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Dive into the research topics where Masaki Ichitani is active.

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Featured researches published by Masaki Ichitani.


Spectroscopy Letters | 2009

Crystal structures and conformations of 5-benzyl-2-thiohydantoin and its 1-acetylated derivative

Ko-Ki Kunimoto; Masaki Ichitani; Toshikazu Ogawa; Soh-ichi Kitoh; Akio Kuwae; Kazuhiko Hanai

ABSTRACT The crystal structures of 5-benzyl-2-thiohydantoin (5-BTH) and 1-acetyl-5-benzyl-2-thiohydantoin (1-Ac-5-BTH) have been determined by X-ray diffraction. In the 5-BTH crystals, the enantiomeric (R)- and (S)-5-BTH molecules are connected to form cyclic dimers via the hydrogen bonds of the thioamide and the amide moieties. On the other hand, the intermolecular hydrogen bonds in 1-Ac-5-BTH crystals form an infinite chain. These differences in the hydrogen bond pattern are also discussed in the IR and Raman spectra. The ab initio molecular orbital calculations (Gaussian 03) with 6-31G(d,p) basis set were carried out for 5-BTH and 1-Ac-5-BTH to get the preferred conformation.


Heterocycles | 2002

Crysatl and Molecular Structures of Racemic and Chiral 4-Phenyl-1,3-thiazolidine-2-thiones

Ko-Ki Kunimoto; Soh-ichi Kitoh; Masaki Ichitani; Norio Funaki; Akio Kuwae; Kazuhiko Hanai

The crystal and molecular structures of (rac)- and (S)-4-phenyl-1,3-thiazolidine-2-thiones (4-PTT) have been studied by X-Ray diffraction and ab initio MO calculations at the level of HF/6-31G*. In racemic crystals, the thioamide groups of the enantiomeric (R)- and (S)-4-PTT pairs are hydrogen-bonded around a crystallographic center of symmetry to form a planar cyclic dimer. On the other hand, in (S)-4-PTT crystals, a cyclic dimer through the hydrogen bonding is formed between the two independent molecules (molecules A and B) in the asymmetric unit and its geometry is distorted.


Bioscience, Biotechnology, and Biochemistry | 2014

Extraction of arbutin and its comparative content in branches, leaves, stems, and fruits of Japanese pear Pyrus pyrifolia cv. Kousui

Chizuru Sasaki; Masaki Ichitani; Ko-Ki Kunimoto; Chikako Asada; Yoshitoshi Nakamura

Arbutin is a tyrosinase inhibitor and is extensively used as a human skin-whitening agent. This study investigated the optimum conditions for extracting arbutin by ultrasonic homogenization from discarded branches pruned from Japanese pear (Pyrus pyrifolia cv. Kousui) trees. The arbutin content was measured in the branches and also in the leaves, stems, fruit peel, and fruit flesh.


Acta Crystallographica Section E-structure Reports Online | 2013

5-Isopropyl-5-methyl-2-sulfanylidene­imidazolidin-4-one

Masaki Ichitani; Soh-ichi Kitoh; Shuhei Fujinami; Mitsuhiro Suda; Mitsunori Honda; Ko-Ki Kunimoto

In the title compound, C7H12N2OS, the 2-sulfanylideneimidazolidin-4-one moiety is nearly planar, with a maximum deviation of 0.054 (2) Å. In the crystal, a pair of N—H⋯O hydrogen bonds and a pair of N—H⋯S hydrogen bonds each form a centrosymmetric ring with an R 2 2(8) graph-set motif. The enantiomeric R and S molecules are alternately linked into a tape along [1-10] via these pairs of hydrogen bonds.


Acta Crystallographica Section E-structure Reports Online | 2013

1-Acetyl-5-(4-fluoro-phen-yl)-2-sulfanyl-ideneimidazolidin-4-one.

Soh-ichi Kitoh; Yijing Feng; Shuhei Fujinami; Masaki Ichitani; Mitsunori Honda; Ko-Ki Kunimoto

In the title compound, C11H9FN2O2S, the 2-sulfanylideneimidazolidin-4-one moiety is essentially planar, with a maximum deviation of 0.0183 (14) Å. The mean plane of this moiety is approximately coplanar with the attached acetyl group and perpendicular to the benzene ring, making dihedral angles of 9.70 (14) and 86.70 (6)°, respectively. In the crystal, molecules are linked by N—H⋯O hydrogen bonds between the amide NH and acetyl C=O groups, forming a C(6) chain along the a-axis direction.


Food Science and Technology Research | 2008

Effect of cyclodextrins on the thermal epimerization of tea catechins

Hisako Okumura; Masaki Ichitani; Takanobu Takihara; Ko-Ki Kunimoto


Analytical Sciences: X-ray Structure Analysis Online | 2007

Crystal Structure of 5-Phenyl-2-thioxo-4-imidazolidinone

Toshikazu Ogawa; Soh-ichi Kitoh; Masaki Ichitani; Akio Kuwae; Kazuhiko Hanai; Ko-Ki Kunimoto


European Journal of Chemistry | 2013

Synthesis and crystal structure of (S)-5-isopropyl-5-methyl-2-thiohydantoin

Masaki Ichitani; Soh-ichi Kitoh; Keiko Tanaka; Shuhei Fujinami; Mitsuhiro Suda; Mitsunori Honda; Akio Kuwae; Kazuhiko Hanai; Ko-Ki Kunimoto


Analytical Sciences: X-ray Structure Analysis Online | 2007

Crystal Structure of 4,4′-Diphenyl-2,2′-dithioxo-[4,4′-biimidazolidine]-5,5′-dione Bis(dimethylsulfoxide) Solvate

Toshikazu Ogawa; Soh-ichi Kitoh; Masaaki Okagawa; Masaki Ichitani; Akio Kuwae; Kazuhiko Hanai; Ko-Ki Kunimoto


Japanese Journal of Food Chemistry and Safety | 2009

HPLC behavior of tea catechins on cyclodextrin-bonded silica column

Hisako Okumura; Yutaka Ikeda; Masaki Ichitani; Takanobu Takihara; Naohiro Kuriyama; Taeko Nakajima; Noriko Shoji; Ko-Ki Kunimoto

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Akio Kuwae

Nagoya City University

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