著者

四津 まり 村田 道雄 安元 健 直木 秀夫

出版者

天然有機化合物討論会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

no.29, pp.240-247, 1987-07-25

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The newt Cynops ensicauda collected in Okinawa, Japan, contained tetrodotoxin (TTX)(1) and its new analogs. Two analogs, compound A and B, were isolated by successive treatment of AcOH extracts on columns of charcoal, BioGel P-2, BioRex70, and Hitachigel 3011C gel. From 3.5kg of the newts 120mg of TTX, 18mg of compound A, and 30mg of compound B were obtained. High resolution FAB mass spectra taken on a JEOL JMS-DX-303HF indicated A to have the same molecular formula as TTX(C_<11>H_<17>O_8N_3) and B to be deoxyTTX (C_<11>H_<17>O_7N_3). ^1H NMR spectra of A showed a high field shift of 11-CH_2 suggested the CH_2OH at C-6 to be axial, 6-epiTTX(2) The axial configuration was further confirmed by NOE measurments. Configuration at C-9 was proved to be the same as TTX. Likewise B was assigned to 11-deoxyTTX(3), and its 11-CH_3 was suggested equatorial as same as TTX. Both 2 and I were in a tautomeric equilibrium between hemilactal (2a,3a) and lactone (2b,3b) forms that were confirmed by NOESY measurments which indicated the saturation transfer between two froms.

著者

菅原 孝太郎 北村 嘉章 佐竹 真幸 村田 道雄 橘 和夫

出版者

天然有機化合物討論会実行委員会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

vol.53, pp.433-438, 2011

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Our continuous efforts for search of new bioactive compounds led to isolation of a polyene-polyol, prorocentrol, from P. hoffmannianum (CCMP 683). Although a ketone-hemiacetal tautomerism was observed during the course of NMR measurements, NMR measurements in pyridine-d_5/D_2O (6:1) at room temperature gave simplified NMR spectra. Detailed COSY and TOCSY analyses led to four 114 spin-networks, which were constructed to gross structure on the basis of HMBC correlations. The stereoconfigurational analysis of prorocentrol was undertaken by extensive utilization of 2D-NMR methods. The conformation of cyclic ethers in the molecule was analyzed based on NOESY correlations and ^3J_<H,H・> A JBCA method was applied for elucidation of the relative configurations of chiral centers in acyclic portions. Where HETLOC did not give sufficient intensity, qualitative utilization of the relationship between HMBC signal intensity and corresponding ^<2,3>J_<C,H> turned out to be effective especially for the methyl bearing portions. Moreover, the universal NMR database method was also applied on the continuous polyol segments as an alternative way for the JBCA to reveal the relative configuration. As a particular property of prorocentrol, suggestive evidences for an association of prorocentrol and okadaic acid were indicated from chromatographic behaviors and changes of NMR chemical shifts.

著者

村田 道雄 佐々木 誠 安元 健

出版者

東京大学

雑誌

一般研究(B)

巻号頁・発行日

1994

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マイトトキシンは、植物プランクトンである渦鞭毛藻が生産する分子量3422のポリエーテル化合物であり、天然物中最大の分子量と非常に強い毒性によって、現在最も注目されている海洋天然物である。われわれは、1993年にマイトトキシンの平面構造とエーテル環が連続している部分の立体化学を明らかにしたが、その他の鎖状部分に関しては未解明の部分が多い。本一般研究Bにおいて、エーテル環をつなぐ部分の立体配座(F-G環の間の2個の不斉炭素とM-N環の間の2個の不斉炭素)を主に有機合成化学的手法により決定することができさらに、C1-C14とC134-C142の側鎖部分に関して立体化学と回転配座を求めた。新たに開発したNMRのスピン結合定数(^<2,3> J_<C,H>と^3 J_<H,H>)と分子力場計算を併用した方法をこの部分に適用した結果、側鎖に存在するすべての不斉炭素を推定することができた。さらに、推定立体構造を有する合成フラグメントと天然物のNMRデータを比較することによって確認作業を進め、同時に、エナンチオ選択的なフラグメントCの合成を行ない、天然の分解物と比較することによって絶対構造を決定することができたので、ここにマイトトキシンの完全構造決定が完成した。

著者

村田 道雄 安元 健

出版者

The Society of Synthetic Organic Chemistry, Japan

雑誌

有機合成化学協会誌 (ISSN:00379980)

巻号頁・発行日

vol.53, no.3, pp.207-217, 1995-03-01 (Released:2010-01-28)

参考文献数

27

被引用文献数

1 3

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Maitotoxin was first discovered as one of the causative toxins responsible for ciguatera, which is a form of seafood poisoning prevalent in coral reef area. The structure (1) has been elucidated to be a polyketide compound with a molecular weight of 3422 Da, which makes the toxin the largest natural non-biopolymer known to date. The structure is partly reminiscent of brevetoxins or ciguatoxins, which comprise trans-fused polycyclic ethers, though maitotoxin possesses about three times as many ether rings as does brevetoxin B. In this paper we review the structure elucidation of maitotoxin with the main focus on spectroscopic methodology, particularly on tandem mass spectrometry (MS/ MS), three-dimensional NMR spectra, and stereostructural analysis using NOE and 3J/H.H data coupled with force field calculations.Collisionally Activated Dissociation (CAD) MS/MS spectra with a negative FAB ionization were successfully measured for fragment B (MW. 2328 Da) of maitotoxin and revealed fragment ions from which the sizes and sequences of ether rings easily were derived. Three dimensional NOESY-HMQC with pulse field gradient was determined for a 13C-enriched specimen (at about 4%) and provided 64 13C-edited NOESY spectra, some of which brought essential NOE information regarding the mode of ether cyclization and stereochemistry.

著者

安元 健 村田 道雄

出版者

公益社団法人 日本農芸化学会

雑誌

化学と生物 (ISSN:0453073X)

巻号頁・発行日

vol.29, no.6, pp.379-387, 1991-06-25 (Released:2009-05-25)

参考文献数

14