bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Dihydrobenzofuran Derivatives from Substituted p-Benzoquinones
Authors: Kozuka Tadashi
Published: July 2006

A series of p-benzoquinones having an ester functional group in the α position of alkyl side chains was prepared. Irradiation of these quinones, except for methyl 3-methyl-2-(4-methyl-3,6-dioxo-1,4-cyclohexadienyl)-butyrate (3e), rapidly gave methyl 3-substituted 2,3-dihydro-5-hydroxybenzofuran-2-carboxylate in fairly good yields, and it was found that rearrangement of the side chain occurred concomitantly. Photolysis of quinone 3e afforded methyl 2-(2,5-dihydroxy-4-methylphenyl)-3-methyl-3-butenoate as the major product. An intermediate was postulated to account for the isolated photoproduct.
Intramolecular 1,3-Dipolar Cycloaddition of Nitrilimines Bearing Alkenyl Groups
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Ishikawa Susumu , Teramura Kazuhiro
Published: July 2006

The reaction of the arylhydrazones of some 2-(alkenyloxy)benzaldehydes(or 1-naphthaldehydes) with Pb(OAc)4 leads, via the nitrilimine intermediates, to intramolecular 1,3-dipolar cycloadducts, 3-substituted 2-aryl-2,3,3a,4-tetrahydro[1]benzopyrano(or naphtho[1′,2′:5,6]pyrano)[4,3-c]pyrazoles, in 10–80% yields. In the presence of an excess of Pb(OAc)4, these cycloadducts were dehydrogenated to 3-substituted 2-aryl-2,4-dihydro[1]benzopyrano(or naphtho[1′,2′:5,6]pyrano)[4,3-c]pyrazoles. In the presence of a large excess of Pb(OAc)4, some of the pyrazoles were acetoxylated to give the corresponding 4-acetoxypyrazoles. The effect of substituents of the alkenyl group on reactivity of the reaction was interpreted in terms of the frontier molecular orbital (FMO) theory.
Syntheses and Properties of the Polymethylenebis(diphenylcyclopropenium) Dications
Authors: Komatsu Koichi , Masumoto Katsuhisa , Waki Yoshinori , Okamoto Kunio
Published: July 2006

A series of polymethylenebis(diphenylcyclopropenium) dications with the polymethylene chain of one to six carbons (4n=1–6) were synthesized and characterized by spectral and analytical means. Among the dications 4n=3–6 which were isolated as perchlorates, 4n=3 was shown by the pKR+ measurements to be destabilized by 1.3 pK units as compared with 4n=4–6. The values of reduction potential exhibited the same tendency. The chromium(II) ion reduction of 4n=6, a representative dication, afforded a polymeric material containing a hexylbenzene unit. The dication 4n=2 was isolable only as a complex salt with SbCl6− and Cl−: the conventional hydride abstraction from 1,2-dicyclopropenylethane using trityl perchlorate resulted in rearrangements affording 4,9,10-triphenylphenanthrene and the unknown monocation C32H25+ containing the tropylium ring. A possible mechanism for these rearrangements is presented. On the other hand, the dication 4n=1 was observable only in a highly acidic solution due to the ready deprotonation yielding a new fully conjugated monocation 17. This cation, characterized by remarkable stability (pKR+ 8.9 in 50% aq acetonitrile), is formally represented as a triafulvene with a cyclopropenium ring substituted at the 4-position, but is shown to have a partially polarized electronic structure by 13C NMR spectroscopy.
Characterization of Nitrogen-containing Active Carbon Catalysts for SO2 Removal
Authors: Nishijima Akio , Hagiwara Hiroyuki , Kurita Minoru , Ueno Akifumi , Sato Toshio , Kiyozumi Yoshimichi , Todo Naoyuki
Published: July 2006

Physical and chemical properties of nitrogen-containing active carbons (ACs), having a much higher activity and capacity for SO2 adsorption than commercial ACs, were investigated to define suitable properties for SO2 removal. The capacity of nitrogen-containing ACs for SO2 adsorption correlates with the amount of their surface basic groups. However, the amount of basic surface groups for the ACs is practically the same as that for commercial ACs, indicating that the ACs have another characteristic property effective for SO2 removal. A study on the chemical state of surface nitrogen atoms by means of an X-ray photoelectron spectrometer has revealed that surface nitrogen species are effective for SO2 adsorption.
The Effect of Ultraviolet Radiation on Wettability of Silane Coupling Agents Coated on Glass
Authors: Esumi Kunio , Meguro Kenjiro , Schwartz Anthony M , Zettlemoyer Albert C
Published: July 2006

The effect of ultraviolet irradiation on wettability of silane coupling agents coated on glass was studied by using contact angle measurements. The water contact angle for the silane coupling agents decreased due to photooxidation as the irradiation progressed. It was found that silane coupling agents which contain vinyl, allyl, or phenyl groups were easily photooxidated by the irradiation.
The Group Coordinate Force Field of Oxymethylene and Thiomethylene Chain Molecules
Authors: Matsuura Hiroatsu , Murata Hiromu
Published: July 2006

Force field was systematically determined in terms of the group symmetry coordinates for series of CH3-(OCH2)mOCH3 (m=1–3), the polymer (–OCH2–)n, and their deuterated derivatives, and of CH3(SCH2)mSCH3, (–SCH2–)n, and their deuterated derivatives. Twenty-five force constants for the oxymethylene molecules and twenty-two force constants for the thiomethylene molecules were adjusted by using 178 and 126 observed wave-numbers, respectively. The force constants obtained were compared with those for related molecules. The results of the normal coordinate treatment on the polymers were discussed in comparison with the results in previous works.
Effect of Protolytic Behavior of Ligands on Formation Rates of Mono-complexes of Nickel(II) Ion with 2,2′-Bipyridine and 1,10-Phenanthroline in Aqueous Solution
Authors: Ando Isao , Nishijima Shigeyoshi , Ujimoto Kikujiro , Kurihara Hirondo
Published: July 2006

The mono-complex formation of nickel(II) ion with 2,2′-bipyridine(bpy) and 1,10-phenanthroline (phen) was studied in aqueous solution by means of a stopped-flow method. The apparent complex formation rates of the Ni(II)–bpy and Ni(II)–phen complexes depended on the pH of the solution. The rate constants of the mono-complex formation with the ligand in the free base form, kf, and that with the monoprotonated ligand, kfh, were evaluated from the rate-[H+] profiles in the region of high hydrogen ion concentration where the pseudo-equilibrium of acid dissociation of the ligands was attained during the complex formation. The rate constants determined for the Ni(II)–phen were kf=(2.6±0.3)×103 mol−1 dm3 s−1 and kfh=2.4±0.3 mol−1 dm3 s−1, which are practically the same as those reported elsewhere. On the other hand, the rate constants for the Ni(II)–bpy were kf=(5.3±1.2)×103 mol−1 dm3 s−1 and kfh=5.0±2.6 mol−1 dm3 s−1, which are quite different from the values reported by other researchers. The validity of the present data was discussed in terms of slow proton-transfer reactions of the ligands.
Macrocyclic Enzyme Model System. Kinetic Activity of [20]Paracyclophane Bearing 1,4-Dihydronicotinamide and 2-Pyridinecarboxylic Acid Moieties as Effected by Zinc Ion
Authors: Murakami Yukito , Aoyama Yasuhiro , Kikuchi Jun-ichi
Published: July 2006

As regards the effect of zinc(II) ion on the reduction of hexachloroacetone, the kinetic activity of a [20]paracyclophane (PCP) bearing 1,4-dihydronicotinamide (HNA) and 2-pyridinecarboxylic acid (Py) moieties, HNA–PCP–Py, has been investigated as an alcohol dehydrogenase model in reference to that of PCP–HNA in the light of their metal-coordination behavior. The reduction ability of PCP–HNA was significantly lowered as it underwent complex formation with zinc. On the other hand, HNA–PCP–Py showed an apparent rate maximum in a relatively lower concentration range of ZnCl2. The kinetic behavior was analyzed on the basis of the formation of two kinds of zinc complexes of HNA–PCP–Py: the 1:1 complex (Remark: Graphics omitted.), in which both Py and HNA moieties are simultaneously coordinated to the same zinc ion, showed a decreased reactivity relative to metal-free HNA–PCP–Py; while the 2:1 complex (HNA–PCP–Py–ZnII–Py–PCP–HNA), in which HNA is free from metal-coordination, exercised a much enhanced activity, 7 times as reactive as metal-free HNA–PCP–Py. A plausible reaction mechanism for the enhanced reactivity has been discussed.
Substitution of Cyano Group by Hydroxyalkyl Group and of Ring Hydrogen by Alkoxyl Group in UV-Irradiation of 2-Pyridinecarbonitrile in Alcohols
Authors: Sugimori Akira , Furihata Toshikazu , Mikayama Shigeyuki , Yoshida Makiko , Nakanishi Yasuo
Published: July 2006

The UV-irradiation of 2-pyridinecarbonitrile(1) in methanol and in ethanol brings about the replacement of the cyano group by the hydroxyalkyl groups and the replacement of the ring hydrogen by the alkoxyl group. Free base-form of 1 in ethanol undergoes exclusively photo-hydroxyethylation, while the pyridinium form of 1 in ethanol undergoes both photo-hydroxyethylation via a singlet excited state and -ethoxylation via a singlet-excited state complex, which is quenched by the electron transfer from the aromatic hydrocarbons to the excited complex.
Reaction of 1-Ethyl-3-methyl-4-imidazoline-2-thione with Methyl Iodide. Kinetic and Thermodynamic Aspects
Authors: Yamada Tetsuya , Kondo Yasuhiko , Kusabayashi Shigekazu
Published: July 2006

The reaction of 1-ethyl-3-methyl-4-imidazoline-2-thione with methyl iodide followed simple second order kinetics in polar solvents, whereas in less polar solvents the reverse process made a significant contribution to the overall rate. The solvent effects on the forward rate constant were linearly related to those on the rate of the reaction of tetramethylthiourea with methyl iodide. A plot of ΔV0\eweq  vs.  Δ\barV° was linear with a slope of 0.33. From the volume changes and enthalpy changes measured, three transition state indices, (Δ2V\eweq⁄Δ2\barV°), nT and α were determined in acetonitrile, ca. 0.33, 0.32, and 0.41, respectively.
Synthesis of Sugar Derivatives of Tervalent Phosphorus Compounds and Their Application to Homogeneous Asymmetric Hydrogenation
Authors: Yamashita Mitsuji , Hiramatsu Koji , Yamada Manabu , Suzuki Nobuyoshi , Inokawa Saburo
Published: July 2006

Diphenylphosphine and diphenylphosphinite derivatives of sugars such as methyl 6-deoxy-4-C-(diphenylphosphino)-2,3-O-isopropylidene-α-l-talopyranoside, methyl 4-O-(diphenylphosphino)-2,3-O-isopropylidene-α-l-rhamnopyranoside, methyl 4-C,4-O-(diphenylphosphino)-2,3-O-isopropylidene-α-l-talopyranoside, 6-deoxy-6-C-(diphenylphosphino)-1,2:3,5-di-O-isopropylidene-α-d-glucofuranose, and 6-O-(diphenylphosphino)-1,2:3,4-di-O-isopropylidene-α-d-galactopyranose were synthesized by the reaction of diphenylphosphine-sodium dihydrobis(2-methoxyethoxy)aluminate (SDMA) and/or diphenylphosphinous chloride-triethylamine with sugar derivatives. Homogeneous asymmetric hydrogenations of several prochiral olefins (α-acetylaminocinnamic acid, methyl α-acetylaminocinnamate, α-benzoylaminocinnamic acid, itaconic acid, and tiglic acid) were carried out using rhodium(I) catalysts with the tervalent chiral phosphorus derivatives of sugars. The highest optical yield for all the five substrates was obtained when di-μ-chloro-bis(cyclooctadiene)dirhodium(I) and 6-O-(diphenylphosphino)-1,2:3,4-di-O-isopropylidene-α-d-galactopyranose were used. The advantages of this method are the simplicity in the synthesis of the chiral phosphorus compound and the comparatively high optical yield in the asymmetric hydrogenation of olefins.
Mechanism of Dye-sensitized Photooxidation of Tryptophan, Tryptamine, and Their Derivatives. Singlet Oxygen Process in Competition with Type I Process
Authors: Inoue Kenzo , Matsuura Teruo , Saito Isao
Published: July 2006

Photosensitized oxidations of tryptophan (Trp), tryptamine, and their derivatives were investigated with a variety of sensitizers. Rose Bengal sensitized photooxidations proceed exclusively via Type II mechanism (singlet oxygen mechanism), whereas for thionine-sensitized photooxidations both Type I (nonsinglet oxygen mechanisms) and Type II mechanisms are operative under a given set of conditions. Rate constants of reaction, in units of 106 M−1 s−1, were determined to be 3 for Trp, 4 for tryptophan methyl ester, 4 for Nb-acetyltryptophan methyl ester, 9 for tryptamine, and 7 for Nb-methoxycarbonyltryptamine in the Rose Bengal-sensitized photooxidations. These values are in good agreement with those obtained from reactions with chemically generated singlet oxygen. Quenching rate constants are somewhat larger than reaction rates constants, indicating that the quenching process is the major path for the interaction of singlet oxygen with these indolic substrates. Oxidation products in chemically generated singlet-oxygen reaction of Trp are compared with those obtained from dye-sensitized photooxidations.
A New and Convenient Synthetic Method for Cyclopropyl Phenyl Sulfides
Authors: Tanaka Kazuhiko , Uneme Hideki , Matsui Shuichi , Kaji Aritsune
Published: July 2006

The reactions of a variety of 1,3-bis(phenylthio)propanes with butyllithium have been shown to produce cyclopropyl phenyl sulfides in good to high yields. A new and convenient in situ preparation of 1-lithiocyclopropyl phenyl sulfide can be readily carried out by treating 1,3-bis(phenylthio)propane with 2 equiv. of butyllithium at 0 °C in THF. The reaction with electrophiles proceeds in good yield. O-Aryl and O-alkyl S-cyclopropyl dithiocarbonates also can be prepared in good yields. 1,2-Bis(phenylthio)ethane was converted to phenyl vinyl sulfide on treatment with butyllithium, while 1,4-bis(phenylthio)butane was recovered unchanged by a similar treatment.
Alkylation of Benzothiazolines and the Stevens Rearrangement of the Resulting 2,3,3-Trisubstituted Benzothiazolinium Salts
Authors: Akiba Kin-ya , Ohara Yoshio , Inamoto Naoki
Published: July 2006

Alkylation of 2-substituted 3-methyl- or 3-ethylbenzothiazolines with Meerwein reagents gave 2-substituted 3,3-dialkylbenzothiazolinium tetrafluoroborates (3). The configuration of two alkyl groups on the nitrogen was assigned by NMR spectra and NOE measurement. In the Stevens rearrangement of 3 with lithium diisopropylamide ethyl group showed a much larger migratory aptitude (Et:Me≥20 :1) than methyl group irrespective of the configuration of 3, and cyclic ammonium ylide with planar π-type carbanion was proposed as an intermediate. 3 suffered nucleophilic attack at the ring sulfur atom by butyllithium to afford a ring-opened ammonium ylide, which collapses to a radical pair to give unusual Stevens rearrangement product, where o-alkylthiophenyl group migrated selectively in preference to alkyl group, because of stabilization by participation of o-alkylthio group.
Ylide-Metal Complexes. VI. The Preparation and Properties of IVA-group Metal (Ge, Sn, Pb) Complexes of Alkylidenetriphenylphosphoranes
Authors: Yamamoto Yoshihisa
Published: July 2006

(Triphenylphosphonium alkylide)triphenylmetal chloride [(C6H5)3\overset+PCHR–M(C6H5)3]Cl− (R: H, Me, i-pr; M: Ge, Sn, Pb) and (triphenylphosphoniumalkylide)metal chloride [(C6H5)3\overset+PCHR]nMCln−, (M=Ge,n= 4; M=Pb, n=2) have been isolated from a reaction mixture of alkylidenetriphenylphosphoranes and IVA-group metal compounds. The ylide in [(C6H5)3\overset+PCH2–Pb(C6H5)3]Cl− is bonded to the lead atom through the carbanionic donor atom.
Apparent Extinction Coefficient for a Scanning Photosedimentometer
Authors: Takahashi Junichi , Muta Akinori
Published: July 2006

Particle-size distributions of subdivided samples were analyzed independently with electron microscopy and a scanning photosedimentometer. Apparent extinction coefficient for the optical scanning system was estimated by the comparative examination of the distributions.
Regioselective Reaction of Allylic Carbanion Derived from 1-Phenylthio-2-octene with Conjugated Cyclopentenone Derivative and Synthesis of Prostaglandin E1
Authors: Nokami Junzo , Ono Toshio , Iwao Atsunori , Wakabayashi Shoji
Published: July 2006

The reaction of the allylic carbanion derived from 1-phenylthio-2-octene with conjugated cyclopentenone derivatives in the presence of hexamethylphosphoric triamide (HMPA) regioselectively gave the 1,4 adduct at the α carbon of the allylic sulfide. The reaction was employed for the synthesis of prostaglandin E1.
Origins and Spin Dependence of Near Infrared Magnetic Circular Dichroism of Iron(III) Hemoproteins
Authors: Yamamoto Takao , Nozawa Tsunenori , Kobayashi Nagao , Hatano Masahiro
Published: July 2006

Temperature variation experiments on near infrared magnetic circular dichroism spectra (700–2000 nm) have demonstrated that metmyoglobin (iron(III) myoglobin) cyanide and metmyoglobin fluoride derivatives which are typical low and high spin iron(III) heme complexes, respectively, exhibit the Faraday C term and the Faraday C and A terms, respectively. The results are consistent with theoretical predictions based on the assignment that the near infrared bands of the iron(III) heme complexes are attributable to the charge-transfer transitions from the occupied a1 and a2 π orbitals to the vacant iron dπ (dxz, dyz) orbitals in a C4v notation.
Viscosities of Aqueous Solutions of Sodium Alkanoates
Authors: Miyajima Koichiro , Sawada Masahiro , Nakagaki Masayuki
Published: July 2006

Viscosities of aqueous solutions of sodium salts of formic acid, acetic acid, propionic acid, and butyric acid were measured in the concentration range 0.01–0.1 mol dm−3 at 15, 25, and 35°C For formate ion, values of Bst, the increment of viscosity B-coefficient arising from structural change of water, and of (dBion⁄dT), the temperature dependence of ionic B-coefficient, are both nearly zero, indicating that formate ion is neither a structure maker nor a structure breaker. For the alkanoate ions the signs of Bst and (dBion⁄dT) are positive and negative, respectively. From these facts, alkanoate ions may be concluded to be hydrophobic structure making ions.
Motion of Methylammonium Ions in Solid CH3NH3NO3 and CH3NH3SCN Studied by 1H NMR
Authors: Ishida Hiroyuki , Ikeda Ryuichi , Nakamura Daiyu
Published: July 2006

The proton spin-lattice relaxation time T1 at 20 MHz and the second moment of 1H NMR absorptions at 40 MHz were determined at various temperatures between 77 and 300 K for CH3NH3NO3 and CH3NH3SCN, and their partially deuterated analogs, CH3ND3NO3 and CH3ND3SCN. A phase transition was located at 242 K for CH3NH3SCN. The fully protonated compounds yielded two T1 minima, the low- and high-temperature one of which could be attributed to the reorientation of the CH3 and NH3+ groups, respectively, of the cation about the C–N bond axis. The activation energy was evaluated for these motional modes.
Intercalation Compounds of FeOCl. Systematics of Amine Containing Lewis Base Intercalants
Authors: Maeda Yonezo , Yamashita Miyako , Ohshio Hiroki , Tsutsumi Naoto , Takashima Yoshimasa
Published: July 2006

New intercalated compounds of FeOCl and aniline derivatives were synthesized by soaking FeOCl in ethanol solution containing Lewis base intercalants. Only those Lewis base intercalants whose acid-dissociation constant is greater than 5 intercalate into the lattice of FeOCl. The acid-strength of the solvent is important for the formation of an intercalation compound. The intercalates of iron(III) chloride oxide FeOCl(G)1⁄n have been characterized by elemental analysis, powder pattern of X-ray diffraction, Fe-57 Mössbauer and infrared spectroscopies. The research on expansion of the b-axis of the unit cell and IR data confirm the location of the “guest” molecule within the van der Waals layer or the FeOCl lattice. Effective vibrating mass and lattice temperature derived from the Mossbauer spectra are affected by chemical bonding in the first coordination sphere of the iron atom.
A Thermodynamic Study of the Synergistic Solvent Extraction of a Series of Zinc(II) and Cadmium(II) Complexes
Authors: Yamada Etsu , Nakayama Eiichiro , Kuwamoto Tooru , Fujinaga Taitiro
Published: July 2006

The extraction of zinc and cadmium using chloroform and benzene solutions constaining diphenylcarbazone (DPC=Hdpc), either alone or combined with pyridine(py) or 1,10-phenanthroline(phen), was studied thermodynamically. The formation constants were measured as functions of the temperature in order to ascertain the free energy, enthalpy, and entropy changes. The thermodynamic parameters support a proposed mechanism for the synergism of zinc in which the coordination number of the zinc ion expands with formation of Zn(dpc)2S, where S is pyridine or 1,10-phenanthroline. On the other hand, the thermodynamic values for the synergistic reaction of cadmium support a mechanism in which pyridine or 1,10-phenanthroline replaces the residual waters of hydration in the first coordination sphere of cadmium.
Coordination Structure of Cu2+ Ion in Highly Concentrated Aqueous CuBr2 Solution, Determined by X-Ray Diffraction Analysis
Authors: Ichihashi Mitsuyoshi , Wakita Hisanobu , Mibuchi Takeharu , Masuda Isao
Published: July 2006

The solute structure of concentrated aqueous copper(II) bromide solutions was determined by the analysis of the radial distribution curves of X-ray diffraction measured on the solutions with varying concentrations, 4.364–1.016 mol dm−3. The mixed-ligand aquabromocopper(II) complexes were found to be present in these solutions, and to have a distorted octahedral geometry. The Cu2+ ion was coordinated with Br− ions at the equatorial sites whose bond lengths were shorter than the axial sites. The interatomic distances of the equatorial Cu–Br and Cu–OH2 bonds were, respectively, 2.42–2.46 and 1.96–1.99 Å, and that of the axial Cu–OH2 bond, 2.37–2.51 Å. The average coordination number of Br− ions in the nearest neighbor of the Cu2+ ion increased from 0.33 to 1.31 as the concentration of CuBr2 increased from 1.016 to 4.364 mol dm−3. Even in the 4.364 mol dm−3 solution, which was nearly saturated, the coordination of the Br− ion at the axial site was not evidenced. In the 1.474 mol dm−3 CuBr2 solution dissolved in an aqueous 6.923 mol dm−3 HBr solution, the tetrabromocopper(II) complex species was proposed to exist in a flattened tetrahedral form, wherein the Cu–Br distance was 2.41 Å.
Preparation, Resolution, and Spectroscopic Properties of Bis[(2-aminoethyl)diphenylphosphine]- and (Ethylenediamine)[1,2-bis(diphenylphosphino)ethane]–Cobalt(III) Complexes of Acetylacetonate, Malonate, Oxalate, and Carbonate Ion
Authors: Atoh Masamichi , Kinoshita Isamu , Kashiwabara Kazuo , Fujita Junnosuke
Published: July 2006

New complexes of the [Co(O–O)(edpp)2]- and [Co(O–O)(en)(dppe)]- type were prepared from trans(Cl, Cl)[CoCl2(edpp)2]ClO4 and trans-[CoCl2(en)(dppe)]ClO4·H2O, respectively, where O–O is an acetylacetonate, malonate, oxalate, or carbonate ion, and en, edpp, and dppe denote ethylenediamine, (2-aminoethyl)diphenylphosphine, and 1,2-bis(diphenylphosphino)ethane, respectively. All the complexes of the former type gave two geometrical isomers of trans(P, P) and trans(P, N) configurations, which were assigned on the basis of the 1H and 3C NMR, and electronic absorption spectra. No trans(N, N) isomers were formed. The yields of the trans(P, N) isomers were always larger than those of the corresponding trans(P, P) isomers. With the decreasing ring members of the O–O chelates, the yield of the trans(P,P) isomer decreases, the trans(P,P)-carbonato complex being formed in trace amounts. The first absorption bands of the trans(P,P) isomers have very strong intensity as compared with those of the corresponding trans(P,N) and the dppe complexes. All the complexes except for [Co(O–O)(en)(dppe)]+ (O–O=malonate and oxalate ions) were resolved by the chemical or SP-Sephadex C-25 column chromatographic method, and the circular dichroism spectra were recorded and compared with those of related complexes.
Reaction Process of Titanium Tetrachloride with Ammonia in the Vapor Phase and Properties of the Titanium Nitride Formed
Authors: Saeki Yuzo , Matsuzaki Ryoko , Yajima Akimasa , Akiyama Masayo
Published: July 2006

The reaction products of gaseous TiCl4 with ammonia were TiCl4·5NH3 at 200 °C, TiCl4·5NH3, TiClN, and NH4Cl at 250–400 °C, TiCl4·5NH3, TiClN, TiNx, and NH4Cl at 450–650 °C, TiNx and NH4Cl at 700–1000 °C, and TiNx, NH4Cl, and HCl at 1100–1400 °C. The N/Ti atomic ratio, x, of the TiNx formed was 1.21 at 700 °C, 1.16 at 800 °C, 1.13 at 900 °C, and 1.10 above 1000 °C. The lattice constants of the TiNx formed are shown. The reaction process can be represented as follows: The reaction of gaseous TiCl4 with ammonia occurs first to form TiCl4·5NH3. Above ca. 220 °C, the TiCl4·5NH3 decomposes to TiClN. Above ca. 430 °C, the TiClN reacts with ammonia to form TiNx. Above ca. 1100 °C, in addition to these reactions, the reaction of TiCl2, formed by the reduction of TiCl4 with hydrogen resulting from the thermal dissociation of ammonia, with ammonia occurs to form TiNx. On heating the TiNx, formed by the vapor-phase reaction, at temperatures higher than 500 °C in an argon atmosphere, the value of x decreased and became close to that of the stoichiometric nitride, being 1.02 at 900–1100 °C.
Direct Synthesis of Cyclic Carbonates in the Presence of Organometallic Compounds. Catalyses by Systems from IVA, VA, and VIA Group Compounds and Lewis Base
Authors: Nomura Ryoki , Kimura Masahiro , Teshima Satoshi , Ninagawa Akira , Matsuda Haruo
Published: July 2006

In the cycloaddition of carbon dioxide to oxiranes to form cyclic carbonates in the presence of organometallic halides of group IVA, VA, and VIA, catalytic activities of organometallic halides are in the order Sb>Te>Sn>>Bi, Ge, and Si. An improvement of their catalytic activities is achieved by addition of an equimolar amount of Lewis base. In binary catalyst systems, the order of catalytic activities is in the order Sn>Te>Sb>>Bi, Ge, and Si. Organotin halide–base systems show the highest catalytic activity.
Preparation of Alkylnickel(II)–Phosphine Complexes by Reactions of Ni(acac)2 with Alkylaluminums in the Presence of Tertiary Phosphine
Authors: Yamamoto Takakazu , Takamatsu Masakatsu , Yamamoto Akio
Published: July 2006

Four new alkylnickel(II)–phosphine complexes, NiR2(PR′3)2 (R=CH3, C2H5; PR′3=triethylphosphine (PEt3), tributylphosphine (PBu3), 1,2-bis(diphenylphosphino)ethane(dpe)) and Ni(CH3)(acac)(PEtPh2) (PEtPh2=ethyldiphenylphosphine), have been prepared by reactions of Ni(acac)2 with AlR2(OC2H5) in the presence of phosphine ligands.
Syntheses and Properties of Di-, Tri-, and Tetracyclopropyltropylium and Di- and Tri-t-butyltropylium Ions
Authors: Komatsu Koichi , Takeuchi Ken’ichi , Arima Makoto , Waki Yoshinori , Shirai Shuzo , Okamoto Kunio
Published: July 2006

The polysubstituted tropylium ions having cyclopropyl or t-butyl groups at the ring positions with the least steric hindrance, i.e. 1,3- and 1,4-dicyclopropyltropylium, 1,3- and 1,4-di-t-butyltropylium, 1,3,-5-tricyclopropyl- and 1,3,5-tri-t-butyltropylium and 1,2,4,6-tetracyclopropyltropylium ions (4), were synthesized, and their properties were compared with the known monosubstituted and unsubstituted cations. The 1H and 13C NMR spectra for the cyclopropyl derivatives and the 13C NMR spectra for the t-butyl derivatives exhibited a gradual upfield shift for the seven-membered ring signals upon consecutive substitution. Accordingly, for the t-butyl derivatives, the pKR+ values were found to linearly increase upon introduction of each substuent; for the cyclopropyl derivatives, a larger extent of the pKR+ increase was observed with each substitution, and the pKR+ of the tetrasubstituted derivative 4 amounted to 9.10 (50% aq MeCN, 25 °C), the highest value presently known for the hydrocarbon cations having the tropylium unit, although the cumulative substituent effect deviated from the linear additivity correlation as the substituent number increased. The substituent effects upon the reduction potential and the CT transition energy (pyrene as a donor) were also examined and shown to have the same tendency in general.
Reactivities of Stable Rotamers. X. Reactions of 9-(2-Formyl-1-naphthyl)fluorene Rotamers and Related Compounds
Authors: Saito Ryo , Oki Michinori
Published: July 2006

Rotational barrier (ap→sp) in 9-(2-formyl-1-naphthyl)fluorene was determined: ΔH\eweq24.0 kcal/mol and ΔS\eweq−7.9 e.u. Oxidation of the aldehyde with chromium(VI) oxide was extremely slow in the ap form, whereas it proceeded smoothly in the sp form. As models of the 2 steps involved in the aldehyde oxidation, oxime formation of the aldehyde and oxidation of related alcohols were carried out to conclude that the second elimination step in the aldehyde oxidation is slow in the ap form because of the steric effect. Dehydration of the oxime of the aldehyde exhibited a large ksp/kap value as well. Sodium tetrahydridoborate reduction and Grignard additions of the aldehyde were also carried out to show that the former gave a large ksp/kap value whereas the latter exhibited rather a small ksp/kap. The implication of the results is discussed.
The Enantioselective Michael Addition of Thiols to Cycloalkenones by Using (2S, 4S)-2-Anilinomethyl-1-ethyl-4-hydroxypyrrolidine as Chiral Catalyst
Authors: Suzuki Keisuke , Ikegawa Akihiko , Mukaiyama Teruaki
Published: July 2006

Catalytic asymmetric addition of thiols to 2-cycloalkenone was studied by using the chiral amino alcohols, derived from l-hydroxyproline or (S)-proline, as base catalysts. Detailed investigation was carried out on the effects of the structure of the catalyst, the reaction medium, the temperature, and the concentration on the enantioselectivity. Good optical yields (47–88%) were achieved by the reaction of arenethiols and 2-cyclohexen-1-one in toluene at −5 °C, by using the catalyst (2S, 4S)-2-anilinomethyl-1-ethyl-4-hydroxypyrrolidine.
Synthetic Studies of Rifamycins. V. A Chiral Synthesis of an Ansa-chain Compound for the C-17–C-29 Portion of Rifamycin W
Authors: Nakata Masaya , Enari Hiroyuki , Kinoshita Mitsuhiro
Published: July 2006

The chiral synthesis of methyl 5,7,9-tri-O-acetyl-2-C-(acetoxymethyl)-2,4,6,8,10,11,12-heptadeoxy-4,6,8,10-tetra-C-methyl-aldehydo-l-glycero-l-talo-l-manno-(E)-11-tridecenuronate 1-(dimethyl acetal) (III), a useful synthetic segment for the C-17-C-29 portion of rifamycin W, is described. The key intermediate, 3-O-(t-butyldimethylsilyl)-2,4,7-trideoxy-5,6-O-isopropylidene-2,4-di-C-methyl-aldehydo-d-glycero-d-talo-heptose (28) was synthesized in 30% yield from methyl 4,6-O-benzylidene-3-deoxy-3-C-methyl-α-d-glucopyranoside in 15 steps. The synthesis involves key steps of highly stereoselective Grignard reaction and regiospecific cis-epoxide ring-opening reaction. The condensation of 28 with 3,3-diethoxy-2-lithio-1-propene afforded about 1.6:1 excess of the “Cram” product (30, 56% yield). The desilylation of 30 followed by homogeneous hydrogenation with (Ph3P)3RhCl gave only the erythro product 34. 3,5-Di-O-benzyl-2,4,6-trideoxy-2,4,6-tri-C-methyl-l-glycero-l-manmo-heptodialdose 1-(diethyl acetal) derived from 34, condensed with the lithium reagent prepared (in ether at −95–−90 °C) from butyllithium and 3-C-(benzyloxymethyl)-3,5,6-trideoxy-5-iodo-1,2-O-isopropylidene-α-d-hexenofuranose, derived from 3-deoxy-3-C-hydroxymethyl-1,2 : 5,6-di-O-isopropylidene-α-d-allofuranose, to afford a 4 : 1 mixture of the “Cram” product and its epimer in 80% yield. The homogeneous hydrogenation of the mixture followed by the debenzylation gave the diastereomerically pure major product, which could be transformed into III in 6 steps.
Study of Ion Transport across Amphoteric Ion Exchange Membrane. I. Electroconductive Membrane Permeability
Authors: Yamauchi Akira , Tsuruyama Shigeru , Masumori Harumi , Nagata Yoshihiko , Kaibara Kozue , Kimizuka Hideo
Published: July 2006

Basic ion transport characteristics of a homogeneous amphoteric ion exchange membrane (Kanegafuchi Chem. Ind. 1.0-PA-29) were studied by measuring the membrane potentials and conductances. Concentration cell systems of NaCl, KCl, CaCl2, and SrCl2 with a concentration range of 10−1–10−3 mol dm−3 were studied and the electroconductive membrane permeabilities were estimated from the electrochemical data. Generally, Cl− is slightly more permeable than cations under the present experimental conditions, except the result that K+ is more permeable at low concentrations. Unlike the usual uniform cation exchange membrane of which transport characteristics to ions strongly depend upon the number of ionic charges, a “1.0-PA-29” amphoteric membrane exhibits different transport properties for the NaCl and KCl systems. In the NaCl system, the membrane was constantly anionic selective, while in the KCl system, biphasic ion selectivities were observed depending upon the external KCl concentration. Fundamental electrochemical properties of the membrane systems were discussed by examining the dependencies of membrane permeability on external electrolyte concentrations and on differences in ionic species. The present result suggests that the ionic size is one of the critical factors determining the transport characteristics across amphoteric ion exchange membrane.
Acid Catalysis of the Transformation of 1-Methoxycarbonyl-2-imidazoline to 1-Methoxycarbonyl-2-imidazolidinone, a Carboxybiotin Model
Authors: Kondo Hiroki , Miura Katsuhito , Sunamoto Junzo
Published: July 2006

The transformation of 1-methoxycarbonyl-2-ethoxy-2-imidazoline into 1-methoxycarbonyl-2-imidazolidinone a 1-carboxybiotin model, is facilitated by acid.
Penetration of Leucine and Norleucine into Lecithin Monolayers from Underlying Aqueous Solutions
Authors: Nakagaki Masayuki , Okamura Emiko
Published: July 2006

The surface pressure of the monolayers of dimyristoyl phosphatidylcholine(DMPC) on leucine and norleucine solutions was measured and the amounts of these amino acids which had penetrated into the DMPC monolayer were calculated by means of a successive approximation. Although the amounts of leucine and norleucine adsorbed onto the solution surface were nearly equal and were larger than that of lysine, the amount of leucine which had penetrated into the DMPC monolayer was remarkably small. That of norleucine was not so small, but was still smaller than that of lysine except for the region where the molecular area of DMPC is large. The partial molecular areas of amino acid, \barA2, and DMPC, \barA3, were calculated in each case. The value of \barA2, was the largest in the case of leucine and the smallest in the case of lysine, which means that the area occupied by lysine is smaller than that of norleucine because the interaction of ε-amino group with DMPC contracts the mixed monolayer. The change in the value of \barA3 due to the interaction with amino acid, however, was not large, which means that the change in the state of DMPC itself is not large and rather independent of the kind of amino acid.
Polarized Absorption Spectra of Aromatic Radicals in Stretched Polymer Film. IV. Radical Ions of 9-Substituted Anthracenes
Authors: Hiratsuka Hiroshi , Nakamura Hitoshi , Tanizaki Yoshie , Nakajima Keihachiro
Published: July 2006

Radical ions of some 9-substituted anthracene derivatives have been prepared in polymer film by γ-irradiation at 77 K. By use of the polarized absorption spectra of these radical ions, the absorption spectra have been resolved into two components (resolved spectra), the transition moments of which are polarized parallel to the molecular long and short axes, respectively. Correlation of the characteristic absorption bands is discussed briefly.
Multiphoton Ionization Spectrum of p-Terphenyl in a Supersonic Free Jet
Authors: Murakami Jun-ichi , Okuyama Katsuhiko , Ito Mitsuo
Published: July 2006

The one-photon absorption spectrum of p-terphenyl vapor was observed in a supersonic free jet by using multiphoton ionization spectroscopy. In the spectrum were observed the progressions of the in-phase and out-of-phase torsional vibrations of the benzene rings. It was concluded that p-terphenyl has a planar structure in the first excited singlet state, whereas it is twisted in the ground state.
Conformation of Condensed Polycyclic Aromatic Hydrocarbons. I. The Molecular and Crystal Structure of Anthra[2,1,9,8-hijkl]benzo[de]naphtho[2,1,8,7-stuv]pentacene
Authors: Fujisawa Shoji , Oonishi Isao , Aoki Junji , Ohashi Yuji , Sasada Yoshio
Published: July 2006

The crystal structure of the title compound, C38H18, has been determined by X-ray analysis. The space group is Pa, with unit cell dimensions a=31.276(4), b=3.7818(4), c=21.663(3) Å, β=124.22(1)° and Z=4. The structure was solved by the direct method and refined by full-matrix least-squares methods to an R value of 0.073 for 2619 reflections. Two crystallographically independent molecules are largely distorted from a planar structure due to the repulsions between the crowded hydrogen atoms, with different conformations to each other. The molecules are stacked face-to-face by van der Waals forces to form column structures along the b axis.
Reaction Process of Vanadium Tetrachloride with Ammonia in the Vapor Phase and Properties of the Vanadium Nitride Formed
Authors: Saeki Yuzo , Shimizu Takashi , Yajima Akimasa , Matsuzaki Ryoko
Published: July 2006

The reaction products of gaseous VCl4 with ammonia were VCl4·4NH3 at 200 °C, VCl4·4NH3, VNx, and NH4Cl at 250–550 °C, and VNx and NH4Cl at 600–1000 °C. At 1100 °C, small amounts of VCl2 and HCl were formed in addition to VNx and NH4Cl. The N/V atomic ratio, x, of the VNx formed was 1.20 at 600 °C, 1.15 at 700 °C, 1.14 at 800 °C, and 1.13 at 900 and 1000 °C. The lattice constants of the VNx formed were shown. The reaction process of gaseous VCl4 with ammonia can be represented as follows: The reaction of gaseous VCl4 with ammonia first occurs to form VCl4·4NH3. Above about 215 °C, the reaction of VCl4·4NH3 with ammonia also occurs to form VNx. At 1100 °C, in addition to these reactions, the reaction of gaseous VCl4 with hydrogen formed by the thermal dissociation of ammonia occurs to form VCl2. On heating the VNx, formed by the vapor-phase reaction, at temperatures higher than 500 °C in an argon atmosphere, the value of x decreased with the increase in the heating temperature to 1.03 at 900–1000 °C.
SbCl5 Complexes of Pyridine N-Oxide and Trimethylamine Oxide as the Oxidizing Agent
Authors: Yamamoto Jiro , Murakami Mitushige , Kameoka Noriaki , Otani Norio , Umezu Masahiro , Matsuura Teruo
Published: July 2006

A 1:1 complex of pyridine N-oxide or trimethylamine oxide with SbCl5 acted as an oxidizing agent to benzyl alcohol, bezoin, furoin, and thiophenols more easily than via the oxides to give benzaldehyde, benzil, furil, and the corresponding disulfides respectively. The trimethylamine oxide–SbCl5 also oxidized p-xylene to p-tolualdehyde under nitrogen and to p-toluic acid under air.
Studies on Dissolved Metalloenzymes in Lake Water. I. Identification of Alkaline Phosphatase
Authors: Kobayashi Kensei , Iwase Kimikazu , Matsui Masahiro , Watanabe Masami , Ueda Hirotaka , Fujiwara Kitao , Haraguchi Hiroki , Fuwa Keiichiro
Published: July 2006

Metalloenzyme (alkaline phosphatase) dissolved in lake water has been identified by means of high performance liquid chromatography (HPLC). Water samples were collected from Lake Kasumigaura in Ibaraki, and filtered with a 0.2–0.45 μm membrane filter immediately after sampling. Filtered water was concentrated to 100–2000 fold by ultrafiltration membrane which could concentrate the components of molecular weight larger than 10000. The enzymatic activity of alkaline phosphatase was measured using p-nitrophenyl dihydrogen-phosphate as a substrate. Chelating agents added to the concentrated lake water inhibited the appearance of enzymatic activity, while the enzymatic activity was recovered with addition of zinc ion. The HPLC chromatograms of the concentrated lake water were examined, where an aqueous porous gel column was used for separation. The effluent at molecular weight of ca. 90000 showed specific activity of alkaline phosphatase. Zinc was also found in the same fraction. These facts suggest that alkaline phosphatase with the nature similar to procaryotes was present in the lake water.
Electron Transfer from Tetrakis(isocyanide)rhodium(I) Monomers, and the Oligomers to Iron(III) and Cobalt(III) Complexes. Enhancement of the Reactivity by the Oligomerization
Authors: Fukuzumi Shunichi , Nishizawa Nobuaki , Tanaka Toshio
Published: July 2006

Electron transfer reactions from tetrakis(isocyanide)rhodium(I) ([RhL4]+ to iron(III) complexes of the [Fe(N–N)3]3+ type (N–N=1,10-phenanthroline, 2,2′-bipyridine) proceed through precursor complexes formed between [RhL4]+ and [Fe(N–N)3]3+ with 1:1, 1:2, and 2:1 stoichiometry. A similar scheme is suggested for the reaction of bis(isocyanide)bis(triphenylphosphine)rhodium(I) with the same oxidants. The intramolecular electron transfer rate constants k1 in the 1:1 precursor complexes have been determined in MeCN at 298 K. In accordance with Marcus theory, the logk1 values are linearly related with the reduction potentials of oxidants with the theoretical slope of 8.5. The [RhL4]+ cations form oligomers in MeCN; [RhL4+]n (n=2,3), and the equilibrium constants for oligomerization have been determined. For a given oxidant [Co(bpy)3]3+ (bpy=2,2′-bipyridine), the logk1 value of [RhL4+]n increases in parallel with the HOMO energy of [RhL4+]n; monomer<dimer<trimer.
Argon Plasma Treatment of Packing Materials for Gas Chromatography and Comparison with Acid Wash and Dimethyldichlorosilane Treatment of Support
Authors: Oka Seiji , Yamamoto Yukio , Hayashi Koichiro
Published: July 2006

Argon plasma treatment of column packings for gas chromatography was examined with commercially obtained diatomaceous earth coated with several kinds of stationary liquid phases, such as squalane, Apiezon L, dioctyl phthalate, Silicone DC, and polyethylene glycol. It was found that the plasma treatment improves chromatographic properties of all the packings examined except those with polyethylene glycol. The effect of the plasma treatment is attributable to the reduction of support adsorptivity by the formation of an inert coating on the support surface. The plasma treatment of Chromosorb W coated with 5% squalane was compared with dimethyldichlorosilane (DMCS) treatment of the acid-washed (AW) support, the so-called AW-DMCS-treatment of support. Although the AW-DMCS-treatment is superior to the plasma treatment for the reduction of support adsorptivity, a complete elimination of the adsorptivity was attained by the plasma treatment of the packing having the AW-DMCS-treated support.
Asymmetric Transformation of 2-Phenyl- and 2-Chloroalkanoic Acids via Chiral Oxazolines
Authors: Shibata Saizo , Matsushita Hajime , Kaneko Hajime , Noguchi Masao , Saburi Masahiko , Yoshikawa Sadao
Published: July 2006

Asymmetric transformation of racemic 2-phenyl- and 2-chloroalkanoic acids via oxazolines into the corresponding optically active acids was investigated using (S)-phenylalaninol as a chiral auxiliary. The asymmetric transformation was performed by metalation of the oxazolines with butyllithium followed by protonation of the resulting lithiooxazolines. 2-Phenyl- and 2-chloroalkanoic acids were obtained in the optical yields of 29–53% and 45–73%, respectively, by the acidic hydrolysis of the chiral oxazolines thus formed. The mechanism of the asymmetric transformation was discussed.
The Conformations of Several 1-Phenylethyl and 1-Phenylpropyl Aryl Sulfoxides. Evidence for Attractive Aryl/Aryl Interaction
Authors: Kobayasm Keiji , Kodama Yoshio , Nishio Motohiro , Sugawara Tadashi , Iwamura Hiizu
Published: July 2006

The conformations of the diastereoisomers of 1-phenylethyl phenyl (1), 1-phenylethyl p-tolyl (2), 1-phenylpropyl phenyl sulfoxides (3) were studied by NMR spectroscopy, largely by means of the computer simulation of the lanthanoid-induced shifts. It has been suggested that the rotamer in which the aromatic group (Ar) is

4C_6H_5CH(R)–SO–Ar& 1:R=& &CH_3,& Ar=&C_6H_5

& 2:& &CH_3,& &C_6H_4CH_3(p)

& 3:& &C_2H_5,& &C_6H_5

gauche to the phenyl (Ph) and anti to the alkyl (R) group is most populated in the conformational equilibria of (RS/SR)-1, 2, 3, and (RR/SS)-3. For (RR/SS)-1 and 2, on the other hand, the most important contributor has been suggested to be the rotamer in which Ar is flanked by Ph and R. The results have been discussed in the light of the presence of attractive interactions between relevant groups.
The Electron Exchange Rates of Anthracene/Anthracene Radical Anion Ion-paired with Various Tetraalkylammonium Cations
Authors: Suga Kosaku , Aoyagui Shigeru
Published: July 2006

The electron exchange reaction between anthracene and its radical anion formed by the sodium reduction of the parent molecule in 1,2-dimethoxyethane, tetrahydrofuran, and a tetrahydrofuran-1,4-dioxane mixture was studied by ESR spectroscopy in the preseuce of tetraalkylammonium cations of various kinds and amounts. Analytical equations were presented to evaluate the rate constants of two competitive electron exchange reactions between anthracene and its anion, which was ion-paired in part with a tetraalkylammonium cation and in part with a sodium cation. The experimental results obeyed the theoretical equations and, consequently, yielded the electron exchange rate constants for the ion pairs of the former type, which were unaffected by the coexistence of the ion pairs of the latter type. They were of the order of 108 M−1s−1 (1 M=1 mol dm−3), a value which was one order of magnitude smaller than the rate constant for the solvent-separated ion pair of anthracene anion with sodium cation. They were smaller for tetraalkylammonium cations with longer carbon chains. These findings are discussed on the basis of the theory of Marcus.
Preparation of New Nitrogen-Bridged Heterocycles. 5. Smooth Michael Additions of 2(3H)-Indolizinone Derivatives
Authors: Kakehi Akikazu , Ito Suketaka , Wada Bunzo , Watanabe Kozo , Nishimura Kenji , Kumagai Aiichiro
Published: July 2006

Michael additions of some 2(3H)-indolizinone derivatives to α,β-unsaturated nitriles, esters, and an amide gave the corresponding double Michael adducts, 3,3-disubstituted 2(3H)-indolizinones, in moderate to high yields, and those to methyl vinyl ketone afforded further condensed products, spiro[cyclohexane-1,3′(2′H)-indolizin]-2′-ones, instead of the expected 1:2 adducts. On the other hand, the reactions of the indolizinones with activated ethylenes having an appropriate leaving group at the β-position or with an acetylenic ester formed unstable 1:1 Michael adducts, which were converted to stable 2-acyloxy- or 2-alkoxy-3-vinylindolizine derivatives by the treatment with some acylating or alkylating agents in comparatively good yields.
A Through-process for the Preparation of Methyl Per-O-acetyl 1-Thio-glycosides from Aldoses
Authors: Koto Shinkiti , Yoshida Toyosaku , Takenaka Kazuhiro , Zen Shonosuke
Published: July 2006

d-Glucose, d-galactose, d-mannose, d-xylose, l-arabinose, l-fucose, l-rhamnose, maltose, cellobiose, lactose, d-glucosamine, d-galactosamine, and d-mannosamine were converted into the corresponding methyl per-O-acetyl 1-thioglycopyranosides by way of a three-step (acetobromination, methylthioation, and acetylation) through-process in a single vessel.
The Crystal and Molecular Structure of Staurosporine, a New Alkaloid from a Streptomyces Strain
Authors: Furusaki Akio , Hashiba Nobuhiro , Matsumoto Takeshi , Hirano Atsushi , Iwai Yuzuru , \={O}mura Satoshi
Published: July 2006

The molecular sturcture of staurosporine, an alkaloid from a Streptomyces strain, has been determined by means of an X-ray crystallographic analysis of its methanol solvate (C28H26N4O3·CH3OH). The crystals are monoclinic, with four formula units in a unit cell with dimensions of a=23.487(6), b=7.636(3), c=15.638(4) Å, and β=116.71(5)°; the space group is C2. 2532 unique intensity data were collected on a four-circle diffractometer with LiF-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using the 20 strongest reflections as the starting set; the 72nd random phase set led to the correct solution. The R value reached 0.047 by block-diagonal least-squares refinements. Staurosporine has been found to contain a unique dimeric indole structure. Because of the steric hindrance, the indolo[2,3-a]carbazole aromatic system in the molecule is slightly bent; the two terminal benzene rings make an angle of 7.5° with each other.