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S Kashino

Publications and source records attributed to S Kashino.

17 recordsLinked to original sources
PubMed2001

Morpholinium 2-chloro-4-nitrobenzoate, 2-chloro-5-nitrobenzoate and 4-chloro-3-nitrobenzoate.

Morpholinium 2-chloro-4-nitrobenzoate, C4H10NO+*C7H3ClNO4-, (I), crystallizes in a non-centrosymmetric space group. The cations and anions are connected by N-H...O hydrogen bonds to afford a 2(1) helical chain. Morpholinium 2-chloro-5-nitrobenzoate, C4H10NO+*C7H3ClNO4-, (II), and morpholinium 4-chloro-3-nitrobenzoate, C4H10NO+*C7H3ClNO4-, (III), both crystallize in a centrosymmetric space group. In (II) and (III), two cations and two anions are held together by N-H.O hydrogen bonds to form a centrosymmetric ring with graph-set descriptor R4(4)(12).

Journal Article↗
PubMed2001

Ammonium hydrogen tartronate at 240 and 20 K.

The low-temperature structure determination of the title compound, alternatively called ammonium hydrogen hydroxypropanedioate, NH(4)(+) x C(3)H(3)O(5)(-), has revealed that the H atom involved in a very short asymmetric O--H...O hydrogen bond [O...O = 2.448 (2) A at 240 K and 2.4393 (10) A at 20 K] is disordered.

Journal Article↗
PubMed2001

2:1 complexes of 2-chloro-4-nitrobenzoic acid and 2-chloro-5-nitrobenzoic acid with pyrazine.

2-chloro-4-nitrobenzoic acid and 2-chloro-5-nitrobenzoic acid form O--H...N hydrogen bonds with pyrazine to afford 2:1 complexes of 2C7H4ClNO4*C4H4N2, (I) and (II), respectively, that are located on inversion centers. The 2C7H4ClNO4*C4H4N2 units in both complexes are connected by weak C--H...O hydrogen bonds; the units build a three-dimensional hydrogen-bond network in (I) and a ribbon structure in (II).

Journal Article↗
PubMed2001

Hydrogen-bonded complexes of 2-pyridone with centrosymmetric and non-centrosymmetric dicarboxylic acids.

2-Pyridone (2-oxopyrimidine) forms hydrogen-bonded complexes with dicarboxylic acids, the molar ratio of 2-pyridone/dicarboxylic acid being 2:1 for the complexes with oxalic acid (ethanedioic acid), 2C(5)H(5)NO.C(2)H(2)O(4), (I), and trans-beta-hydromuconic acid (trans-hex-3-enedioic acid), 2C(5)H(5)NO.C(6)H(8)O(4), (II), and 1:1 for the complexes with trans-glutaconic acid (trans-pent-2-enedioic acid), C(5)H(5)NO.C(5)H(6)O(4), (III), and L-tartaric acid (L-2,3-dihydroxybutanedioic acid), C(5)H(5)NO.C(4)H(6)O(6).H(2)O, (IV). Common features in the hydrogen-bonding patterns were found for the centrosymmetric and non-centrosymmetric acids, respectively. The 2-pyridone molecule takes the lactam form in these crystals.

Crystallography, X-Ray↗
PubMed2001

Potassium hydrogen trans-glutaconate monohydrate at 295, 245 and 40 K, and its rubidium analogue at 298 K.

A centrosymmetric and short O-H.O hydrogen bond was found in isomorphic crystals of potassium hydrogen trans-glutaconate monohydrate (potassium hydrogen trans-pent-2-ene-1,5-dioate, K(+).C(5)H(5)O(4)(-).H(2)O), (I), and rubidium hydrogen trans-glutaconate monohydrate (rubidium hydrogen trans-pent-2-ene-1,5-dioate, Rb(+).C(5)H(5)O(4)(-).H(2)O), (II). The O.O distance at room temperature is 2.444 (3) A in (I), and 2.417 (4) A in (II). The O.O distance for (I) showed no significant decrease at low temperatures.

Journal Article↗
PubMed2001

XAFS study on metal endohedral fullerenes.

Structure of metal endohedral fullerenes is studied by XAFS and XANES. The Sc-Sc distance of 2.23(1) A determined from Sc K-edge XAFS supports the formation of a triangular Sc3 cluster in Sc3@C82 as is found by MEM analysis for the X-ray diffraction. Gd L(III)-edge XAFS of Gd@C82 shows that the first and the second neigboring Gd-C distances are 2.51(2) and 2.85(4) A, respectively. The La-La distance of La2@C80 has been determined to be 3.90(1) A at 40 K. This value does not change when increasing temperature [3.90(2) A at 240 K]. The position and the valenece of the Eu atom in Eu@C60 are also discussed based on Eu L(III)-edge XAFS and XANES.

Journal Article↗
PubMed2001

XAFS study on a pressure-induced superconductor Cs3C60 under high pressure.

Cs K-edge XAFS of Cs3C60 which is a pressure-induced superconductor were measured at 21 and 34 kbar by using a diamond anvil cell (DAC) in order to obtain the structural information under high pressure, and to clarify the origin of the pressure-induced superconductivity. The distances and the mean square displacements between the Cs and C atoms are consistent with those determined by X-ray powder diffraction. Consequently, the high-pressure XAFS can give the reliable structural-information on a fullerene superconductor under high pressure. We also show the procedure of the analysis of high-pressure XAFS with DAC in detail.

Journal Article↗
PubMed2001

A new polymorph of barium chloroanilate trihydrate.

Single crystals of a new polymorph of the title compound, barium(II) 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone trihydrate, Ba2+.C6Cl2O4(2-).3H2O, have been grown in sodium metasilicate gel. Each Ba2+ cation is coordinated by eight O atoms. The Ba2+ cations are bridged by an O atom of a ligand around the centre of symmetry at Wyckoff position 4a and by the O atom of a water molecule around the centre of symmetry at Wyckoff position 4b, forming a sheet parallel to the (100) plane. Loose contacts are found around one of the water molecules, as observed in the Cmca form.

Journal Article↗
PubMed2001

1:2 Complexes of chloranilic acid with pyrazole and imidazole, and the acetonitrile solvate of a 1:1 complex with imidazole.

2,5-Dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid) forms X-H.Y (X, Y = N or O) and C-H.Cl hydrogen bonds with pyrazole and imidazole to afford bis(pyrazolium) dichloroanilate and bis(imidazolium) dichloroanilate, (I) and (II), both 2C(3)H(5)N(2)(+).C(6)Cl(2)O(4)(2-), and imidazolium chloroanilate acetonitrile solvate, C(3)H(5)N(2)(+).C(6)HCl(2)O(4)(-).C(2)H(3)N, (III). Their crystal structures demonstrate three novel supramolecular architectures based on supramolecular synthons to build a ladder, (I), a two-dimensional network, (II), and a flat ribbon, (III).

Journal Article↗
PubMed2000

Selenium dioxide oxidations of dialkyl-3H-azepines: the first synthesis of 2-azatropone from oxidation of 2, 5-Di-tert-butyl-3H-azepine

Oxidation reactions of 2,5- and 3,6-di-tert-butyl-3H-azepines (1 and 2) with selenium dioxide (SeO(2)) were performed. The oxidation of 1 with SeO(2) gave 3-tert-butyl-7,7-dimethyl-4-oxo-octa-2,5-dienal 3 in 36% yield, 4-tert-butyl-5-(3,3-dimethyl-2-oxo-butylidene)-1, 5-dihydro-pyrrol-2-one 4 in 13% yield, 2, 6-di-tert-butyl-2-pyridinecarbaldehyde 5 in 12% yield, and 4, 7-di-tert-butyl-2H-azepin-2-one (2-azatropone) 6 in 6% yield, respectively. Oxidation of 2 with SeO(2) gave 2, 2-dimethyl-1-[2-(5-tert-butyl)-pyridyl]propanol 7 in 55% yield, and 3,6-di-tert-butyl-2H-azepine 8 in 5% yield, respectively. We found that selenium dioxide oxidation of 1 affords 4-oxo-octa-2,5-dienal 3 by a new ring cleavage reaction of 1, and we described the first synthesis of 2-azatropone 6 from this oxidation of 1. In the case of 2, pyridylpropanol 7 was obtained as the major product. We now report in detail result of these oxidation reactions, which have led to the synthesis of a novel azatropone derivative.

Journal Article↗
PubMed2000

Ethylammonium and diethylammonium salts of chloranilic acid.

In the crystals of two title salts of chloranilic acid (2,5-dichloro-3,6-dihydroxy-p-benzoquinone), namely ethylammonium chloranilate, C(2)H(8)N(+).C(6)HCl(2)O(4)(-), (I), and diethylammonium chloranilate, C(4)H(12)N(+).C(6)HCl(2)O(4)(-), (II), the chloranilate ions are present as a hydrogen-bonded dimer which has an inversion center. The ethylammonium and diethylammonium ions link the dimers through N-H.O hydrogen bonds, forming a three-dimensional hydrogen-bond network in (I) and a one-dimensional chain in (II).

Journal Article↗
PubMed1993

C-H...O packing motifs in some cyclopenta[a]phenanthrenes.

An analysis has been made of the C-H...O interactions in cyclopenta[a]phenanthrenes, for which structural data on fifteen 15,16-dihydrocyclopenta[a]-phenanthren-17-ones are available. These compounds mostly contain only one O atom, a carbonyl group at the 17-position, and therefore the only groups available for interactions are C-H groups. In addition, the crystal structure of a second polymorph of the 11-ethyl derivative is described. M(r) = 260.33, Pbca, a = 17.012 (2), b = 21.042 (2), c = 7.6465 (6) A, V = 2737.2 (4) A, Z = 8, Dx = 1.264 Mg m-3, Cu K alpha, lambda = 1.5418 A, mu = 0.56 mm-1, F(000) = 1104, T = 295 K, final R = 0.090 for 1669 reflections above 2 sigma (F). The conformation of the ethyl group is gauche [C(12)-C(11)-C(18)-C(19) = 75.8 (7) degrees], differing from the cis value of -1.3 (5) degrees for the Pnaa form. The molecular distortion in the Pbca polymorph is also larger than that in the Pnaa polymorph; this distortion is evidenced by torsion angles (13-20 degrees) in the bay region and by an out-of-plane displacement (0.8 A) of the C atom of the methylene portion of the ethyl group [the C atom attached to C(11)]. Packing diagrams and intermolecular distances were analyzed for all the dihydrocyclopenta[a]phenanthrenes for which structural data are available. There appear to be three types of packing. The first type consists of a dimer herringbone formed by the interactions of two molecules by way of the ketone group and the C-H of C(12) of the adjacent ring. The second type of packing also involves a dimer but involves C-H and O-C groups at either ends of the molecule. The third type is a layer structure and involves compounds that crystallize with a unit-cell length of 7.5-7.6 A (or, in a very planar structure, 13.8 A). The translational stacking (approximately 4 A apart) found in polycyclic aromatic hydrocarbons is not observed in the crystal structures of these dihydrocyclopenta[a]-phenanthrenes because of the bulk of methyl or methylene groups and the dipole moment of the carbonyl group.

Crystallography, X-Ray↗
PubMed1991

Incarnal. A new antibacterial sesquiterpene from Basidiomycetes.

A new sesquiterpene, incarnal, was isolated from culture fluid of Gloeostereum incarnatum (Japanese name: Nikawaurokotake). Incarnal inhibited the growth of gram-positive bacteria at 6.25-12.5 micrograms/ml. The structure of incarnal has been determined to be (1-hydroxy-2,10,10-trimethyl)-3-methylene- tricyclo[6.3.0.0(2.6)]undec-5,7-diene-4,9-dione by X-ray diffraction and spectroscopic methods.

Anti-Bacterial Agents↗
PubMed1986

Bay region distortions in cyclopenta[a]phenanthrenes.

Two newly synthesized cyclopenta[a]phenanthrenes, namely the 1-methyl (VIII) and 7,11-dimethyl (VII) derivatives of the parent ketone 15,16-dihydrocyclopenta[a]phenanthren-17-one (I), have been tested for their capacity to produce skin tumors in mice. The former (VIII) is essentially inactive, whereas the latter (VII) is very potent in both repeated application and two-stage tests. X-ray crystallographic structure analyses have been carried out on seven derivatives of (I), namely its 11-methyl (II), 11,12-dimethyl (III), 11-methoxy (V), 11-ethyl (VI) and 7,11-dimethyl (VII) analogues (carcinogens), the 1-methyl derivative (VIII), and 11,12,15,16-tetrahydro-11-methyl-17-oxocyclopenta[a]phenanthrene (IV) (both non-carcinogens). The detailed molecular structures resulting from these studies have shown the effects of steric interactions and substitutions on the bay-region geometry. The methyl group on C(11) causes distortions of the molecule in the bay region. Out-of-plane distortions in the bay regions of the 11-methyl derivatives (II, III, VII) are greater than for the 11-methoxy or the 11-ethyl derivatives (V, VI). Molecules (except for III and IV) are packed in the crystals with interactions that include C = O...H interactions; this packing is in layers that are nearly parallel to each other. A hydrogen atom of the 11-methyl group appears, from computer modeling, to interact sterically with the hydrogen atom of the bay-region expoxide group in the activated diol-epoxide; this steric interaction may force one conformer of the diol-epoxide to be the predominant form, thereby accounting for the importance of a bay-region methyl group. Further computer modeling has been used to analyze possible modes of interaction of the diol-epoxides of cyclopenta[a]phenanthrenes with DNA.

Animals↗
PubMed1984

The bay-region geometry of some 5-methylchrysenes: steric effects in 5,6- and 5,12-dimethylchrysenes.

The presence of a bay-region methyl group in carcinogenic polycyclic aromatic hydrocarbons leads to considerable distortion in the molecule. This is illustrated in the structures, obtained by X-ray diffraction techniques, of 5,12- and 5,6-dimethylchrysene. The molecular distortions result from steric requirements, such as that the minimum H...H distance is 1.8 A and the minimum C...C distance is 2.90 A; distortions to accommodate these requirements may be both in-plane (by increasing the angles at carbon atoms in the bay-region from 120 degrees to approximately 124 degrees) and out-of-plane by torsion about certain bonds in the bay-region. It is shown that more in-plane distortions are found for 5-methylchrysene derivatives than for methylbenz[a]anthracene derivatives and this, it is suggested, results from the nature of the flexibility of the chrysene compared with the benz[a]anthracene fragment at the bay-region.

Carcinogens↗