bluuebunny/crossref_metadata_2025 huggingface dataset:
Photochemical Nucleophilic Substitution Reactions of Methyl Substituted Derivatives of p- and o-Nitroanisole
Authors: Sawaura Masaki , Mukai Toshio
Published: July 2006

Photosubstitution reactions of several methyl substituted derivatives of p- and o-nitroanisole with hydroxide ion were investigated. The methyl substituent seemed to show an uncertain (probably electronic) effect in addition to the steric effect for the replacement of both the methoxy and the nitro groups. Mainly, the replacement reaction of the nitro group is discussed.
Persistent Nitrogen-centered Free Radicals, N-(Arylthio)-3,5-di-t-butylphenylaminyls. Decomposition Reactions
Authors: Miura Yozo , Yamamoto Akifumi , Kinoshita Masayoshi
Published: July 2006

N-(4-Chlorophenylthio) -3,5-di-t-butylphenylaminyl was decomposed in oxygen-free benzene, and the products were examined. On the basis of the results, the decomposition mechanism of the radical is described.
A Product from the Photo-induced Reaction of Cholesterol in the Presence of Lead Tetraacetate and Iodine
Authors: Suginome Hiroshi , Kato Kimitoshi
Published: July 2006

The irradiation of a benzene solution of cholesterol in the presence of lead tetraacetate and iodine gives cholest-5-en-3β-yl A-homo-4-oxacholest-5-en-3α-yl ether in a 23% yield.
Reaction of Thiobenzophenone S-Oxide (Diphenylsulfine) with Carbon Nucleophiles
Authors: Ohno Atsuyoshi , Uohama Misao , Oka Shinzaburo
Published: July 2006

The reaction of diphenylsulfine with a Grignard reagent or alkyllithium gives a variety of products depending on the structure of the Grignard reagent or alkyllithium.
The Reaction of 2-Ethoxy-1,3-oxathiolane with Carbonyl Compounds in the Presence of ZnCl2 or HgCl2
Authors: Tanimoto Shigeo , Jo Shigeo , Sugimoto Toyonari , Okano Masaya
Published: July 2006

In the reaction of 2-ethoxy-1,3-oxathiolane with carbonyl compounds in the presence of ZnCl2 or HgCl2, it has been found that only the breaking of the endocyclic bond (C–O or C–S bond) occurs, while the breaking of the exocyclic C–O bond to give the 1,3-oxathiolan-2-ium ion is unfavorable. This behavior is different from that of 2-ethoxy-1,3-dithiolane, in which the breaking of the endocyclic C–S bond occurs by means of HgCl2 and the exocyclic C–O bond, by means of ZnCl2.
“Anomalous” Raman Polarization as Observed in Anthracene Anion
Authors: Fujimoto Etsuko , Kamisuki Toshio , Maeda Shiro
Published: July 2006

An example of “anomalous” Raman polarization is presented by measuring the polarization dispersion of a resonant depolarized line of anthracene anion near the first absorption band. The molecular origin of the asymmetric Raman tensor is discussed on the basis of a vibronic effect associated with the resonant electronic level.
Kinetic Study of the Penetration of an Anthraquinoid Acidic Dye into Cationic Micelles
Authors: Miyashita Yuuji , Hayano Shigeo
Published: July 2006

The penetration of an anthraquinoid acidic dye into the micelle of a cationic surfactant, hexadecyltrimethylammonium bromide (HTAB), was studied kinetically by the stopped-flow method. The rate-determining step of this process was considered to be the dye reorientation from the micelle surface to its core. The apparent rate constants, kapp, of the dye penetration were determined by the first-order kinetics. The kapp values were a function of the surfactant micellar concentration. Above a certain micellar concentration (CMC) the kapp values become constant. The constant kapp was about 0.37–0.38 s−1 regardless of the total dye concentration. In the lower micellar concentration, there was a linear relationship between the kapp value and the number of the dye molecules which penetrated into a single micelle, n. This n was one of the factors which governed the dye penetration process.
Theoretical Treatment of Solvent Effects on the Frequency Shifts of Electronic Spectra of Anions
Authors: Abe Takehiro
Published: July 2006

A theoretical expression for the spectral solvent shifts of an anion has been presented by assuming the system to consist of a large anion, its counter cations, and numerous solvent molecules. In the zeroth-order all the component particles in the system do not interact with one another. The interaction energy among the particles for the ith-excited state of the system, in which only the anion is in the ith-excited state, is calculated by the second-order perturbation treatment as the sum of electrostatic interaction energies between pairs of particles. The expression derived from the difference between the interaction energies of the ground and excited states of the system contains the dipole-dipole and dipole-induced dipole interaction terms and the dispersion force terms and is somewhat different from the previous results for neutral solutes (Bull. Chem. Soc. Jpn., 38, 1314 (1965)). Effects of the counter cations are discussed. This expression is applied to the spectral shifts of an Eosin-Y2− anion, a Meisenheimer complex, and Janovsky complexes.
The Formation and Electronic Relaxation of Intermolecular Exciplex in the Vapor Phase
Authors: Hanashima Yukio , Itoh Michiya
Published: July 2006

The intermolecular exciplex formation and electronic relaxation of 1,4-dicyanonaphthalene (DCN) with pentamethylbenzene (PMB) in the vapor phase have been studied by means of nanosecond fluorescence spectroscopy. The exciplex formation and decay-rate constants were independent of the excitation energy, while the decay-rate constants of DCN fluorescence was dependent on the excitation energy. The rate constants of the exciplex formation and decay kinetics were discussed in comparison with the collisional relaxation rate of the upper vibrational states.
Magnetic Circular Dichroism Studies of 4,4′-Disubstituted Biphenyls
Authors: Uchimura Hiroyuki , Tajiri Akio , Hatano Masahiro
Published: July 2006

The magnetic circular dichroism (MCD) and ultraviolet (UV) absorption spectra of 4,4′-disubstituted biphenyls were measured. The MCD spectra showed diverse spectral patterns reflecting the natures of the substituent groups. These observed MCD spectra were reproduced by the theoretical calculations based on the Pariser-Parr-Pople-SCF-CI method. The dihedral angles of 4,4′-disubstituted biphenyls were estimated to be about 20° by comparing the observed MCD spectra with the calculated ones. The assignments for the MCD bands of 4,4′-disubstituted biphenyls were given on the basis of these calculations. The substituent effects of biphenyls were interpreted by the use of the coefficients of the configuration interactions.
Asymmetric Transformation of N-Acyl-Dl-amino Acids
Authors: Hongo Chikara , Yamada Shigeki , Chibata Ichiro
Published: July 2006

The asymmetric transformation which converted N-acyl-Dl-amino acids to the desired optically active isomers was studied. N-Acylamino acids such as N-butyrylproline, N-acetylleucine, and N-benzoylphenylglycine were easily racemized in the presence of a catalytic amount of acetic anhydride in melted states or in acetic acid or chloroform solutions. The racemic modification of these N-acylamino acids crystallized as a true racemic mixture suitable for optical resolution by a preferential crystallization procedure under the conditions of racemization. By combining preferential crystallization of the desired enantiomer by seeding from a supercooled melt or a supersaturated solution of a racemic modification and simultaneous racemization of the opposite isomer, N-acyl-Dl-amino acid was partially converted to an optically active isomer and the whole reaction mixture became optically active (10–40% enantiomeric excess).
Use of Propagators in the Hückel Model. IV. Chemical Reactivity in Radiation Field
Authors: Ohmae Takayuki , Nishikawa Kiyoshi , Deguchi Kisaburo , Aono Shigeyuki
Published: July 2006

The propagator approach is applied to chemical reactivity in the presence of radiation field. The Woodward-Hoffmann’s rule in photochemical reactions is generally derived. As an illustrative example, the ring closure or ring opening reactions are discussed.
The Formation Constants and Configurations of the Complexes of Cr(II), Mn(II), Fe(II), Co(II), Cu(II), and Zn(II) with 2,2′-Bipyridine and of Co(II) with 2,2′:6′,2″-Terpyridine in Hexamethylphosphoric Triamide
Authors: Abe Yuriko , Wada Goro
Published: July 2006

The absorption spectra and the first formation constants, K19 of complexes [M(bpy)]2+ (M(II)=Cr(II), Mn(II), Fe(II), Co(II), Cu(II), and Zn(II), bpy=2,2′-bipyridine) were determined spectrophotometrically in hexamethylphosphoric triamide(HMPA). The values of log K1 obtained were 4.61±0.02, 3.10±0.12, 4.82±0.04, 5.84±0.07, 7.33±0.02, and 1.77±0.07 for respective metal ions. The configurations of complexes [M(bpy)]2+ were discussed on the basis of these data. The K1 values of [Cr(bpy)]2+, [Mn(bpy)]2+, [Fe(bpy)]2+, and [Co(bpy)]2+ in HMPA are slightly larger than those in H2O, indicating that their configurations are tetrahedral, whereas the value of [Cu(bpy)]2+ in HMPA is slightly smaller than that in H2O, indicating that its configuration in HMPA is either square planar or tetragonal. It seems that [Zn(bpy)]2+ is octahedral in HMPA, because its K1 value is smaller about three orders of magnitude than that in H2O. In addition, the second formation constant, K2, of complex [Co(bpy)2]2+, and the first and second formation constants of complexes [Co(terpy)]2+ and [Co(terpy)2]2+ (terpy=2,2′:6′,2″-terpyridine) were also determined to be logK2=3.59±0.03 for the bpy complex, and logK1=4.87±0.01 and logK2=3.35±0.01 for the terpy complexes, respectively. These three complexes are concluded to be octahedral.
The Kinetics and Mechanisms of the Racemization of Tris(N,N′-dimethylethanediimine)iron(II)
Authors: Tachiyashiki Satoshi , Yamatera Hideo
Published: July 2006

Tris(N,N′-dimethylethanediimine)iron(II) (trivial name: tris(glyoxal-bis-N-methylimine)iron(II)1)), [Fe(gmi)3]2+, has been resolved for the first time, and its racemization mechanism has been investigated in acid solutions. A mechanism similar to that for tris(2,2′-bipyridine)iron(II) was verified from the acid dependence of the racemization rate. At 69.4 °C, 30% of the racemization proceeded by means of an intramolecular bondrupture mechanism and the remainder by means of an intramolecular twist mechanism. The activation enthalpy and the activation entropy for the twist path were 148(ΔH\eweq⁄kJ mol−1) and 110(ΔS\eweq⁄J K−1 mol−1) respectively. These values were compared with 127 and 114 for [Fe(bpy)3]2+ (bpy=2,2′-bipyridine) and with 119 and 91 for [Fe(phen)3]2+ (phen=1,10-phenanthroline). The racemization rate was larger in organic solvents, increasing in the order water<nitromethane<formamide[Fe(bpy)3]2+>[Fe(gmi)3]2+. A salt effect on the racemization rates was also observed.
The Solvent Extraction of Np(III) by Means of Bis(2-ethyhexyl)hydrogenphosphate in an Octane Solution and the Absorption Spectrum of the Organic Phase
Authors: Kawasuji Isamu , Satô Akiko , Suzuki Shin
Published: July 2006

Tervalent neptunium in an HClO4 solution was extracted by means of bis(2-ethylhexyl)hydrogenphosphate, HDEHP, in an octane solution. The oxidation state of neptunium in the organic phase was determined by spectrophotometry. The intense peak in the absorption spectrum of tervalent neptunium was found at 348 nm, this peak was attributed to the f→d transition. The oxidation rate of the Np(III)–HDEHP complex in an oxygen-free octane solution was about 10%/h.
Kinetics of the Oxidation of N-(2-Hydroxyethyl)ethylenediamine-N,N′,N′-triacetate Complex of Di-μ-oxo-bis[oxomolybdenum(V)] with Hexachloroiridate(IV) and μ-Hyperoxo-bis[pentaamminecobalt(III)] Ions in Aqueous Media
Authors: Sasaki Yoichi , Kawamura Reiko
Published: July 2006

Kinetics of outer-sphere oxidations of [Mo2vO4(hedta)(H2O)]− (1) (H3hedta=N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid) with [IrIVCl6]2− ([H+]=10−5.8–0.10 M (1 M=1 mol dm−3); ionic strength, I=0.1 M (adjusted with LiClO4); 25–45 °C) and with [(NH3)5CoIII(μ-O2(−))CoIII(NH3)5]5+ ([H+]=0.01–0.30 M; I=0.1 and 2.0 M; 10–30 °C), were studied under pseudo-first-order conditions (the reductant in large excess). The following reaction scheme is consistent with the observed rate laws:

1\oversetKa\ightleftharpoons[Mo2vO4(hedta)(OH)]2− (2)+H+

1+[IrIVCl6]2−\xrightarrowk(a)(MovMoVI)+[IrIIICl6]3−

2+[IrIVCl6]2−\xrightarrowk(b)(MoVMoVI)+[IrIIICl6]3−

1+[μ−O2−]5+\oversetKIP(a)\ightleftharpoonsIP(a)(ion-pair)

2+[μ−O2(−)]5+\oversetKIP(b)\ightleftharpoons+IP(b)(ion-pair)

IP(b)\xrightarrowke(b)(MoVMoVI)+[μ−O2(2−)]4+

(MoVMOVI)+oxidant\xrightarrowfast2(Mo(VI)).

At 25 °C and I=0.1 M, Ka, k(a), k(b), kIP(a), KIP(b), and ke(b) are 7.9×10−4 M, 23 M−1 s−1, 1.11×104 M−1 s−1, 40.5 M−1, 1046 M−1, and 2.56 s−1, respectively. Activation parameters for the k(b) path are ΔH\eweq=38±8 kJ mol−1 and ΔS\eweq=−25±29 J K−1 mol−1. The product ke(b)KIP(b)Ka is 7.35×10−2 s−1 at 25 °C and I=2.0 M, and the corresponding activation parameters are ΔH\eweq=67±8 kJ mol−1 and ΔS\eweq=−34±29 J K−1 mol−1. The oxidation of 2 is ca. 104 times as fast as that of 1. The results are compared with the oxidation reactions of other Mo2VO42+-complexes.
Studies on Electronic Spectrum and Electron Spin Resonance of Vanadium(IV) Complexes with Organophosphorus Compounds and High Molecular Weight Amines
Authors: Sato Taichi , Nakamura Takato
Published: July 2006

In the extraction of vanadium(IV) from aqueous solutions containing hydrochloric acid and/or a mixture of hydrochloric acid and lithium chloride by bis(2-ethylhexyl) hydrogenphosphate (DEHPA; HX), trioctylmethylammonium chloride (Aliquat-336), trioctylamine (TOA), trioctylphosphine oxide (TOPO) and tributyl phosphate (TBP), the complexes formed in the organic phases have been examined by spectrophotometry and electron spin resonance spectroscopy. It is found that in the extraction by DEHPA, the vanadium in the organic phase exists as the monomeric species, VO(X2H)2, or the polymeric one, (VOX2)n, and that in the extractions by Aliquat-336, TOA, TOPO, and TBP, tetravalent vanadium complexes are stable in the organic phases extracted from a mixed solution of hydrochloric acid and lithium chloride, while complexes containing pentavalent vanadium and VOV4+ ions are formed in the organic phases extracted from hydrochloric acid solutions.
Synthesis and Magnetic Properties of Octaethylporphyrinatoiron(III) Perchlorate and Its Mono(amine) Adduct. Intermediate-spin State (S=3/2) Model for Ferricytochrome c′
Authors: Ogoshi Hisanobu , Sugimoto Hiroshi , Watanabe Ei-ichi , Yoshida Zen-ichi , Maeda Yutaka , Sakai Hiroshi
Published: July 2006

Octaethylporphyrinatoiron(III) perchlorate, its mono(pyridine) and mono(4-substituted pyridine) adducts and bis(tetrahydrofuran)octaethylporphyrinatoiron(III) perchlorate were prepared to mimic the ferricytochrome c′. Magnetic susceptibilities, M\ddotossbauer spectra, and ESR spectra have been measured. Magnetic properties in the crystalline state revealed; (i) Octaethylporphyrinatoiron(III) perchlorate, OEPFeIIIClO4 and bis(tetrahydrofuran)octaethylporphyrinatoiron(III) perchlorate, OEPFeIII(THF)2ClO4 are of intermediate-spin state (S=3/2). (ii) Magnetic susceptibilities and M\ddotossbauer parameters of mono (pyridine) and mono(4-substituted pyridine)octaethylporphyrinatoiron(III) perchlorate, OEPFeIII(4-X-py)ClO4 [X=CHO, X=CN, and X=H] are rather similar to those of the low-spin(S= 1/2) states. Absorption spectra showed that octaethylporphyrinatoiron(III) perchlorate is of intermediate-spin state in dichloromethane solution, but of high spin state in acetone solution. Close spectral resemblance of these complexes to the ferricytochrome c′ at physiological pH suggests that the latter is in intermediate-spin state.
Preparation and Physicochemical Properties of Tervalent Cobalt Complexes of Porphyrins
Authors: Sugimoto Hiroshi , Ueda Nobuhiro , Mori Masayasu
Published: July 2006

Tervalent cobalt complexes of octaethylporphyrin (OEP) and tetraphenylporphyrin (TPP), [CoIII(OEP)(H2O)2]X (X=ClO4, BF4), [CoIII(OEP)(THF)2]ClO4, [CoIII(TPP)(H2O)2]X (X=ClO4), and [CoIII(TPP)(H2O)Y] (Y=Cl, Br, SCN, N3) were synthesized. Molecular weight measurements indicate that only [CoIII(TPP)(H2O)2]BF4 and [CoIII(TPP)(H2O)2]ClO4 aggregate at higher concentrations in chloroform. In polar solvents such as methanol, all are monomeric. In nonpolar solvents, all the complexes show Soret bands at shorter wavelengths and somewhat paramagnetic 1H NMR spectra; these anomalies are absent in polar solvents. Tetrafluoroborates and perchlorates react with ethyl vinyl ether smoothly to form 2,2-diethoxyethylcobalt(III) complexes which are easily converted to formylmethylcobalt(III) complexes. 1H NMR and absorption spectra of the amine adducts prepared in this study, [CoIII(OEP)(L)2]ClO4 (L=pyridine, 2-methylimidazole) and [CoIII(TPP)(L′)2]ClO4 (L′=pyridine, 4-cyanopyridine, 4-methylpyridine), indicate that the two amine molecules coordinate to the central cobalt atom. As regards redox potentials for the Co(III)/Co(II) couple as measured by cyclic voltammetry, the cobalt(III) porphyrins are categorized into three groups: (i) BF4 and ClO4 salts with redox potentials at about 0.7 V; (ii) halides and pseudohalides with those at 0.2–0.3 V; and (iii) bis(amine) adducts with those at −0.3–+0.1 V. In polar solvents, however, the redox potentials of (i) and (ii) are very similar to one another.
Neighboring Effect of Mercapto Group in the Silver Ion-promoted Aminolysis of S-Monoacyldihydrolipoamide
Authors: Nambu Yoko , Endo Takeshi , Okawara Makoto
Published: July 2006

The aminolysis of N-benzyl-8-S-(p-nitrobenzoyl)dihydrolipoamide has been enhanced remarkably with excess silver perchlorate compared with that of N-benzyl-S,S′-bis(p-nitrobenzoyl)dihydrolipoamide. From the results of kinetics and complex formation followed by UV and IR spectra, the large enhancement in the reaction has been concluded to be derived from the activation of acyl group through the binding of two equivalents of silver ion to the neighboring mercapto group.
Electrochemical Conjugate Additions of the Allyl Groups in Substituted Allyl Halides to α,β-Unsaturated Esters
Authors: Satoh Shohei , Suginome Hiroshi , Tokuda Masao
Published: July 2006

Electrolysis of allyl halides and diethyl fumarate (2) in N,N′-dimethylformamide containing 0.2 M† tetraethylammonium tosylate gave a conjugate addition product, ethyl 3-(ethoxycarbonyl)-5-hexenoate, in a moderate yield. The electrochemical reaction of 1-chloro-3-methyl-2-butene (4) with 2, that of allyl chloride 4 with methyl crotonate (6), and that of methyl 4-halo-2-butenoate with 2 likewise gave the corresponding conjugate addition products, ethyl 3-(ethoxycarbonyl)-6-methyl-5-heptenoate, methyl 3,4,4-trimethyl-5-hexenoate, and ethyl 3-(ethoxycarbonyl)-4-(methoxycarbonyl)-5-hexenoate, respectively. The addition reaction of 4 to 2 takes place at the α-carbon terminus of 4 exclusively, whereas the addition of 4 to 6 at the γ-carbon terminus of 4. These regioselectivities of the additions and pathways of the reactions are discussed.
Reduction by a Model of NAD(P)H. 35. Spectroscopic Detection of Charge-transfer Intermediate
Authors: Ohno Atsuyoshi , Yamamoto Hiroyuki , Oka Shinzaburo
Published: July 2006

4,4-Disubstituted 1,4-dihydropyridine derivatives are employed as models of NAD(P)H. Electronic and ESR spectroscopies have proved that these models form charge-transfer complexes with certain substrates, which supports a mechanism of the reduction with 1,4-dihydronicotinamide derivatives to be initiated by initial electron-transfer.
Synthesis and Kinetic Investigation of the Atropisomerization of meso-Tetra(2-cyanophenyl)porphine
Authors: Hatano Keiichiro , Anzai Kazunori , Kubo Tadashi , Tamai Shoko
Published: July 2006

Tetra(2-cyanophenyl)porphine (ToCNPP) has been synthesized and isolated into the four respective atropisomers. The rotation of a cyanophenyl ring about the bond to the methine carbon of the porphyrin leads to interconversion reactions among the isomers. The isomerization reactions have been studied kinetically by the separation and quantitative measurement of each isomer on thin layer chromatography plates. The results show that the free energy of activation for the hindered rotation is an average of ΔG*=110 kJ/mol at 50 °C. This is the highest barrier ever measured in similar porphyrin atropisomers. The apparent interaction between adjacent cyano groups is observed. The energy of interaction is estimated to be about 2.0 kJ per mole unit of interaction.
Asymmetric Synthesis of Axially Dissymmetric 1,1′-Binaphthyls via an Intramolecular Ullmann Coupling Reaction of (R)- and (S)-2,2′-Bis(1-bromo-2-naphthylcarbonyloxy)-1,1′-binaphthyl
Authors: Miyano Sotaro , Tobita Masayuki , Hashimoto Harukichi
Published: July 2006

An Ullmann reaction of the chiral bifunctional substrate containing two 1-bromo-2-naphthyl moieties, (S)-2,2′-bis(1-bromo-2-naphthylcarbonyloxy)-1,1′-binaphthyl, gives an intramolecularly coupled 12-membered cyclic diester in a 36% isolated yield. The intramolecular coupling reaction proceeds with virtually complete dia-stereoselectivity to induce S-chirality into the newly formed bond between the two naphthyl units.
The Biotransformation of Foreign Substrates by Tissue Cultures. I. The Hydroxylation of Linalool and Its Related Compounds with the Suspension Cells of Nicotiana tabacum
Authors: Hirata Toshifumi , Aoki Tadashi , Hirano Yoshio , Ito Takashi , Suga Takayuki
Published: July 2006

It was found that the tissue cultures of Nicotiana tabacum “Bright Yellow” possess the ability to transform selectively the trans-methyl group in the 3-methyl-2-butenyl group of such foreign substrates as linalool and the related compounds into the hydroxymethyl group. Also, the cultures were found to have the ability to hydrolize the acetoxyl group of their acetates.
Muramyl Dipeptide Derivatives with Multiprenylacetyl Group. Synthesis and Immunological Activities
Authors: Fukuda Tsunehiko , Kobayashi Shigeru , Yukimasa Hidefumi , Terao Shinji , Fujino Masahiko , Shiba Tetsuo , Saiki Ikuo , Azuma Ichiro , Yamamura Yuichi
Published: July 2006

Several linear and branched all-trans-multiprenylacetic acids were synthesised, and introduced to the 6 position of the sugar moiety of muramyl dipeptide and its analog, via an amino acid as a linking unit. Compared with the saturated stearoyl derivative, all the compounds having a multiprenylacetyl group exhibited more potent adjuvant activity on the induction of delayed-type hypersensitivity to N-acetyl-3-(4-arsonophenylazo)-l-tyrosine. The derivatives with larger branched side chains tended to have increased activity.
Neighboring Group Participation in Solvolysis. XIII. Kinetic Isotope Effects in Solvolysis of 2-Arylethyl p-Nitrobenzenesulfonates
Authors: Yukawa Yasuhide , Ando Takashi , Token Katsuo , Kawada Mitsuru , Matsuda Kenichi , Kim Seung-Geon , Yamataka Hiroshi
Published: July 2006

Carbon-14 kinetic isotope effects (k12⁄k14) were determined for the solvolysis of phenethyl (1a) and 2-(p-methoxyphenyl)ethyl (1b) p-nitrobenzenesulfonates in acetic, formic, and trifluoroacetic acids. Phenyl-1 carbon effects were all in the range of 1.02–1.04 except for the acetolysis of 1a (k12⁄k14=1.005), which has been proved to proceed mainly via the aryl unassisted (ks) pathway. In all other reactions, which proceed mainly via the aryl assisted (kΔ) pathway, the phenyl-1 carbon apparently changes its bonding in the transition states. A large α-carbon effect (1.131) and a small β-carbon effect (1.013) as well as a medium phenyl-1 effect (1.022) were observed for the formolysis of 1b, whose mechanism is thought to be exclusive kΔ without troublesome ion-pair return. These observations, together with α- and β-deuterium effects reported already, enabled us to describe the qualitative nature of the bridged transition-state structure of the kΔ pathway, i.e., advanced Cα–O bond rupture, slight Cα–CPh−1 bond formation, Cα–Cβ double bond formation, slight Cβ–CPh−1 bond rupture, and breakdown of aromaticity at the phenyl-1 position. These characteristics are very similar to those of the phe-nonium ion.
Circular Dichroism of Chromium(III) Complexes. VII. Circular Dichroism in the Spin-forbidden Transitions of cis-[Cr(N2)(O)4] Type Complexes with Ethylenediaminetetraacetate Analogues
Authors: Kaizaki Sumio , Mori Hisako
Published: July 2006

Potassium (2S,4S)-2,4-pentanediaminetetraacetatochromate(III) monohydrate was newly prepared and was found to be formed stereospecifically with a Λ(ΛΔΛ) absolute configuration as has been revealed for the corresponding Co(III) complex. The circular dichroism spectra in the spin-forbidden transitions of this new complex along with the known analogues, (−)589-ethylenediamine-N,N′-diacetato-N,N′-dipropionatochromate(III) and (+)589-(S,S)-2,2′-(ethylenediimino)disuccinatochromate(III) complexes, were measured and discussed in comparison with those in the first spin-allowed transitions on the basis of the theoretical relations between the rotational strengths for the spin-forbidden and the spin-allowed transitions in trigonal and tetragonal fields.
Kinetics and Mechanism of Reduction of Hexacyanoferrate(III) by Sodium Tetrahydroborate
Authors: Bhattacharjee Mitra , Bhattacharjee Apurba K , Mahanti Mahendra K
Published: July 2006

A kinetic investigation of the reduction of hexacyanoferrate(III) by sodium tetrahydroborate in buffered aqueous solution has been carried out. The rate of the reaction is proportional to the concentration of both, tetrahydroborate and hydrogen ions. The effect of the addition of some inorganic salts has been studied. The temperature has been varied, and the Arrhenius parameters have been evaluated. The rate of hydrolysis of tetrahydroborate has been separately studied. It has been observed that the activation energies for both the reactions—the reduction of hexacyanoferrate(III) and the hydrolysis of tetrahydroborate—are equal. A plausible mechanism for the reduction of hexacyanoferrate(III) has been proposed.
The Rate Constants of the Reactions of Hydrogen and Oxygen Atoms with Fluoroethylenes
Authors: Sugawara Ko-ichi , Okazaki Kiyoshi , Sato Shin
Published: July 2006

The pulse-radiolysis technique combined with the atomic resonance absorption method was used for the measurement of the room-temperature rate constants of the reactions of hydrogen and oxygen atoms with fluoroethylenes. The rate constants obtained at 298±2 K are as follows, in units of 10−12 cm3 molecule−1s−1 (1 cm3molecule−1 s−1=6.022×1017 m3 mol−1s−1). The standard deviation is within 10%.

(Remark: Graphics omitted.)

The correlation between the rate constants and the reactivity index calculated by the INDO method is discussed.
Pressure Effects on the Reaction of Hydroxide Ion with Sodium 2-Bromoethanesulfonate
Authors: Asano Tsutomu , Okada Toshio
Published: July 2006

Kinetic effect of pressure on the reaction of hydroxide ion with 2-bromoethanesulfonate was studied. The reaction was moderately accelerated by pressure and the activation volumes suggest that the presence of the negative charge on the sulfonato group does not produce any measurable solvation increase during activation.
The Separation of Aluminium Trichloride and Iron Trichloride by Selective Hydrogen Reduction
Authors: Shoji Yuichi , Matsuzaki Ryoko , Saeki Yuzo
Published: July 2006

When a gaseous mixture generated by heating a mixture of AlCl3 and FeCl3 (<19wt%) was introduced, with a hydrogen stream, into a reaction zone held at various temperatures, the iron content in the sublimate decreased markedly above 300 °C; AlCl3 containing less than 10ppm of iron was obtained at 600 °C.
The Reductive Coupling of Organic Halide Using Hydrazine and a Palladium Catalyst. II. Homocoupling of 1-Iodoalkanes
Authors: Nakajima Riichiro , Morita Kazuhiro , Hara Tadashi
Published: July 2006

The hydrogenolysis and dimerization of iodoalkanes were catalyzed by Pd in the presence of an appropriate reducing agent. Hydrazine was found to be effective for the coupling of 1-iodoeicosane to give tetracontane, C40H82, in a 74% yield. The yield of the coupling product decreased with the decrease of the number of the carbon atoms in the 1-iodoalkanes. Both alkylhydrazines and alkenes were shown not to take part in the reaction as a reaction intermediate.
The Synthesis of New Electron Acceptors, 9,10-Bis[cyano(ethoxycarbonyl)methylene]-9,10-dihydroanthracene and 10-[Cyano(ethoxycarbonyl)methylene]-9-anthrone
Authors: Nogami Takashi , Kanda Yasuhiro , Tanaka Hidekazu , Mikawa Hiroshi
Published: July 2006

We synthesized two new electron acceptor molecules. Their electron affinities were estimated by measuring the charge-transfer absorption spectra with three donor molecules in a 2-methyltetrahydrofuran solution. The former molecule was estimated to have an electron affinity comparable to 1,3,5-trinitrobenzene, and the latter, to m-dinitrobenzene.
A Convenient Synthesis of 3-(Diethoxymethyl)alkanals
Authors: Saigo Kazuhiko , Okagawa Shuji , Nohira Hiroyuki
Published: July 2006

3-(Diethoxymethyl)alkanals were obtained in moderate yields by the diisobutylaluminium hydride reduction of ethyl 3-(diethcxymethyl)alkanoates, which were simply synthesized in one pot by the copper (II)-catalyzed reaction of ethyl diazoacetate with 1-trimethylsiloxy-1-alkenes, followed by the ring cleavage of the resulting cyclopropanes with concentrated sulfuric acid in the presence of triethyl orthoformate.
Preparation of Dl-Alanine by the Reaction of (±)-2-Chloropropionic Acid with Aqueous Ammonia under Pressure
Authors: Ogata Yoshiro , Inaishi Morio
Published: July 2006

The effects of experimental conditions (molar ratio of reactants, concentration, temperature, and pressure) on the yield of Dl-alanine produced by the reaction of (±)-2-chloropropionic acid with aqueous ammonia have been studied. Molar ratio of NH3: CH3CHClCO2H (ca. 10:1) much lower than that reported in the literature (68:1) can give a comparable yield (ca. 78%) by the reaction under pressure at 70 °C for 5 h, a much shorter time than that reported in the literature (over 96 h). Addition of ammonium carbonate does not increase the yield against the literature.
Theory of Molecular Deformation Due to the Vibronic Interaction between Two Closely-spaced Electronic Levels. II. Green’s Function Treatment
Authors: Nishikawa Kiyoshi , Kimura Minoru , Aono Shigeyuki
Published: July 2006

Vibronic interaction between two closely-spaced electronic levels was investigated by use of the temperature Green’s function. A Green’s function version for the mean field approximation was derived which is capable of reproducing results obtained in the preceding work. The spectrum of phonon in the normal phase was then calculated and the critical (strictly speaking, characteristic, since we are dealing with a finite system) temperature Tc was obtained where the phonon becomes completely soft causing lattice distortion. The fluctuation effect was investigated and the mean field theory was examined for its applicability. When the level spacing is comparable to or larger than the value of the electron-phonon coupling constant, the mean field theory is satisfactory, but when the two levels are nearly degenerate, it is not so good because the problem in question is in the regime involving extremely strong coupling.
Thermal Decomposition Studies of Ammonium Heptamolybdate(6–) Tetrahydrate by Means of High-temperature Oscillating X-Ray Diffraction with a Rotating Anode Type Large Capacity Generator
Authors: Isa Kimio , Ishimura Hajime
Published: July 2006

Ammonium heptamolybdate(6–) tetrahydrate (AHM) was studied by means of high temperature oscillating X-ray diffraction with a large capacity generator of 12 kW. Experimental conditions were determined precisely. It was possible to settle the maximum value of diffracted patterns, and the inherited error was about 1.5%. Thermal decomposition of AHM was studied by means of TG-DTA, but the first decrease of TG could not be explained as a single process of decomposition. Moreover it could also not be explained by means of high-temperature oscillating X-ray diffraction with a standard generator. However, with a large capacity generator, the first decrease of TG could be explained to be a convolution of three steps of decomposition. Moreover, the second and third steps could be explained by observing the microscopic structural change. In a high-temperature oscillating XRD, (heating rate 2 °C/min), a peak temperature of 96 °C was recognized, which had not been reported before. Also from 110 °C to 226 °C, a row of the small peak has been found. Finally, the first stage of decomposition which was thought to be a single step in the experiment of TG-DTA, could be seperated into three steps. Moreover, the onset and offset temperatures of changes of characteristic diffraction intensity are determined. It was proved that high-temperature oscillating X-ray diffraction is a powerful analysing method in thermal analysis.
The Phosphorescence Spectra of Methyl-substituted 9,10-Anthraquinones in Solutions at 77 K
Authors: Kuboyama Akira , Matsuzaki Sanae Y
Published: July 2006

The phosphorescence spectra and their lifetimes of 9,10-anthraquinone and its 2-methyl and 2,3-dimethyl derivatives in various kinds of glassy solutions at 77 K have been obtained. In the non-hydrocarbon solutions, 2-methylanthraquinone shows, in most cases, a dual phosphorescence, consisting of a nπ* phosphorescence and a ππ* phosphorescence with different lifetimes, while 2,3-dimethylanthraquinone shows a very broad ππ* phosphorescence spectrum. The quinone-solvent interactions and the relative positions of the close-lying 3nπ* and 3ππ* levels of these quinones are discussed on the basis of the experimental results.
Kinetics and Mechanism of 1,4-Cycloaddition between Tetracyanoethylene and Styrenes. II. Effect of Para Substituents
Authors: Uosaki Yasuhiro , Nakahara Masaru , Osugi Jiro
Published: July 2006

The 1,4-cycloaddition of TCNE to p-methyl-, p-chloro-, and p-bromostyrenes by way of the EDA complex has been studied in chloroform at 25 °C by the spectrophotometric method. The Hammett correlation obtained from the kinetic data provides −5.5±0.2 as the reaction constant ρ. The negative value is large in magnitude relative to other common 1,4-cycloadditions, suggesting some large partial charges in the rate-determining transition state. A linear correlation between the logarithmic forms of the reaction rate and the EDA-complex formation constant is in favor of the reaction scheme where the complex is on the pathway of the cycloaddition.
A Theoretical Approach to the Dielectric Relaxation of Alcohol Solutions. II. The Effect of Dilution with Inert Solvents on the Principal Relaxation Times of Primary Alcohols
Authors: Minami Ryuichi , Itoh Koichi , Takahashi Hiroaki , Higasi Keniti
Published: July 2006

The concentration dependence of the principal relaxation times, τp, of primary alcohol/inert solvent solutions are analyzed based on the equation,

τp=2(1+KxA)τH,

where xA is the alcohol mole fraction, K the equilibrium constant corresponding to the formation of hydrogen bonded multimers, and τH the time constant characterizing the rotational activation process of the terminal OH groups of the multimers. By applying Eyring’s absolute rate theory to the activation process, we calculated τP as a function of temperature and alcohol concentration. The results reproduce quite well the τP values observed for the ethanol/cyclohexane, 1-hexanol/cyclohexane, and 1-propanol/benzene solutions.
The Application of Polarization Coherent Anti-Stokes Raman Spectroscopy to the Line-shape Analysis of Liquid Sample
Authors: Igarashi Ryosaku , Iida Fumisato , Hirose Chiaki , Fujiyama Tsunetake
Published: July 2006

The polarization CARS spectra were observed for a few typical Raman lines at various experimental settings. Based upon the observed and calculated spectra, the usefulness and the validity of the polarization CARS method for the study of the overlapped Raman lines observed for a condensed system have been emphasized.
Kinetic Studies of the Electron Transfer Reactions in Iron(II) and Iron(III) Systems. XI. Electron Transfer Reaction between Aquairon(II) and Tris(1,10-phenanthroline)iron(III) in Water Mixed with Methanol, Ethanol, 1-Propanol, and Ethylene Glycol
Authors: Wada Goro , Takahashi Kumiko , Isobe Masako
Published: July 2006

The electron transfer reaction Fe2+aq+Fe(phen)33+→Fe3+aq+Fe(phen)32+ has been investigated in order to find out the influence of the dielectric nature of media on the reaction rates, by the method of stopped-flow spectrophotometry. As the reaction media, were used aqueous mixtures with various alcohols, such as methanol, ethanol, 1-propanol, and ethylene glycol at their various mole fractions x. The second-order rate constant k grows larger approximately linearly with the increase in x, in a sequence: methanol<ethylene glycol<ethanol<1-propanol. When In k is plotted against D−1 (the reciprocal dielectric constant), all points come together on a single straight line with a positive slope, indifferent to the kinds of the alcohols used. This fact suggests that the reaction proceeds through three successive elementary processes, Fe2+aq+Fe(phen)33+\overseti→[Fe(H2O)62+·Fe(phen)33+]\oversetii→[Fe(H2O)63+·Fe(phen)32+]\oversetiii→Fe3+aq+Fe(phen)32+, in which Process i is the formation of an outer-sphere ion-pair between two reacting ions, Process ii the intramolecular electron transfer in the intermediate complex, and Process iii the separation of the ion-pair into the product ions, the last being the rate-determining step. The reaction scheme is compared with that of the reaction Fe2+aq+Fe(OH)2+→Fe(OH)2++Fe2+aq, where the first step of the ion-pair formation is rate-determining.
Equilibrium and Structure of Deprotonated Bis(glycylglycinato)copper(II) in Aqueous Solution
Authors: Nakasuka Noriyuki , Makimura Kenya , Kajiura Hiroko
Published: July 2006

Potentiometric titration was carried out at 25.0±0.1 °C and at an ionic strength of 1.00 mol dm−3 in sodium perchlorate for a system of copper(II)–dipeptide(A)–a second ligand(B) in an aqueous solution to obtain the formation constants of mixed ligand complexes CupHqArBs. A was glycylglycine or glycinamide, and B was ethylamine or 2-aminoethanol. The structure of CuH−1A2 in solution is discussed. It was found that the ligand A acts as a unidentate ligand and the other deprotonated H−1A as a terdentate one for the most part; only about 2% of this complex are in a bidentate-bidentate form.
Multiple Paths for Photo-methylation and -methoxylation of Methyl 2-Pyridinecarboxylate in Methanol
Authors: Sugiyama Toru , Furihata Toshikazu , Takagi Kyoko , Sato Michitsugu , Akiyama Shinya , Satô Gen P , Sugimori Akira
Published: July 2006

UV-irradiation of methyl 2-pyridinecarboxylate in methanol in the absence of added acid brings about methylation at the 5-position via the excitation of C=O of the ester group, while in the presence of added acid the 4-position of the pyridine ring is methylated. In the presence of sulfuric acid methoxylation via an excimer is dominant over methylation. In the presence of hydrochloric acid methylation via chlorine atoms becomes dominant.
Application of the Water-gas Shift Reaction. I. Hydrogenation and Hydroformylation Reactions of Olefins with Carbon Monoxide and Water Catalyzed by Rhodium Phosphine Complexes
Authors: Okano Tamon , Kobayashi Teruyuki , Konishi Hisatoshi , Kiji Jitsuo
Published: July 2006

The hydrogenation of methyl crotonate with CO and H2O is efficiently catalyzed by RhH2(O2COH)[P(i-Pr)3]2 or [RhCl(C7H8)]2/P(i-Pr)3/n-BuLi (C7H8=norbornadiene). Both catalyst precursors are shown to form the same active species; transRh(OH)(CO)[P(i-Pr)3]2. The catalytic activity of the system ([RhCl(C7H8)]2/phosphine/n-BuLi) increases with increase of the basicity of the phosphine ligands (phosphine=P(i-Pr)3>P(n-Bu)3>PPh(i-Pr)2>PPh2(i-Pr)>PPh3). This reaction is also applicable to the hydrogenation of the C=C bond of electronwithdrawing olefins and the C=O bond of ketones and aldehydes. Interestingly, the catalysis for the C=C bond, to which less electron-withdrawing groups are attached, gives dominantly aldehydes due to hydroformylation. The mechanism is also discussed.
α,β-Unsaturated Carboxylic Acid Derivatives. XXI A Novel Synthesis of α-Dehydroamino Acid Derivatives by the Arbusov Reaction of α-Phosphoranylideneamino-2-alkenoates
Authors: Shin Chung-gi , Yonezawa Yasuchika , Watanabe Kazuhiro , Yoshimura Juji
Published: July 2006

The reaction of ethyl 2-azido-2-alkenoate with organic tervalent phosphorus reagent gave the corresponding 2-phosphoranylideneamino derivative as an stable intermediate. This transformed gradually at room temperature, or immediately on a silica-gel column to give the corresponding 2-phosphinylamino derivative in a good yield. The Arbusov reaction of the intermediate which occurred during the transformation was found to be applicable for the other azido olefins. The formation mechanism and the configurational determination of the new products are discussed.
Synthesis of Macrocyclic [n.n.n](1,3,5)Cyclophane Polylactones
Authors: Kanishi Masayuki , Kunizaki Jun-ichi , Inanaga Junji , Yamaguchi Masaru
Published: July 2006

A series of new macrocyclic cyclophane polylactones has been synthesized by one-step condensation of the appropriate tri(acid chloride)s and triols using the silver cyanide-promoted esterification procedure.
Restricted Rotation Involving the Tetrahedral Carbon. XL. Barriers to Rotation of 9-(1-Methyl-2-propenyl)triptycenes
Authors: Kikuchi Hiromi , Hatakeyama Shiro , Yamamoto Gaku , Oki Michinori
Published: July 2006

9-(1-Methyl-2-propenyl)triptycenes were prepared by addition of substituted benzynes to 9-(1-methyl-2-propenyl) anthracene or Dields-Alder addition of p-benzoquinone to the anthracene followed by enolization and methylation. The crystals of these compounds were pure or enriched isomers of the possible rotamers but the rotational barriers were too low to obtain every possible isomer in a pure state at room temperature. The barriers to rotation were obtained by both classical and dynamic NMR methods. These values were almost the same when the peri-substituent was either a chloro or a bromo but were definitely lower when the peri-substituent was a methyl or a methoxyl.
Prediction of Adsorption Isotherms of Organic Compounds from Water on Activated Carbons. II. Relative Adsorbabilities of Elements
Authors: Abe Ikuo , Hayashi Katsumi , Kitagawa Mutsuo
Published: July 2006

In order to predict the adsorbability of organic compounds out of water onto activated carbon, the contribution of individual atoms to the adsorbability is calculated. The contribution of the carbon atom is positive, that of nitrogen and oxygen atoms is negative, and that of the hydrogen atom is very small.
A Short-step Synthesis of 4-Hydroxyproline
Authors: Hara Junko , Inouye Yoshinobu , Kakisawa Hiroshi
Published: July 2006

The reaction of N-benzyl-, N-diphenylmethyl-, or N-(1-phenylpropyl)-α-methoxycarbonylmethanimine N-oxide newly prepared with acrylaldehyde in benzene, followed by hydrogenolysis over palladium hydroxide and by acid hydrolysis, gave 4-hydroxyprolines.
The Synthesis of 2,5-Dialkylcyclopentanones from Aliphatic Aldehydes and Formaldehyde
Authors: Watanabe Yoshihisa , Sakamoto Fukashi , Shim Sang Chul , Mitsudo Take-aki
Published: July 2006

Aliphatic aldehydes react with formaldehyde in the presence of dimethylamine hydrochloride at 200 °C to form 2,5-dialkylcyclopentanones in moderate yields. Propanal, butanal, and pentanal give 2,5-dimethyl-, 2,5-diethyl-, and 2,5-dipropylcyclopentanone respectively, but ethanal gives only a tarry material.
Photoelectrochemical Properties of CdSnO3 and LaRhO3 Electrodes in Aqueous Solutions
Authors: Yoneyama Hiroshi , Ohkubo Toshikazu , Tamura Hideo
Published: July 2006

CdSnO3 sinter electrodes work as n-type photoanodes with a high electrochemical stability in alkaline solutions. A thin film LaRhO3 electrode prepared on a substrate platinum plate shows p-type photoresponse in aqueous solutions, giving rise to the hydrogen evolution with a fair stability. The threshold wavelength beyond which no photoresponse appears is ca. 700 nm for the former and 950 nm for the latter electrode.
The Character of Acid Sites on the Gypsum Surface
Authors: Okazaki Susumu , Yamazaki Mituo
Published: July 2006

The maximum value in the number of acid sites per unit of surface area of the gypsum formed in the reaction between Ca(NO3)2 and H2SO4 was observed at the heat-treatment temperature of 200 °C, corresponding to the dehydration temperature for the change from its hemihydrate form to soluble anhydrite. The IR-absorption spectra of the gypsum showed no bands assignable to isolated OH groups or Ca–OH species. The IR spectra of the pyridine adsorbed on the gypsum showed only the bands due to Lewis-acid sites. The gypsum heat-treated at temperatures lower than 500 °C showed catalytic activities for the double-bond isomerization of 1-butene. The cis-/trans- ratio of 2-butene was 2–2.5, showing that the catalytic activity was due to Lewis acid, not to Brönsted acid. The isomerization of cyclopropane to propene was scarcely promoted by the gypsum at 250 °C. This fact is another indication of the absence of Brönsted acid sites on the heat-treated gypsum. Most of the weak Lewis acid sites (H0≤+4.8) were ascribable to exposed Ca2+ ions surrounded by monodentate sulfate ions on the surface of metastable anhydrite III-CaSO4.
The Aluminium(III) Ion-assisted Aquation of the Pentaammine fluorochromium(III) Ion
Authors: Iida Masayasu , Yamatera Hideo
Published: July 2006

The aquation of the pentaamminefluorochromium(III) complex was found to be assisted by the aluminium ion. The observed pseudo-first-order rate constant, kobsd, can be written approximately as: kobsd=kAl[Al3+] (kAl=7.5×10−4 dm3 mol−1 s−1 at 35 °C, pH 3.0, I=2.0 mol dm−3). The rate constant decreased with an increase in the hydrogen-ion concentration, and this hydrogen-ion dependence was explained by assuming that the attack of aluminium ions on CrF(NH3)52+ was blocked by the protonation of the fluoro ligand. The analysis of the experimental results gave 3.0±0.1 for the logarithm of the protonation constant. The effects of ClO4− and Co(CN)63− on the reaction rate were explained by considering the formation of ion-pairs between the anions and the reacting cations.
Kinetics of the Formation of Alkoxy-derived Barium Metasilicate
Authors: Yamaguchi Osamu , Tominaga Kazuhiro , Shimizu Kiyoshi
Published: July 2006

Amorphous BaSiO3 or a mixture of this and BaSiO3·H2O was formed by the simultaneous hydrolysis of barium and silicon alkoxides. The temperature of hydrolysis and the time of aging influence the crystallization of amorphous BaSiO3 into BaSiO3·H2O. The decomposition of BaSiO3·H2O into crystalline BaSiO3 was analyzed by isothermal thermogravimetry. Decomposition isotherms were constructed by the equation −ln(1−α)=kt and the activation energy was determined as 143.5 kJ/mol. The kinetics of crystallization of amorphous into crystalline BaSiO3 was interpreted by the equation 1−(1−α)1⁄3=kt. Activation energies were 276 kJ/mol and 204 kJ/mol for the initial and final stages, respectively.
Synthesis of Four Stereoisomers of γ-Hydroxyarginine via the Corresponding Isomers of γ-Hydroxyornithine
Authors: Mizusaki Koichi , Makisumi Satoru
Published: July 2006

Diastereomeric γ-hydroxy-l- and d-ornithines were prepared by reduction of the corresponding γ-oxoornithines synthesized from l- and d-histidines with sodium borohydride. The isomeric composition of the product obtained from l-histidine was estimated to be 68% erythro and 32% threo isomers and that of the product from d-histidine 65% erythro and 35% threo isomers by automatic amino acid analysis after conversion of the basic amino acids into neutral Nδ-acetyl derivatives. The diastereoisomers of each γ-hydroxyorni thine were separated by chromatography on a Dowex 50 column, four optically active isomers being isolated as their hydrochlorides in crystalline state. Guanidination of these isomers with 1-amidino-3,5-dimethylpyrazole nitrate (ADPN) gave the corresponding optically active isomers of γ-hydroxyarginine which were isolated as crystalline hydrochlorides. Erythro-γ-hydroxy-l-arginine hydrochloride shows a specific rotation which agrees very closely with that of natural product of γ-hydroxyarginine.