研究者業績

臼杵 豊展

ウスキ トヨノブ  (Usuki Toyonobu)

基本情報

所属
上智大学 理工学部物質生命理工学科 教授
学位
学士(理学)(東北大学)
修士(理学)(東北大学)
博士(理学)(東北大学)

連絡先
t-usukisophia.ac.jp
研究者番号
50514535
J-GLOBAL ID
200901076489387829
researchmap会員ID
5000046104

学歴

 3

論文

 113
  • Wakana Fuse, Akiho Imura, Nao Tanaka, Toyonobu Usuki
    Tetrahedron Letters 60 928-930 2019年2月22日  査読有り責任著者
  • Akiho Imura, Nao Tanaka, Toyonobu Usuki
    Tetrahedron Letters 60(6) 489-492 2019年2月  査読有り責任著者
  • Anna P. Kondo, Takaaki B. Narita, Chihiro Murata, Tetsuhiro Ogura, Ayame Mikagi, Toyonobu Usuki, Tamao Saito
    Current Microbiology 76 376-381 2019年2月1日  査読有り
  • Toyonobu Usuki
    Natural Product Communications 13(12) 1615-1618 2018年12月30日  査読有り責任著者
  • Ayame Mikagi, Dai Tokairin, Toyonobu Usuki
    Tetrahedron Letters 59(52) 4602-4605 2018年12月  査読有り責任著者
  • Nao Tanaka, Manami Kurita, Yuko Murakami, Toyonobu Usuki
    European Journal of Organic Chemistry 2018(21) 6002-6009 2018年11月25日  査読有り責任著者
  • Toyonobu Usuki, Masahiro Yoshizawa-Fujita
    Application of Ionic Liquids in Biotechnology 227-240 2018年11月16日  筆頭著者責任著者
  • Mizuno, H., Usuki, T.
    ChemistrySelect 3(6) 1781-1786 2018年2月12日  査読有り責任著者
  • Songyot Anuchapreeda, Nattakanwadee Khumpirapang, Kawinnat Rupitiwiriya, Leelawat Tho-iam, Aroonchai Saiai, Siriporn Okonogi, Toyonobu Usuki
    Bioorganic and Medicinal Chemistry Letters 28(3) 410-414 2018年  査読有り責任著者
    Curcuma cf. viridiflora Roxb., also known as Mah-Lueang in Thai, belongs to the Zingiberaceae family and is grown from rhizomes. The rhizome of the plant has been used for medicinal purposes, in particular, to treat paralysis in Thai traditional medicine. However, no biologically active compounds have been reported from Mah-Lueang yet. In this study, natural compounds were isolated from Mah-Lueang and structurally determined by spectroscopic methods, including electrospray ionization mass spectrometry and nuclear magnetic resonance. The four isolated compounds were identified as furanodiene (1), dehydrocurdione (2), germacrone-4,5-epoxide (3), and zedoarondiol (4). These sesquiterpenes were investigated for antileukemic activities against KG1a and Molt4 cells. Leukemic cell proliferation is regulated by the Wilms’ tumor 1 (WT1) transcription factor. Compound 1 showed the strongest cytotoxicity against both KG1a and Molt4 cells. Noncytotoxic concentrations (20% inhibitory concentration values) of all compounds were able to decrease the WT1 protein expression and total cell numbers in both cell lines. The four compounds showed good inhibitory activities for WT1 protein expression. Compounds 3 and 4 showed excellent antileukemic activities for both cell lines. In summary, four sesquiterpene compounds with antileukemic activities against the KG1a and Molt4 cell lines were identified in Mah-Lueang extracts.
  • 臼杵豊展
    有機合成化学協会誌 76(5) 422-425 2018年  査読有り招待有り
  • Usuki, T., Onda, S., Yoshizawa-Fujita, M., Rikukawa, M.
    Scientific Reports 7(1) 6890 2017年7月31日  査読有り責任著者
    Sweet potato, Ipomoea batatas, is a widely cultivated vegetable worldwide. The leaves contain polyphenolic natural products called caffeoylquinic acids (CQAs), which possess biological activities including inhibition of aggregation of amyloid peptides. The present study describes an efficient extraction and isolation procedure for CQAs from sweet potato leaves using a cellulose-dissolving ionic liquid. The results showed that, compared to methanol, use of 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) allowed the extraction of a 6.5-fold greater amount of CQAs. This protocol will enable the efficient extraction of other organic compounds and biopolymers from natural materials.
  • Koki Munakata, Masahiro Yoshizawa-Fujita, Masahiro Rikukawa, Toyonobu Usuki
    AUSTRALIAN JOURNAL OF CHEMISTRY 70(6) 699-704 2017年  査読有り責任著者
    Lemon myrtle is the richest natural source of citral, which has potential medicinal applications. In this study, citral was extracted from lemon myrtle using cellulose-dissolving ionic liquids (ILs), 1-ethyl-3-methylimidazolium methylphosphonate ([C(2)mim][(MeO)(H)PO2]), N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium chloride ([DEME]Cl), and N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium 2-methoxyacetate ([DEME][MOAc]). The extraction yield of citral obtained using ILs was up to 2.1 times higher than that obtained using ethanol. The ILs could be recycled and reused nine times for the extraction of citral. The present method provides a greener process when compared with conventional approaches and may be applicable for the extraction of other natural products.
  • Chihiro Murata, Masahiro Yoshizawa-Fujita, Masahiro Rikukawa, Toyonobu Usuki
    Asian Journal of Chemistry 29(2) 309-312 2017年  査読有り責任著者
  • Daisuke Watanabe, Rina Suzuki, Toyonobu Usuki
    Tetrahedron Letters 58(12) 1194-1197 2017年  査読有り責任著者
    Desmosine is a crosslinking pyridinium amino acid of elastin, which is a useful biomarker for the diagnosis of chronic obstructive pulmonary disease (COPD) by LC–MS/MS analysis. We previously reported a synthesis of desmosine-d4, which is useful as an internal standard for quantitative LC–MS/MS analysis of desmosines, by deuterogenation of an alkyne group however, the isotopic purity of the desmosine-d4was only ca. 50%. The present report describes a new synthesis of desmosine-d4that improves the isotopic purity to ca. 90% by exchanging the protons of the amino groups to deuterium using deuterogenation.
  • Keita Ogawa, Takahiro Hayashi, Yong Y. Lin, Toyonobu Usuki
    Tetrahedron 73(27-28) 3838-3847 2017年  査読有り責任著者
    Elastin is a vital extracellular matrix protein, which is known for providing elasticity in numerous tissues. It is formed by the self-assembly and subsequent crosslinking of elastin precursor, tropoelastin. Two tetrafunctional, pyridinium-based amino acids desmosine and isodesmosine are exclusively found in elastin and play an important role as crosslinkers. Structural elucidation of elastin has eluded scientists to date, owing to the highly cross-linked structure and insoluble nature. Therefore, in this study, we aimed to synthesize a desmosine-containing cyclic peptide as a partial elastin mimic, in order to eventually facilitate the elucidation of the crosslinking pattern of elastin by mass spectrometric analysis.
  • Toyonobu Usuki, Akira Komatsu
    Tetrahedron Letters 58(29) 2856-2858 2017年  査読有り
    Monoalkynylpyridines were prepared via a Sonogashira cross-coupling reaction between monoiodopyridines and alkynes. Mild hydrogenation of the obtained monoalkynylpyridines was then conducted to produce the corresponding monoalkylpiperidines in moderate to excellent yields. The hydrogenation reaction was carried out under H2 (1 atm) in the presence of 10 wt% Pd/C (5 eq) in either AcOH or MeOH at room temperature. The present mild method is therefore useful for the quick and easy preparation of monoalkylpiperidines.
  • Toyonobu Usuki, Koki Munakata
    Bulletin of the Chemical Society of Japan 90(10) 1105-1110 2017年  査読有り
    The essential oil components linalool, β-ionone, cis- and trans-linalool oxide pyranoid, and trans-linalool oxide furanoid, which are found in the flowers of Osmanthus fragrans var. aurantiacus, were efficiently extracted using a cellulosedissolving ionic liquid 1-ethyl-3-methylimidazolium methylphosphonate ([C2mim][(MeO)(H)PO2]) as an extraction solvent. Investigation of extraction time revealed that the ionic liquid contributed to the efficient extraction of these essential oils over a shorter extraction time. Scanning electron microscopy (SEM) and fluorescence microscopy observations of the flower petals confirmed the efficiency of the ionic liquid in this extraction process.
  • He, J., Ma, S., Cantor, J., Usuki, T., Dolios, G., Wang, R., Turino, G.M., Lin, Y.Y.
    Current Topics in Peptide and Protein Research 17 105-124 2016年12月  査読有り
    Elastin matrix are significant structural constituents of skin, blood vessels, lung, and other connective tissues, where they provide physical recoil to distorting forces and contribute to normal physiological function. Degradation of elastin-containing tissues can occur in prevalent diseases resulting in complex mixtures of elastin-derived peptides, which remain largely uncharacterized due to the insoluble nature of elastin and its complex crosslinking structure. We compared proteolytic activity of several proteinases that cause degradation of human lung elastin matrix. The resulting peptides were characterized by high performance liquid chromatography and tandem mass spectrometry (LC-MS/MS), which results in the identification of several hundreds of linear peptides that belong to non-crosslinking domains of soluble elastin precursor tropoelastin. The analysis of the proteolytically cleaved sites of tropoelastin domains suggested that two alanine-rich lysine peptide chains at the domains 19 and 25 of tropoelastin are involved in the crosslink formation and it is proposed that a tetrafunctional crosslink structure is formed by condensation between the two domains, KAAAK (K at the loci 375 and 379) and KSAAK (K at the loci 529 and 533) of tropoelastin. The proposed crosslink can be chemically synthesized as a molecular model for the elastin crosslinking structure. We further compared in vitro proteolysis of a normal lung and a lung from a chronic obstructive pulmonary disease (COPD) patient. The proteolysis showed the three proteases HNE, MMP12 and PR3 are the most effective toward elastin matrix degradation, which may also occur in vivo during COPD. The proteolysis of the COPD lung produced decreased amount of desmosine/isodesmosine (DES/IDS) crosslink peptides compared to that of the normal lung but involved more proteolytic sites, which indicated significant pathological degradation of the crosslinks had occurred within the elastin matrix of the COPD lung resulting in an altered structural integrity. This finding could be a basis for progression of lung tissue breakdown once COPD is initiated and be a mechanism for clinical progression of COPD.
  • Chihiro Murata, Tetsuhiro Ogura, Shuhei Narita, Anna P. Kondo, Natsumi Iwasaki, Tamao Saito, Toyonobu Usuki
    BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 26(5) 1428-1433 2016年3月  査読有り
    4-Methyl-5-pentylbenzene-1,3-diol (MPBD) is a secondary metabolite of SteelyA polyketide synthase, which controls cell aggregation and spore maturation of Dictyostelium discoideum. In this study, chemical synthesis of MPBD and its derivatives was achieved. Structure-activity relationship (SAR) studies for antimicrobial activities against Escherichia coli and Bacillus subtilis were also conducted. (C) 2016 Elsevier Ltd. All rights reserved.
  • Chihiro Murata, Quang Thuong Tran, Shingo Onda, Toyonobu Usuki
    Tetrahedron Letters 57(48) 5368-5371 2016年  査読有り
  • Manami Kurita, Miho Tanigawa, Shuhei Narita, Toyonobu Usuki
    Tetrahedron Letters 57(52) 5899-5901 2016年  査読有り
    Cnicin is a germacranolide sesquiterpene lactone that possesses potent inhibitory activity against the protozoan parasite Trypanosoma brucei, which causes human African trypanosomiasis (HAT). Although cnicin has an interesting structure and attractive biological activity, synthetic studies of cnicin have not yet been reported. This report describes the synthesis of the protected side chain carboxylic acid moiety at C8 of cnicin via two routes starting from L-ascorbic acid. In addition, esterification between the synthetic side chain and salonitenolide derivative, which can be achieved via hydrolysis of cnicin and protection of the primary alcohol, was conducted. Thus, a semi-synthesis of cnicin was achieved.
  • Ayano Tanaka-Yanuma, Satoshi Watanabe, Keita Ogawa, Sho Watanabe, Naoto Aoki, Tetsuhiro Ogura, Toyonobu Usuki
    TETRAHEDRON LETTERS 56(48) 6777-6781 2015年12月  査読有り
    Isolated from the Jamaican cyanobacterium Lyngbya majuscula, the jamaicamides are unique, mixed polyketide-peptides reported to be sodium channel blockers. The polyketide moiety contains an (E)-chloroolefin, an undetermined methyl stereocenter (C9), and an (E)-olefin (C10-C11). Herein we report the stereo- and regioselective synthesis of the polyketide moiety of the jamaicamides via a Julia-Kocienski coupling as the key step. (C) 2015 Elsevier Ltd. All rights reserved.
  • Takuya Sato, Shihori Hara, Makiko Sato, Keita Ogawa, Michael Adams, Toyonobu Usuki
    BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 25(23) 5504-5507 2015年12月  査読有り
    Cynaropicrin is a guaianolide sesquiterpene lactone, which has potent in vitro and in vivo inhibitory activity against Trypanosoma brucei, the protozoan parasite that causes human African trypanosomiasis (HAT; sleeping sickness). Herein, we describe the synthesis of cynaropicrin's deuterated derivative, cynaropicrin-d(4), by the replacement of the side chain of natural cynaropicrin. The synthesized cynaropicrin-d(4) could be employed as an internal standard for liquid chromatography-mass spectrometry (LC-MS) analysis, in the pharmacokinetic study of cynaropicrin. This could potentially advance the study of this therapeutic lead. (C) 2015 Elsevier Ltd. All rights reserved.
  • Yohei Koseki, Takanori Sugimura, Keita Ogawa, Rina Suzuki, Haruka Yamada, Noriyuki Suzuki, Yoshiro Masuyama, Yong Y. Lin, Toyonobu Usuki
    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY 2015(18) 4024-4032 2015年6月  査読有り
    Isodesmosine is a crosslinking pyridinium amino acid of elastin and is an attractive biomarker for the diagnosis of chronic obstructive pulmonary disease (COPD). In this paper, we describe the total synthesis of isodesmosine. The key features of this synthesis are stepwise and regioselective palladium-catalyzed Negishi and Sonogashira cross-coupling reactions for efficient introduction of amino acid segments on the pyridine ring.
  • Takahiro Tanigawa, Akira Komatsu, Toyonobu Usuki
    Bioorganic & Medicinal Chemistry Letters 25(10) 2046-2049 2015年5月  査読有り
  • Rina Suzuki, Hiroto Yanuma, Takahiro Hayashi, Haruka Yamada, Toyonobu Usuki
    TETRAHEDRON 71(12) 1851-1862 2015年3月  査読有り
    Desmosine is a crosslinking pyridinium amino acid of elastin and is an attractive biomarker for the diagnosis of chronic obstructive pulmonary disease (COPD). Herein, we describe the total synthesis of natural desmosine and its deuterated derivatives. The synthesized deuterated derivatives could be used as internal standards for the development of an isotope-dilution liquid chromatography-mass spectrometry (LC-MS/MS) analytical method for the accurate determination of desmosine in clinical samples. The key features of our synthesis are stepwise chemo- and regioselective palladium-catalyzed Sonogashira and Negishi cross-coupling reactions for the efficient introduction of the amino acid side chains onto the pyridine core. (C) 2015 Elsevier Ltd. All rights reserved.
  • Haruka Yamada, Takahiro Hayashi, Toyonobu Usuki
    Bulletin of the Chemical Society of Japan 88(5) 673-683 2015年  査読有り
    Desmosine, a COPD biomarker and elastin crosslinker, is a tetrasubstituted pyridinium amino acid. In this paper, the total synthesis of desmosine is described utilizing stepwise and regioselective palladium-catalyzed Sonogashira cross-coupling reactions of trihalopyridines and terminal alkynes as key steps. The 13-step synthesis starting from 4-hydroxypyridine was achieved in 11% overall yield.
  • Shingo Onda, Toyonobu Usuki, Masahiro Yoshizawa-Fujita, Masahiro Rikukawa
    Chemistry Letters 44(11) 1461-1463 2015年  査読有り
    A protocol for extracting the terpene trilactone bilobalide from Ginkgo biloba leaves using the cellulose-dissolving ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) was developed. Extraction with [C4mim]Cl/MeOH (1:1 w/w) at 80°C afforded bilobalide with a yield of 0.14% w/w, which was 1.4 times higher than that achieved using conventional MeOH at 80°C (0.098% w/w).
  • Takanori Sugimura, Akira Komatsu, Yohei Koseki, Toyonobu Usuki
    TETRAHEDRON LETTERS 55(46) 6343-6346 2014年11月  査読有り
    1,2,3,5-Tetrasubstituted pyridinium amino acid isodesmosine is a crosslinking amino acid of elastin and is an attractive biomarker for the diagnosis of chronic obstructive pulmonary disease (COPD). Herein, we report an application of the Chichibabin pyridine synthesis to the total synthesis of isodesmosine. Specifically, the appropriate protected lysine and the corresponding aldehyde were reacted using Pr(OTf)(3) in H2O/MeOH. (C) 2014 Elsevier Ltd. All rights reserved.
  • Toyonobu Usuki, Takanori Sugimura, Akira Komatsu, Yohei Koseki
    ORGANIC LETTERS 16(6) 1672-1675 2014年3月  査読有り
    The tetrasubstituted pyridinium amino acids isodesmosine and desmosine are cross-linkers of elastin and are attractive biomarkers for the diagnosis of chronic obstructive pulmonary disease (COPD). In this study, the biomimetic total synthesis of isodesmosine and desmosine via a lanthanide-promoted Chichibabin pyridine synthesis using the corresponding aldehyde and amine hydrochloride is reported.
  • Stefanie Zimmermann, Gerda Fouche, Maria De Mieri, Yukiko Yoshimoto, Toyonobu Usuki, Rudzani Nthambeleni, Christopher J. Parkinson, Christiaan van der Westhuyzen, Marcel Kaiser, Matthias Hamburger, Michael Adams
    MOLECULES 19(3) 3523-3538 2014年3月  査読有り
    Sesquiterpene lactones (STLs) are natural products that have potent antitrypanosomal activity in vitro and, in the case of cynaropicrin, also reduce parasitemia in the murine model of trypanosomiasis. To explore their structure-antitrypanosomal activity relationships, a set of 34 natural and semi-synthetic STLs and amino-STLs was tested in vitro against T. b. rhodesiense (which causes East African sleeping sickness) and mammalian cancer cells (rat bone myoblast L6 cells). It was found that the alpha-methylene-gamma-lactone moiety is necessary for both antitrypanosomal effects and cytotoxicity. Antitrypanosomal selectivity is facilitated by 2-(hydroxymethyl)acrylate or 3,4-dihydroxy-2-methylenebutylate side chains, and by the presence of cyclopentenone rings. Semi-synthetic STL amines with morpholino and dimethylamino groups showed improved in vitro activity over the native STLs. The dimethylamino derivative of cynaropicrin was prepared and tested orally in the T. b. rhodesiense acute mouse model, where it showed reduced toxicity over cynaropicrin, but also lost antitrypanosomal activity.
  • Toyonobu Usuki, Makiko Sato, Shihori Hara, Yukiko Yoshimoto, Ryosuke Kondo, Stefanie Zimmermann, Marcel Kaiser, Reto Brun, Matthias Hamburger, Michael Adams
    BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 24(3) 794-798 2014年2月  査読有り
    Cynaropicrin is a guaianolide sesquiterpene lactone with a 5-7-5 tricyclic skeleton, four exo-olefins, and two hydroxyl groups. Recently, it was found that the compound is a potent in vitro and in vivo inhibitor of the protozoan parasite Trypanosoma brucei, which causes human African trypanosomiasis (HAT; sleeping sickness). In this Letter, chemical derivatization of cynaropicrin and the structure-activity-relationship (SAR) study against T. brucei is described. (C) 2013 Elsevier Ltd. All rights reserved.
  • Toyonobu Usuki, Hiroto Yanuma, Takahiro Hayashi, Haruka Yamada, Noriyuki Suzuki, Yoshiro Masuyama
    Journal of Heterocyclic Chemistry 51(1) 269-273 2014年1月30日  査読有り筆頭著者責任著者
  • Yuko Murakami, Rina Suzuki, Hiroto Yanuma, Jiangtao He, Shuren Ma, Gerard M. Turino, Yong Y. Lin, Toyonobu Usuki
    ORGANIC & BIOMOLECULAR CHEMISTRY 12(48) 9887-9894 2014年  査読有り
    Desmosine-CH2, an analog of the elastic tissue degradation biomarker desmosine, can be regarded as a potential internal standard for precise quantification of desmosines by LC-MS/MS. In this study, the chemical synthesis of desmosine-CH2 was completed in 22% overall yield in five steps. The LC-MS/MS analysis of desmosine-CH2 was also achieved.
  • Yuki Egoshi, Ryosuke Kondo, Yukiko Yoshimoto, Toru Sugiyama, Toyonobu Usuki
    Tetrahedron Letters 54(51) 7029-7030 2013年12月  査読有り
  • 臼杵豊展
    有機合成化学協会誌 71(9) 891-899 2013年9月  査読有り招待有り
  • Satoshi Watanabe, Sho Watanabe, Naoto Aoki, Toyonobu Usuki
    SYNTHETIC COMMUNICATIONS 43(10) 1397-1403 2013年5月  査読有り
    The jamaicamides, isolated in Jamaica from the cyanobacterium Lyngbya majuscula, are new mixed polyketide-peptides that are known to be sodium channel blockers. The polyketide moiety contains an (E)-vinyl chloride, an undetermined methyl stereocenter (C9), and an (E)-olefin. Herein, we report the synthesis of the (E)-olefin moiety of the polyketide of the jamaicamides utilizing a KocienskiJulia coupling. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view the free supplemental file. GRAPHICAL ABSTRACT
  • Tetsuhiro Ogura, Toyonobu Usuki
    TETRAHEDRON 69(13) 2807-2815 2013年4月  査読有り
    The first total synthesis of the diaiylheptanoid acerogenins E and K, isolated from Acer nikoense MAXIM., is described. Formation of the 13-membered m,m-cyclophane skeleton was successfully achieved on the basis of a domino process involving a Miyaura arylborylation intramolecular Suzuki reaction. The cyclization precursor was prepared via a Wittig reaction and Claisen Schmidt condensation, which proceeded in moderate yields. The total synthesis of acerogenin G and centrolobol was also achieved from a common synthetic intermediate. (C) 2013 Elsevier Ltd. All rights reserved.
  • Hiroto Yanuma, Toyonobu Usuki
    HETEROCYCLES 87(1) 55-63 2013年1月  査読有り
    Neodesmosine, isolated from the hydrolysate of bovine ligamentum nuchae, is a crosslinking pyridinium amino acid of elastin. In this study, the first total synthesis of neodesmosine is reported via a Negishi cross-coupling reaction between 3,5-dihalogenated pyridines and the corresponding iodo amino acid.
  • Shuren Ma, Gerard M. Turino, Takahiro Hayashi, Hiroto Yanuma, Toyonobu Usuki, Yong Y. Lin
    Analytical Biochemistry 440(2) 158-165 2013年  査読有り
    Chemical synthesis of the deuterium isotope desmosine-d4 has been achieved. This isotopic compound possesses all four deuterium atoms at the alkanyl carbons of the alkyl amino acid substitution in the desmosine molecule and is stable toward acid hydrolysis this is required in the measurement of two crosslinking molecules, desmosine and isodesmosine, as biomarkers of elastic tissue degradation. The degradation of elastin occurs in several widely prevalent diseases. The synthesized desmosine-d4 is used as the internal standard to develop an accurate and sensitive isotope-dilution liquid chromatography- tandem mass spectrometry analysis, which can serve as a generalized method for an accurate analysis of desmosine and isodesmosine as biomarkers in many types of biological tissues involving elastin degradation. © 2013 Elsevier Inc. All rights reserved.
  • Shuhei Narita, Tetsuhiro Ogura, Toyonobu Usuki
    JOURNAL OF CHEMISTRY 2013(4) 1-5 2013年  査読有り
    Magnolignan, 2,2'-dihydroxy-5,5'-dipropyl-biphenyl (1), is a down-regulator of melanin synthesis that inhibits the maturation of tyrosinase. In this study, a concise total synthesis of 1 was achieved in five steps with 50% overall yield starting from commercially available trans-anethole (2) via a Suzuki-Miyaura reaction.
  • Yuko Murakami, Hiroto Yanuma, Toyonobu Usuki
    TETRAHEDRON-ASYMMETRY 23(22-23) 1557-1563 2012年12月  査読有り
    Desmopyridine, isolated from the acid hydrolysates of bovine ligamentum nuchae, is an elastin crosslinker and an amino acid that has a 3,4,5-trisubstituted pyridine skeleton. Herein we report the first total synthesis of (+)-desmopyridine in 10% yield over six steps starting from 4-aminopyridine via chemo- and regioselective palladium-catalyzed Sonogashira and Negishi cross-coupling reactions. (C) 2012 Elsevier Ltd. All rights reserved.
  • Hiroto Yanuma, Toyonobu Usuki
    TETRAHEDRON LETTERS 53(44) 5920-5922 2012年10月  査読有り
    Desmosine, a crosslinking pyridinium amino acid of elastin, is an attractive biomarker for the diagnosis of chronic obstructive pulmonary disease (COPD). In this study, the total synthesis of (+)-desmosine is reported utilizing chemo- and regioselective Sonogashira and Negishi cross-coupling reactions in 15% yield over six steps. (C) 2012 Elsevier Ltd. All rights reserved.
  • Toyonobu Usuki, Nanae Yasuda, Masahiro Yoshizawa-Fujita, Masahiro Rikukawa
    Planta Medica 78(11) 1265 2012年7月  査読有り
  • Tohru Taniguchi, Toyonobu Usuki
    Supramolecular Chemistry 2012年1月27日  
  • Hiroshi Goto, Toyonobu Usuki
    PHYTOCHEMICAL ANALYSIS 23(1) 84-87 2012年1月  査読有り
    Introduction - Terpene trilactones (TTLs), unique components of Ginkgo biloba extracts, are believed to play important roles in the biological activity of these materials. The investigation of seasonal and gender-related variations in the natural content of TTLs in the leaves is a challenging problem that must be addressed in order to establish more efficient extraction/isolation protocols for TTLs. Objective - The aims of this work were (i) to modify the extraction/isolation protocols of TTLs from G. biloba leaves by means of boiling and filtration procedures, and (ii) to investigate seasonal and gender-related variations in the TTL content of the leaves via (1)H-NMR analysis. Methodology - When extracting TTLs from G. biloba leaves, procedures for boiling and filtration were improved in this work. Moreover, quantitative (1)H-NMR analysis using DMF as a reference was performed and correlated to the colour (green/yellow) and gender (male/female) variations in the natural compositions of TTLs in the leaves. Results - Extraction procedures were modified to include boiling in ethyl acetate and filtration was achieved with celite. (1)H-NMR analysis of TTLs suggested that green female leaves contained the largest amount of TTLs, while no TTLs were present in yellow male leaves. Conclusion - The present results provide a method for quickly supplying laboratory-scale quantities of TTLs from natural sources to enable the study of their structure-activity relationships. Copyright (C) 2011 John Wiley & Sons, Ltd.
  • Toyonobu Usuki, Haruka Yamada, Takahiro Hayashi, Hiroto Yanuma, Yohei Koseki, Noriyuki Suzuki, Yoshiro Masuyama, Yong Y. Lin
    CHEMICAL COMMUNICATIONS 48(26) 3233-3235 2012年  査読有り筆頭著者責任著者
    Desmosine, a crosslinking amino acid of elastin, is an attractive biomarker for diagnosis of chronic obstructive pulmonary disease (COPD). In this study, the first total synthesis of (+)-desmosine was achieved in 11% overall yield in 13 steps utilizing stepwise and regioselective Sonogashira cross-coupling reactions.
  • Etsuko Suzuki, Makiko Sato, Ryota Takezawa, Toyonobu Usuki, Takashi Okada
    JOURNAL OF PHYSIOLOGICAL SCIENCES 61(5) 421-427 2011年9月  査読有り
    Bilobalide, a unique constituent of Ginkgo biloba, has been reported to potentiate population spikes in hippocampal CA1 pyramidal cells and to protect the brain against cell death. In this study, the effects of bilobalide on synaptic transmission and its plasticity in rat hippocampal subfields were electrophysiologically investigated. Bilobalide (50 mu M) significantly potentiated the input-output relationship at Schaffer collateral (SC)-CA1 synapses but not at medial perforant path (MPP)-dentate gyrus (DG), lateral perforant path (LPP)-DG, or mossy fiber (MF)-CA3 synapses. Facilitative effects of bilobalide on synaptic plasticity were only observed at MPP-DG synapses, in which the induction of long-term depression was blocked in the presence of bilobalide. However, no effect on synaptic plasticity was observed at SC-CA1 synapses. These results suggest that bilobalide has differential effects on synaptic efficacy in each hippocampal subfield.
  • Ayano Tanaka, Toyonobu Usuki
    TETRAHEDRON LETTERS 52(39) 5036-5038 2011年9月  査読有り
    The jamaicamides, isolated from cyanobacterium Lyngbya majuscula in Jamaica, are unique mixed polyketide-peptides that are reported to be blockers of the sodium channels. The peptide moiety contains a pyrrolinone ring and a beta-methoxy enone functionality. Herein, we report the stereoselective synthesis of the N-(Boc)(2)-protected peptide moiety of the jamaicamides by utilizing Meldrum's acid starting from L-alanine and N-Boc-beta-alanine. (C) 2011 Elsevier Ltd. All rights reserved.
  • Yohei Koseki, Haruka Yamada, Toyonobu Usuki
    Tetrahedron: Asymmetry 22(5) 580-586 2011年3月  査読有り

MISC

 2

書籍等出版物

 2

講演・口頭発表等

 281

共同研究・競争的資金等の研究課題

 22

その他

 7