Naoki Takeuchi
Nihon University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Naoki Takeuchi.
Phytochemistry | 1994
Yasuo Fujimoto; Hongcheng Wang; Mitsuru Satoh; Naoki Takeuchi
Abstract New C 17 - and C 14 -polyacetylenes, and two known polyacetylenes were isolated from the dried roots of Panax quinquefolium . The structures of the new polyacetylenes were determined by their 1 H and 13 CNMR, and mass spectral data. The C 17 -polyacetylenes exhibited strong cytotoxic activity (IC 50 =0.1≈0.5 μg ml −1 ) against leukaemia cells (L1210) in tissue culture.
Phytochemistry | 1992
Yasuo Fujimoto; Wang Hongcheng; Makoto Kirisawa; Mitsuru Satoh; Naoki Takeuchi
Abstract Two new C 17 -polyacetylenes and a C 14 -polyacetylene were isolated from dried roots of Panax quinquefolium . Their structures were determined by their 1 H NMR, 13 C NMR and mass spectral data. The cytotoxic activity of C 17 -polyacetylenes against leukemia cells (L 1210) was ca 20 times that of the C 14 -polyacetylene.
Heterocycles | 1993
Naoki Takeuchi; Takako Nakano; Kaori Goto; Seisho Tobinaga
Naturally occurring dihydroisocoumarins, (±)-hydrangenol (1) and (±)-phyllodulcin (2) were synthesized from the enaminones (3) and (4) by the annelation reactions with ethyl acetoacetate (5)
Heterocycles | 1992
Naoki Takeuchi; Kaori Goto; Yuki Sasaki; Takashi Fujita; Kohsuke Okazaki; Kohji Kamata; Seisho Tobinaga
Naturally occurring dihydroisocoumarins, (+)- and (−)-mellein (2 and 3), metabolites of fungals, Cercospora sp. and Aspergillus sp., etc., were synthesized from the isoxazoles (32) and (33) by the annelation reactions with dimethyl 3-oxoglutarate
Journal of The Chemical Society, Chemical Communications | 1980
Naoki Takeuchi; Kazue Ochi; Masayuki Murase; Seisho Tobinaga
A short synthesis of (±)-phyllodulcin (1), a sweet principle of Hydrangea serrata Seringe var. thunbergii Sugimoto, from the enaminone (2) by annelation with dimethyl 3-oxaglutarate is described.
Heterocycles | 1994
Naoki Takeuchi; Mitsuharu Tanabe; Masanori Hagiwara; Kaori Goto; Takeshi Koike; Seisho Tobinaga
Treatment of a nitrodienamine (1) with indoles in trifluoroacetic acid gave condensation products
Chemical & Pharmaceutical Bulletin | 1991
Yasuo Fujimoto; Mitsuru Satoh; Naoki Takeuchi; Makoto Kirisawa
Chemical & Pharmaceutical Bulletin | 1993
Naoki Takeuchi; Takashi Fujita; Kaori Goto; Naomi Morisaki; Naoko Osone; Seisho Tobinaga
Chemical & Pharmaceutical Bulletin | 1995
Yoko Aida; Toshio Kasama; Naoki Takeuchi; Seisho Tobinaga
Chemical & Pharmaceutical Bulletin | 2001
Mitsuru Satoh; Naoki Takeuchi; Takeshi Nishimura; Takashi Ohta; Seisho Tobinaga