bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Synthesis and Crystal Structure of Bis(cyclo-l-histidyl-l-histidyl)copper(II) Perchlorate Tetrahydrate
Authors: Hori Fumio , Kojima Yoshitane , Matsumoto Keiji , Ooi Shun’ichiro , Kuroya Hisao 
Published: July 2006

Abstract
The title compound was prepared, and its structure then determined by X-ray structure analysis. The crystal is trigonal with the space group P3221, a=8.450(3), c=42.00(6)Å, and Z=3. The crystal structure has been determined from the diffractometer data and refined by a least-squares method to an R value of 0.103 for 1349 independent reflections with I&gt;3σ(I). The cyclo-l-histidyl-l-histidyl is coordinated to the Cu atom via the N atoms of the respective imidazolyl groups. The coordination of Cu is not planar but distorted toward the tetrahedral configuration, the interplanar angle betweent (Remark: Graphics omitted.) planes being 29°. The complex has virtually D2 symmetry: there are two pseudo two-fold axes and one crystallographically imposed two-fold axis which relates two chelate rings. The chelate rings assume the δ conformation, and the ligating cyclo-l-histidyl-l-histidyl is of a folded form with a bowsprit-boat 2,5-piperazinedione ring. The electronic and circular dichroism spectra in the visible region are presented.
The Formation of the Cd-bearing Ferrite by the Air Oxidation of an Aqueous Suspension
Authors: Kaneko Ken , Takei Katsumori , Tamaura Yutaka , Kanzaki Tadao , Katsura Takashi 
Published: July 2006

Abstract
When the Cd2+/Fetotal ratio in the initial solution is below 0.1, almost all cadmium ions are incorporated into the ferrite with the spinel-type structure by the air oxidation of an aqueous suspension at a pH 9.0 and at 65 °C. The Cd-bearing ferrite thus obtained is a ferromagnet and is oxidized to form a completely oxidized Cd-bearing ferrite at 150 °C in the air; this ferrite is still a ferromagnet and belongs to the Fe2O3–CdFe2O4 binary system, with the same spinel type structure. When the Cd2+/Fetotal ratio in the initial solution increases to 0.5, the crystalline phases formed is complicatedly changed; the products are also significantly affected by the pH value of the suspension. The most favorable pH value at 65 °C to form the Cd-bearing ferrite is proposed to be 10.0.
Photochemical Reactions of N-Acyl-2,3-dihydrobenzoxazol-2-ones
Authors: Ishida Sadahiro , Hashida Yoji , Shizuka Haruo , Matsui Kohji 
Published: July 2006

Abstract
Photo-Fries rearrangements of N-acyl-2,3-dihydrobenzoxazol-2-ones are described. Irradiation of N-acyl-2-3-dihydrobenzoxazol-2-ones in acetonitrile afforded a mixture of 2-acyl-2,3-dihydrobenzoxazol-2-one and 6-acyl-2,3-dihydrobenzoxazol-2-one together with other minor products. However, 2,3-dihydrobenzoxazol-2-one and N-methyl-2,3-dihydrobenzoxazol-2-one were very photostable. The reaction scheme involving Norrish type I dissociation has been discussed.
Interactions between Sulfur Ylides and Electrophilic Monosulfides
Authors: Matsuyama Haruo , Matsumoto Masae , Kobayashi Michio , Minato Hiroshi 
Published: July 2006

Abstract
The catalytic activities of electrophilic monosulfides, Ar–S–R* (R*=CN, CF3, OMe), for the transylidation reactions of sulfur ylide, Ph(Me)\overset⊕S–\overset\ominusC(CO2Me)2, with alkyl sulfides and pyridines were investigated. Among these monosulfides, methyl arenesulfenates reacted with dimethylsulfonium phenacylide (or dimethylsulfonium ethoxycarbonylmethylide) to give α-(arylthio)phenacylides (or α-(arylthio)ethoxycarbonylmethylides) and methanol. The 13C-NMR spectra of several sulfur ylides and aryl thiocyanates were investigated in CDCl3, and the presence of S-ylide-thiocyanate adduct intermediates was established.
Furanoeremophilan-14β,6α-olide. A New Furanosesquiterpene Lactone of an Eremophilane-type from Ligularia Hodgsoni Hook, f.
Authors: Ishizaki Yoshiaki , Tanahashi Yoshiaki , Tsuyuki Takahiko , Takahashi Takeyoshi , Tori Kazuo 
Published: July 2006

Abstract
A new sesquiterpene lactone of an eremophilane-type was isolated from Ligularia Hodgsoni Hook, f., and the structure including the absolute stereochemistry was shown to be furanoeremophilan-14β,6α-olide.
Reaction of Coordinated Phosphines. V. Aryl and Alkyl Transfer from Tertiary Phosphine to Transition Metal
Authors: Kikukawa Kiyoshi , Yamane Toru , Ohbe Yoshihiro , Takagi Makoto , Matsuda Tsutomu 
Published: July 2006

Abstract
A carbon-phosphorus bond cleavage was observed in the reaction of MCl2(PR3)2 (M=Ni, Co, or Pd, R=Ph, n-C8H17) with p-tolyllithium, p-tolylmagnesium halide, lithium aluminum hydride, or magnesium amalgam, and the reactivity was most pronounced with Ni followed by Co and Pd. Reaction of NiCl2(PPh3)2 with p-tolyllithium gave biphenyl and 4-methylbiphenyl, along with 4,4′-dimethylbiphenyl. Phenyllithium was formed in the reaction mixture, and the recovered tertiary phosphine contained tri-p-tolylphosphine, di-p-tolylphenylphosphine, and p-tolyldiphenylphosphine as well as triphenylphosphine. 1-Octene was formed in the reaction of NiCl2{P(n-C8H17)3}2 with p-tolyllithium. Thermal decomposition of Ni(mesityl)X(PEt3)2 (X=mesityl or Br) and Co(mesityl)2(PPhEt2)2 at 30 °C gave vinyl mesitylene.
Studies on Nucleosides and Nucleotides, VII. Preparation of Pyrimidine Nucleoside 5′-Phosphates and N3,5′-Purine Cyclonucleosides by Selective Activation of the 5′-Hydroxyl Group
Authors: Kimura Junji , Fujisawa Yoshiyuki , Yoshizawa Toyokichi , Fukuda Kazuhiro , Mitsunobu Oyo 
Published: July 2006

Abstract
The reaction of thymidine or uridine with 1.5 molar equivalents each of dibenzyl hydrogenphosphate, diethyl azodicarboxylate, and triphenylphosphine in HMPT at room temperature for 1 day, followed by debenzylation, afforded dpT and pU in 73 and 78% yields, respectively. Neither nucleoside 3′-phosphate nor 3′,5′-diphosphate was formed. 5′-O-Benzoyl thymidine 3′-(2-cyanoethyl)phosphate also reacted smoothly with thymidine at room temperature giving d-bzT3′p(CNEt)5′T in a 54% yield. Adenosine and Guanosine gave the corresponding N3,5′-cyclonucleosides as main products, less than 1% pA and pG being formed.
The Cross-Aldol Reaction of 3-Alkoxy-2-cyclohexen-1-ones with α,β-Enals. A Synthesis of 4-(trans-2-Butenylidene)-3,5,5-trimethyl-2-cyclohexen-1-ones
Authors: Torii Sigeru , Inokuchi Tsutomu , Ogawa Hidenori 
Published: July 2006

Abstract
The cross-aldol reaction of 3-alkoxy-2-cyclohexen-1-ones with α,β-enals afforded the corresponding 3-alkoxy-6-(1 -hydroxy-2-alkenyl(or aryl)-2-cyclohexen-1-ones in 78–98 % yields. The condensation of a kinetic enolate anion of 3-ethoxy-5,5-dimethyl-2-cyclohexen-1-one with trans-2-butenal, and subsequent dehydration together with methylation, afforded 4-(trans-2-butenylidene)-3,5,5-trimethyl-2-cyclohexen-1-ones, one of the most important constituents of tobacco flavour, in a 74% yield.
X-Ray Fluorescence Spectroscopy of Inorganic Solids. III. Si Kα and Kβ Spectra in Binary Silicates
Authors: Kikuchi Niro , Maekawa Takashi , Yokokawa Toshio 
Published: July 2006

Abstract
The Si Kα and Kβ spectra of several silicates were measured. The Kα spectra showed negative energy shifts referred to SiO2; these are consistent with the results for the binary silicate glasses. On the other hand, the Kβ shifts were positive and the absolute values were about ten times as large as the Kα shifts in each compound. A linear relation was observed between Kα and Kβ energy shifts. The Si 1s energy shift for the orthosilicate was estimated from the Kβ spectral splitting of Na2Si2O5. The stability of the silicon–oxygen bond was discussed with the aid of the shifts in Kβ and the Si 1s. The above linear relation suggests that the silicon–oxygen bond strength is lowered (the Kβ energy is increased) with decreasing Goulombic interaction (lowering Kα energy) between silicon and oxygen in the silicates.
Synthetic Studies of Laurencin and Related Compounds. IV. Synthesis of cis-2-Ethyl-8-formyl-3,4,7,8-dihydro-2H-oxocin-3-one 3-Ethylene Acetal and Related Compounds
Authors: Masamune Tadashi , Matsue Hajime , Murase Hisashi 
Published: July 2006

Abstract
The synthesis of cis-2-ethyl-8-formyl-3,4,7,8-dihydro-2H-oxocin-3-one and its derivatives, key intermediates for synthesis of laurencin, from methyl 2-ethyl-2,5-dihydro-2-furoates is described. The structure and configuration of these compounds and the synthetic intermediates are defined clearly on the basis of the chemical and spectral evidence.
Preparation and Circular Dichroism of Dichloro-(S)-2-(butylphenylphosphinomethyl)pyrrolidine-palladium(II)([PdCl2L]) and Its Related Complexes, and the Absolute Configuration of [PdCl2L] Determined by X-Ray Analysis
Authors: Kinoshita Isamu , Kashiwabara Kazuo , Fujita Junnosuke , Yamane Takashi , Ukai Hitoshi , Ashida Tamaichi 
Published: July 2006

Abstract
(S)-2-(Butylphenylphosphinomethyl)pyrrolidine(L) was prepared from (S)-proline via four main reaction steps. A pair of diastereomers of the PdCl2L complex, the isomerism of which comes from chiral configuration of the phosphorus atom, crystallized in different forms (needle and block), which were separated by hand picking. The molecular structure and absolute configuration of one(block) of the dichloro complexes was determined by X-ray analysis. Crystallographic data are: P212121, Z=4, a=13.576(4), b=16.351(3), c=8.041(2) Å, and R=7.8% for 1659 reflections. The Pd atom has a distorted square planar coordination of four donor atoms. The Pd-Cl bond distance trans to Pd-P, 2.367 Å, is longer than that trans to Pd–N, 2.296 Å. The absolute configuration of the coordinated phosphorus atom was determined to be R by assuming S configuration for the asymmetric carbon atom of the aminophosphine. The corresponding diastereomers of the dibromo complex were also prepared from each diastereomer of the chloro complex. The circular dichroism spectra of these diastereomers were compared with one another and with those of other related complexes, and the vicinal effects due to the chiral phosphorus atoms in these complexes were examined.
Phosphinyl- and Phosphinothioylamino Acids and Peptides. IV. Further Examples of Use of the Diphenylphosphinothioyl Group for the Protection of Amino Acids
Authors: Ikeda Shigeru , Tonegawa Fumio , Shikano Etsuro , Shinozaki Kozo , Ueki Masaaki 
Published: July 2006

Abstract
The preparation and purification of diphenylphosphinothioyl(Ppt)-amino acids were studied. The side-chain functional groups of tyrosine and cysteine were found to react also with diphenylphosphinothioyl chloride to form O-Ppt and S-Ppt derivatives. Acidic reagents for the removal of N-Ppt group were examined by using N,O-bis-Ppt-tyrosine ethyl ester (III) as the most difficult model, HCl in HCO2H–CH2Cl2 being found to be most preferable. The O- and S-Ppt bonds were stable during the course of acidic treatments, but could be removed by alkaline hydrolysis. An application of Ppt-amino acids to the solid phase peptide synthesis is given.
Synthesis of 3-Ethoxycarbonyl-1,2,3,4,5,10-hexahydroindeno[1,2-d]azepine
Authors: Kimura Masaru , Morosawa Shiro 
Published: July 2006

Abstract
3-Ethoxycarbonyl-1,2,3,4,5,10-hexahydroindeno[1,2-d]azepine (10b) was synthesized from 1-benzylpiperidin-4-one and 1-benzyl-4-[o-(hydroxymethyl)phenyl]hexahydroazepin-4-ol. Compound 10b is of particular interest as an intermediate for the preparation of the hitherto unknown indeno[1,2-d]azepine. It was found that 1-ethoxycarbonyl-4-[o-(hydroxymethyl)phenyl]hexahydroazepin-4-ol and 1-ethoxycarbonyl-4-[o-(hydroxymethyl)phenyl]piperidin-4-ol (16b) give 1-ethoxycarbonylspiro[azepin-4,1′(3H)-isobenzofuran] and 1-ethoxycarbonylspiro[3H-isobenzofuran-1,4′-piperidine] (17b), respectively. Treatment of 16b with 88% formic acid gave 17b and 2-ethoxycarbonyl-2,3,4,9-tetrahydro-1H-indeno[2,1-c]pyridine.
The Nature of Athabasca Tar Sand (Canada) and Tar Sand Derivatives. A Comparison with Coal-hydrogenolysis Products
Authors: Yoshida Ryoichi , Yoshida Tadashi , Ikawa Yasuko , Okutani Takeshi , Hirama Yasuko , Nakata Yoshinori , Yokoyama Shinichi , Makabe Masataka , Hasegawa Yoshihisa 
Published: July 2006

Abstract
Solvent extracts of Athabasca tar sand were analyzed by the Brown-Ladner method, the Takeya et al. method, and the Speight method on the basis of the 1H-NMR data and by 13C-NMR spectroscopy. The structural characteristics of Athabasca tar sand derivatives were also compared with those of coal-hydrogenolysis products. The results show that the structural characteristics of hexane solubles, monomers consisting of one aromatic ring substituted highly with C6 aliphatic chains, resemble those of the oil fraction produced during the initial stage of the hydrogenolysis of Taiheiyo coal. However, the structural characteristics of the hexane insoluble-benzene solubles, oligomers consisting of 2 aromatic rings substituted highly with C4–5 aliphatic chains, are different from those of any coal-hydrogenolysis products. In addition, the close agreement between the fa value obtained by the Brown-Ladner method and 13C-NMR may indicate that, for solvent extracts of Athabasca tar sand, the assumption in the Brown-Ladner method that the atomic H/C ratio of aliphatic structures is 2 is proper.
Stereochemical Studies of the Hydrogenation with Asymmetrically Modified Nickel Catalysts; The Hydrogenation of Methyl 2-Alkyl-3-oxobutyrate
Authors: Tai Akira , Watanabe Hiroshi , Harada Tadao 
Published: July 2006

Abstract
The hydrogenation of methyl 2-methyl-3-oxobutyrate (I) to methyl 3-hydroxy-2-methylbutyrate (III) was carried out with various types of asymmetrically modified nickel catalysts (MNi). The use of MNi always resulted in the deviation of the ratio, 2S/2R=((2S,3R)-III+(2S,3S)-III)/((2R,3R)-III+(2R,3S)-III, from 1/1, in spite of the use of racemic I. A catalyst giving a larger 2S/2R value always gave a larger 3R/3S value. These results led to the conclusion that the configurations at the C-2 and C-3 positions of the product were determined in the process of the formation of the complex between the substrate and the modifying reagent (the absorption step), not at the step of the hydrogen addition to the adsorbed substrate (the rate-determining step). The best optical yield and the highest ratio of erythro-III/threo-III were obtained when (R,R)-tartaric acid-MNi was used as a catalyst. The amounts of the isomers produced were in the following order: 2S,3R&gt;&gt;2R,3R≈2R,3S&gt;2S,3S. Stereochemical models are proposed to account for the formation of the 2S,3R-isomer in a large excess.
Reaction of Coordinated Phosphines. IV. Mechanism of Carbon-Phosphorus Bond Cleavage in Triarylphosphines and Trialkylphosphines by Palladium(II) Acetate
Authors: Kikukawa Kiyoshi , Takagi Makoto , Matsuda Tsutomu 
Published: July 2006

Abstract
Reaction of triphenylphosphine with an equimolar amount of Pd(OAc)2 in acetic acid at room temperature in the presence of styrene gave trans-stilbene(94%), H3PO4(0.8%), PhP(O)(OH)2(40%), Ph2P(O)(OH)(19%), and Ph3P=O(35%). Reactions of tributyl- and trioctylphosphine with Pd(OAc)2 in acetic acid at 90 °C yielded butene(20%) and octene(1-; 22%, 2-; 17%), respectively, as main products. The phenylation of some olefins with triphenylphosphine in acetic acid-d, as well as other features of the reaction lead to the conclusion that nucleophilic attack on coordinated phosphorus atom is the most probable pathway for the formation of the phenylation agent (phenylpalladium species) in the reaction system among the others, ortho-metallation and oxidative addition.
Double Diels-Alder Reactions of Coumalic Acid with 1,3-Dienes
Authors: Imagawa Takeshi , Nakagawa Tsunefumi , Kawanisi Mituyosi , Sisido Keiiti 
Published: July 2006

Abstract
Thermal reaction of coumalic acid with 1,3-butadienes gave after diazomethane treatment dimethyl tricyclo[3.2.1.02,7]oct-3-ene-2,4-dicarboxylate via double Diels-Alder reaction. This represents the simplest synthesis of such a tricyclic system. The reaction with cyclopentadiene was also studied.
Studies on Chrysanthemate Derivatives. VI. A Stereoselective Synthesis of trans-3-(2,2-Dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic Acid and Related Compounds
Authors: Nakada Yasuo , Endo Rokuro , Muramatsu Shigeki , Ide Junya , Yura Yasuo 
Published: July 2006

Abstract
A new method is described for the stereoselective synthesis of trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid (2t) via ethyl 3,3-dimethyl-4,6,6,6-tetrachlorohexanoate (3a) as a key intermediate. The key intermediate (3a) was obtained by addition of carbon tetrachloride to ethyl 3,3-dimethyl-4-pentenoate, prepared by condensation of 3-methyl-2-buten-1-ol and triethyl orthoacetate followed by Claisen rearrangement. Treatment of 3a with sodium t-pentyloxide in benzene gave ethyl trans-2,2-dimethyl-3-(2,2,2-trichloroethyl)-1-cyclopropanecarboxylate (6t) in good yield. Dehydrochlorination and hydrolysis of 6t using potassium hydroxide in ethanol afforded 2t in high yield.
Photochemical Reduction of Di-t-butyl Thioketone
Authors: Ohno Atsuyoshi , Uohama Misao , Nakamura Kaoru , Oka Shinzaburo 
Published: July 2006

Abstract
Photochemical reduction of the title compound has been studied and the result is compared with that from the reaction with thiobenzophenone, an aromatic thioketone.
1,3,5-Triarylpyrazoles as Phosphorescing Impurities in 1,3,5-Triaryl-2-prazolines
Authors: Yamamoto Hiroyoshi , Sano Yumiko , Shirota Yasuhiko , Seki Hajime , Mikawa Hiroshi 
Published: July 2006

Abstract
The origin of the phosphorescence observed for 1,3,5-triphenyl-2-pyrazoline and its substituted derivatives was investigated. Unlike the previously accepted conclusion, our conclusion is that the phosphorescence originates from the corresponding pyrazoles formed from the pyrazolines by the action of light.
Hydrogen Atom Abstraction of p-Chloranil Triplet in 1,4-Dioxane in the Presence and Absence of Tetrachlorohydroquinone
Authors: Kobashi Harumichi , Tomioka Yasunaka , Morita Toshifumi 
Published: July 2006

Abstract
Mechanisms of hydrogen atom abstraction by triplet p-chloranil [CA(T)] from 1,4-dioxane (DOH) and tetrachlorohydroquinone (CAH2) were studied in detail by means of nanosecond laser flash photolysis. A broad band around 740 nm in the transient absorption spectrum of CA in DOH was assigned to the charge-transfer band of the triplet EDA complex between CA and DOH. Efficiencies for the hydrogen atom abstraction from DOH and CAH2 were determined to be 0.13 and 0.58, respectively. The former value indicates that the hydrogen atom abstraction from DOH is less effective than a physical process in deactivation of the triplet complex. From the latter value together with the measured value of the quenching rate constant (1.7×109 dm3 mol−1 s−1) of the triplet by CAH2, it is inferred that the hydrogen atom abstraction of CA(T) from CAH2 takes place competing with an efficient radiationless deactivation via the triplet exciplex between CA(T) and CAH2 as a common intermediate.
Clustering Reactions of the Protonated Nitrogen N2H+ with Hydrogen Molecule in the Gas Phase
Authors: Hiraoka Kenzo 
Published: July 2006

Abstract
Clustering reactions of the protonated nitrogen N2H+ with hydrogen molecule, N2H+(H2)n−1+H2=N2H+(H2)n(n–1, n), were studied in a pulsed electron beam mass spectrometer with a high-pressure ion source. The values of enthalpy change −ΔSn−1,n(kcal/mol) and the entropy change −ΔSn−1,n(e.u.) obtained from the van’t Hoff plots of equilibrium constants were (0, 1) 7.2, 22.6, (1, 2) 1.5, 14.0. No cluster ions larger than N2H+(H2)2 were observed even at −187 °C. The relatively low values of enthalpy change for the clustering reactions (0, 1) and (1, 2) suggest that the positive charge in N2H+ is delocalized, the N2H+ ion very weakly interacting with additional hydrogen molecules electrophilicly. The calculated entropy change also suggests that hydrogen molecules in N2H+-(H2)n are weakly bound to the core ion N2H+, having considerable freedom of motion in the cluster ion. The thermochemical study proves that the cluster ion N2H+(H2)2 does not have the structure of the protonated hydrazine N2H6+.
The Electronic Spectra and Nonaqueous Oxidation and Reduction Potentials of Azoxybenzenes, and Their Mutual Correlation
Authors: Kubota Tanekazu , Miyazaki Hiroshi , Yamakawa Masumi , Ezumi Kiyoshi , Yamamoto Yoshiko 
Published: July 2006

Abstract
The near-ultraviolet absorption spectra of various p,p′- and m,m′-disubstituted azoxybenzenes were recorded in aprotic and protic solvents. The PPP-SCFMO-CI calculation was used in analyzing the spectra and the solvent effect on them. The π-π* bands of azoxybenzene could be well interpreted on the basis of the electronic structure of benzaldehyde N-phenyl oxime (a nitrone). In addition, the half-wave potentials of reduction (E1⁄2red) and oxidation (E1⁄2oxd) were also measured in nonaqueous solvents. These electrochemical data and the above spectral data satisfied a good linear relation: (E1⁄2oxd–E1⁄2red)=k1·Eho→luUV+k2, this equation having been previously proposed by us. In the Appendix, we have discussed the physical meaning of the constant term, k2, from the quantitative standpoint, using a series of alternant hydrocarbons as a typical example. Finally, a good linear relation between the E1⁄2red or E1⁄2oxd values and the substituent constants was demonstrated and discussed in azoxybenzenes.
Anharmonic Potential Functions of Simple Molecules. III. Computation of Vibration-Rotation Energies of XYZ and X2Y2 Type Linear Molecules through Direct Numerical Diagonalization: Application to the N2O Molecule
Authors: Suzuki Isao 
Published: July 2006

Abstract
A formalism has been developed for the calulation of vibration-rotation energy levels of linear XYZ and X2Y2 type molecules through direct numerical diagonalization of vibration hamiltonian matrix. The procedure of evaluating vibration as well as vibration-rotation energies can be described mostly in matrix algebra and thus easily converted to computer languages. The N2O molecule was chosen as an example of numerical treatment. Several approaches have been checked in evaluating Bv and Dv and they are discussed from the view point of accuracy and efficiency in computations. It is found that the variational approach of computing Bvr, contribution of rotational hamiltonian to Bv, is very efficient and accurate. Some peculiar features of the molecular potential of the X2Y2 type molecule are discussed in connection with their adaptation on the direct numerical diagonalization method.
Molecular Dynamics of the Inclusion Complexes of Cyclohexaamylose with Some Aromatic Amino Acids and Dipeptides
Authors: Inoue Yoshio , Katôno Yukio , Chûjô Riichirô 
Published: July 2006

Abstract
The molecular dynamics of the inclusion complexes of cyclohexaamylose as a model of enzyme have been studied by means of carbon-13 NMR spectroscopy. As substrates we have chosen l-phenylalanine, l-tyrosine, l-tryptophan, glycyl-l-phenylalanine, and l-phenylalanyl-l-lysine. The molecular motion of both the cyclohexaamylose and the substrates in D2O–DCl solutions have been investigated by dividing the spin-lattice relaxation time into two contributions, the overall molecular reorientation and the anisotropic internal rotation. Upon complex formation, the correlation times for the internal motion of the phenyl ring of phenylalanine residue increase by a factor of up to 8, while those for the overall reorientation increase by a factor of only 2. These results indicate that the complex formation of the substrate with the cyclohexaamylose are induced by the insertion of aromatic side chain into a cavity of cyclohexaamylose even in the aqueous solution. The overall correlation times of the substrates are about three to seven times snorter than those of the host molecule. Thus the forces which bind the host cyclohexaamylose and the substrate are relatively weak. It was observed that the tightness of the inclusion varies with the types of aromatic amino acids and dipeptides.