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S Ohba

Publications and source records attributed to S Ohba.

At least 55 records · Page 3Linked to original sources
PubMed2000

[N,N'-Bis(3-carboxysalicylidene)-1,2-diphenyl-(RR,SS)-1,2-ethanediyldiaminato-O,N,N',O'](methanol-O)oxovanadium(IV) and [N,N'-bis(3-carboxysalicylidene)-2,3-dimethyl-2,3-butanediyldiaminato-O,N,N',O']oxovanadium(IV) monohydrate.

The two title mononuclear oxovanadium (IV) complexes, [VO(C(30)H(22)N(2)O(6))(CH(3)OH)] and [VO(C(22)H(22)N(2)O(6))].H(2)O, respectively, have distorted square-pyramidal coordination and the 3-carboxy groups form intramolecular hydrogen bonds with the coordinated salicyl O atoms. In (I), methanol coordinates to the vanadium atom trans with respect to the oxo ligand.

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PubMed2000

[N,N'-Bis(salicylidene)-1,2-diphenyl-(RS,SR)-1,2-ethanediaminato]nickel(II).

In crystals of the title compound, [Ni(C(28)H(22)N(2)O(2))], the coordination geometry around the Ni atom is square planar with a slight tetrahedral distortion. The five-membered N,N'-chelate ring adopts a distorted gauche conformation with the two phenyl groups in axial and equatorial orientations.

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PubMed2000

Triethylammonium hydrogen fumarate.

In crystals of the title compound, the hydrogen fumarate anions form one-dimensional chains through an O-H.O hydrogen bonding along the c and (a+b)/2 directions. There are three sites of the hydrogen fumarate, two of which have an inversion centre.

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PubMed2000

cis-Diaquabis(trans-cinnamato-O,O')zinc(II).

The title complex, [Zn(C(9)H(7)O(2))(2)(H(2)O)(2)], shows a distorted octahedral coordination and has a crystallographic twofold rotation axis. Intermolecular O-H.O hydrogen bonding forms a two-dimensional network in the ab plane.

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PubMed2000

Charge-transfer complexes of N-methyl-, N-isopropyl-, N-butyl- and N-isobutylcarbazole with 3,5-dinitrobenzoic acid.

In the title four compounds, C(13)H(11)N.C(7)H(4)N(2)O(6), (I), C(15)H(15)N.C(7)H(4)N(2)O(6), (II), C(16)H(17)N.C(7)H(4)N(2)O(6), (III), and C(16)H(17)N.C(7)H(4)N(2)O(6), (IV), the donor and acceptor molecules are stacked alternately to form one-dimensional columns. In (I), the N-methyl group of the donor is nearly eclipsed with respect to one of the nitro groups of the neighboring acceptor in a column, whereas the N-isopropyl, N-butyl and N-isobutyl groups are in anti positions with respect to one of the nitro groups of the neighboring acceptor in compounds (II)-(IV).

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PubMed2000

Charge-transfer complexes of N-methyl-and N-ethylcarbazole with 3,5-dinitrobenzonitrile.

In the two title compounds, N-methylcarbazole-3,5-dinitrobenzonitrile (1/1), C(13)H(11)N.C(7)H(3)N(3)O(4), (I), and N-ethylcarbazole-3,5-dinitrobenzonitrile (1/1), C(14)H(13)N.C(7)H(3)N(3)O(4), (II), the donor and acceptor molecules are stacked alternately to form one-dimensional columns. In (I), the N-methyl group of the donor is nearly eclipsed with respect to one of the nitro groups of the neighboring acceptor in a column, whereas the N-ethyl group is anti with respect to the cyano group of the neighboring acceptor in (II).

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PubMed2000

Charge-transfer complexes of 4-(dimethylamino)pyridine with 2,4-, 3,4- and 3,5-dinitrobenzoic acid.

In the three title crystal structures 4-(dimethylamino)pyridinium 2,4-dinitrobenzoate, (I), 4-(dimethylamino)pyridinium 3,4-dinitrobenzoate, (II), and 4-(dimethylamino)pyridinium 3,5-dinitrobenzoate, (III), all C(7)H(11)N(2)(+).C(7)H(3)N(2)O(6)(-), the ions are connected by an N-H.O hydrogen bond. Dihedral angles between the pyridine and phenyl rings are 69.9 (1), 26.7 (1) and 56.2 (1) degrees in (I), (II) and (III), respectively. Donor-acceptor pi-pi stacking is observed in (II) and (III), but not in (I).

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PubMed2000

N-Benzyl-N-(2-methoxyphenyl)cyclohex-1-enecarboxamide.

The title amide, C(21)H(23)NO(2), (I), does not photocyclize in the solid state. The methoxy group is involved in intermolecular steric interactions and so prevents the rotation of the N-phenyl group in the crystal.

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PubMed2000

N-Methyl-N-[(Z)-2-phenylpropenyl]thiobenzamide.

The crystal structure of the title thiobenzamide, C(17)H(17)NS, was determined to investigate the relationship between the photoreactivity in solid state and the structure. The geometry was confirmed to be the Z isomer.

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PubMed2000

trans-Diaquabis(N-acetylanthranilato-O,O')copper(II).

The title monomeric copper(II) complex, [Cu(C(9)H(8)NO(3))(2)(H(2)O)(2)], (I), shows a square-planar coordination and has an inversion centre at the Cu atom. The carboxylate group of the N-acetylanthranilate ion acts as a monodentate donor ligand to copper and as an acceptor of an intramolecular O-H.O hydrogen bond from the coordinated water molecule, with an O.O distance of 2.581 (2) A.

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PubMed2000

catena-Poly[[tetrakis(micro-2,2-dimethylpropionato-O:O')dicopper(II)]-micro-dioxane-O:O'] and catena-poly[[tetrakis(micro-3,3-dimethylbutyrato-O:O')dicopper(II)]-micro-dioxane-O,O'].

The title two compounds, [Cu(2)(C(5)H(9)O(2))(4)(C(4)H(8)O(2))](n), (I), and [Cu(2)(C(6)H(11)O(2))(4)(C(4)H(8)O(2))](n), (II), are isomorphous. The binuclear Cu(II) units have a cage structure and are linked by the dioxane molecules to form a zigzag chain along the c axis. The binuclear copper unit and the dioxane ligand each have a centre of symmetry.

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PubMed2000

Access to Wieland-Miescher ketone in an enantiomerically pure form by a kinetic resolution with yeast-mediated reduction.

Both enantiomers of Wieland-Miescher ketone [3,4,8, 8a-tetrahydro-8a-methyl-1,6(2H,7H)-naphthalenedione], in a highly enantiomerically enriched form, became readily available by a newly developed kinetic resolution with yeast-mediated reduction. From a screening of yeast strains, Torulaspora delbrueckii IFO 10921 was selected. The collected cells of this strain, obtained by an incubation in a glucose medium, smoothly reduced only the isolated carbonyl group of the (S)-enantiomer, while the (R)-enantiomer remained intact. Starting from both enantiomers ( approximately 70% ee) prepared by an established proline-mediated asymmetric Robinson annulation, the reduction with T. delbrueckii gave the (R)-enantiomer (98% ee) and the corresponding alcohol (4aS,5S)-4,4a, 5,6,7,8-hexahydro-5-hydroxy-4a-methyl-2(3H)-naphthalenone (94% ee, 94% de) in preparative scale in nearly quantitative yields. An approach for the asymmetric synthesis of the Wieland-Miescher ketone was also successful. 2-Methyl-2-(3-oxobutyl)-1,3-cyclohexanedione, the prochiral precursor, was reduced with this strain to give a cyclic acetal form of (2S, 3S)-3-hydroxy-2-methyl-2-(3-oxobutyl)cyclohexanone, in a stereomerically pure form.

Ketones↗
PubMed2000

Transsphenoidal "cross court" approach using a slightly modified speculum to reach pituitary adenomas with lateral growth.

BACKGROUND: The purpose of this study was to evaluate the usefulness of an oblique "cross court" transsphenoidal approach using a speculum with slightly modified projections for pituitary adenomas showing lateral extension. METHOD: The projection of the speculum on the side of the cavernous lesion was shortened by 5 mm. The tip of the longer projection was placed in the sphenoid sinus, while the end of the shorter projection was placed on the concha sphenoidalis. An oblique transsphenoidal view was then easily obtained by opening the speculum. The contralateral nasal incisura had to be widened in some cases to achieve a more oblique view. FINDINGS: Twenty-eight patients diagnosed with pituitary adenoma showing lateral growth underwent adenomectomy under direct observation of the medial portion of the cavernous sinus using this approach. Postoperative normalization of hyperendocrinopathy or gross total removal of the tumour was achieved in the majority of patients. INTERPRETATION: An oblique transsphenoidal approach using this speculum and contralateral minor maxillary osteotomy afforded a direct view of the medial cavernous sinus, sufficient for the removal of adenomas showing minor to moderate lateral growth.

Adenoma↗
PubMed2000

catena-Poly

The two title compounds, [Cu(3)(C(6)H(11)O(2))(6)(C(7)H(9)N)(2)](n), (I), and [Cu(2)(C(5)H(9)O(2))(4)(C(7)H(9)N)(2)], (II), have chain and finite-molecular structures, respectively. In (I), binuclear cage units and mononuclear 2,6-dimethylpyridine complexes, both of which have inversion centres, are arranged alternately and are linked by the carboxylate ions to form one-dimensional chains along the a axis. In (II), the binuclear cage unit has an inversion centre and the coordination geometry around the Cu atom is typical square pyramidal, with 2,6-dimethylpyridine at the apical position.

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PubMed2000

Racemic and chiral 1-[N-(chloroacetyl)carbamoylamino]-2, 3-dihydro-1H-inden-2-yl chloroacetate.

In the racemic crystals of (1S,2R)- or (1R, 2S)-1-[N-(chloroacetyl)carbamoylamino]-2,3-dihydro-1H-inden- 2-yl chloroacetate, C(14)H(14)Cl(2)N(2)O(4), (I), the enantiomeric molecules form a dimeric structure via the N-H.O cyclic hydrogen bond of the carbamoyl moieties. In the chiral crystals of (-)-(1S, 2R)-1-[N-(chloroacetyl)carbamoylamino]-2,3-dihydro-1H-inden- 2-yl chloroacetate, C(14)H(14)Cl(2)N(2)O(4), (II), the N-H.O intermolecular hydrogen bond forms a zigzag chain around the twofold screw axis. The melting points and calculated densities of (I) and (II) are 446 and 396 K, and 1.481 and 1.445 Mg m(-3), respectively.

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