Special Issue

Yoshito Kishi's Special Issues, Vol. 72, No. 1, 2007

70 data found. 61 - 70 listedFirst Previous
Note | Special issue | Vol 72, No. 1, 2007, pp.647-648
Published online: 11th July, 2006
DOI: 10.3987/COM-06-S(K)1
Ajmalinimine Is an Artifact Not an Alkaloid

Mauri Lounasmaa* and Pirjo Sainio (née Hanhinen)

*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, FIN-02150, HUT Espoo, Finland

Abstract

It is suggested that ajmalinimine (1), isolated from Rauwolfia serpentina Benth, is an artifact formed from 17-O-acetylajmaline (2) during the isolation and/or purification procedure.

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Note | Special issue | Vol 72, No. 1, 2007, pp.649-654
Published online: 28th July, 2006
DOI: 10.3987/COM-06-S(K)2
Parviflorene J, a Cytotoxic Sesquiterpene Dimer with a New Rearranged Skeleton from Curcuma parviflora

Mayu Tamaki, Samir Kumar Sadhu, Takashi Ohtsuki, Kazufumi Toume, Takashi Koyano, Thaworn Kowithayakorn, Masahiko Hayashi, Kanki Komiyama, and Masami Ishibashi*

*Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan

Abstract

A new sesquiterpenoid dimer, parviflorene J, was isolated from Curcuma parviflora. The structure was elucidated using spectroscopic methods. Parviflorene J possessed an unprecedented backbone-rearranged skeleton and showed cytotoxicity against cultured tumor cell lines.

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Note | Special issue | Vol 72, No. 1, 2007, pp.655-663
Published online: 22nd December, 2006
DOI: 10.3987/COM-06-S(K)17
Cytotoxic Haterumadienone Congeners from the Okinawan Marine Sponge Dysidea Sp.

Katsuhiro Ueda,* Takayuki Ogi, Atsushi Sato, Eric R. O. Siwu, Masaki Kita, and Daisuke Uemura

*Department of Chemistry, Biology and Marine Sciences, Faculty of Science, University of Ryukyus, Nishihara-cho, Okinawa 903-0213, Japan

Abstract

20-Hydroxyhaterumadienone (1) and haterumadienelactol (2), new haterumadienone (3) congeners, were isolated from the sponge Dysidea sp. together with puupehenone (6) and three known metabolites (7-9) related to 6. The absolute stereochemistry of 1 and the relative stereochemistry of 2 were determined by spectroscopic and chemical analyses. The metabolites (1 and 2) inhibited the division of fertilized sea urchin eggs.

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Note | Special issue | Vol 72, No. 1, 2007, pp.665-671
Published online: 6th February, 2007
DOI: 10.3987/COM-06-S(K)20
Palladium-Catalyzed Coupling Reaction of Haloheteroaromatic Compounds in Water

Naoki Inoue, Osamu Sugimoto,* and Ken-ichi Tanji*

*Laboratory of Organic Chemistry, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan

Abstract

Palladium-catalyzed coupling reaction of π-deficient heteroaromatic halide in water was accomplished with excellent to good yields without any side reactions such as hydrolysis.

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Note | Special issue | Vol 72, No. 1, 2007, pp.673-676
Published online: 29th December, 2006
DOI: 10.3987/COM-06-S(K)27
Biosynthesis of Cypridina Luciferin in Cypridina noctiluca

Shin-ichi Kato, Yuichi Oba,* Makoto Ojika, and Satoshi Inouye

*Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Aichi 464-8601, Japan

Abstract

Luminescence in the marine ostracods Cypridina noctiluca and Vargula hilgendorfii is produced by Cypridina luciferin-luciferase reaction. In this study, a feeding experiment with stable isotope-labeled amino acids was performed in C. noctiluca. The results of LC/ESI-MS analyses indicated that C. noctiluca is able to synthesize Cypridina luciferin de novo from three amino acids (L-tryptophan, L-isoleucine, and L-arginine).

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Note | Special issue | Vol 72, No. 1, 2007, pp.677-680
Published online: 26th December, 2006
DOI: 10.3987/COM-06-S(K)29
Practical Approach for Hydroheteroarylation of Alkynes Using Bench-Stable Catalyst

Kyalo Stephen Kanyiva, Yoshiaki Nakao,* and Tamejiro Hiyama*

*Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoudai-katsura, Nishikyo, Kyoto 615-8510, Japan

Abstract

A simple and convenient method for hydroheteroarylation of alkynes using air-stable catalyst precursors is described. The addition of a solution of AlMe3 in hexane to Ni(acac)2 and tri(cyclopentyl)phosphonium tetrafluoroborate ([Cyp3PH]BF4) rapidly generates an active Ni(0)/Cyp3P catalyst for cis-hydroheteroarylation of alkynes under mild conditions. The catalytic reaction is applicable to a wide range of heteroarenes to give heteroaryl-substituted ethenes in excellent stereo- and regioselectivities.

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Note | Special issue | Vol 72, No. 1, 2007, pp.681-689
Published online: 6th February, 2007
DOI: 10.3987/COM-06-S(K)38
Synthesis of Enantiomerically Enriched 2-Substituted Pyrrolidine Analogues of Norhygrine. Applicatin of the Hetero-Diels-Alder Addition of Sulfur Dioxide

Mãris Turks and Pierre Vogel*

*Laboratory of Glycochemistry and Asymmetric Synthesis, ISIC, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland

Abstract

The Vogel’s reaction cascade (one-pot hetero-Diels-Alder addition of SO2, ionization of the sultines into zwitterions and their quenching by electron-rich alkenes) has been applied to the preparation of enantiomerically-enriched (1S)-2((2R)-1-benzoylpyrrolidin-2-yl)pentan-3-one (14). Reaction of SO2 with (-)-(1E,3Z)-2-methyl-1-((1S)-1-phenylethoxy)penta-1,3-dien-3-ol benzoate (5: derived from (S)-1-phenylethanol (97% ee)) and allyltrimethylsilane in the presence of a Lewis acid at -78°C provides (-)-(2Z,1’S,4S,5S)-4-methyl-5-(1’-phenylethoxy)octa-2,7-dien-3-ol benzoate (9). Selective cleavage of the benzyl ether of 9 and subsequent SN2 displacement with Ph2P(O)N3 provided an azide 11 that was converted into 14.

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Note | Special issue | Vol 72, No. 1, 2007, pp.691-695
Published online: 9th March, 2007
DOI: 10.3987/COM-06-S(K)54
Diastereodifferentiating [4+2]-Photocycloaddition of Tegafur with Naphthalene

Kazue Ohkura,* Tatsuyuki Sugaoi, Masayuki Takahashi, and Koh-ichi Seki*

*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan

Abstract

Upon UV-irradiation, the prodrug of 5-fluorouracil, tegafur, that has an asymmetric carbon attached to N1 couples with naphthalenes by way of stereoselective [4+2]-cycloaddition, to give the corresponding ethenoquinazolines as diastereoisomers. The configuration of the resulting adducts is unambiguously derived from X-ray crystal structural analysis.

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Note | Special issue | Vol 72, No. 1, 2007, pp.697-708
Published online: 16th February, 2007
DOI: 10.3987/COM-07-S(K)56
Regioselective Synthesis of Methyl 3-Thiothiophene-2-carboxylate Derivatives Utilizing a Dehydration-Type Ti-Dieckmann Condensation

Ryohei Nagase, Hideki Gotoh, Mayumi Katayama, Naoki Manta, and Yoo Tanabe*

*School of Science, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan

Abstract

Regioselective dehydration-type Ti-Dieckmann condensation of 3-(methoxycarbonylmethylthio)propanethioates successfully afforded methyl thiophene-2-carboxylates and methyl 4,5-dihydrothiophene-2-carboxylates, utilizing TiCl4 - Et3N and TiCl4 - (sec-Bu)2NH, respectively.

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Note | Special issue | Vol 72, No. 1, 2007, pp.709-721
Published online: 2nd March, 2007
DOI: 10.3987/COM-07-S(K)63
Catalytic Enantioselective Aziridination of Alkenes Using Chiral Dirhodium(II) Carboxylates

Minoru Yamawaki, Masahiko Tanaka, Takumi Abe, Masahiro Anada, and Shunichi Hashimoto*

*Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812, Japan

Abstract

The enantioselective aziridination of alkenes with [N-(4-nitrophenylsulfonyl)imino]phenyliodinane catalyzed by dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh2(S-TCPTTL)4, is described. While such enantioselectivities are highly dependent on the properties of the alkenes, 2,2-dimethylchromene was found to be a particularly suitable substrate which can be efficiently transformed into the aziridine product in 98% yield with 94% ee.

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