bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Facile Synthesis of 1,2-Divinylcycloalkanols and Their Behavior in the Oxy-Cope Rearrangement
Authors: Kato Tetsuya , Kondo Hisao , Nishino Masaki , Tanaka Minoru , Hata Go , Miyake Akihisa 
Published: July 2006

Abstract
The reaction of 2-chlorocycloalkanones with vinylmagnesium chloride gives 1,2-divinylcycloalkanols. Divinylation proceeds via a rearrangement of initially formed 2-chloro-1-vinylcycloalkanols to 2-vinylcycloalkanones followed by further vinylation of 2-vinylcycloalkanones. Thermal sigmatropic rearrangement of 1,2-divinylcycloalkanols gives 5-cycloalken-1-ones in good yields. The influence of the size of rings on the reaction pathways is discussed.
Transformation of D : A-Friedo-18β-lup-19-en-3-one into D : B-Friedo-18β,19αH-lup-5-en-3β-ol and a Comment on the Structure of Guimarenol
Authors: Yokoyama Yasushi , Moriyama Yoshihiko , Tsuyuki Takahiko , Takahashi Takeyoshi , Itai Akiko , Iitaka Yoichi 
Published: July 2006

Abstract
D:A-friedo-18β-lup-19-en-3-one was transformed into D:B-Friedo-18β,19αH-lup-5-en-3β-ol by two routes, 1) bromination-dehydrobromination of an enol benzoate of D:A-friedo-18β,19αH-lupan-3-one and 2) BF3·Et2O-catalyzed backbone rearrangement of 3β,4β-epoxy-D:A-friedo-18β, 19αH-lupane. The 18βH,19αH-configuration in these D:A- and D:B-friedo-type lupane derivatives was determined by means of X-ray diffraction for a 3α,4α-epoxide derived from D:A-friedo-18β,19αH-lupan-3β-ol. The synthetic D:B-friedo-18β,19βH-lup-5-en-3β-ol was found to be not identical with guimarenol isolated from Ceropegia dichotoma.
The Application of Magnetic Circular Dichroism to the Study of the Tautomerism of Cytosine and Isocytosine
Authors: Kaito Akita , Hatano Masahiro , Ueda Toru , Shibuya Susumu 
Published: July 2006

Abstract
The MCD and absorption spectra of cytosine and isocytosine and their N-substituted derivatives were measured in the wave-number region of 30000–50000 cm−1. On the basis of the experimental results, the tautomerism of cytosine and isocytosine was discussed. The transition energies, the oscillator strengths, and the Faraday B terms of the tautomeric forms of cytosine and isocytosine were calculated within the framework of the intermediate neglect of the differential overlap(INDO) approximation. The calculated results are in good agreement with the experimental data.
The Rate Constants of the Reactions of the Metastable Nitrogen Atoms, 2D and 2P, and the Reactions of N(4S)+NO→N2+O(3P) and O(3P)+NO+M→NO2+M
Authors: Sugawara Ko-ichi , Ishikawa Yo-ichi , Sato Shin 
Published: July 2006

Abstract
The pulse-radiolysis technique was used for the measurement of the quenching rates of the metastable nitrogen atoms, 2D and 2P, both in nitrogen and in helium. The rate constants obtained for N(2D) were (1.3±0.2)×10−14 cm3 molecule−1 s−1 (1 cm3 molecule−1 s−1=6.022×1017 m3 mol−1 s−1) in nitrogen and (4.6±0.4)×10−17 in helium; these values were larger than those for the higher energy metastable nitrogen atoms, N(2P), (3.3±0.3)×10−17 in nitrogen and (4.2±1.3)×10−18 in helium. The room temperature rate constants of the reactions of these atoms with nitrogen monoxide and with ethylene were also measured. All of these rate constants were found to be of the order of 3×10−11 cm3 molecule−1 s−1. The rate constants of the reactions, N(4S)+NO→N2+O(3P) and O(3P)+NO+M→NO2+M, were also measured and compared with literature values.
Interaction of 9-Aminoacridinium and 10-Methylacridinium Cations with Polyelectrolytes, with Emphasis on the Bound-dye Spectra
Authors: Yamaoka Kiwamu , Takatsuki Mineo , Nakata Kinya 
Published: July 2006

Abstract
Visible and UV absorption spectra of two dyes, 9-aminoacridinium (AA) and 10-methylacridinium (MeA) cations, were measured at 25 °C in the presence of three different polyelectrolytes—sodium salts of poly(p-styrenesulfonate) (NaPSS), polyphosphate (NaPP), and polyacrylate (NaPA)—for polymer residue-to-dye ratios from zero to near unity. The optical titration curves of AA-polyanion systems showed a slightly sigmoidal curvature. The method of extended principal component analysis was applied to the experimental spectra of the AA–NaPSS, –NaPP, –NaPA and MeA–NaPSS systems. Only two absorbing component dyes, i.e., bound and unbound, were verified to exist in each system. The equilibrium constant of the binding between dye and polyanion, the pure spectrum of bound dye, and the adjustable parameter α, by which the sigmoidal titration curve is characterized, were determined. In each of the above systems, the bound-dye spectrum behaves in opposition to the common notion of “metachromasy,” showing a bathochromic shift without any new band. The spectra of MeA changed only moderately by the addition of NaPSS. The ultrafiltration of the MeA–NaPP and –NaPA solutions confirmed that most of the MeA cations remain unbound.
The Micelle-promoted Selective Hydrolysis of Anionic and Nonionic Ester Substrates by Hydroxamic Acids and Histidine Derivatives
Authors: Ueoka Ryuichi , Matsuura Hidehiko , Nakahata Syuji , Ohkubo Katsutoshi 
Published: July 2006

Abstract
The hydrolyses of anionic 3-nitro-4-acyloxybenzoic acid (S2−–S16−) and nonionic p-nitrophenyl carboxylate (S2–S16) substrates catalyzed by hydroxamic acids (C6–C12) and histidine derivatives (AcetHis and LauHis) were performed with and without alkyltrimethylammonium (DTAC, CTAB, and OTAC) surfactants at pH 7.45. The present reaction was characterized by the selectively efficient hydrolysis of the same substrate of S6− or S10 by the comicellar Cm (m=8, 10, or 12)–CTAB (or OTAC) or LauHis–CTAB (or OTAC) catalysts. Relevant factors to such a selective hydrolysis of a specific substrate by the comicellar catalysts were discussed by taking notice of the electrostatic-charge-attraction force, steric hindrance, and hydrophobic interaction. The investigation of the binding constants in the present micellar reaction system demonstrated the importance of an appropriate hydrophobic interaction between a substrate and micelles for the selective rate enhacement of ester-hydrolysis.
Phase Transitions in N-Propylpyridinium–TCNQ Ion-radical Complex Salts
Authors: Murakami Mutsuaki , Yoshimura Susumu 
Published: July 2006

Abstract
N-Propylpyridinium (TCNQ)x crystallized in two complex salts (x=2, 2.5), both of which displayed initial irreversible and subsequent reversible first-order phase transitions with a sharp discontinuity in the electrical conductivity. The reversible transitions of both salts are essentially the same in spite of their differences in stoichiometry. The transitions were accompanied by crystal structure changes; the changes in the physical properties were ascribed to the crystalline distortion in both the one-dimensional TCNQ chain and the motion of the cation molecules. The high-temperature phase was metallic, with a zero activation energy for conduction; the source of the metallic behavior was also discussed. The electronic and infrared absorption spectra suggest that the high-temperature modification has a less distorted stacking of TCNQ molecules in the column.
The Heats of Solution of Optically Active Compounds and the Corresponding Racemic Compounds
Authors: Matsumoto Masayuki , Amaya Kazuo 
Published: July 2006

Abstract
The heats of solution of crystalline amino acids and hydroxy acid in water at 298.15 K were measured with a twin isoperibol calorimeter. It was found, as was expected from the theory, that the difference in the heat of solution between optically active compounds and their corresponding racemic compounds was appreciably large compared with the heat of mixing of concentrated aqueous solutions of d- and l-optical isomers.
Thermal Decomposition Reactions of Analogous Penta-amminenitrosylcobalt(III) Complexes
Authors: Miyokawa Kikuo , Masuda Hakaru , Masuda Isao 
Published: July 2006

Abstract
The thermal behavior of five complexes, [Co(NH3)6]Cl3 (1), [Co(NH3)5NO2]Cl2 (2), [Co(NH3)5NO]Cl2 (3), [(NH3)5Co–N(O)–NO–Co(NH3)5]Cl4·2H2O (4), and [(NH3)5Co–NO–ON–Co(NH3)5]Cl4·4H2O (5), has been investigated. The pyrolysis-gaschromatographic technique has been successfully applied to the N2- and N2O analyses of the gases evolved on the pyrolysis of the complexes. The thermal decomposition of these complexes is characterized predominantly by the reduction process of Co(III) to Co(II). In the simple nitrosyl 3, the NO− group reduces the Co(III) ion and dissociates as NO. As for the remaining complexes, a thermally induced transient-state tends to dissociate H+ from the coordinated ammonia as follows : CoIII–NH3→[CoIII–NH2δ−···Hδ+]→CoII+NH2+H+. The NH2 species is subsequently decomposed as NH2→2/3NH3+1/6N2. Moreover, H+ is captured by an anionic species and/or the NH3 present in the system, that is, by Cl− and NH3 forming NH4Cl in the case of 1, by NO2− and NH3 forming NH4NO2, which then decomposes to N2 and H2O, in 2, and by N2O22− forming H2N2O2, which then decomposes to N2O and H2O, in 4. The 5 complex undergoes an exothermic decomposition, affording a larger amount of N2 and N2O than those to be expected from the above stoichiometry, suggesting an oxidative behavior of the bridged, dimeric (–NO–ON–)2− group towards ammonia.
The Conformations of 2-Phenylpropionaldehyde and Some Aliphatic Ketones. The Possible Importance of the CH/π and CH/n Interactions in Determining the Molecular Geometry of a Mobile System
Authors: Zushi Shoji , Kodama Yoshio , Nishihata Ken , Umemura Koshiro , Nishio Motohiro , Uzawa Jun , Hirota Minoru 
Published: July 2006

Abstract
The conformations have been studied by means of NMR spectroscopy, largely by the computer simulation of the lanthanoid-induced shifts, for a series of aliphatic carbonyl compounds with the following structures: CH3CH(C6H5)CO–R; R=H, CH3, C2H5, i-C3H7, and t-C4H9. It has been suggested that two rotamers are important in the conformational equilibria of these ketones, in which the R–C–C–C6H5 dihedral angle is ca. 30° and ca. 90°. The relative stability of the above two rotamers has been found to depend on the nature of the alkyl group, R. The results have been discussed in light of the possible weak attractive forces, the CH/π and CH/n interactions.
Dynamic Behavior and Nature of Active Sites Directly Observed by Means of Photoluminescence Spectroscopy
Authors: Iwasawa Yasuhiro , Ogasawara Sadao 
Published: July 2006

Abstract
The dynamic behavior and properties of the active sites (Types I, II, and III) of SiO2-supported Mo catalysts during a redox reaction with H2 or O2 (in connection with a general two-stage redox mechanism) were observed directly by means of a photoluminescence technique.
Catalysis by Heteropolyacid. V. Catalytic Alkylation of Toluene by Mixed-coordination type, H4[SiMo12−nWnO40], Heteropolyacid
Authors: Nomiya Kenji , Saijoh Hidehiko , Miwa Makoto 
Published: July 2006

Abstract
To compare the specific difference between molybdenum and tungsten ions on the catalytic reaction, we investigated the alkylation of toluene with benzyl chloride by mixed-metal heteropolyacids, H4[SiMo12−nWnO40] (n=0, 1, 10, and 11). Molybdenum-rich compound is more active than tungsten-rich one.
The Direct Alkylamination of 1-Aminoanthraquinone Promoted by Cobalt(II) Chloride
Authors: Yoshida Katsuhira , Matsuoka Masaru , Yamashita Yoshio , Nagamori Shoichi , Kitao Teijiro 
Published: July 2006

Abstract
The reaction of 1-aminoanthraquinone with primary aliphatic amines in the presence of cobalt(II) chloride under atmospheric oxygen preferentially gave the corresponding 1-amino-4-(alkylamino)anthraquinones. The reaction did not proceed with aqueous ammonia, bidentate amines, secondary aliphatic amines, and primary arylamines. While, with alicyclic amines the reaction mainly afforded 1-amino-2,4-bis(alkylamino)anthraquinones.
Kinetics and Mechanism of Ligand Exchange of Tris(acetylacetonato)iron(III) in Acetylacetone
Authors: Kido Hiroaki , Saito Kazuo 
Published: July 2006

Abstract
Tris(acetylacetonato[2-14C])iron(III) undergoes ligand exchange in acetylacetone at 4–16 °C without side reactions. The exchange rate is expressed by Rate=(ka+kb[H2O])[complex]([complex]≈0.01 M, [H2O]≈0.05 M), and the rate constant (10.2 °C) and activation parameters are ka=(8.9±1.2)×10−4 s−1, ΔH\eweq=14.4±0.9 kcal mol−1, ΔS\eweq=−22±3 cal K−1 mol−1 and kb=(2.22±0.20)×10−2 M−1 s−1, ΔH\eweq=16.9±0.4 kcal mol−1, ΔS\eweq=−6.1±1.3 cal K−1 mol−1 (1 cal=4.18 J, 1 M=1 mol dm−3). No deuterium isotope effect on the rate. The rate-determining steps seem to correspond to the formation of intermediates containing a one-ended acac− and an Hacac molecule (the ka path), and the anion and a water molecule (the kb path), by the SN2 mechanism.
Syntheses and Reactions of Optically Active Alkoxyaminosulfonium Salts
Authors: Okuma Kentaro , Minato Hiroshi , Kobayashi Michio 
Published: July 2006

Abstract
The optically active methoxymorpholino-p-tolylsulfonium salt has been synthesized by the reaction of optically active N-p-toluenesulfinylmorpholine with methyl trifluoromethanesulfonate. The sulfonium ion methylated benzylethylphenylamine and benzyl ethyl sulfide with asymmetric induction to give the optically active benzylethylmethylphenylammonium ion and benzylethylmethylsulfonium ion respectively. The optically active methoxymorpholino-p-tolylsulfonium salt and diaminosulfonium salts have been prepared in a one pot reaction between N-p-toluenesulfenyImorpholine and 1-chlorobenzotriazole with methanol in the presence of 1-menthol at −80 °C.
Catalytic Property of Calcined Iron Sulfate Treated with Hydrogen Chloride in Alkylation of Toluene and Benzene with Alkyl Chlorides
Authors: Arata Kazushi , Hino Makoto , Yabe Katsumasa 
Published: July 2006

Abstract
Alkylation was carried out at room temperature over catalysts prepared by calcination of FeSO4, Fe2O3, and Fe(OH)3 in the air at various temperatures and subsequent exposure to HCl at room temperature for 20 min. The FeSO4–HCl catalysts heat-treated at 700 and 750 °C showed very high activity and selectivity, the other catalysts except for the sulfate treated at 800 °C being almost inactive. The FeSO4(700 °C)–HCl catalyst was found to consist of FeCl3 and α-Fe2O3 by means of Mössbauer effect, the absorption peak areas being 14 and 86% for portions of iron based on the chloride and oxide, respectively. The results of DTA and TGA experiments suggest that the coordinate bond of water molecule on FeCl3 of the FeSO4(700 °C)–HCl catalyst is stronger than that on FeCl3 of the FeSO4 (600, 800, and 900 °C)–HCl and commercial FeCl3. The FeSO4(700 °C)–HCl catalyst showed a much higher activity than pure FeCl3. The iron(III) chloride formed by reaction of HCl and α-Fe2O3 obtained by thermal decomposition of the sulfate at 700 or 750 °C was found to be a very strong Lewis acid catalyst.
The Crystal and Molecular Structure of Tetracyclo[6.4.3.0.02,7]pentadec-4-en-13-one
Authors: Koshibe Shigeru , Kai Yasushi , Yasuoka Noritake , Kasai Nobutami 
Published: July 2006

Abstract
The X-ray molecular structure of the photocycloadduct of bicyclo[4.3.0]non-1(6)-en-7-one with 1,4-cyclohexadiene has been determined. The crystals belong to the monoclinic system, space group P21/c, Z=4, a=8.108(1), b=8.836(1), c=7.095(1) Å, and β=95.38(1)° at 22 °C; a=7.975(1), b=8.760(1), c=16.949(2) Å, and β=94.85(1)° at −160 °C. The structure was solved by the direct method and refined by the least-squares procedure to R=0.052 (22 °C) and 0.053 (−160 °C) for 1777 and 2349 non-zero reflections respectively. The ring junction between the four- and six-membered rings is trans. The molecule has the cis-anti-trans structure. No essential difference is observed between the molecular structure at 22 °C and −160 °C except for the thermal motions.
The Deuteron Magnetic Resonance of Tin(II) Chloride Dihydrate Single Crystals in High- and Low-temperature Phases
Authors: Kiriyama Hideko , Nakamura Osamu 
Published: July 2006

Abstract
The deuteron magnetic resonance spectra of SnCl2·2D2O single crystals have been measured from 208 to 300 K in order to elucidate the static and dynamic structures of water molecules in connection with the phase transition occuring at 234 K. The deuteron quadrupole coupling constants (asymmetry parameters) were determined at 208 K for four non-equivalent water deuterons. These values are 194.2±0.3 (0.066±0.004), 193.2±0.5 (0.112±0.003), 223.3±0.4 (0.206±0.003), and 244.0±0.4 kHz (0.058±0.003), depending largely on the hydrogen-bond strength or the D···O distance. The deuteron arrangements deduced from the EFG tensors agreed well with the ordered structure reported by an earlier ND study. The dynamical process of deuterons responsible for the high-temperature disordered structure was analyzed with the aid of the ND results and was ascribed to a combination of the flip motion of water molecules about each two-fold axis and their rotational motion around each pseudo-three-fold axis.
Precise Complexometric Coulometric Titration of Disodium Dihydrogen Ethylenediaminetetraacetate Dihydrate and Aluminium
Authors: Tanaka Tatsuhiko , Hotta Kousei , Yoshimori Takayoshi 
Published: July 2006

Abstract
The purity of recrystallized disodium dihydrogen ethylenediaminetetraacetate dihydrate was determined accurately by titration with zinc ion coulometrically generated from an amalgamated zinc anode. The reagents used were of 99.446% ±0.002% homogeneity when the sample was dehydrated and stored in a hygrostat (relative humidity, ca. 58% at 20 °C) over 1 year. Aluminium of high purity (99.99%) was coulometrically titrated with the purified reagent. Aluminium was allowed to react with a certain amount of the reagent, excess of the reagent being titrated with zinc ion anodically generated. The end point was determined potentiometrically using a mercury electrode. The purity was found to be 99.976% with a standard deviation of 0.010% for 6 degree of freedom. Cause of the lower result (0.01%) is discussed.
A Cation-exchange Study of Cerium(III) and Thulium(III) Tartrate Complexes
Authors: Ohyoshi Emiko , Ohyoshi Akira 
Published: July 2006

Abstract
The tartrate complexes of Ce(III) and Tm(III) were studied by the cation-exchange method, where a series of solutions prepared so as to keep the [Htart−] value nearly constant, while the [tart2−] value was varied, was used for the estimation of the protonated complexes. Three kinds of complexes, M(Htart)2+, M(Htart)(tart), and M(tart)2−, were found in the lower pH region of the solutions.
A Convenient Synthesis of Telluronium Ylides
Authors: Tamagaki Seizo , Akatsuka Ryuji , Kozuka Seizi 
Published: July 2006

Abstract
Several telluronium ylides were readily prepared by mixing the corresponding telluroxides and a variety of active methylene compounds in CHCl3 at ambient temperature or under reflux. Arylselenonium ylides could also be obtained in a similar way.
Kinetics and Mechanisms of Ligand Exchange Reactions of Tris(acetylacetonato)-chromium(III), -cobalt(III), -ruthenium(III), and -rhodium(III) in Acetylacetone
Authors: Kido Hiroaki 
Published: July 2006

Abstract
Tris(acetylacetonato[2-14C])-cobalt(III), -chromium(III), -ruthenium(III), and -rhodium(III) undergo ligand exchange in acetylacetone (Hacac) at 85–190 °C without decomposition of the complexes. The exchange rate is proportional to the complex concentration, and the first-order rate constant k0 decreases in the sequence Co(III)&gt;Cr(III)&gt;Ru(III)&gt;Rh(III), k0⁄10−5 s−1 being 2.4 (93 °C), 5.6 (117 °C), 9.5 (158 °C), and 2.4 (185 °C), respectively. The activation enthalpies and entropies and deuterium isotope effect on k0 are significantly different between the Co(III) and the Cr(III), Ru(III) and Rh(III) complexes. An intermediate involving an one-ended acetylacetonate and a solvent molecule(Hacac) is concluded to be formed in the rate-determining step. The SN1 and the SN2 mechanism are assigned to the exchange reactions of the Co(III) complex and the others, respectively, for the rate-determining steps.
New Effective Nickel(II) Catalysts for the Cross-coupling of an Aryl Grignard Reagent with Aryl Halide
Authors: Ibuki Eiichi , Ozasa Shigeru , Fujioka Yasuhiro , Okada Motofumi , Terada Katsutoshi 
Published: July 2006

Abstract
It has been found that seventeen nickel complexes of the Ni–O4, Ni–S4, Ni–O2N2, Ni–O3N3, Ni–N4, Ni–N6, and Ni–(C5)2 types exhibit a high catalytic activity for the selective cross-coupling reaction of an aryl Grignard reagent with aryl iodide, which make possible the synthesis of unsymmetrical aromatics of a high purity and in a high yield.
Synthesis of 1-Substituted 3-(Dialkylaminoalkoxy)-4,5,6,7-tetrahydro-1H-indazoles
Authors: Soga Takeo , Niwa Hirosuke , Shiraishi Takanori 
Published: July 2006

Abstract
4,5,6,7-Tetrahydro-3-indazolone was prepared by catalytic hydrogenation of 3-indazolone, and its reaction with dialkylaminoalkyl chloride was studied. In addition, a number of 1-substituted 3-(dialkylaminoalkoxy)-4,5,6,7-tetrahydro-1H-indazoles were prepared.
Grignard Reaction of Peroxides Containing Neighboring Nitrogen Atom
Authors: Okubo Masao , Komatsu Takutomo , Tsuruta Ky\={o}ko , Sonoda Yasuyo 
Published: July 2006

Abstract
The substituent effect on the reaction of bis(2-aryl-1,2,3,4-tetrahydro-1-isoquinolyl) peroxide with PhMgBr as well as the product obtained on the reaction of 2-p-tolyl-1,2,3,4-tetrahydro-1-isoquinolyl t-butyl peroxide with PhMgBr were interpreted in terms of the coordination of the neighboring nitrogen atom to Mg atom.
A Nephelometric Analysis of Mercury(II) with Potassium Salt of α,α′-Bis(dithiocarboxyoxy)-p-xylene
Authors: Yamamoto Daijiro , Tsukada Masamichi , Hirota Yasuaki , Mizuno Haruo 
Published: July 2006

Abstract
Potassium salt of α,α′-bis(dithiocarboxyoxy)-p-xylene (abbreviated as K2-XDX) was synthesized as a chelating agent with p-xylene-α,α′-diol, carbon disulfide, and potassium hydroxide. Since a mercury(II)–XDX chelate complex suspension scattered pearl-blue light strongly because of the formation of a colloidal solution, the nephelometric analysis of small amounts of mercury(II) was undertaken. The calibration curve was found to be linear in the two ranges of 0.03–1.00 and 0.50–25.00 μg cm−3 of the mercury(II) ion respectively, but no suitable masking agents for interfering metal ions were found. The mole ratio of mercury(II) to XDX in the complex was found to be 1 to 1. These data for the complex suggested that XDX and mercury(II) combined alternately to form the (–Hg–XDX–)n complex. The molecular weight of this complex could be calculated as about 2×107 from the Zimm plot on the basis of the light-scattering method.
Optical Resolution by Preferential Crystallization and Replacing Crystallization of Dl-Allothreonine
Authors: Miyazaki Hideya , Morita Hiroyuki , Shiraiwa Tadashi , Kurokawa Hidemoto 
Published: July 2006

Abstract
The ternary solubility diagram, X-ray diffraction pattern, and infrared spectra have suggested that Dl-allothreonine [Dl-aThr] exists as a conglomerate. The optical resolution by successive preferential crystallization gave both d- and l-aThr of 95% optical purities in 9—13% degrees of resolution. The successive replacing crystallization was more successfully achieved by the coexisting 4-hydroxy-l-proline, as an optically active cosolute, in a racemic supersaturated solution. d-aThr of 94% optical purity was allowed to crystallize preferentially without seeding d-aThr in 24% degree of resolution, whereas l-aThr of 81% optical purity from the mother liquor was allowed to crystallize by seeding l-aThr in 22% degree of resolution. Recystallization of the obtained d- and l-aThr from water gave an optically pure form.
Facile Synthesis of Linear and Angular 2-Methylfurobenzopyranone
Authors: Rao Y Jayaprakash , Krupadanam G L David 
Published: July 2006

Abstract
A route for the synthesis of 2-methylfurobenzopyranone by the oxidative cyclization of sodium salt of 7-hydroxy-6 or 8-allyl-4H-[1]benzopyran-4-one using PdCl2(PhCN)2 complex has been developed.