Sachiko Yamada
University of Tokyo
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Tetrahedron Letters | 1975
Takahiro Torii; Kazuo Tachibana; Sachiko Yamada; Takahiko Tsuyuki; Takeyoshi Takahashi
Takahiro Torii, Kazuo Tachibana, Sachiko Yamada, Takahiko Tsuyuki, and Takeyoshi Takahashi Department of Chemistry, Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan (Received in Japan 23 April 1975; received in UK for publication 1) May 1915) Different names, that is, dendropanoxide, 1) epoqglutinane, 2, aa campanulin,3) have been given to a triterpene oxide, C30H500, isolated from a number of plants of the families Araliaceae and Ericaceae. 4) Two alternative structures, D:B-friedo-olean-3,10-oxide (L)2q395) and D:Efriedo-olean-3,5oxide (2), 1,2,4) have been proposed for the triterpene. Finally, the structure of this triterpene oxide (dendropanoxide 6) ; epoxyglutinane ; campanulin) has recently been determined to be D:B-friedo-olean-38,108-oxide (L> by X-ray study.) Dendropanoxide (1) and friedelin (2)8) are triterpenes closely related each other in view of biogenetic considerations. We now describe the conversion of friedelin (2) into dendropanoxide (1). Friedelin (2) was converted via friedelan-38-01 (5)8a9b99) into friedel-3ene (r)8a9b) by the known procedures. Epoxidation of 2 with m-chloroperbenzoic acid gave 3a,4a_epoxyfriedelane @lo) and 38,48-epoxyfriedelane (z), m-p. 202204, M+ at m/e 426 (C30H500); PMR (CDC13): d 2.95 (lH, br., Wli2 6 Hz; Ct3)H), in a ratio of about 2 : 1. The 8-epoxide (2 ; 300 mg) in ether was treated with BF -Et20 3 at 10 until a complete disappearance of the starting material (30 ruin) to give a mixture showing four spots on silica gel TLC impregnated with silver nitrate. The least polar material was separated by silica gel column chromatography impregnated with silver nitrate to afford an oxide (1 ; 65 mg), m.p. 206-208, [aID + 71 (CHC13 ; C, l-O), M+ at m/e 426 (C30H500); PMR (CDC13): b 3.75 (lH, d, J = 5 Hz; C(3) -H), which was found to be identical (mop., mixed m.p., Cal, , IR, PMR, mass spectrum and TLC) with dendropanoxide
Bulletin of the Chemical Society of Japan | 1976
Shuzo Yamada; Sachiko Yamada; Kazuo Tachibana; Yoshihiko Moriyama; Yoshiaki Tanahashi; Takahiko Tsuyuki; Takeyoshi Takahashi
Archive | 1980
Sachiko Yamada; Masayuki Ohmori; Hiroaki Takayama
Archive | 1983
Hiroaki Takayama; Sachiko Yamada; Keiko Nakayama; Tatsuo Suda
Archive | 1981
Hiroaki Takayama; Sachiko Yamada; Masayuki Ohmori
Chemical & Pharmaceutical Bulletin | 1979
Sachiko Yamada; Keiko Nakayama; Hiroaki Takayama; Akiko Itai; Yoichi Iitaka
Archive | 1989
Sachiko Yamada; Koichi Niimura; Kenji Fukushima; Yuji Maeda
Archive | 1982
Hiroaki Takayama; Sachiko Yamada; Masayuki Ohmori
Tetrahedron Letters | 1972
Sachiko Yamada; Shuzo Yamada; Yoshihiko Moriyama; Yoshiaki Tanahashi; Takeyoshi Takahashi
Vitamins | 1994
Sachiko Yamada; Hiroaki Takayama