfinate gave 3-(p-tolylsulfonyl)cyclopentanone in a 92.5% yield. The alkylation of the sulfone, after the protection of the ketone, with cis-1-bromo-3-hexene, followed by desulfonylation with 5% hydrochloric acid in tetrahydrofuran, afforded 3-(cis-3-hexenyl)-2-cyclopentenone in a good yield. The retroaldol-aldol condensation of the cyclopentenone in a stainless steel autoclave in presence of 5% sodium hydroxide yielded cis-jasmone in a 80% yield.
The Synthesis of 1,2-Diazacoronene
Authors: Tokita Sumio , Hiruta Kimihiro , Kitahara Kiyoshi , Nishi Hisao 
Published: July 2006

Abstract
1,2-Bis(ethoxycarbonyl)-1,2-dihydro-1,2-diazacoronene-7,8-dicarboxylic anhydride (5) was obtained from diethyl 1,2-dihydro-1,2-diazabenzo[ghi]perylene-1,2-dicarboxylate, maleic anhydride, and chloranil. Treatment of the anhydride 5 with sodium hydroxide gave 1,2-diazacoronene-7,8-dicarboxylic anhydride (7). When 7 was heated with soda lime, 1,2-diazacoronene was obtained.
Synthesis of (±)-Dihydromahubanolide Using 2-Methylthio-4-pentenoic Acid Dianion
Authors: Tanaka Kazuhiko , Terauchi Makoto , Kaji Aritsune 
Published: July 2006

Abstract
A new and mild method for the synthesis of (±)-dihydromahubanolide has been developed by the use of 2-methylthio-4-pentenoic acid dianion.
The Function of Magnesium(II) N,N′-Dicyclohexylamidinide Complexes as a Carbon Dioxide Carrier
Authors: Matsumura Noboru , Ohba Takayuki , Inoue Hiroo 
Published: July 2006

Abstract
It is found that magnesium(II) N,N′-dicyclohexylamidinide complexes are useful reagents for the fixation of carbon dioxide and the transfer of the captured carbon dioxide moiety to active methylene compounds.
Solvent Effects on the Intensities of Forbidden Bands of Molecules. Absorption Spectra of Acetone and Cyclopentanone
Authors: Nakashima Kenichi , Uchida-Kai Kuniko , Koyanagi Motohiko , Kanda Yoshiya 
Published: July 2006

Abstract
The near ultraviolet absorption spectra of acetone and cyclopentanone have been studied in various fluid solutions at room temperature. The intensity enhancements observed are ascribed to perturbation of dispersion forces between solute and solvent molecules. The results are parallel to those of the Ham effect in benzene. No correlation was found between the intensity increments and solvent polarities. This is at variance with the correlation that has been reported in the S1(Lb)–S0 transition spectra of pyrene and coronene.
High Pressure Organic Chemistry. V. Diels-Alder Reactions of Furan with Acrylic and Maleic Esters
Authors: Kotsuki Hiyoshizo , Nishizawa Hitoshi , Ochi Masamitsu , Matsuoka Kiyoshi 
Published: July 2006

Abstract
A series of Diels-Alder reactions of furan with acrylic and maleic esters has been investigated under conditions of high pressure. The approximate endo/exo ratios of the adducts with acrylic and maleic esters were 6 : 4 and 8 : 2 respectively. The observed isomer distributions are ascribed to the kinetic control.
Photoreduction of Bisviologen Compounds, Viologen–(CH2)n–Viologen, by 2-Propanol
Authors: Furue Masaoki , Nozakura Shun-ichi 
Published: July 2006

Abstract
In order to study the polymer effect in the photoreduction of viologen-containing polymers by 2-propanol, bisviologen compounds, V2+–(CH2)n–V2+, were subjected to photoreduction. The rates of photoreduction occur in the order n=2&gt;3&gt;4&gt;5&gt;MV2+. The structure of the photoreduced species was found to be predominantly the doubly reduced species, V+–(CH2)n–V+, in the cases of n=2 and 3, and mixtures of the doubly reduced and singly reduced species, V+–(CH2)n–V2+, in the cases of n=4 and 5. Intramolecular dimeric association of V+ units was observed for all the compounds except for n=2, where the intramolecular association was structurally inhibited. The variation of rate and structure distribution of reduced species was interpreted in terms of the local concentration effect in the photoreduction step.
Proton and Carbon-13 Nuclear Magnetic Resonance Studies of the Effects of Retinal on the Dynamic Structure and Stability of Lipid Bilayer
Authors: Inoue Yoshio , Hanafusa Yoshito , Toda Masakazu , Chûjô Riichiro 
Published: July 2006

Abstract
The effects of retinal and vitamin A on the dynamic structure and stability of hen egg yolk lecithin bilayers have been studied by means of carbon-13 and proton NMR spectroscopies. 13C spin-lattice relaxation and paramagnetic ion permeability studies on lecithin bilayers indicate a marked decrease in flexibility of the lipid acyl chain and a breakdown of membrane impermeableness to ion by the intercalated all-trans- and 11-cis-retinal, whereas the effect of incorporated vitamin A on the fluidity of bilayers is small and its impermeableness to ion remains effective even in the presence of higher concentration of vitamin A. The experimental results are discussed in connection with the mechanism of the permeability change in photoreceptive disk membrane.
Infrared Study of the Oxidation of 2–Propanol on TiO2
Authors: Nakajima Takashi , Miyata Hisashi , Kubokawa Yutaka 
Published: July 2006

Abstract
Oxidation of 2-propanol on TiO2 was studied by infrared spectroscopy as well as analysis of reaction products. Propene and acetone are formed from isopropoxide species on TiO2. Only adsorbed acetone is oxidized to carbon dioxide via carboxylate species. Propene undergoes no oxidation.
Oxidative Addition of Esters of Formic Acid and β-Lactones to Ni(0)-Complexes Involving Cleavage of the C–O Bond
Authors: Yamamoto Takakazu , Ishizu Junichi , Yamamoto Akio 
Published: July 2006

Abstract
Reactions of esters of formic acid, HCOOR (R=C2H5, CH2C6H5), with Ni(0)-complexes (mixtures of bis(1,5-cyclooctadiene)nickel (Ni(cod)2) and tertiary phosphines (PR′3)) lead to decarbonylation of HCOOR to afford (Ni(CO)n (PR″3)4−n and ROH. Vinyl formate gives a mixture of CH3CHO, Ni(CO)n(PR′3)4−n, C2H4, and CO2 on interaction with the Ni(0)-complexes. β-Lactones liberate CO2 on treatment with the Ni(0)-complexes. Oxidative addition of the reactants to Ni involving cleavage of the C–O bond(s) accounts for the formation of the products.
Convenient Synthesis of 2,7-Disubstituted 5H-1,3,4-Thiadiazolo[3,2-a]pyrimidin-5-ones and Related Compounds
Authors: Tsuji Tadakazu , Takenaka Keiko 
Published: July 2006

Abstract
2,7-Disubstituted 5H-1,3,4-thiadiazolo[3,-2-a]pyrimidin-5-ones were synthesized from the reaction of 3-amino-6-methyl-2-thiouracil with carboxylic acid or from that of thiosemicarbazide with carboxylic acid and β-keto ester in the presence of phosphorus pentaoxide and methanesulfonic acid. The synthesis of related compounds is also described.
Elementary Patterns in Protein-Nucleic Acid Interactions. III. Crystal Structure of Adenine: Phthalic Acid (3:1) Complex Hexahydrate
Authors: Takenaka Akio , Sasada Yoshio 
Published: July 2006

Abstract
Crystal of adenine :phthalic acid (3:1) complex hexahydrate were obtained from an aqueous solution containing equimolar amounts of adenine and N,N-phthaloyl-Dl-glutamic acid. The space group is P\bar1 with unitcell dimensions of a=14.232(2), b=16.730(2), c=7.336(1) Å, α=78.97(1), β=96.14(1), and γ=68.99(1)°. The structure was solved by the direct method and its parameters were refined by a block-diagonal least-squares technique. The two carboxyl groups of the phthalic acid are dissociated and they are hydrogen-bonded to the amino group and the protonated N(1) of the two adeninium monocations. The geometrical characteristics in adeninium monocations are explained with the electronic structures perturbed by the surroundings. A typical feature of the C–H···N hydrogen bond is observed between the adeninium cations. The third adenine molecule is neutral and disordered. A comparison of the dissociation constants of the related compounds suggests that the protonation of adenine occurs when the hydrogen bonds are formed between the carboxyl group of acidic amino acid residue in protein and the unpaired adenine base in nucleic acid.
Electric Linear Dichroism Study of Sodium Poly(p-styrenesulfonate) and Its 9-Aminoacridinium Complex in Aqueous Solutions
Authors: Matsuda Koichiro , Yamaoka Kiwamu 
Published: July 2006

Abstract
Electric linear dichroism (ELD) of sodium poly(p-styrenesulfonate) (NaPSS) and its 9-aminoacridinium (AA) complex at a mixing ratio of polymer residue-to-dye of 6.14 was studied in aqueous solutions at 20 °C. ELD signals were measured in the electric field strength range 0—ca. 19 kV/cm at the absorption peak wavelengths; they showed a saturating trend at extremely high fields. The average angles between the orientation axis of NaPSS and the transition moments of chromophores were estimated to be 60° at 224.5 nm and 57° at 262 nm for the side chain phenyl group and 50° at 404 nm for the bound AA by using theoretical orientation functions derived for mono- and polydisperse systems. The ELD spectra were measured at fixed field strengths; 275–215 nm for NaPSS and 440–282 nm for NaPSS–AA. The reduced dichroism of NaPSS remained nearly constant throughout the 262 nm band but steadily changed below 224 nm in the 224.5 nm band, indicating that another band exists in the far UV region. The ELD spectrum of the NaPSS–AA complex revealed that the two electronic 1La and 1Lb transition moments of the bound AA are tilted at different angles to the orientation axis of the NaPSS backbone.
The Analysis of Lanthanoid-induced 13C Shifts for Naphthylamines. Contact Shifts Induced by Gd-chelates and the Spin-delocalization Mechanism
Authors: Hirayama Masatoshi , Akutsu Kenji , Fukuzawa Kazuko 
Published: July 2006

Abstract
The 13C shifts of 1- and 2-naphthylamines induced by Gd(fod)3 and Gd(dpm)3 were shown to consist predominantly of a contact contribution, based on the fact that these shifts excellently correlate with the hyperfine coupling constants obtained from the graphical analysis of 13C shifts induced by other Ln(fod)3, where Ln is La, Pr, Nd, Sm, Eu, Dy, Ho, Er, or Yb. It was found from the INDO MO calculations of the spin densities of ligand moieties that these Gd-induced shifts parallel the spin-density distribution of the naphthylmethyl radical better than that of the naphthylamine cation radical and that these shifts are best interpreted in terms of the superposition of the β-spin of the naphthylmethyl radical and the α-spin of the naphthyl radical. This may suggest that a direct spin transfer occurs through space from Gd3+ to the amine molecule, in addition to the normal through-bond delocalization via the N-lone pair.
Pattern Formation by Rhythmic Crystallization of Methyl Mesitylcarbamate
Authors: Iwamoto Kazutoshi , Mitomo Shun-ichi , Fukide Jun-ichi , Shigemoto Tadashi , Sen\={o} Manabu 
Published: July 2006

Abstract
Rhythmic crystallization behavior of methyl mesitylcarbamate from chloroform solutions under appropriate conditions was found. Effects of temperature, evaporation rate of solvent, and sample weight per area on this behavior are studied in detail, and the qualitative explanation based on the autocatalytic branching process is proposed.
Kinetics of Racemization and Dissociation of Tris(1,10-phenanthroline)iron(II). Hydrophobic Interaction between the Complex Cation and Alkylammonium Cations
Authors: Tachiyashiki Satoshi , Yamatera Hideo 
Published: July 2006

Abstract
The rates of racemization and dissociation of [Fe(phen)3]2+ were determined in the presence of series of alkali-metal bromides, symmetrical tetraalkylammonium bromides, and alkyltrimethylammonium bromides. The alkali-metal bromides did not affect the racemization rate, but they decreased the dissociation rate. The retarding effect increased with increasing bromide concentrations and decreased in the order of Li+&gt;Na+&gt;K+&gt; Rb+&gt;Cs+. The alkylammonium bromides increased the racemization rate up to three fold and decreased the dissociation rate down to half the rate in pure water; alkylammonium ions with longer alkylchains induced greater changes of the rates. The effect of alkylammonium ions on the reaction rates was analyzed in terms of the formation of 1:1 aggregates of the complex cation with the alkylammonium cation caused by hydrophobic interactions. The equilibrium constant for the aggregate formation was greater for the alkylammonium ions with longer alkyl chains. The reaction rate constants of the hydrophobic aggregates remain almost constant with the increase in the alkyl chain length. The rate behaviors of the hydrophobic aggregates are discussed in terms of the reaction mechanisms of racemization and dissociation of [Fe(phen)3]2+.
Formation of Mixed-ligand Complexes of Cobalt(II) with Bromide and Substituted Pyridines in 1,2-Dibromoethane
Authors: Sawada Kiyoshi , Miura Kazue , Suzuki Toshio 
Published: July 2006

Abstract
The equilibria of a series of complexes of the CoBr2(R-py)2 type (where R-py=2-methyl-(2Me-py), 3-methyl-(3Me-py), 4-methyl-(4Me-py), 4-acetyl-(4Ac-py), and 4-cyanopyridine (4CN-py), and pyridine(py)) with TBA·Br (tetrabutylammonium bromide) in 1,2-dibromoethane have been investigated spectrophotometrically. In the presence of an excess of R-py, the dibromocomplex gives rise to the following configurational equilibrium:
CoBr2(R-py)2+2R-py\oversetkc\ightleftharpoonsCoBr2(R-py)4
(tetrahedral)&(octahedral)
with logKc=0.67, 0.11, and 0.53±0.03 for the 4Me-py, 3Me-py, and py complexes respectively. The substitution equilibria of the tetrahedral complexes are written as:
CoBr2(R-py)2+TBA·Br\oversetk3\ightleftharpoons(TBA)CoBr3(R-py)+R-py,
(TBA)CoBr3(R-py)+TBA·Br\oversetk4\ightleftharpoons(TBA)2CoBr4+R-py.
The successive formation constants, logK3, were determined as 2.23, 2.44, and 2.89±0.03 for the 4Me-py, 3Me-py, and py complexes respectively. The constants logK4 for the 4Me-py, 3Me-py, 2Me-py, py, 4Ac-py and 4CN-py complexes are −1.07, −0.94, 0.09, −0.74, −0.09, and 0.47±0.01 respectively. The values of logK3 and logK4 show a linear correlation with the basicity of R-py, pKb, except for the 2Me-py complex.
Temperature-jump Studies of the Complex Formation of Nickel(II) l-Glutamate in Aqueous Solutions
Authors: Tamura Kiyoshi , Harada Shoji , Funaki Yoshinori , Yasunaga Tatsuya 
Published: July 2006

Abstract
Temperature-jump relaxation studies have been carried out on aqueous nickel(II)–l-glutamic acid solutions. The observed relaxation phenomenon is ascribed to the successive complex formation reactions:
Ni2++L2− \oversetk1\undersetk-1\ightleftharpoons NiL,
NiL+L2− \oversetk2\undersetk-2\ightleftharpoons NiL22−,
NiL22−+L2− \oversetk3\undersetk-3\ightleftharpoons NiL34−,
where L2− denotes a glutamate ion. The rate constants are: 2.0×104, 1.1×104, and 9.2×103 M−1 s−1 (1 M=1 mol dm−3) for k1, k2, and k3, and 0.048, 0.69, and 27 s−1 for k−1, k−2, and k−3, respectively, at 25 °C and I=0.1. The rate-determining step of the complex formation reactions, which follows the initial formation of ion-pairs, is the dissociation of a water molecule from the inner hydration sphere of the nickel; the glutamate ion acts as a bidentate ligand forming a five-membered chelate ring in the complexes.
Chemistry of Chiral Vitamin B6 Analogs. IV. Syntheses of Chiral Pyridoxal and Pyridoxamine Analogs Having a Branched “Ansa Chain” between 2′- and 5′-Positions
Authors: Ando Makoto , Tachibana Yoji , Kuzuhara Hiroyoshi 
Published: July 2006

Abstract
Racemic 15-formyl-14-hydroxy-5,5-dimethyl-2,8-dithia[9](2,5)pyridinophane (4), an analog of pyridoxal having a branched “ansa chain” between 2′- and 5′-positions, was synthesized from 2,5-bis(chloromethyl)-3-hydroxy-O,O′-isopropylidene-4-pyridinemethanol. Optical resolution of 4 was achieved via the formation of Schiff base with 3-amino-3-deoxy-1,2:5,6-di-O-isopropylidene-d-glucofranose, giving the levorotary enantiomer of 4 (4a). Racemic 15-aminomethyl-14-hydroxy-5,5-dimethyl-2,8-dithia[9](2,5)pyridinophane (5), the same type of pyridoxamine analog as 4, and its levorotary enantiomer were synthesized from the corresponding 4 and 4a. Both levorotary and dextrorotary enantiomers of 5 were also obtained by the optical resolution of the racemate via the formation of chiral dibenzoyltartaric acid salts of 5.
The C(1)–C(10) Bond Cleavage and B Ring Aromatization of Some 6-Hydroxy-5βH-abieta-6,8,11,13-tetraen-18-oic Acid 18,6-Lactones
Authors: Matsumoto Takashi , Imai Sachihiko , Ondo Kenji , Takeyama Nobuaki , Kataoka Hideo , Yamamoto Yasuhiro , Fukui Kenji 
Published: July 2006

Abstract
Fusion of 6-hydroxy-5βH-abieta-6,8,11,13-tetraen-18-oic acid 18,6-lactone (2) with potassium hydrogensulfate at 220 °C afforded bis[3-(2,3-dihydro-7-isopropyl-3,4-dimethyl-2-oxonaphtho[2,3-b]furan-3-yl)propyl] ether (12) in 37% yield, together with two minor products in 12% yield: 2,3-dihydro-7-isopropyl-3,4-dimethyl-3-propylnaphtho[2,3-b]furan-2-one and 3-allyl-2,3-dihydro-7-isopropyl-3,4-dimethylnaphtho[2,3-b]furan-2-one. Treatment of 12 with p-toluenesulfonic acid at 160 °C gave 2,3-dihydro-7-isopropyl-3,4-dimethyl-3-(3-tosyloxypropyl)naphtho[2,3-b]furan-2-one, which was converted into 2,3-dihydro-3-(3-hydroxypropyl)-7-isopropyl-3,4-dimethylnaphtho[2,3-b]furan-2-one (16). The alcohol 16 was further characterized as its acetate (17). After several attempts, the above C(1)–C(10) bond cleavage and B ring aromatization reaction were improved by use of concentrated sulfuric acid in refluxing acetic acid. Under these conditions, 2 gave 17 in 47% yield. Hydrolysis of 17 with hydrochloric acid afforded 16. Subsequently, 12-hydroxy-, 12-methoxy-, 12-acetoxy-, and 12-nitro-6-hydroxy-5βH-abieta-6,8,11,13-tetraen-18-oic acid 18,6-lactones were each refluxed with concentrated sulfuric acid in acetic acid to give 6-hydroxy-, 6-methoxy-, 6-acetoxy-, and 6-nitro-3-(3-acetoxypropyl)-2,3-dihydro-7-isopropyl-3,4-dimethylnaphtho[2,3-b]furan-2-ones, respectively. From the present study, the 12-acetoxy derivative seems to be a suitable intermediate for the synthesis of coleon A.
Microwave Spectra of cis- and trans-1-Chloro-1,2-difluoroethylene
Authors: Ogata Teruhiko 
Published: July 2006

Abstract
The microwave spectra of the 35Cl and 37Cl isotope species of cis- and trans-HFC=CFCl have been studied in the 8–50 GHz region. The rotational constants and the Cl quadrupole coupling constants in MHz are obtained and listed. The quadrupole coupling constants and the structures obtained for cis- and trans-HFC=CFCl are consistent with the results of other haloethylenes.
(Remark: Graphics omitted.)
Solvent Effects in the Conversion of Phenyldiazomethane into Stilbene and Spirooxetane in the Reaction with Chloranil
Authors: Oshima Takumi , Nishioka Ryoji , Nagai Toshikazu 
Published: July 2006

Abstract
A stereochemical study was made of the reaction of phenyldiazomethane(1) with chloranil(2) at 20 °C in 28 aprotic solvents. The products were trans-spirooxetane(4) and cis-trans mixtures of stilbene(3) (ca. 2–5 times cis-rich). The molar ratios of cis-3 to the sum of the trans-3 and 4 tended to increase, whereas the 4 to trans-3 ratios decrease with the increase in the solvent basicity and polarity. These effects of solvents on the product distributions were interpreted in terms of the effects of the solvent basicity and polarity on the stereoselective formation of the diazonium betaine intermediate and on the conformational isomerism. Moderately successful linear-free-energy(LFE) relationships were established for these product ratios with the aid of the combination of the empirical solvent basicity parameter, Dπ, and the Kirkwood function, f(ε), or ET values as the solvent polarity parameters.