Special Issue

Isao Kuwajima's Special Issues, Vol. 90, No. 1, 2015

62 data found. 31 - 60 listedFirst Previous Next Last
Paper | Special issue | Vol 90, No. 1, 2015, pp. 316 - 326
Published online: 7th May, 2014
DOI: 10.3987/COM-14-S(K)20
Bisindole Alkaloids Condensed with a Cyclopropane Ring, Part 2. Cyclopropano-vinorelbine and Its Derivatives

Péter Keglevich, László Hazai, Zsófia Dubrovay, Zsuzsanna Sánta, Miklós Dékány, Csaba Szántay, Jr., György Kalaus, and Csaba Szántay*

*Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, H-1111 Budapest, Szt. Gellért tér 4, Hungary

Abstract

Vinorelbine condensed with a cyclopropane ring in the position 14 and 15 of the vindoline monomer part was synthesized and was found to have excellent antitumor activity. Further derivatives of cyclopropano-vinorelbine were prepared, the vincristine-like derivative, the N1-formyl-cyclopropano-vinorelbine, and the hydrated vinorelbine analogue, i.e. 5’-desmethylene-cyclopropano-vinblastine.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 327 - 343
Published online: 24th June, 2014
DOI: 10.3987/COM-14-S(K)24
Synthetic Studies on Saframycin Anibiotics: An Improved Synthesis of Tricyclic Lactam Intermediate and Construction of the Core Ring System of Saframycin A

Shinya Kimura, Shintaro Kawai, Masayuki Azuma, Yoshifumi Umehara, Yu-ichi Koizumi, Masashi Yokoya, and Naoki Saito*

*Department of Medicinal Chemistry, Pharmaceutical Chemistry, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan

Abstract

An improved synthesis of the tricyclic lactam intermediate of saframycin antibiotics and the construction of the core ring system having a cyano group at C-21 position were presented.1 The stereochemistry of several key intermediates was determined by X-ray crystallographic analysis.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 344 - 356
Published online: 19th June, 2014
DOI: 10.3987/COM-14-S(K)25
Group-Assisted Purification (GAP) for Protection of Amino Acids Using N-Phosphonyl Functional Groups

Guanghui An, Cole Seifert, Hao Sun, Yi Pan, and Guigen Li*

*Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, U.S.A.

Abstract

Various phosphonyl halides have been synthesized and utilized as protection groups for amino acids. The protection synthesis was performed via GAP (Group-Assisted Purification) procedure under convenient conditions without the use of column chromatography and recrystallization. The synthesis can be carried out on applicational scales with excellent yields (82% - 98%). The phosphonyl protection of amino acids would provide a new greener tool for GAP peptide synthesis.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 357 - 371
Published online: 10th June, 2014
DOI: 10.3987/COM-14-S(K)26
Design and Synthesis of Conformationally Constrained Bicyclo[2.2.2]octane-Based Unusual α-Amino Acid Derivatives via the Diels–Alder Reaction

Sambasivarao Kotha* and Milind Meshram

*Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India

Abstract

We report a simple synthetic approach to various conformationally constrained bicyclic α-amino acid derivatives using the DielsAlder reaction as a key step. Moreover, we have investigated the reactivity pattern of various anthracene derivatives in relation to the DielsAlder chemistry.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 372 - 404
Published online: 12th June, 2014
DOI: 10.3987/COM-14-S(K)29
Synthesis and Evaluations of GLP-1 Secretion and Anti-Diabetic Effect in KKAy Mice of New Tricyclic Compounds

Daisuke Minehira, Daisuke Takeda, Shota Miyawaki, Atsushi Kato, Isao Adachi,* Akira Miyazaki, Ryuta Miyatake, Masahito Umezaki, Kyoko Miura, Yoshiro Kitahara, Kenji Sugimoto, Yuji Matsuya, and Naoki Toyooka*

*Graduate School of Science and Technology, Toyama University, Gofuku 3190, Toyama 930-8555, Japan

Abstract

Glucagon-like peptide-1 (GLP-1), which belongs to the family of incretins, plays important role for the regulation of plasma glucose. Accordingly, GLP-1-based therapies for type 2 diabetes have recognized as one of the most interesting target. In this study, we have found the new tricyclic compounds having strong GLP-1 secretion from human intestinal L cells, and anti-diabetic properties in spontaneously obese and diabetic KKAy mice. The most potent compound 5ka was obtained as the unexpected product, and we would like to report the details of the synthesis, structure elucidations, pharmacological activities on secretion of GLP-1, and anti-diabetic effects using diabetic KKAy mice.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 405 - 424
Published online: 13th June, 2014
DOI: 10.3987/COM-14-S(K)32
Stereoselective Approach toward Ophiodilactones Based on an Intramolecular [2 + 2] Cycloaddition Reaction

Takaaki Matsubara, Jun Ishihara, and Susumi Hatakeyama*

*Graduate School of Biomedical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan

Abstract

The highly enantio- and diastereoselective synthesis of a promising precursor of ophiodilactones A and B, tetrameric phenylpropanoids isolated from the ophiuroid Ophiocoma scolopendrina, is described. The synthesis involves an organocatalytic asymmetric Michael reaction, intramolecular [2 + 2] cycloaddition of a ketene to an alkene, Baeyer-Villiger oxidation, and construction of the C2 quaternary center as major transformations.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 425 - 431
Published online: 30th June, 2014
DOI: 10.3987/COM-14-S(K)38
2-Debromonagelamide U, 2-Debromomukanadin G, and 2-Debromonagelamide P from Marine Sponge Agelas sp.

Kenta Nakamura, Taishi Kusama, Naonobu Tanaka, Kanae Sakai, Tohru Gonoi, Jane Fromont, and Jun'ichi Kobayashi*

*Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812, Japan

Abstract

Two new monomeric bromopyrrole alkaloids (1 and 2) and one new dimeric bromopyrrole alkaloid (3) were isolated from an Okinawan marine sponge Agelas sp. Spectroscopic analyses of these compounds revealed the structures of 13 to be 2-debromonagelamide U, 2-debromomukanadin G, and 2-debromonagelamide P, respectively. Antimicrobial activity of 13 was evaluated.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 432 - 441
Published online: 23rd July, 2014
DOI: 10.3987/COM-14-S(K)41
Base Pair Recognition Ability of 2-(Methylamino)pyrimidin-4-yl Nucleobase in Parallel Triplex DNA

Yoshiyuki Hari,* Satoshi Kashima, Yuya Matsuda, Akihiro Sakata, Ryutaro Takamine, Shin Ijitsu, and Satoshi Obika*

*Graduate School of Pharmaceutical Science, Osaka University, 1-6 Yamadaoka, Suita, Osaka 560-0871, Japan

Abstract

A phosphoramidite bearing a 2-(methylamino)pyrimidin-4-yl nucleobase was synthesized and the modified oligonucleotide (triplex-forming oligonucleotide, TFO) was successfully obtained using the phosphoramidite on an automated DNA synthesizer. UV-melting experiment of triplex DNA between the synthesized TFO and duplex DNA targets indicated that the 2-aminopyrimidin-4-yl unit in TFO could be a useful core structure for recognition of a TA base pair in duplex DNA.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 442 - 461
Published online: 4th August, 2014
DOI: 10.3987/COM-14-S(K)42
Total Synthesis of Marine Sesquiterpenoid Sinularianin B and 8-epi-Sinularianin B

Koichiro Ota and Hiroaki Miyaoka*

*School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan

Abstract

The enantioselective total synthesis of marine sesquiterpenoid sinularianin B, isolated from the Formosan soft coral Sinularia sp., has been accomplished in 16 steps based on a highly concise synthetic strategy. The synthesis features two highly stereoselective sulfone-mediated reactions, including a key tandem intermolecular−intramolecular alkylation developed in our laboratory, and a palladium-catalyzed desulfonylation of an allyl sulfone through π-allyl palladium complex formation.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 462 - 481
Published online: 19th August, 2014
DOI: 10.3987/COM-14-S(K)43
Synthesis of Bicyclic Dioxetanes Bearing a Hydroxyphenanthrene or Hydroxy[4]helicene Moiety and Their Base-Induced Chemiluminescent Decomposition

Yohei Koyama, Nobuko Watanabe, Hisako K. Ijuin, and Masakatsu Matsumoto*

*Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan

Abstract

Six bicyclic dioxetanes bearing a 1-hydroxyphenanthren-3-yl 2-iv, 3-hydroxyphenanthren-1-yl 2-ov, 4-hydroxyphenanthren-2-yl 2-oh, 2-hydroxyphenanthren-4-yl 2-ih, 4-hydroxy[4]helicen-2-yl 3-iv and 2-hydroxy[4]helicen-4-yl group 3-ov were synthesized and their base-induced chemiluminescent decomposition was investigated in a TBAF (tetrabutylammonium fluoride) / MeCN system. For dioxetanes in the iv-series 2-iv and 3-iv including α-naphthol-analog 17a and those in the ov-series 2-ov and 3-ov including β-naphthol-analog 17b, we investigated how the chemiluminescence properties changed with an increase in the number of fused benzene rings of a hydroxyarene moiety attached to a dioxetane ring. The results showed that a) maximum wavelength of chemiluminescence λmaxCL tended to shift to a longer wavelength region as the number of fused benzene rings increased, b) the kCTID values for the iv-series were >1000 times larger than those for the ov-series regardless of the number of fused benzene rings, and c) a dioxetane in the iv-series tended to have a higher singlet-chemiexcitation efficiency ΦS than the corresponding dioxetane in the ov-series. This tendency could be explained by the “syn/anti” rotational isomerism of an aromatic electron donor, where an anti-rotamer gives ΦS far more effectively than a syn-rotamer.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 482 - 501
Published online: 20th August, 2014
DOI: 10.3987/COM-14-S(K)47
Synthesis and Biological Evaluation of C-Aromataxane Derivatives as P-Glycoprotein-Mediated Multi Drug Resistance Reversal Agents

Takayuki Doi,* Naoko Yamaguchi, Kosuke Ohsawa, Kazuoki Nakai, Masahito Yoshida, Kazuhiro Satake, Yuji Mitani, Hiroshi Nakagawa, Takashi Takahashi, and Toshihisa Ishikawa

*Graduate School of Pharmaceutical Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan

Abstract

Synthesis and evaluation of C-aromataxane derivatives as P-glycoprotein-mediated MDR reversal agents have been demonstrated. Several derivatives possessing N-benzoylphenylisoserine at the C2 or C14 position of the template 2a were readily synthesized and were evaluated their affinity for P-glycoprotein. Most of the synthesized derivatives exhibited much lower cytotoxicity in both KB-3-1 cells and MDR KB-G2-cells than paclitaxel (1), and it should be noted that the compound (14R)-5a exhibited high Km and Vmax/Km values, and cytotoxicity of paclitaxel (1) in MDR KB-G2 cells was significantly recovered (98% reduction, IC50 30 nM) in the presence of 5a (5.0 μM). The structural features such as endo-cage conformation and the stereochemistry at the C14 position is crucial to exhibit an excellent affinity for P-glycoprotein.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 502 - 514
Published online: 8th August, 2014
DOI: 10.3987/COM-14-S(K)49
Perylene-Based, Bis(terpyridine)-Ru(II) Complexes: Synthesis, Electrochemical and Photovoltaic Properties

Hany El-Batal, Juan Manríquez Rocha, Perla F. Méndez, Luis A. Godínez, Kai Guo, Xiaopeng Li, Xiaocun Lu, Chrys Wesdemiotis, Charles N. Moorefield, and George R. Newkome*

*Departments of Polymer Science and Chemistry, The University of Akron, Akron, OH 44325-4717, U.S.A.

Abstract

Perylene-based, terpyridine-Ru(II) complexes are synthesized and their electrochemical and photoelectrochemical properties are studied; their fabrication into dye-sensitized solar cells are described (DSSCs) and their resultant photovoltaic properties are evaluated.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 515 - 528
Published online: 7th August, 2014
DOI: 10.3987/COM-14-S(K)51
A New Class of Structurally Simple and Highly Emissive Fluorophores with a Pyridine–Acetylene–Phenol Conjugate

Yuki Ohishi, Hajime Abe,* and Masahiko Inouye*

*Department of Chemical Biology, Graduate School of Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, 930-0194, Japan

Abstract

A model compound for pyridine–acetylene–phenol conjugates was prepared, and its hydrogen-bonding and spectroscopic properties were studied. Pyridine and phenol moieties worked as a hydrogen-bonding acceptor and an donor, respectively, so that the conjugate model efficiently bound to MeOH. The absorption and fluorescence spectra showed remarkable additive effects against acid and base, illustrating the application of the conjugates to recognition-sensitive fluorophores.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 529 - 539
Published online: 6th August, 2014
DOI: 10.3987/COM-14-S(K)56
Thermal [2+2]-Cycloadditions of Diphenylketene with Aryl- and Hetaryl-Substituted Thioketones

Grzegorz Mlostoń,* Katarzyna Urbaniak, Anna Szychowska, Anthony Linden, and Heinz Heimgartner*

*Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland

Abstract

The reaction of diphenylketene (1) with aryl- and hetaryl-substituted thioketones (2) gave the corresponding 3,3,4,4-tetraarylthietan-2-ones (3) in good yields. Remarkably, the reactions with bis-hetaryl-substituted thioketones occurred significantly faster compared with those involving the bis-aryl-substituted thioketones. The structure of compound 3c has been established by X-ray crystallography.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 540 - 562
Published online: 22nd July, 2014
DOI: 10.3987/COM-14-S(K)57
Mn(III)-Based Oxidative Cyclization of N-Aryl-3-oxobutanamides. Facile Synthesis and Transformation of Substituted Oxindoles

Nobutaka Kikue, Tetsuya Takahashi, and Hiroshi Nishino*

*Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, Kurokami 2-39-1, Chûou-Ku, Kumamoto 860-8555, Japan

Abstract

The oxidation of 3-oxo-N-phenylbutanamides 1 with manganese(III) acetate in ethanol afforded dimeric 3,3'-biindoline-2,2'-dione derivatives 3–5. A similar reaction of N,2-disubstituted N-aryl-3-oxobutanamides 6 in acetic acid produced 3-acetylindolin-2-ones 7 bearing various substituents in good to excellent yields. The acetylindolinones 7 were easily deacetylated by treatment using neutral alumina in diethyl ether. Both the acetylindolinones 7 and deacetylated indolinones 8 were transformed by reduction into the substituted 1H-indoles.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 563 - 578
Published online: 4th August, 2014
DOI: 10.3987/COM-14-S(K)61
Synthesis of Model Compounds Related to Linear β-D-(1→6)-Galactosyl Side-Chains of Polysaccharides from Astragalus mongholicus Bunge

Noriyasu Hada, Ryo Shimura, Kyoko Hakamata, Hiroaki Kiyohara, Haruki Yamada, Tadahiro Takeda, and Fumiyuki Kiuchi*

*Faculty of Pharmacy, Keio University, 1-5-30 Shiba-Kouen, Minato-ku, Tokyo, Japan

Abstract

Stereocontrolled efficient syntheses of β-(16)-linked di-, tetra- and octa-galactans as model compounds of arabino-3,6-galactans isolated from Astragalus mongholicus are described. The syntheses consisted of simple glycosylation cycles: an acceptor and a donor prepared from a common compound were coupled, and the glycosylation product was converted to the acceptor and donor of the next glycosylation.

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Paper | Special issue | Vol 90, No. 1, 2015, pp. 579 - 599
Published online: 24th July, 2014
DOI: 10.3987/COM-14-S(K)66
Studies toward the Total Synthesis of Amphidinolide N: Stereocontrolled Synthesis of the C13–C29 Segment

Makoto Sasaki,* Yuki Kawashima, and Haruhiko Fuwa

*Laboratory of Biostructural Chemistry, Graduate School of Life Sciences, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, 980-8577, Japan

Abstract

A stereocontrolled synthesis of the C13–C29 segment of amphidinolide N, a marine macrolide natural product that is extremely potent cytotoxic, is described.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 601 - 606
Published online: 26th March, 2014
DOI: 10.3987/COM-14-S(K)6
A New Indole Alkaloid from Voacanga grandifolia

Azusa Haseo, Alfarius Eko Nugroho, Yusuke Hirasawa, Toshio Kaneda, Osamu Shirota, Abdul Rahman, Idha Kusumawati, Noor Cholies Zaini, and Hiroshi Morita*

*Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan

Abstract

A new bisindole alkaloid, voacalgine F (1), has been isolated from the bark of Indonesian Voacanga grandifollia (Miq.) Rolfe. Its structure was elucidated on the basis of 1D and 2D-NMR data analysis.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 607 - 616
Published online: 4th April, 2014
DOI: 10.3987/COM-14-S(K)8
Novel Intramolecular Cyclization-Skeletal Reorganization of 2-Arylthiazoles under Photoirradiation

Noriyoshi Arai,* Moe Mizota, and Takeshi Ohkuma*

*Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan

Abstract

Photoirradiation of 2-arylthiazoles derivatives linked with an alkene moiety through a three-atom spacer was investigated. The main products were unexpected tetrahydrofuran-fused thiazepine derivatives with concomitant formation of [2+2] cycloaddition products and regioisomeric thiazoles. The product distribution was little influenced by the reaction conditions and substituents of the substrates.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 617 - 624
Published online: 3rd April, 2014
DOI: 10.3987/COM-14-S(K)11
Studies on the Effect of N-Heterocyclic Carbene as a Ligand for Nickel(II)-Catalyzed Polymerization of Thiophenes

Atsunori Mori,* Makoto Fujio, and Shunsuke Tamba

*Chemical Science & Technology, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan

Abstract

Effect of N-heterocyclic carbene (NHC) ligand in the nickel-catalyzed polythiophene synthesis is studied. One-pot protocol to form nickel-NHC ligand with the corresponding HCl salt of NHC and Ni(acac)2 in the presence of a base and following deprotonation and polymerization smoothly affords poly(3-hexylthiophen-2,5-diyl) (2a). Among NHC ligands examined, imidazolidine derived NHC bearing 2,6-diisopropylphenyl group as an N-substituent is found to be the optimum ligand.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 625 - 630
Published online: 2nd April, 2014
DOI: 10.3987/COM-14-S(K)12
Synthesis of Unprotected CH2-Skipped Piperazine-Pyridine Alternating Cycles with Azide End-Group

Andi Kipper, Indrek Kalvet, Kaido Tämm, Lauri Sikk, Peeter Burk, Kuldar Kõiv, and Uno Mäeorg*

*Institute of Chemistry, University of Tartu, Ravila 14a, Tartu 50411, Estonia

Abstract

This work describes synthesis of CH2-skipped alternating piperazine-pyridine cycles with azide end-group starting from piperazine, 1-methylpiperazine and pyridine-2,6-dicarboxylic acid. This compound can be used to enhance binding efficiency by shielding repulsion between negatively charged phosphate groups in DNA-oligonucleotide hybridization techniques.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 631 - 644
Published online: 4th April, 2014
DOI: 10.3987/COM-14-S(K)14
Phenol and Aniline Oxidative Coupling with Alkenes by Using Hypervalent Iodine Dimer for the Rapid Access to Dihydrobenzofurans and Indolines

Toshifumi Dohi, Yosuke Toyoda, Tomofumi Nakae, Daichi Koseki, Hiroko Kubo, Tohru Kamitanaka, and Yasuyuki Kita*

*College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, 525-8577, Japan

Abstract

A highly reactive hypervalent iodine dimer, [Ph(CF3COO)I]-O-[I(OCOCF3)Ph], is utilized as successful promoter in the oxidative phenolic coupling with styrenes leading to 2-aryldihydrobenzofurans. The extensions of the substrates in this study have led to the development of a new expeditious construction of the pyrroloindoline structure from aniline and enamide derivatives.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 645 - 658
Published online: 21st May, 2014
DOI: 10.3987/COM-14-S(K)21
Diversity Oriented Approach to Oxepine Derivatives: Further Expansion via Diels‒Alder Reaction

Sambasivarao Kotha* and Rashid Ali

*Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India

Abstract

Oxepine derivatives have been assembled via Diels‒Alder (DA) reaction as a key step and the latent dienes suitable for the DA reaction have been generated in situ from the sultine derivatives, which in turn were achieved by using commercially available rongalite. The “drug like” molecules assembled here may find useful applications in medicinal as well as bioorganic chemistry.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 659 - 672
Published online: 3rd June, 2014
DOI: 10.3987/COM-14-S(K)23
N-(2,3,4,5,6-Pentafluorophenyl)maleimide as a Powerful Dienophile in Dearomatizing Diels-Alder Reactions

Koichi Hagiwara, Masafumi Iwatsu, Daisuke Urabe, and Masayuki Inoue*

*Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

Abstract

Here we demonstrate that N-(2,3,4,5,6-pentafluorophenyl)maleimide effectively promotes dearomatizing Diels-Alder reactions of 2,5-dimethylbenzene-1,4-diol and naphthalen-2-ol derivatives. The present reactions successfully converted the sp2-rich components to the desired products with multiple sp3-carbons in a single step. The adduct was further derivatized into the intermediate for our synthesis of 9-demethyl-10,15-dideoxyryanodol, an analogue of a sp3-rich natural product, in two steps.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 673 - 680
Published online: 9th June, 2014
DOI: 10.3987/COM-14-S(K)28
Pd-Catalyzed Intramolecular Oxidative Coupling Reaction of 1,1’-Carbonyldiindoles

Takumi Abe and Minoru Ishikura*

*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan

Abstract

The palladium-catalyzed intramolecular oxidative coupling reaction of 1,1’-carbonyldiindoles was achieved by using Pd(OAc)2 and Cu(OAc)2, producing 1,1’-carbonyl-2,2’-biindolyls, which were then converted to tjipanazoles D and I.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 681 - 689
Published online: 18th June, 2014
DOI: 10.3987/COM-14-S(K)34
Generation and Reactions of Heteroaromatic Arynes Using Hypervalent Iodine Compounds

Keisuke Gondo, Juzo Oyamada, and Tsugio Kitamura*

*Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo-machi, Saga, Japan

Abstract

The heterocyclic aryne precursors, (phenyl)[1-phenyl-6-(trimethylsilyl)benzotriazol-5-yl]iodonium triflate and [3-ethoxycarbonyl-6-(trimethylsilyl)indazol-5-yl](phenyl)iodonium triflate, were prepared from the cycloadducts of 4,5-bis(trimethylsilyl)benzyne generated from (phenyl)[2,4,5-tris(trimethylsilyl)phenyl]iodonium triflate. These precursors provide the corresponding arynes, 1-phenyl-5,6-didehydrobenzotriazole and 3-ethoxycarbonyl-5,6-didehydroindazole, to give the corresponding polycyclic heteroaromatic compounds in good to high yields.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 690 - 697
Published online: 23rd July, 2014
DOI: 10.3987/COM-14-S(K)35
Design of Aza-Polyquinanes via Fischer Indole Cyclization under Green Conditions

Sambasivarao Kotha* and Ajay Kumar Chinnam

*Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India

Abstract

We have demonstrated a simple and an efficient synthetic route for the synthesis of aza-polyquinane derivatives involving Fischer indole cyclization as a key step under low melting mixture conditions.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 698 - 705
Published online: 7th July, 2014
DOI: 10.3987/COM-14-S(K)36
Synthesis of Photoreactive Diazirinyl Salicin Derivative to Elucidate Functional Analysis of the Bitter Taste Receptor

Munenori Sakurai, Takuma Yoshida, Lei Wang, Yuta Murai, Katsuyoshi Masuda, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, and Makoto Hashimoto*

*Division of Applied Science, Graduate School of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan

Abstract

Salicin (salicyl alcohol glucoside) is a substance well known for its bitter taste. A photoreactive diazirinyl derivative of salicin will be utilized for the functional analysis of interactions between the bitter taste receptor and salicin. Glucosides of salicyl derivatives are more difficult than phenol derivatives that are unsubstituted at the ortho-position. A diazirinyl salicin derivative was synthesized at moderate yields by glucosidation of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide and 2-hydroxy-4-[3-(trifluoromethyl)-3H-diazirin-3-yl]benzaldehyde in the presence of a phase-transfer catalyst, nBuEt3NBr, followed by reduction and deprotection.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 706 - 714
Published online: 17th July, 2014
DOI: 10.3987/COM-14-S(K)40
Synthetic Study of Afritoxinone A: Stereoselective Construction of Furopyranone Moiety

Hideki Abe, Toshihiro Yoshie, Takumi Wagatsuma, Toyoharu Kobayashi, and Hisanaka Ito*

*School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan

Abstract

Stereoselective construction of the furopyranone moiety of the natural product afritoxinone A was demonstrated. This synthetic methodology features (i) stereoselective 1,4-addition of a tricyclic ring system, (ii) oxidative cleavage of the diol, followed by hydration of the resulting dialdehyde group, and (iii) acetalization via cationic cyclization of the pyranediol with the tert-butyl ester tether.

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Short Paper | Special issue | Vol 90, No. 1, 2015, pp. 715 - 722
Published online: 8th August, 2014
DOI: 10.3987/COM-14-S(K)50
The Cycloaddition of 2-Phenylamino-1-azaazulene with Diphenylacetylene Using Palladium Catalytic Systems

Hiroyuki Fujii,* Shigeki Oka, Ippei Nakamura, Yu Kawai, Reiko Ikeda, Takeo Konakahara, and Noritaka Abe

*Scientific Research Center, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan

Abstract

Selective cycloaddition was achieved by the reaction of 2-phenylamino-1-azaazulene (3) with diphenylacetylene (4) in the presence of Pd catalyst providing N-(1-azaazulen-2-yl)-2,3-diphenylindoles.

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