2 0 0 0 IR Structure elucidation of dicarboxylate complex of SnIV porphyrin with a ring current effect model
- 著者
- Iwamoto Hajime Hori Kenji Fukazawa Yoshimasa
- 出版者
- Elsevier
- 雑誌
- Tetrahedron (ISSN:00404020)
- 巻号頁・発行日
- vol.62, no.12, pp.2789-2798, 2006-03-20
- 被引用文献数
- 12
A new simple model of porphyrin ring current effect was proposed based on a line current approximation. It can reproduce the porphyrin-induced shifts for several Sn(IV)(tpp) and Sn(IV)(oep) dicarboxylate complexes quite satisfactorily. Perpendicular arrangement of the aromatic rings in the diaromatic-carboxylate complexes of Sn(IV)(tpp) and Sn(IV)(oep) was clarified with this porphyrin ring current effect model. There are two structures, exo and endo, in solution in dinaphthalene-1- and 2- carboxylate complexes of Sn(IV)(tpp) and Sn(IV)(oep). The exo conformer is in dynamic equilibrium with the endo form in solution. Thermodynamic data of these conformational equilibria are given.
- 著者
- Arai Tsukasa Toda Yuta Kato Kiyotaka Miyamoto Kensuke Hasegawa Tsuyoshi Yamada Kosumi Ueda Junichi Hasegawa Koji Inoue Tsuyoshi Shigemori Hideyuki
- 出版者
- Elsevier
- 雑誌
- Tetrahedron (ISSN:00404020)
- 巻号頁・発行日
- vol.69, no.34, pp.7001-7005, 2013-08
- 被引用文献数
- 15 1
A new sesquiterpene with an α-methylene-γ-lactone moiety, artabolide (1), and three known derivatives 2–4 were isolated from Artemisia absinthium. The structure of 1 was elucidated by 1D and 2D NMR analyses, and the absolute configuration was determined using the modified Mosher's method and X-ray crystal structural analysis. Approximately 2.5 μg/plant treatment of artabolide (1) exhibited ca. 50% inhibition of polar auxin transport in radish hypocotyls, while 2–4 showed no significant inhibitory activity. Therefore, these results support the importance of the α-methylene-γ-lactone moiety for the inhibition of polar auxin transport.
1 0 0 0 OA Synthesis and biological activities of the tris-oxazole macrolactone analogs of mycalolides
- 著者
- Kita Masaki Oka Hirotaka Usui Akihiro Ishitsuka Tomoya Mogi Yuzo Watanabe Hidekazu
- 出版者
- Elsevier
- 雑誌
- Tetrahedron (ISSN:00404020)
- 巻号頁・発行日
- vol.68, no.42, pp.8753-8760, 2012-10
- 被引用文献数
- 7
Mycalolides are tris-oxazole macrolides isolated from the marine sponge Mycale sp., which shows cytotoxic, antifungal, and actin-depolymerizing activities. To develop an efficient synthetic route of mycalolides and to evaluate its functional mechanism of biological activities, tris-oxazole macrolactone analogs of mycalolides were synthesized through the use of ring-closing metathesis (RCM). The presence/absence of protecting groups at C3, solvent polarity, and reaction temperature significantly affected the stereoselectivity of RCM (E/Z=2.5/1.0–1.0/2.5). The 19E- and 19Z-stereoisomers both exhibited moderate cytotoxicity against tumor cells, but neither showed significant actin-depolymerizing properties or antimycotic activity against pathogenic fungi. Thus, both the side-chain (actin-binding) moiety and the macrolactone moiety were suggested to be essential for the potent biological activities of the parent molecules.
- 著者
- Kawaguchi Takumi Suzuki Tomohiro Kobayashi Yuka Kodani Shinya Hirai Hirofumi Nagai Kaoru Kawagishi Hirokazu
- 出版者
- Elsevier
- 雑誌
- Tetrahedron (ISSN:00404020)
- 巻号頁・発行日
- vol.66, no.2, pp.504-507, 2010-01-09
- 被引用文献数
- 26