研究者データベース

梅澤 大樹(ウメザワ タイキ)
地球環境科学研究院 物質機能科学部門 生体物質科学分野
准教授

基本情報

所属

  • 地球環境科学研究院 物質機能科学部門 生体物質科学分野

職名

  • 准教授

学位

  • 博士(理学)(大阪市立大学)

ホームページURL

科研費研究者番号

  • 20503618

J-Global ID

研究キーワード

  • 含塩素化合物   全合成   クロロスルフォリピッド   有機合成化学   ブロモペルオキシダーゼ   ウラソゾ   紅藻   ハロゲン   付着生物   フジツボ   Laurencin   付着阻害   Omaezallene   ローレンシン   天然物合成   有機合成   Natural Product Synthesis   Organic Synthesis   

研究分野

  • ナノテク・材料 / 生物分子化学
  • ライフサイエンス / 水圏生命科学
  • ナノテク・材料 / 生物分子化学

職歴

  • 2013年 北海道大学 地球環境科学研究科(研究院) 准教授
  • 2008年 - 北海道大学大学院地球環境科学研究院 助教

学歴

  •         - 2006年   大阪市立大学   理学研究科   物質分子系専攻
  •         - 2006年   大阪市立大学
  •         - 2001年   大阪市立大学   理学部   物質科学科
  •         - 2001年   大阪市立大学

所属学協会

  • 日本付着生物学会   有機合成化学協会   日本化学会   

研究活動情報

論文

  • Kinoshita-Terauchi Nana, Shiba Kogiku, Umezawa Taiki, Matsuda Fuyuhiko, Motomura Taizo, Inaba Kazuo
    JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 192 113 - 123 2019年03月 [査読有り][通常論文]
  • Taiki Umezawa, Nurcahyo Iman Prakoso, Miho Kannaka, Yasuyuki Nogata, Erina Yoshimura, Tatsufumi Okino, Fuyuhiko Matsuda
    Chemistry & biodiversity 16 1 e1800451  2019年01月 [査読有り][通常論文]
     
    Omaezallene derivatives (nor-bromoallene, nor-bromodiene, and bromoenynes) were successfully synthesized. Their antifouling activity and toxicity to the cypris larvae of the barnacle Amphibalanus amphitrite and ecotoxicity to the marine crustacean Tigriopus japonicus were studied. It was revealed that the two side chains of omaezallene were essential to its antifouling activity because the activities of nor-bromoallene and nor-bromodiene were significantly diminished. The bromoenyne was found to exhibit potent antifouling activities comparable to omaezallene with low toxicity and ecotoxicity. Preparation of bromoenyne framework is much easier than that of bromodiene moiety in omaezallene. Based on the antifouling activities of the bromoenynes, the synthesis of fluorescent probes and evaluation of their biological activities were also carried out.
  • Umezawa Taiki
    JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN 76 5 426 - 429 2018年05月 [査読有り][通常論文]
  • Kumagai Momochika, Nishikawa Keisuke, Matsuura Hiroshi, Umezawa Taiki, Matsuda Fuyuhiko, Okino Tatsufumi
    Molecules 23 5 2018年05月 [査読有り][通常論文]
  • Julie G. Petitbois, Loida O. Casalme, Julius Adam V. Lopez, Walied M. Alarif, Ahmed Abdel-Lateff, Sultan S. Al-Lihaibi, Erina Yoshimura, Yasuyuki Nogata, Taiki Umezawa, Fuyuhiko Matsuda, Tatsufumi Okino
    JOURNAL OF NATURAL PRODUCTS 80 10 2708 - 2715 2017年10月 [査読有り][通常論文]
     
    NMR-and MS-guided fractionation of an extract of an Okeania sp. marine cyanobacterium, collected from the Red Sea, led to the isolation of four new metabolites, including serinolamides C (1) and D (2) and lyngbyabellins O (3) and P (4), together with the three known substances lyngbyabellins F (5) and G (6) and dolastatin 16 (7). The planar structures of the new compounds were determined using NMR and MS analyses. The absolute configurations of 1 and 2 were determined by Marfey's analysis of their hydrolysates. The absolute configuration of 3 was ascertained by chiral-phase chromatography of degradation products, while that of 4 was determined by comparison to 3 and 5. The cytotoxic and antifouling activities of these compounds were evaluated using MCF7 breast cancer cells and Amphibalanus amphitrite larvae, respectively. Compounds 3, 4, and 7 exhibited strong antifouling activity, and 3 and 7 were not cytotoxic. A structure-activity relationship was observed for the cytotoxicity of the lyngbyabellins with the presence of a side chain (4 is more active than 3) leading to greater activity. For the antifouling activity, the acyclic form without a side chain (3) was the most active.
  • Suzuki J, Miyano N, Yashiro S, Umezawa T, Matsuda F
    Organic & biomolecular chemistry 15 31 6557 - 6566 2017年08月 [査読有り][通常論文]
     
    A 3,4-disubstituted pyrrolidine ring was effectively cyclized through SmI2-mediated reductive coupling between allyl chloride and an alpha,beta-unsaturated ester, although little has been reported about SmI2-promoted C-C bond formation of an allyl chloride with an alpha,beta-unsaturated ester. Selection of either the 3,4-cis- or 3,4-trans-selective cyclization can be accomplished simply by changing the additives from NiI2 to HMPA during reductive cyclization conducted in H2O-THF. Total synthesis of (-)-kainic acid and (+)-allo-kainic acid, which are pyrrolidine alkaloids used in neuroscience and neuropharmacology as useful molecular probes, was successfully achieved by using the stereo-complementary ring closure reactions promoted by SmI2 for the construction of the 2,3,4-trisubsituted pyrrolidine scaffold of kainoids.
  • Julius Adam V. Lopez, Julie G. Petitbois, Charles S. Vairappan, Taiki Umezawa, Fuyuhiko Matsuda, Tatsufumi Okino
    ORGANIC LETTERS 19 16 4231 - 4234 2017年08月 [査読有り][通常論文]
     
    Two new chlorinated fatty acid amides, columbamides D (1) and E (2), along with apratoxins A and C and wewakazole, were isolated from the organic extract of a Moorea bouillonii sample from Sabah, Malaysia. Structure elucidation was accomplished by a combination of MS and NMR analyses. The total synthesis of all four stereoisomers of 1 was completed, and the absolute configuration was determined by chiral-phase HPLC and Marfey's analysis.
  • Taiki Umezawa, Yuki Hasegawa, Ira S. Novita, Junya Suzuki, Tatsuya Morozumi, Yasuyuki Nogata, Erina Yoshimura, Fuyuhiko Matsuda
    MARINE DRUGS 15 7 2017年07月 [査読有り][通常論文]
     
    Biofouling, an undesirable accumulation of organisms on sea-immersed structures such as ship hulls and fishing nets, is a serious economic issue whose effects include oil wastage and clogged nets. Organotin compounds were utilized since the 1960s as an antifouling material; however, the use of such compounds was later banned by the International Maritime Organization (IMO) due to their high toxicity toward marine organisms, resulting in masculinization and imposex. Since the ban, there have been extensive efforts to develop environmentally benign antifoulants. Natural antifouling products obtained from marine creatures have been the subject of considerable attention due to their potent antifouling activity and low toxicity. These antifouling compounds often contain isocyano groups, which are well known to have natural antifouling properties. On the basis of our previous total synthesis of natural isocyanoterpenoids, we envisaged the installation of an isocyano functional group onto glucosamine to produce an environmentally friendly antifouling material. This paper describes an effective synthetic method for various glucosamine-based isocyanides and evaluation of their antifouling activity and toxicity against cypris larvae of the barnacle Amphibalanus amphitrite. Glucosamine isocyanides with an ether functionality at the anomeric position exhibited potent antifouling activity, with EC50 values below 1 mu g/mL, without detectable toxicity even at a high concentration of 10 mu g/mL. Two isocyanides had EC50 values of 0.23 and 0.25 mu g/mL, comparable to that of CuSO4, which is used as a fouling inhibitor (EC50 = 0.27 mu g/mL).
  • Loida O. Casalme, Arisa Yamauchi, Akinori Sato, Julie G. Petitbois, Yasuyuki Nogata, Erina Yoshimura, Tatsufumi Okino, Taiki Umezawa, Fuyuhiko Matsuda
    ORGANIC & BIOMOLECULAR CHEMISTRY 15 5 1140 - 1150 2017年02月 [査読有り][通常論文]
     
    The total synthesis of dolastatin 16, a macrocyclic depsipeptide first isolated from the sea hare Dolabella auricularia as a potential antineoplastic metabolite by Pettit et al., was achieved in a convergent manner. Dolastatin 16 was reported by Tan to exhibit strong antifouling activity, and thus shows promise for inhibiting the attachment of marine benthic organisms such as Amphibalanus amphitrite to ships and submerged artificial structures. Therefore, dolastatin 16 is a potential compound for a new, environmentally friendly antifouling material to replace banned tributyltin-based antifouling paints. The synthesis of dolastatin 16 involved the use of prolinol to prevent formation of a diketopiperazine composed of L-proline and N-methyl-D-valine during peptide coupling. This strategy for the elongation of peptide chains allowed the efficient and scalable synthesis of one segment, which was subsequently coupled with a second segment and cyclized to form the macrocyclic framework of dolastatin 16. The synthetic dolastatin 16 exhibited potent antifouling activity similar to that of natural dolastatin 16 toward cypris larvae of Amphibalanus amphitrite.
  • Taiki Umezawa, Keisuke Nishikawa, Tatsufumi Okino, Fuyuhiko Matsuda
    JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN 74 7 689 - 699 2016年07月 [査読有り][通常論文]
     
    Biofouling is adverse growth of marine organisms on manmade submersible structures such as ships' hulls and cause significant economic and environmental problems. As a fouling inhibitor, tributyltin (TBT) has been widely used for controlling the sessile organisms since the early 1960s. Unfortunately, serious pollution of the marine environment due to the deleterious effect of TBT prompted the International Maritime Organization (IMO) to call in 2008 for a ban on the use of tributyltin (TBT) on ships. Since marine invertebrates prevent settlement of other benthic marine organisms through the use of natural substances with antifouling properties without causing serious environmental problems, natural antifouling products with good antifouling properties but without biocidal properties have attracted considerable attention. Among these, 10-isocyano-4-cadinene and omaezallene show promise as lead compounds for the development of new environmentally friendly antifouling agents due to its potent antifouling activity against the cypris larvae of the barnacle Amphibalanus amphitrite and low toxicity. 10-Isocyano-4-cadinene, an isocyanosesquiterpene, was isolated from nudibranchs of the family Phyllidiidae. On the other hand, omaezallene is a bromoallene-containing C-15-acetogenin isolated from the red alga Laurencia sp. Herein, we wish to describe our research on the isolations, structure elucidations, total syntheses, and evaluation of the antifouling activities of the natural products and their derivatives. The absolute configurations of the natural products were unambiguously established through our asymmetric total syntheses.
  • Taiki Umezawa, Akinori Sato, Yasuto Ameda, Loida O. Casalme, Fuyuhiko Matsuda
    TETRAHEDRON LETTERS 56 1 168 - 171 2015年01月 [査読有り][通常論文]
     
    A convenient and scalable synthesis of two unusual amino acid units found in dolastatin 16, dolaphenvaline, and dolamethylleuine, is described. Dolastatin 16, which was first isolated from the sea hare Dolabella auricularia by Pettit, exhibits not only strong inhibition of growth for a variety of human cancer cell lines but also potent antifouling activity against the larvae of the barnacle Balanus amphitrite. The key element of the synthesis is an organocatalytic Mannich reaction to construct two contiguous stereocenters in the amino acid units with almost complete enantio- and diastereoselectivity. (C) 2014 Elsevier Ltd. All rights reserved.
  • Kensuke Kaneko, Kenji Washio, Taiki Umezawa, Fuyuhiko Matsuda, Masaaki Morikawa, Tatsufumi Okino
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 78 8 1310 - 1319 2014年08月 [査読有り][通常論文]
     
    The marine red alga genus Laurencia is one of the richest producers of unique brominated compounds in the marine environment. The cDNAs for two Laurencia nipponica vanadium-dependent bromoperoxidases (LnVBPO1 and LnVBPO2) were cloned and expressed in Escherichia coli. Enzyme assays of recombinant LnVBPO1 and LnVBPO2 using monochlorodimedone revealed that they were thermolabile but their K-m values for Br- were significantly lower than other red algal VBPOs. The bromination reaction was also assessed using laurediol, the predicted natural precursor of the brominated ether laurencin. Laurediol, protected by trimethylsilyl at the enyne, was converted to deacetyllaurencin by the LnVBPOs, which was confirmed by tandem mass spectrometry. Native LnVBPO partially purified from algal bodies was active, suggesting that LnVBPO is functional in vivo. These results contributed to our knowledge of the biosynthesis of Laurencia brominated metabolites.
  • Taiki Umezawa, Fuyuhiko Matsuda
    TETRAHEDRON LETTERS 55 19 3003 - 3012 2014年05月 [査読有り][通常論文]
     
    Chlorosulfolipids (CSLs) are an intriguing family of natural products featuring highly chlorinated linear hydrocarbon skeletons. Although CSLs were first isolated in 1962, chemical synthesis of CSLs was hampered because relevant methods for stereoselective construction of the polychlorinated motifs of CSLs were scarce. Since Carreira's first total synthesis of the CSL mytilipin A in 2009, several groups, including our own, have reported total syntheses of CSLs. As a result of these total syntheses, important progress has been made in the development of reliable synthetic methods for stereoselective polychlorination. In this digest, we summarize the total syntheses of CSLs by focusing on synthetic methods for stereoselective polychlorination of the organic frameworks of CSLs. (c) 2014 Published by Elsevier Ltd.
  • Taiki Umezawa, Yuko Oguri, Hiroshi Matsuura, Shohei Yamazaki, Masahiro Suzuki, Erina Yoshimura, Takeshi Furuta, Yasuyuki Nogata, Yukihiko Serisawa, Kazuyo Matsuyama-Serisawa, Tsuyoshi Abe, Fuyuhiko Matsuda, Minoru Suzuki, Tatsufumi Okino
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 53 15 3909 - 3912 2014年04月 [査読有り][通常論文]
     
    Natural antifouling products have been the subject of considerable attention. We screened marine algae for antifouling activity and discovered omaezallenes, the new bromoallene-containing natural products isolated from the red alga Laurenciasp. Described is the isolation, structure elucidation, and total syntheses of omaezallenes. The relative and absolute configurations of natural omaezallenes were unambiguously established through total synthesis. The antifouling activities and ecotoxicity of omaezallenes were also evaluated.
  • Keisuke Nishikawa, Taiki Umezawa, Mary J. Garson, Fuyuhiko Matsuda
    JOURNAL OF NATURAL PRODUCTS 75 12 2232 - 2235 2012年12月 [査読有り][通常論文]
     
    The marine sponge metabolite 10-isothiocyanato4-cadinene (1) was first isolated by Garson et al. from Acanthella cavernosa in 2000. The same structure 1 was later reported by Wright et al. from the nudibranch Phyllidiella pustulosa and its sponge diet, but with different NMR data. The syntheses of both enantiomers of 1 were accomplished through the isothiocyanation of 10-isocyano-4-cadinene (2) previously synthesized by our group. The correct spectroscopic data and specific rotation value of the structure 1 were determined on the basis of the syntheses. The NMR data of synthetic 1 matched those of the isothiocyanate isolated by Garson and differed from those reported by Wright. The spectroscopic data and specific rotation values of 10-epi-10-isothiocyanato-4-cadinene (6) and di-1,6-epi-10-isothiocyanato-4-cadinene (8) were also established through the syntheses of these diastereomers. Structure 6 has been reported as a natural product by Mitome et al., but the NMR data for the synthetic sample of 6 differ from those of the natural isolate.
  • Andrea Roxanne J. Anas, Takaya Kisugi, Taiki Umezawa, Fuyuhiko Matsuda, Marc R. Campitelli, Ronald J. Quinn, Tatsufumi Okino
    JOURNAL OF NATURAL PRODUCTS 75 9 1546 - 1552 2012年09月 [査読有り][通常論文]
     
    Bioassay-guided investigation of the cyanobacterium Anabaena compacta extracts afforded spumigin J (1) and the known thrombin inhibitor spumigin A (2). The absolute configuration of 1 was analyzed by advanced Marfey's methodology. Compounds 1 and 2 inhibited thrombin with EC50 values of 4.9 and 2.1 mu M, and 0.7 and 0.2 mu M in the cathepsin B inhibitory assay, respectively. The MM-GBSA methodology predicted spumigin A with 2S-4-methylproline as the better thrombin inhibitor.
  • Taiki Umezawa, Tomoya Seino, Fuyuhiko Matsuda
    ORGANIC LETTERS 14 16 4206 - 4209 2012年08月 [査読有り][通常論文]
     
    A novel three-component coupling between trimethylsilylmethylphosphonate, acyl fluoride, and aldehyde has been developed. A sequential nucleophilic addition of lithio-trimethylsilylmethylphosphonate to the acyl fluoride and Horner-Wadsworth-Emmons reaction of an aldehyde with the lithio-beta-ketophosphonate generated in situ by desilylation at the alpha-position of the alpha-silyl-beta-ketophosphonate by fluoride took place cleanly in a one-pot operation. Various E- and Z-enones were obtained in high yields with high stereoselectivities by this one-pot procedure.
  • Taiki Umezawa, Manabu Sueda, Takao Kamura, Teppei Kawahara, Xuerong Han, Tatsufumi Okino, Fuyuhiko Matsuda
    JOURNAL OF ORGANIC CHEMISTRY 77 1 357 - 370 2012年01月 [査読有り][通常論文]
     
    Total syntheses of kalkitoxin, isolated from the Caribbean Lyngbya majuscula, and its analogues, 3-epi-, 7-epi-, 8-epi-, 10-epi-, 10-nor-, and 16-nor-kalldtcocin, were achieved via oxazolidinone-based diastereoselective 1,4-addition reaction of a methyl group and efficient T1C14-mediated thiazoline ring formation as the key steps. The biological activities of synthetic kalkitoxin and its analogues were evaluated with brine shrimp.

作品等

  • 若手研究者のための有機合成セミナー
    2008年

その他活動・業績

  • Taiki Umezawa, Akinori Sato, Yasuto Ameda, Loida O. Casalme, Fuyuhiko Matsuda TETRAHEDRON LETTERS 56 (1) 168 -171 2015年01月 [査読無し][通常論文]
     
    A convenient and scalable synthesis of two unusual amino acid units found in dolastatin 16, dolaphenvaline, and dolamethylleuine, is described. Dolastatin 16, which was first isolated from the sea hare Dolabella auricularia by Pettit, exhibits not only strong inhibition of growth for a variety of human cancer cell lines but also potent antifouling activity against the larvae of the barnacle Balanus amphitrite. The key element of the synthesis is an organocatalytic Mannich reaction to construct two contiguous stereocenters in the amino acid units with almost complete enantio- and diastereoselectivity. (C) 2014 Elsevier Ltd. All rights reserved.
  • Taiki Umezawa, Fuyuhiko Matsuda TETRAHEDRON LETTERS 55 (19) 3003 -3012 2014年05月 [査読無し][通常論文]
     
    Chlorosulfolipids (CSLs) are an intriguing family of natural products featuring highly chlorinated linear hydrocarbon skeletons. Although CSLs were first isolated in 1962, chemical synthesis of CSLs was hampered because relevant methods for stereoselective construction of the polychlorinated motifs of CSLs were scarce. Since Carreira's first total synthesis of the CSL mytilipin A in 2009, several groups, including our own, have reported total syntheses of CSLs. As a result of these total syntheses, important progress has been made in the development of reliable synthetic methods for stereoselective polychlorination. In this digest, we summarize the total syntheses of CSLs by focusing on synthetic methods for stereoselective polychlorination of the organic frameworks of CSLs. (c) 2014 Published by Elsevier Ltd.
  • 金子賢介, 鷲尾健司, 梅澤大樹, 松田冬彦, 森川正章, 沖野龍文 日本水産学会大会講演要旨集 2014 119 2014年03月27日 [査読無し][通常論文]
  • 前田武志, 梅澤大樹, 松田冬彦 日本化学会講演予稿集 94th (4) 1492 2014年03月12日 [査読無し][通常論文]
  • 佐藤彰則, 梅澤大樹, 松田冬彦 日本化学会講演予稿集 94th (4) 1468 2014年03月12日 [査読無し][通常論文]
  • 梅澤大樹 上原記念生命科学財団研究報告集(CD-ROM) 27 ROMBUNNO.11 2013年12月10日 [査読無し][通常論文]
  • 金子賢介, 鷲尾健司, 梅澤大樹, 松田冬彦, 森川正章, 沖野龍文 マリンバイオテクノロジー学会大会講演要旨集 15th 68 2013年06月01日 [査読無し][通常論文]
  • 梅澤大樹, 清野智也, 松田冬彦 日本化学会講演予稿集 93rd (4) 1202 2013年03月08日 [査読無し][通常論文]
  • 梅澤大樹, 清野智也, 松田冬彦 日本化学会講演予稿集 92nd (4) 1156 2012年03月09日 [査読無し][通常論文]
  • 梅澤 大樹, 松田 冬彦 有機合成化学協会誌 69 (10) 1122 -1133 2011年10月01日 [査読無し][通常論文]
  • 梅澤大樹, 鈴木将洋, 小栗祐子, 松浦裕志, 沖野龍文, 松田冬彦 天然有機化合物討論会講演要旨集 53rd 637 -642 2011年09月02日 [査読無し][通常論文]
  • 梅澤大樹 化学と工業 64 (9) 688 -689 2011年09月01日 [査読無し][通常論文]
  • Keisuke Nishikawa, Hiroshi Nakahara, Yousuke Shirokura, Yasuyuki Nogata, Erina Yoshimura, Taiki Umezawa, Tatsufumi Okino, Fuyuhiko Matsuda JOURNAL OF ORGANIC CHEMISTRY 76 (16) 6558 -6573 2011年08月 [査読無し][通常論文]
     
    The first enantioselective total synthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, and determination of its absolute stereochemistry were achieved. 10-Isocyano-4-cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, intermolecular Diels-Alder reaction and samarium diiodide induced Barbier-type cyclization were employed as key steps. The absolute configuration of 10-isocyano-4-cadinene was determined as (1S,6S,7R,10S) by comparison of the optical rotations between natural and synthetic samples. In addition, the authors successfully synthesized 10-epi- and di-1,6-epi-10-isocyano-4-cadinene through the same synthetic pathway. Antifouling activities against Balanus amphitrite with the cadinenes were also evaluated.
  • Taiki Umezawa, Masayuki Shibata, Kensuke Kaneko, Tatsufumi Okino, Fuyuhiko Matsuda ORGANIC LETTERS 13 (5) 904 -907 2011年03月 [査読無し][通常論文]
     
    Asymmetric total synthesis of danicalipin A was achieved. The synthesis was characterized by diastereoselective introduction of chlorine atoms. Biological activities with synthetic danicalipin A, its enantiomer, and racemate were also evaluated toward brine shrimp. Both enantiomers of danicalipin A showed almost the same activity.
  • Journal of Synthetic Organic Chemistry, Japan 69 (10) 1122 -1133 2011年 [査読無し][通常論文]
  • Taiki Umezawa, Tetsuro Shinada, Yasufumi Ohfune CHEMISTRY LETTERS 39 (12) 1281 -1282 2010年12月 [査読無し][通常論文]
     
    The synthesis of (1) C-labeled 5,6,11-trideoxytetrodotoxin has been successfully achieved This is the first example of the C-13-labeled analogs in tetrodotoxin congeners
  • Tetsuro Shinada, Makoto Hamada, Kota Miyoshi, Masato Higashino, Taiki Umezawa, Yasufumi Ohfune SYNLETT (14) 2141 -2145 2010年09月 [査読無し][通常論文]
     
    K2HPO4 is an efficient catalyst for the transesterification reaction to produce methyl esters. Various functional groups are compatible under the mild reaction conditions.
  • K. C. Nicolaou, Christine F. Gelin, Jae Hong Seo, Zhihong Huang, Taiki Umezawa JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 132 (28) 9900 -9907 2010年07月 [査読無し][通常論文]
     
    A devised synthetic strategy toward the QRSTU ring system 4 of the marine-derived biotoxin maitotoxin (1) delivered, in addition to 4, its diastereoisomers 85-epi-QRSTU and 86-epi-QRSTU ring systems 5 and 6. The convergent route to these maitotoxin fragments involved coupling of UT and Q building blocks 9 (obtained from 2-deoxy-D-ribose) and 10 (obtained from D-ribose) followed by ring-closing metathesis to afford enol ether 8, whose elaboration to the targeted QRSTU ring system 4 required its conversion to hydroxy ketone 7. The latter compound (7) was transformed to the final product through a hydroxy dithioketal cyclization, followed by oxidation/methylation of the resulting O,S-mixed ketal to install the last of the five methyl groups contained within the target molecule (4). (13)C NMR spectroscopic analysis of synthesized fragments 4, 5, and 6 and comparisons with maitotoxin provided strong support for the originally assigned structure of the QRSTU domain of the natural product.
  • Keisuke Nishikawa, Hiroshi Nakahara, Yousuke Shirokura, Yasuyuki Nogata, Erina Yoshimura, Taiki Umezawa, Tatsufumi Okino, Fuyuhiko Matsuda ORGANIC LETTERS 12 (5) 904 -907 2010年03月 [査読無し][通常論文]
     
    The first enantioselective total synthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, was achieved. The cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, an intermolecular Diels-Alder reaction and a SMl(2)-induced Barbier-type reaction were employed as key steps. The absolute configuration of 10-isocyano-4-cadinene was determined to be (1S, 6S, 7R, 10S) on the basis of the total synthesis. Antifouling activities against Balanus amphitrite with both enantiomers of 10-isocyano-4-cadinene were also evaluated.
  • K. C. Nicolaou, Michael O. Frederick, Antonio C. B. Burtoloso, Ross M. Denton, Fatima Rivas, Kevin P. Cole, Robert J. Aversa, Romelo Gibe, Taiki Umezawa, Takahiro Suzuki JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 130 (23) 7466 -7476 2008年06月 [査読無し][通常論文]
     
    As the largest secondary metabolite to be discovered as of yet, the polyether marine neurotoxin maiitotoxin constitutes a major structural and synthetic challenge. After its originally proposed structure (1) had been questioned on the basis of biosynthetic considerations, we provided computational and experimental support for structure 1. In an effort to provide stronger experimental evidence of the molecular architecture of maitotoxin, its GHIJKLMNO ring system 21 was synthesized. The (13)C NMR chemical shifts of synthetic 3 matched closely those corresponding to the same domain of the natural product providing strong evidence for the correctness of the originally proposed structure of maitotoxin (1).
  • Taiki Umezawa, Toshihiro Hayashi, Hiroshi Sakai, Hidetoshi Teramoto, Takeshi Yoshikawa, Masashi Izumida, Yoshinori Tamatani, Tadashi Hirose, Yasufumi Ohfune, Tetsuro Shinada ORGANIC LETTERS 8 (21) 4971 -4974 2006年10月 [査読無し][通常論文]
     
    The first total synthesis of 5,6,11-trideoxytetrodotoxin (1) and its 4-epimer were achieved. The synthesis is characterized by the stereoselective construction of the quaternary amino carbon center at C8a by an asymmetric transferring Strecker synthesis and the highly efficient conversion of cyanohydrin 4 to 1 via intramolecular cyclization reactions.
  • Shinada Tetsuro, Umezawa Taiki, Hayashi Toshihiro, Sakai Hiroshi, Kawakami Tadashi, Teramoto Hidetoshi, Yoshikawa Takeshi, Izumida Masashi, Tamatani Yoshinori, Hirose Tadashi, Ohfune Yasufumi International Symposium on the Chemistry of Natural Products 2006 "P -107" 2006年07月23日 [査読無し][通常論文]
  • Kozuma Hayato, Umezawa Taiki, Ando Takeshi, Shinada Tetsuro, Ohfune Yasufumi International Symposium on the Chemistry of Natural Products 2006 "P -216" 2006年07月23日 [査読無し][通常論文]
  • Tetsuro Shinada, Tadashi Kawakami, Hiroshi Sakai, Hiromi Matsuda, Taiki Umezawa, Masaki Kawasaki, Kosuke Namba, Yasufumi Ohfune BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 79 (5) 768 -774 2006年05月 [査読無し][通常論文]
     
    Stereoselective synthesis of both optically active cis- and trans-1-amino-2-hydroxycyclohexane-1-carboxylic acids (Ahhs) 1a and 1b was accomplished by an asymmetric version of the Strecker synthesis. Stereochemical aspects of their chiral induction processes are investigated.
  • Tetsuro Shinada, Tadashi Kawakami, Hiroshi Sakai, Hiromi Matsuda, Taiki Umezawa, Masaki Kawasaki, Kosuke Namba, Yasufumi Ohfune BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 79 (5) 768 -774 2006年05月 [査読無し][通常論文]
     
    Stereoselective synthesis of both optically active cis- and trans-1-amino-2-hydroxycyclohexane-1-carboxylic acids (Ahhs) 1a and 1b was accomplished by an asymmetric version of the Strecker synthesis. Stereochemical aspects of their chiral induction processes are investigated.
  • SHINADA Tetsuro, UMEZAWA Taiki, ANDO Tsuyoshi, KOZUMA Hayato, OHFUNE Yasufumi Tetraheron Letters 47 (12) 1945 -1947 2006年03月 [査読無し][通常論文]
     
    An efficient synthesis of N-acyl-N'-substituted guanidines by condensation reaction of thiourea and (Me3Si)(2)NH in the presence of EDCI is described. Various guanidines were synthesized in a simple manner. (c) 2006 Elsevier Ltd. All rights reserved.

共同研究・競争的資金等の研究課題

  • 環境にやさしい付着阻害剤の開発を指向した天然物誘導体合成と付着阻害メカニズム解明
    科研費:基盤研究(B)
    研究期間 : 2018年04月 -2022年03月 
    代表者 : 梅澤 大樹
  • 海洋生物の防御機能を模倣したバイオマス循環型船底付着阻害剤の合成的探索研究
    環境省:環境総合研究推進費
    研究期間 : 2016年04月 -2018年03月 
    代表者 : 梅澤 大樹
  • 文部科学省:科学研究費補助金(若手研究(B))
    研究期間 : 2015年 -2016年 
    代表者 : 梅澤 大樹
  • 文部科学省:科学研究費補助金(若手研究(B))
    研究期間 : 2011年 -2012年 
    代表者 : 梅澤 大樹
     
    研究実施計画に基づいて、クロロスルフォリピッドを合成するための2つのフラグメントの合成、およびそれらをカップリングするための反応条件についても併せて検討した。各種検討の結果、2つのフラグメントのうちの1つの効率的な合成法をほぼ確立するとともに、もう片方のフラグメントを効率的に合成するための新規合成方法論(アルデヒド、トリメチルシリルメチルホスホネート、酸フッ化物を用いた3成分カップリング)を確立することに成功した。この合成方法論は、様々な官能基を有する化合物に対して適用でき、各種有機化合物を合成するために有用な方法であり、この方法を用いた天然有機化合物合成へと応用することも可能である。本合成方法論は、OrganicLetters誌にて報告した。クロロスルフォリピッド本体の合成については、合成したフラグメントをカップリングするため、モデル化合物による検討をすすめている。

教育活動情報

主要な担当授業

  • 生体物質科学特論Ⅱ
    開講年度 : 2018年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 天然物化学、化学生態学 Natural Product Chemistry, Chemical Ecology
  • 化学Ⅱ
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 有機化合物、官能基、分子構造、化学的性質、化学反応、機能性有機物、生体関連有機物質
  • 基礎自然科学実験
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 細胞、顕微鏡、DNA、生き物の生態、酸化・還元反応、解剖、かおり物質、COD、医薬品、合成、地形、地球環境、岩石、鉱物、堆積物、超電導、レーザー光、音、アンプ作り
  • 自然科学実験
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 自然科学実験


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