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EuTiO3-xHx (x ≤ 0.3) is prepared by low temperature CaH2 reduction of Eu2Ti2O7 and EuTiO3 (475—650 °C, 2 d) and characterized by XRD and magnetic measurements.

Compounds (V) and (VI) are formed from the same building blocks under slightly different conditions and their crystal structures are determined by single crystal XRD.

The pentacyclic indole skeleton of diterpene alkaloids of the paspaline family is constructed starting via 1,2-addition of 2-lithioindole to enone compound (IV) followed by a one-pot sequential reaction including intramolecular electrophilic aromatic substitution at the indole 3-position.

The title system efficiently catalyzes the coupling of hydrophobic as well as hydrophilic aryl halides (I) in water.

The reaction of the quinoxaline 4-oxides 7a,b with 2-chloroacrylonitrile resulted in the 1,3-dipolar cycloaddition reaction and further alteration to give the 4-hydroxy-2,3-dihydro-1H-1,2-diazepine[3,4-b]quinoxalines 8a,b and 9a,b, respectively, which were converted into the 4-oxo-2,3,4,6-tetrahydro-1H-1,2-diazepino[3,4-b]-quinolaxines 10a,b-q12a,b, respectively. The 2,3-dihydro-4-hydroxy form of 9a,b and the 2,3,4,6-tetrahydro-4-oxo form of 10a,b-12a,b were assigned by means of the NOE and 13 C-nmr spectral data

Chemical state analysis of Sn–Sb–O solid surfaces was performed by means of Auger electron spectroscopy (AES). Differential and numerically integrated AE spectra were curve-fitted using standard spectra obtained from pure substances. The fitting revealed, for the first time, the possibility of differentiating two antimony oxide components, Sb(III) and Sb(V), by AES. Using the AE spectral parameters obtained for these two chemical states, a correlation between the Sb AE peak positions and the average Sb oxidation number was constructed and it was applied for the determination of the average Sb oxidation state in Sn–Sb mixed oxide systems.

The reaction of the silylated base of 1,2-benzisoxazol-3(2H)-one (1) and its 7-methyl derivative 5 and 5-methyl-1,2-benzisothiazol-3(2H)-one (9), respectively, with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose followed by basic deprotection gave the corresponding β-D-ribonucleosides, and the silylated base of 1, when treated with 1-O-acetyl-2,3,5-tri-O-benzoyl-α-D-arabinofuranose in the presence of stannic chloride, afforded the corresponding α-arabinonucleoside. Structural proofs of these nucleosides are provided from elemental analyses and 1 H and 13 C nmr spectra

X-Ray crystal structure analysis has become very easy and an enormous number of crystal structures have been determined. Although such a development is partly brought about by the four-circle diffractometer, recent developments in technique of crystal structure analysis and computation require another diffractometer for quick data collection. Two methods are proposed; the synchrotron radiation to obtain more intense X-rays, and the Imaging-plate as a two-dimensional detector. Several types of diffractometer using the Imaging-plate have been made, for example, IPD-WAS, R-AXIS IIc, DIP-320 W and FIXD. The three-dimensional intensity data can be collected within 35 hours whereas about 23 days are necessary for the four-circle diffractometer. The data will be collected more quickly at photon Factory, using the synchrotron radiation.Recently an unstable intermediate structure has been observed by the step-wise structure analysis for the crystalline-state racemization of the cobaloxime complex crystal using the above IPD-WAS. A desolvation process has been observed for another cobaloxime complex crystal. Such a dynamical process observed in crystals should make clear the reaction mechanism more precisely.A new type of diffractometer is now designed to analyze the crystal structure within a submillisecond at SPring-8. Some structures at the excited states will be analyzed in near future.

Treatment of 3-(9-methylundeca-7,9-dienyl)-9-methylene-2,8-dioxabicyclo[4.3.0]nonane-5,7-dione (3) with SnCl 4 in CH 2 Cl 2 at -80°C produced intramolecular [2+2] cycloadducts (6a-d) rather than intramolecular Diels-Alder adducts

(S)-1,2-Alkanediols, which were the opposite configuration to those produced by baker’s yeast-mediated bioreduction of corresponding 1-hydroxy-2-alkanones, were prepared by baker’s yeast-mediated oxidation. Treatment of racemic 1,2-alkanediols with baker’s yeast under the aerobic condition followed by removal of the corresponding 1-hydroxy-2-alkanones, which were produced by enantioselective oxidation of (R)-1,2-alkanediols, afforded (S)-1,2-alkanediols.

The structures of two diastereomers, (1R * ,6aS * , 14aS * ,14bR * ,13E)- and (1R * ,6aR * ,14aR * ,14bS * ,13E)-1,14a-dimethyl-1,2,6,6a,7,8,9,10,11,12-decahydro-4H,5H,14aH-6a,14c-epoxy-3-cyclobuta[1',2':1,2]cyclopentadeca[2,3,4-b,c]furan-4,5-dione, in which a cyclobutane moiety is fused to a 13-membered ring are reported for the first time. The two diastereomers exhibit similar conformations except for the configuration about the methyl carbon (C15)

Reaction of aldehydes (prim-, sec-, and tert-) with diazoacetamide (8, 9) of N-substituted glycinate in the presence of Zr(IV) chloride in CH 2 Cl 2 affords β-keto amides (11,12) in good to high yields, which on treatment with n-Bu 4 NF in THF are led to N-protected 3-acyltetramic acids (13, 14)

Diels-Alder reaction of 1,6-bis(trimethylsilyloxy)-2,4-hexadiene with α-substituted acrylates and 5 to 7- and 9 to 11-membered α-(methylene)lactones has been carried out to examine correlation of dienophile structure with endo/exo selectivity. While the conformationally flexible acrylates produced cycloadducts of endo/exo = 59:41 to 74:26, the 5 to 7-membered lactones with rigid s-cis conjugate system provide cyloadducts of endo/exo = 13:87 to 32:68 and the 9 to 11-membered lactones which can take both s-cis and s-trans conformation afforded endo/exo ratios of 37:63 to 57:43.

Highly stereoselective elongation of a functionalized E isoprene unit on the Z terminal methyl of prenol was achieved by the N-ylide rearrangement of N-tiglyl-β-methallyldimethyl ammonium salt. (E,Z)-Rearrangement product was converted into 13-cis-retinol via useful conjugated triene isoprenoid synthon.

Reactions of four diastereomeric 2-(2-(trimethylsilyl)ethenyl)cyclopropyl acetates 7, derived from enol silyl ether 4 and Fischer carbene complex 6, with 2.2 equiv of MeLi at −80 ° to −30 °C afforded cyclopentenol 8 as a single diastereomer and acyclic enol silyl ethers 9 via the corresponding cyclopropanolates in ratios depending on the vinylsilane geometry. Predominant formation of 8 over 9 from (Z)-7 irrespective of the stereochemistry at C-1 was observed. This is the first example of oxyanion-accelerated vinylcyclopropane-cyclopentene rearrangement which proceeds at unprecedentedly low temperatures.

Li(sec-Bu)3BH-mediated reductive cyclization of optically pure 8-((S)-p-tolylsulfinyl)-(2E,7Z)-octadienoate 9 and 7-(p-tolylsulfinyl)-2,6-heptadienoate 16 afforded trans-2-((p-tolylsulfinyl)-methyl)cyclohexane-1-carboxylate and trans-2-((p-tolylsulfinyl)methyl)cyclopentane-1-carboxylate, respectively, as a single isomer. © 1997 Elsevier Science Ltd. All rights reserved.

The α-carbanion-stabilizing ability of the phenylthio and trimethylsilyl groups was compared based on the relative rate of the base-catalyzed Brook rearrangement of the β-substituted α-silylallylalcohol.

Conformationally restricted analogues of (±)-(Z)-2-aminomethyl-1-phenyl-N,N-diethylcyclopropanecarboxamide [milnacipran, (±)-1] were designed on the basis of its characteristic cyclopropane structure and were synthesized enantioselectively to develop efficient NMDA receptor antagonists. Among these analogues, (1S,2R)-1-phenyl-2-[(R)-1-amino-2-propynyl]-N,N-diethylcyclopropanecarboxamide (2d) had one of the most potent affinities for the receptor, with a Ki value of 0.29 μM. The blockade of NMDA receptor channels expressed by Xenopus oocytes by 2d was investigated in detail, and 2d was identified as a new class of open channel blocker against this receptor.

The [3 + 2] annulation using β-[2-(pyridyl)thio] and β,β-dichloro derivatives of acryloylsilane and the lithium enolate of methyl ketones successfully proceeded to afford 4-alkyl-4-hydroxy-3-(2-pyridylthio)cyclopentanone and 4-alkyl-3-chloro-4-hydroxy-2-cyclopentenone, respectively.

The lanthanide deficient perovskite Ce 2/3 TiO 3 was synthesized in vacuum at 1400°C, and the actual formula was found to be Ce 2/3 TiO 2.95 from thermogravimetry. Its crystal structure was refined to the same structure as in La 2/3 TiO 3 , i.e. the orthorhombic double perovskite structure Pmmm having the crystallographic ordering of Ce vacancy along the c -axis. No obvious magnetic ordering was observed between 2 and 300 K in DC susceptibility–temperature ( χ – T ) curves. It was also suggested that the valence of the Ce ions is changed to 3+ (4f 1 ) from the initial valence 4+ (4f 0 ) during the sample firing in vacuum, as is the case for CeTiO 3 and Ce 1− x A x TiO 3 (A=Sr and Ba). Inverse susceptibility–temperature (1/ χ – T ) curves deviated from the Curie–Weiss law below ∼60 K. Magnetization–field ( M – H ) curves exhibited almost only paramagnetic profiles down to 2 K.

The selection of odor-active conformers and the construction of a model for a targeted odor type, i.e., for the lily-of-the-valley odor, were examined. The disagreement of the odors of 1,3,4,5-tetrahydro-2-benzoxepin derivative 1 and 3-[4-(tert-butyl)phenyl]-2-methylpropanal (2) is discussed in terms of their stable conformers. The conformer active for the lily-of-the-valley odor was investigated by conformational analyses of several related compounds. Based on the integrated model consisting of the assumed active conformers (Fig. 5), compounds anticipated to possess the lily-of-the-valley odor were designed and synthesized. The odor of synthetic 7-(tert-butyl)-1,2,4,5-tetrahydro-3H-benzocyclohepten-3-one (8) and 3-[4-(tert-butyl)phenyl]cyclopentanone (13) were evaluated by perfumers to have a floral odor and to recall the lily-of-the-valley and lilac odors, respectively. Our methodology to design new odoriferous compounds, based on conformational analysis, selection of odor-active conformers, and construction of a model, proved to be satisfactory.

Various 3-sulfonyl-1,2,4-triazole-1-carboxamides (5a–h) were synthesized and their hydrophobicities were evaluated from their retention time in reversed-phase HPLC chromatography. Although the compounds have rather complex structures, a good linear relationship was observed between log k′ of these compounds derived from the retention time of HPLC and log PH for water–hexadecane partition coefficients of related alcohols. In regards with the rotation about the O2S–C(ester part) single bond, the preference for a gauche conformer relative to the anti form was revealed by both X-ray structural analysis of 5a and calculations at the AM1 level. In this conformation, substituents are arrayed to have the largest separation between the hydrophilic and hydrophobic parts. This can be rationalized as the primary reason for the good linearity.

The catalytic cross-coupling between ArZnX and ICH2(CH2)nP(O)(OEt)2 (n = 0−3) has been investigated to determine the utility of the Rh catalyst during the alkyl-aryl cross-coupling and to develop a...

Neutron diffraction and X-ray absorption measurements were carried out for a silver–lead oxide Ag5Pb2O6. The powder neutron diffraction patterns could be fitted to the trigonal P 3 ¯ 1 m structure, as was found by X-ray diffraction. From the bond-valence-sum (BVS) analysis, the valences of the Ag and Pb ions were estimated to be about 1+ and 3.7+, respectively. The X-ray absorption measurements indicated that the ionic state of Ag is close to 1+, while that of Pb stands between 3+ and 4+. The deviation of the valence of the Pb ion from 4+ suggests a contribution of Pb orbitals to the metallic conduction as well as the possible superconductivity of this material, consistently with a recent band-structure calculation.

Structure, magnetism and transport properties have been investigated for the perovskite La2NiRuO6. The crystal structure can be refined to monoclinic P21/n where Ru4+ and Ni2+ are settled with ordered arrangement. An electrical resistivity measurement shows that this compound is insulating below room temperature. Magnetization measurements show a magnetic transition at around 20 K. From AC magnetic susceptibility measurements, it is assumed that this transition is brought about by antiferromagnetic order.