巻号一覧
67 巻, 11 号
Special Issue in English
選択された号の論文の11件中1～11を表示しています
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Preface
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–Challenges and Possibilities–Iwao Ojima2009 年 67 巻 11 号 p. 1093
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスPDF形式でダウンロード (56K)
Accounts
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Masami Ishibashi, Midori A. Arai2009 年 67 巻 11 号 p. 1094-1104
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスDuring our studies related to the search for bioactive natural products, we recently examined extracts of various natural resources including unexplored myxomycetes, marine organisms, as well as several medicinal plants collected in the north–eastern part of Thailand and Bangladesh. Here we describe our recent results from our screening programs targeting signaling molecules in cancer–related biological pathways such as TRAIL, Wnt, and Hedgehog signalings.抄録全体を表示PDF形式でダウンロード (1762K) -
Takeshi Honda, Takeshi Masuda2009 年 67 巻 11 号 p. 1105-1114
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスSubstitution of 7–OH with small hydrophobic groups on zanamivir resulted in the retention of low nanomolar inhibitory activities against not only influenza A virus sialidase but also influenza A virus in cell culture. These compounds were prepared by treatment of the corresponding 7–substituted sialic acids derived from 4–modified N–acetyl–D–mannosamine (ManNAc) using enzyme–catalyzed aldol condensation.
A series of 7–alkyl ether derivatives related to Zanamivir were synthesized using direct alkylation of the C–7 alcohol of sialic acid. An alkyl ether moiety of less than 12 carbons in length showed low nanomolar inhibitory activity against influenza A virus sialidase.
A series of ester prodrugs of compound (10b) was synthesized and their efficacy was evaluated in an influenza infected mouse model by intranasal administration. The compound (25c: CS–8958), octanoyl ester prodrug of the C–9 alcohol of compound (10b), was found to be much longer acting than Zanamivir.
Polyvalent sialidase inhibitors bearing 4–guanidino–Neu5Ac2en analogues on the polyglutamic acid backbone, via a spacer of alkyl ether at the C–7 position, were synthesized. The multivalent conjugates (32) and (33) showed enhancement of antiviral activity against influenza A virus and more potent efficacy in vivo re-lative to monomeric sialidase inhibitors.抄録全体を表示PDF形式でダウンロード (1590K) -
Hisahiro Hagiwara, Masato Nozawa2009 年 67 巻 11 号 p. 1115-1124
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスTotal synthesis of salvinorin A (1), a densely functionalized neoclerodane diterpenoid, having the most potent hallucinogenic activity and a selective κ–opioid agonist, has been completed in 20 steps starting from enantiomerically–pure Wieland–Miescher ketone derivative 23. Subsequently, alternative total synthesis of salvinorin A (1) has been developed via palladium–catalyzed double carbonylation to bis–enol triflate followed by samarium diiodide–mediated double conjugate reduction in 13 steps. Forskolin (2), a highly oxygenated labdane diterpenoid and an activator of adenylate cyclase, has been synthesized in 12 steps and 12% overall yield from ptychantin A (62), which has been isolated from liverwort Ptychanthus striatus in sufficient yield. Tuning of the synthetic pathway enabled more expedient synthesis of forskolin (2) in 11 steps with 17% overall yield from ptychantins A (62) and B (63). In addition, synthesis of 1,9–dideoxyforskolin (3), an inhibitor of glucose transporter, has been accomplished in 8 steps and 37% overall yield from ptychantin A (62).抄録全体を表示PDF形式でダウンロード (465K) -
Masaya Sawamura2009 年 67 巻 11 号 p. 1125-1135
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスSynthesis, properties and applications to transition metal catalysis of extremely compact, caged trialkylphosphines (SMAPs) in the form of molecules or silica–supported materials are described. The new phosphines are air–stable despite their strongly electron–rich character. Soluble phosphine Ph–SMAP showed high ligand performance in the Rh–catalyzed hydrosilylation and hydrogenation of ketones. The silica–supported SMAP (Silica–SMAP) displayed a unique coordination behavior to form 1:1 P–metal complexes, which appeared to be useful as platforms to create highly active catalytic centers. As a result, Silica–SMAP enabled the Rh–catalyzed hydrosilylation and hydrogenation of extremely hindered ketones such as di–tert–butyl ketone as well as Ir–catalyzed directed ortho–borylation of functionalized arenes with a broad substrate scope.抄録全体を表示PDF形式でダウンロード (867K) -
Kaoru Adachi, Yasuyuki Tezuka2009 年 67 巻 11 号 p. 1136-1143
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスCurrent challenges and future perspectives of topological polymer chemistry have been reviewed. A variety of novel cyclic and multicyclic macromolecular topologies has now been realized by intriguing synthetic protocols. In particular, the electrostatic polymer self-assembly of telechelic precursors having cyclic ammonium salt groups accompanying polyfunctional carboxylate counteranions has been exploited in dilution to produce topologically significant, non–covalent constructions of a dynamic nature. The subsequent covalent conversion through the ring–opening or through the ring–emitting reaction of cyclic ammonium salt groups by carboxylate counteranions provides cyclic and multicyclic polymer products effectively. Furthermore, the metathesis condensation process with functional cyclic polymer precursors has been demonstrated as a promising synthetic means to construct a variety of complex polymer topologies.抄録全体を表示PDF形式でダウンロード (269K) -
Yoshihiko Kotake2009 年 67 巻 11 号 p. 1144-1151
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスPladienolide, a naturally occurring antitumor molecule discovered by a cell–based reporter gene expression assay, shows prominent antitumor activities in diverse in vitro and in vivo systems based on a unique mechanism of action. The first total synthesis of pladienolides B and D was accomplished to confirm absolute configuration of ten asymmetric centers of pladienolides. Despite the unique mechanism of action, the target protein of pladienolide remained unclear. Binding protein identification by using several types of pladienolide’s derivatives as ‘chemical probes’ demonstrated that splicing factor SF3b is a pharmacologically relevant protein target of pladienolide.抄録全体を表示PDF形式でダウンロード (602K) -
Kenji Watanabe, Hiroki Oguri, Hideaki Oikawa2009 年 67 巻 11 号 p. 1152-1160
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスNonribosomal peptide synthetase (NRPS) is a programmable modular machinery which produces a number of biologically active small–molecule peptides. Recent progress on understanding the catalytic mechanism of NRPS enabled us to engineer this complex catalytic system. We demonstrated both in vivo and in vitro enzymatic synthesis of complex natural antitumor peptides echinomycin and saframycin. An Escherichia coli–based expression system served as a flexible yet robust platform for producing complex natural products and their analogs by deletion, mutation and swapping of a specific subunit. The excised thioesterase domain of echinomycin exhibited remarkable substrate tolerance and created a cyclic peptide library. On the other hand, saframycin NRPS catalyzed highly unusual seven–step transformations to construct a pentacyclic tetrahydro–isoquinoline skeleton.抄録全体を表示PDF形式でダウンロード (760K) -
Kouichi Ohe, Koji Miki2009 年 67 巻 11 号 p. 1161-1171
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスThe in situ generation of vinylidene and alkylidene complexes based on the activation of alkynes with transition metal compounds was investigated. The cyclic oxacarbene complexes are produced through the formation of vinylidene complexes followed by the electrocyclization with the neighboring subunit of an alkyne. During the course of the study, it was found that a transition metal–induced 5–exo–dig cyclization of alkynes having nucleophilic conjugate subunits affords new types of hetero arene–substituted carbene complexes, such as (2–furyl)–, (2–pyrroryl), and (2–thienyl)carbene complexes. The 5–exo–dig cyclization of propargyl esters followed by 1,2–migration of carboxylates leads to the formation of vinylcarbene complexes. The in situ generation of metal–carbenoid species is highly atom–efficient and widely applicable to organic syntheses. In this account, the in situ generation of carbenoid species from a range of alkynes and synthetic applications to catalytic carbene transfer reactions, such as cycloaddition, annulation, ylide–associated reactions, insertion reactions, cycloisomerization, and isomerization reactions are highlighted and reviewed.抄録全体を表示PDF形式でダウンロード (467K) -
Katsuhiko Inomata2009 年 67 巻 11 号 p. 1172-1182
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセス“Syn–effect” has been recognized as a major cause of stabilizing the syn–conformation at the transition state of a number of reactions against the steric hindrance. This account deals with the origin of the “syn–effect” on the basis of the stereochemical outcome in the isomerization of vinylic sulfones leading to the formation of allylic sulfones and in the related various reactions. We proposed that a σ→π* interaction between the σ–orbital(s) of the allylic C–H σ–bond(s) (or of the C–H σ–bond(s) at the α–position for carbonyl compounds) and the antibonding orbital (π*) of the C=C double bond (or of the C=O double bond for carbonyl compounds) is the most important and essential factor for the “syn–effect”, though the contribution of a 6π–electron homoaromaticity and/or of a hydrogen bonding cannot be entirely ruled out.抄録全体を表示PDF形式でダウンロード (1039K) -
Cynthia B. Gilley, Matthew J. Buller, Yoshihisa Kobayashi2009 年 67 巻 11 号 p. 1183-1193
発行日: 2009年
公開日: 2010/05/20
ジャーナル オープンアクセスStereocontrolled formal total synthesis of proteasome inhibitor omuralide is described. This is featured by the application of Ugi 4–center 3–component condensation reaction to prepare a highly functionalized pyroglutamic acid. To this end, a novel convertible isocyanide was developed, which is readily available by preparative synthesis from nitrotoluene. The hydrolysis of the sterically hindered C–terminal amide derived from the isocyanide was facilitated by the conversion to N–acylindole. By careful design of the γ–ketoacid precursor, a substrate–controlled diastereoselective Ugi reaction was successfully accomplished. Also, several highly functionalized pyroglutamic acid amides were prepared with high diastereoselectivity.抄録全体を表示PDF形式でダウンロード (464K)
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