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Regular & Special Issues

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Published online: 15th January, 2019

Communication | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)75
α-Glucoside Formation from 2-Deoxy-2-(2,2,2-trichloroethoxycarboxamido)-α-D-glucopyranosyl Acetate Using an Activating System That Used a Combination of Ytterbium(III) Triflate and a Catalytic Boron Trifluoride Diethyl Etherate Complex

Takashi Yamanoi,* Yoshiki Oda, Akihiko Koizumi, Tsubasa Kawaguchi, Shin Yagihara, and Akihiro Yoshida

*Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan

Abstract

This study describes the formation of α-glucoside from 3,4,6-tri-O-benzyl-2-deoxy-2-(2,2,2-trichloroethoxycarboxamido)-α-D-glucopyranosyl acetate using an activating system that used a combination of ytterbium(III) triflate and a catalytic boron trifluoride diethyl etherate complex. This glucoside formation using various types of alcohol acceptors proceeded with high α-stereoselectivity. The novel glucoside method employed in this study is a useful technique for producing 2-amino-2-deoxy-α-D-glucopyranoside derivatives because a 2,2,2-trichloroethoxycarbonyl group from an N-protecting group is easily removable.

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Published online: 8th January, 2019

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)89
Further Studies on the Gold-Catalyzed Oxidative Domino Cyclization/Cycloaddition to Give Polyfunctional Tetracycles

Tobias Groß, Korany A. Ali, Anne Jäger, and Peter Metz*

*Faculty of Chemistry and Food Chemistry, Organic Chemistry I, Technische Universität Dresden, Bergstraße 66, 01069 Dresden, Germany

Abstract

Enyne aldehydes and ketones with ester and ether functions in the tether between the reactive functional groups were subjected to a gold(III)-catalyzed domino process in the presence of a pyridine N-oxide as external oxygen donor. The resulting tetracyclic ketoethers were formed in high yields under mild conditions and with excellent induced diastereoselectivity for substrates featuring a stereogenic center within the enyne tether.

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Published online: 8th January, 2019

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)74
Second-Generation Synthesis of a Chiral Building Block for Oxygenated Terpenoids via a Ring-Contractive Coupling with a Secondary Alcohol

Sayuri Saito, Hiroyuki Yamakoshi, and Seiichi Nakamura*

*Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan

Abstract

A much improved second-generation synthesis of a chiral building block, developed for the syntheses of C17-oxygenated steroids/triterpenoids and C9-oxygenated labdane diterpenoids, was accomplished by exploiting a ring-contractive coupling between an α-bromo-δ-valerolactone and (R)-seudenol, wherein the use of t-BuOK as a base allowed clean conversion to the corresponding tetrahydrofuran-2-carboxylate even with a small excess of the alcohol component.

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Published online: 7th January, 2019

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)88
Synthesis of Indolo[1,2-a]indole Derivatives by Cationic Au(I)-catalyzed Exo-selective Cycloisomerization and Their Photophysical Properties

Madhurima Hazra, Daisuke Inoue, Mamoru Ito, Kyalo Stephen Kanyiva, and Takanori Shibata*

*Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan

Abstract

Cationic Au(I)-catalyzed intramolecular cycloisomerization of N-(2-alkynylphenyl)indoles proceeded efficiently in exo-selective manner, and (Z)-10-(arylidene)indolo[1,2-a]indole derivatives were obtained in moderate to high yields. Their photophysical properties were also measured.

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Published online: 26th December, 2018

Communication | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)71
Separation of Minor Actinides from Lanthanides Using Immobilized Ligand Systems: The Role of the Counterion

Ashfaq Afsar, Petr Distler, Laurence M. Harwood,* Jan John, Jasraj S. Babra, Zoe Y. Selfe, Joeseph Cowell, and James Westwood

*Chemical Sciences Division, University of Reading, Whiteknights, Reading RG6 6AD, U.K.

Abstract

A CyMe4-BTPhen functionalized silica gel that selectively extracts Am(III) over Eu(III) from 4 M HNO3 with a separation factor > 154 has been developed. Evidence is presented that the counterion surrounding the M(III) in the proposed 1:1 [BTPhen:M(III)] complex plays an important role in the complexation of Am(III) and Eu(III).

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Published online: 26th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)49
Identification of Target Protein for Batzelladines as CD4

Jun Shimokawa* and Kazuo Nagasawa*

*Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan

Abstract

Batzelladines are a family of polycyclic guanidine alkaloids. Among the congeners, batzelladines A-E were reported to inhibit the interaction of human immunodeficiency virus (HIV) gp120 protein with human CD4. Here, we designed a batzelladine photoaffinity probe bearing trifluoromethyl-3H-diazirine and biotin groups, and employed it to establish the identity of the target protein of batzelladines as CD4.

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Published online: 26th December, 2018

Communication | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)66
Syntheses and Acid-Stimulus Responsiveness of Aminobenzopyranoxanthene Spiroethers

Ryosuke Hosoda, Shinichiro Kamino,* Masashi Ueda, and Daisuke Sawada*

*Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama-shi, Okayama 700-8530, Japan

Abstract

Novel aminobenzopyranoxanthene spiroethers (ABPX-SEs) based on the spirocyclization of the hydroxymethyl group were synthesized from ABPX spirolactones (ABPX-SLs). The addition of an acid induces a ring-opening reaction to yield two colored monocationic and dicationic spiro-ring species of ABPX. The acid-stimulus responsiveness of the ABPX-SEs is lower than that of ABPX-SLs in polar organic solvents. In addition, the ABPX-SEs exhibit stepwise structural changes of the three equilibrium species at acidic pH, although rapid conversion from the spirolactone to dicationic species occurs in the case of ABPX-SLs.

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Published online: 26th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)57
Synthesis of LSD1 Inhibitor–Pyrrole Imidazole Polyamide Conjugates for Region-Specific Alterations of Histone Modification

Rui Qin, Shihori Takayanagi, Yusuke Kondo, Jiawei Li, Naoki Shiga, Masaya Nakajima, Ken-ichi Shinohara, Natsumi Yoda, Takayoshi Suzuki, Atsushi Kaneda, and Tetsuhiro Nemoto*

*Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan

Abstract

Synthetic method of LSD1 inhibitor–pyrrole-imidazole polyamide conjugates for region specific alterations of histone modification is described. A (1S,2R)-tranylcypromine (PCPA) unit was coupled with an L-lysine part using a nosyl strategy. Conjugation of the inhibitor part with PIP tetramer units was achieved by amide bond formation using PyBOP as a condensation reagent.

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Published online: 21st December, 2018

Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14007
Reversible Formation of an Inter-Molecular Compound Comprising 3ʹ-Aminofluorene-9-spiro-5ʹ-imidazolidine-2ʹ,4ʹ-dithione and Benzene

Yorimasa Takazawa, Tatsuo Yamamoto, Mitsuaki Suzuki, and Tomomi Sakata*

*Department of Chemistry, Faculty of Science, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan

Abstract

We herein describe the synthesis of 3ʹ-aminofluorene-9-spiro-5ʹ-imidazolidine-2ʹ,4ʹ-dithione through the reaction of fluorene-9-spiro-4ʹ-thiazolidine-2ʹ,5ʹ-dithione with hydrazine, and subsequent investigation of the interactions of the synthesized spirocycle-containing imidazolidinedithione with organic solvents. Recrystallization from a solvent containing benzene led to the formation of an inter-molecular compound consisting of 3ʹ-aminofluorene-9-spiro-5ʹ-imidazolidine-2ʹ,4ʹ-dithione and benzene in a 2:1 ratio through both intramolecular N-H∙∙∙S hydrogen bonds and additional weak N-H∙∙∙π interactions. The trapped benzene molecule was reversibly released by dissolution of the inter-molecular compound in acetone and subsequent concentration under reduced pressure at room temperature, and also by heating at 130–150 °C.

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Published online: 20th December, 2018

Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-13982
Regiospecific Synthesis of 1-(3,4-Dihydro-2H-benzo[b][1,4]oxazin-3-yl)indolizine Derivatives Through a Three-step Sequence from 2-Arylindolizine

Min Zhang, Xinwei He, Shanqing Li, and Yongjia Shang*

*College of Chemistry and Materials Science, Anhui Normal University, 189 Jiuhua Nan Road, Wuhu, Anhui, 241000, China

Abstract

A three-step sequence for the synthesis of new indolizine derivatives containing 1,4-benzoxazine subunits is presented. Two formyl groups were firstly introduced into 2-arylindolizine via Vilsmeier-Haack reaction. Subsequent aldimine condensation gave regiospecific indolizin-1-imine product, which underwent DMAP-catalyzed cascade reaction with α-bromoketones, giving 1-(3,4-dihydro-2H-benzo[b][1,4]oxazin-3-yl)indolizine derivatives in moderate to good yields. A wide range of substrates were tolerated in this reaction. The mechanism for DMAP-catalyzed process was briefly discussed with a tentative catalytic cycle proposed.

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Published online: 20th December, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14002
Multigram-Scale and Column Chromatography-Free Synthesis of L-Azetidine-2-carboxylic Acid for the Synthesis of Nicotianamine and Its Derivatives

Tomohiro Takaishi, Kyosuke Wakisaka, Christopher J Vavricka, Hiromasa Kiyota, and Minoru Izumi*

*Graduate School of Environmental and Life Science, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan

Abstract

Multigram-scale synthesis of L-azetidine-2-carboxylic acid from L-aspartic acid was achieved in 13 conventional synthetic steps, without the need for purification by silica-gel column chromatography and expensive reagents. Nicotianamine and its fluorescence-labeled derivatives could be obtained from this synthetic strategy.

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Published online: 19th December, 2018

Communication | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)61
Synthesis of a Tetracyclic Aminobenzimidazole Derivative via Tandem Cyclization of Triphenylguanidine

Yuki Akamatsu, Shinichiro Kamino, and Daisuke Sawada*

*Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-Naka, Kitai-ku, Okayama, 700-8530, Japan

Abstract

We developed a new reaction for the one-pot synthesis of a fused cyclic compound from triphenylguanidine, which was thought to be tandem cyclization, with a moderate yield. In this reaction, conditions such as the metal reagent, oxidant, solvent, and ligand affected whether single or tandem cyclization was preferred.

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Published online: 19th December, 2018

Communication | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)79
An Intermolecular [4+3] Cycloaddition Reaction Using 3-Hydroxy-2-pyrone Derivatives with an Oxyallyl Cation

Takahiro Suzuki,* Takamune Yanagisawa, and Keiji Tanino*

*Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan

Abstract

An intermolecular [4+3] cycloaddition reaction using 3-hydroxy-2-pyrone derivatives with (2-silyloxy)allyl acetate was developed under Brønsted acid conditions to yield highly functionalized seven-membered carbocycles. The transformations of the cycloadducts are described.

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Published online: 19th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)70
Synthesis and Evaluation of Topoisomerase I Inhibitors Possessing the 5,13-Dihydro-6H-benzo[6,7]indolo[3,2-c]quinolin-6-one Scaffold

Tsutomu Fukuda,* Yuri Matsuo, Fuyuki Matsuoka, Naoki Yoshioka, Gen Onodera, Masanari Kimura, Fumito Ishibashi, and Masatomo Iwao

*Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan

Abstract

Novel topoisomerase I inhibitors possessing the 5,13-dihydro- 6H-benzo[6,7]indolo[3,2-c]quinolin-6-one (BIQ) scaffold were designed and synthesized. This scaffold was constructed using sequential and regioselective functionalization of the pyrrole core through palladium-catalyzed cross-coupling, conventional electrophilic substitution, directed lithiation, and subsequent diphenylphosphoryl azide (DPPA)-mediated lactam ring construction. The obtained BIQs were evaluated for their topoisomerase I inhibitory activities and their antiproliferative activities in the panel of 39 human cancer cell lines established by the Japanese Foundation for Cancer Research (JFCR39).

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Published online: 19th December, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14009
Synthesis of 4-Amino-6-aryl-6H-pyrrolo[1,2-a][1]benzazepine-5-carbonitriles from 1-(2-Bromophenyl)-1H-pyrroles and Arylidenemalononitriles

Kazuhiro Kobayashi,* Akane Nakajima, Takashi Nogi, and Takuma Ueyama

*Applied Chemistry Field, Chemistry and Biotechnology Course, Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan

Abstract

A convenient method for the preparation of 4-amino-6-aryl-6H-pyrrolo[1,2-a][1]benzazepine-5-carbonitriles has been developed. The method is based on the hydrogen bromide-mediated cyclization reaction of 2-{aryl[2-(1H-pyrrol-1-yl)phenyl]methyl}propanedinitriles, produced by the treatment of 2-(1H-pyrrol-1-yl)phenyllithiums with arylidenemalononitriles. The lithium compounds can be easily generated by the bromine/lithium exchange between 1-(2-bromophenyl)-1H-pyrroles and butyllithium.

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Published online: 18th December, 2018

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)69
Efficient Synthesis of Benzofuran Fused 1-Azaazulene

Hiroyuki Fujii,* Yusuke Hironaka, and Noritaka Abe

*Science Research Center, Yamaguchi University, Yamaguchi 753-8512, Japan

Abstract

The synthesis of benzofuran fused 1-azaazulene (cyclohepta[d]benzo[4,5]furano[2,3-b]pyrrole) (4) was achieved by one pot reaction of 2-chloro-1-azaazulene (1) with 2-iodophenol (2) under the conditions in the presence of Pd(OAc)2 and without using a ligand.

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Published online: 18th December, 2018

Review | Regular issue | Prepress
DOI: 10.3987/REV-18-895
Recent Advancements in the Synthesis of Half-Esters and Their Applications

Jianjun Shi and Satomi Niwayama*

*Division of Sustainable and Environmental Engineering, Graduate School of Engineering, Muroran Institute of Technology, 27-1, Mizumoto-cho, Muroran, Hokkaido, 050-8585, Japan

Abstract

Half-esters are important building blocks for the synthesis of pharmaceuticals, polymers and natural products. Therefore, synthetic methodologies for both chiral and racemic half-esters have been actively investigated for decades. This short review summarizes recent progress in the synthesis of half-esters and their applications including the studies from our laboratories.

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Published online: 18th December, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14012
Synthesis of [1,4]Dithiino[2,3-d]pyrimidine-6-carbonitrile Derivatives via the Reaction of 2-[(4-Chloropyrimidin-5-yl)sulfanyl]acetonitriles with Carbon Disulfide

Kazuhiro Kobayashi,* Kota Yamasaki, Daiki Fujiwara, Kazuma Nozaki, Hidetaka Hiyoshi, and Kazuto Umezu

*Applied Chemistry Field, Chemistry and Biotechnology Course, Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan

Abstract

An efficient procedure has been developed for the preparation of 7-(alkylsulfanyl)[1,4]dithiino[2,3-d]pyrimidine-6-carbonitrile derivatives from 4,6-dichloro-2-(methylsulfanyl)pyrimidine (DCSMP). 2-{[4-Chloro-2-(methylsulfanyl)pyrimidin-5-yl]sulfanyl}acetonitriles are prepared via the reaction of the 5-lithio derivative of DCSMP with sulfur and then 2-bromoacetonitrile. These can be converted into the desired products on treatment with carbon disulfide in the presence of sodium hydride followed by alkyl halides. This is the first construction of the [1,4]dithiino[2,3-d]pyrimidine structure.

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Published online: 17th December, 2018

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)45
Palladium Acetate-catalyzed One-Pot Synthesis of Mono- and Disubstitued Pyridines

Shunya Mikami and Masahiro Toyota*

*Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan

Abstract

A Pd-catalyzed one-pot synthesis of mono- and disubstituted pyridines was developed. The substituted pyridines were obtained from ketones or an aldehyde and 1,3-diaminopropane using a combination of catalytic Pd(OAc)2 and Cu(OAc)2. High-concentration reaction conditions enabled this catalytic reaction to be acid-free.

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Published online: 17th December, 2018

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)67
Preparation and Optical and Electrochemical Properties of Phthalocyanine with Four Bis(carbomethoxy)tetrathiafulvalene Units

Takeshi Kimura* and Tadafumi Chiba

*Center for Instrumental Analysis, Iwate University, 4-3-5 Ueda, Morioka, Iwate 020-8551, Japan

Abstract

α-Octaoctylphthalocyaninato Ni(II) with four bis(carbomethoxy)tetrathiafulvalene units was prepared from β-tetrakis(o-xylylenedithio)-α-octaoctyl- phthalocyaninato Ni(II) via C-S bond cleavage, carbonylation, and condensation with 4,5-bis(carbomethoxy)-1,3-dithiol-2-one. The structure of the product was determined by NMR and MALDI-TOF-MS and the electrochemical and optical properties were examined by cyclic voltammetry, UV-vis spectra, and ESR spectrum.

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Published online: 14th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)52
First Total Synthesis of Palmarumycin C6 based on Double Oxa-Michael Addition of 1,8-Dihydroxynaphthalene to 3-Bromo-1-indenone

Hirokazu Tsukamoto, Yumi Nomura, and Takayuki Doi*

*Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan

Abstract

Synthetic studies on palmarumycin C6 with a naphthyl acetal at the C-3 position in 4,7-dihydroxy-1-indanone as a lower homologue of spirobisnaphthalenes are described herein. We investigated three approaches: 1) Nazarov cyclization of benzoylketene acetal, 2) intramolecular Friedel-Crafts acylation of naphtho[1,8-de]-1,3-dioxin-2-aryl-2-acetic acid chloride, and 3) double oxa-Michael addition of 1,8-dihydroxynaphthalene to 3-bromo-1-indenone. The last approach successfully afforded the natural product after the removal of acetates that serve as protecting groups for phenolic hydroxyls under acidic conditions.

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Published online: 14th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)60
Synthesis, Conformation, and Biological Activities of a Des-A-Ring Analog of 18-Deoxy-aplog-1, a Simplified Analog of Debromoaplysiatoxin

Yoshiki Ashida, Ryo C. Yanagita,* Yasuhiro Kawanami, Mutsumi Okamura, Shingo Dan, and Kazuhiro Irie

*Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan

Abstract

10-Me-Aplog-1 as a simplified analog of tumor-promoting debromoaplysiatoxin and a potent activator of protein kinase C (PKC) is a promising chemotherapeutic agent. In this study, we synthesized a des-A-ring analog (4) of 18-deoxy-aplog-1 as a synthetically-accessible analog. Compound 4 retained the conformation of the PKC-recognition part of aplogs. Moderate affinity for conventional PKC isozymes (α, β, γ) and anti-proliferative activity against NCI-H460 (lung) and MKN45 (stomach) human cancer cell lines were observed. The results suggest that 4 could serve as a lead compound for the development of conventional PKC isozyme-selective chemotherapeutic agents.

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Published online: 13th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)46
Synthesis and Hybridization Properties of Oligonucleotides Including 2ʹ-N-alkoxycarbonyl-2ʹ-amino-LNA Derivatives

Takashi Osawa, Shoko Yamashita, Ayumi Nakanishi, Yuta Ito, and Yoshiyuki Hari*

*Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514, Japan

Abstract

2ʹ-Amino-LNA is an attractive material that helps in realizing the practical use of oligonucleotides because it can stabilize complexes with complementary strands and various substituents can be introduced on the 2ʹ-amino group. Here, 2ʹ-N-alkoxycarbonyl derivatives of 2ʹ-amino-LNA were newly designed, synthesized, and incorporated into oligonucleotides. The results of UV-melting analysis indicated that 2ʹ-N-alkoxycarbonyl-modified 2ʹ-amino-LNA could enhance the stability of the duplex formed with single-stranded RNA and the triplex formed with double-stranded DNA.

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Published online: 12th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)58
Mechanistic Insight into Catalytic Aerobic Chemoselective α-Oxidation of Acylpyrazoles

Seiya Taninokuchi, Ryo Yazaki,* and Takashi Ohshima*

*Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan

Abstract

Mechanistic studies on catalytic aerobic chemoselective α-oxidation of acylpyrazoles, including control experiments, kinetic isotope effect experiments, and radical clock experiments, are described. The key to promoting the reaction was the in-situ generation of a copper(II) peroxo complex, which serves as a Lewis acid/Brønsted base cooperative catalyst for efficient enolization. The present catalysis was applicable to late-stage α-oxidation of functionalized acylpyrazoles. A preliminary diastereoselective reaction using readily available chiral acylpyrazoles demonstrated that the present catalysis provided access to optically active α-hydroxy acid derivatives.

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Published online: 12th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)14
Exploration of Moderate Conditions and Substrate Variation in the Direct Condensation between Phthalide and Primary Amine Catalyzed by GaCl3. Are Aliphatic Amines Less Reactive than Aromatic Ones?

Ichiro Takahashi,* Yoshinori Nishiwaki, Kenta Saitoh, Takatoshi Matsunaga, Akihiro Aratake, Toshio Morita, and Shinzo Hosoi

*Department of Applied Chemistry and Biotechnology, Faculty of Engineering, University of Fukui, 9-1 Bunkyo 3-chome, Fukui-shi, 910-8507, Japan

Abstract

Direct condensation between phthalide and a primary amine in the presence of Lewis acid was achieved for the first time in organic solvent-diluted reaction systems catalyzed by GaCl3. The peripheral aspects of this reaction is discussed.

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Published online: 12th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)73
Asymmetric Synthesis of 2,3-Dimethoxy-8-oxoberbine, Precursor of O-Methylbharatamine

Maria Chrzanowska,* Agnieszka Dreas, and Zofia Meissner

*Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland

Abstract

The enantiospecific and enantioselective syntheses of 2,3-dimethoxy-8-oxoberbine were performed using the lateral metallation methodology. In the enantiospecific synthesis (4S)-2,2,4-trimethyl-3-(o-toluoyl)oxazolidine incorporating (S)-alaninol as the chiral auxiliary was applied. The addition reaction of benzylic anion generated in situ from chiral oxazolidine into 6,7-dimethoxy-3,4-dihydroisoquinoline led to the protoberberine with high enantiomeric excess. Enantioselective synthesis of 2,3-dimethoxy-8-oxoberbine was performed with achiral 2,2-dimethyl-3-(o-toluoyl)oxazolidine in the presence of chiral ligands. Among them (–)-sparteine and (+)-sparteine surrogate turned out to be the most efficient ones.

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Published online: 11th December, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14001
Three New Chromone Derivatives from Cassia pumila and Their Anti-Tobacco Mosaic Virus Activity

Guang-Hui Kong, Yu-Ping Wu, Yin-Ke Li, Jing Li, Wei-Song Kong, Xin Liu, Yong Xu, Guang-Yu Yang, Qiu-Fen Hu,* and Wan-Li Zeng*

*Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming 650031, China

Abstract

Three new (1-3), together with four known chromone derivatives (4-7), were isolated from Cassia pumila. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1-3 were evaluated for their anti-tobacco mosaic virus (Anti-TMV) activity. The results showed that compounds 1-3 showed potential anti-TMV activities with inhibition rates of 28.3%, 31.2%, and 34.8%, at the concentration of 20 µM, respectively. These rates are close to that of positive control.

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Published online: 10th December, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(F)68
β-Trichloroacetylation of Cyclic Amines: Application to Synthesis of Chiral Azabicyclo-N-oxyls

Masami Kuriyama, Satoshi Kamogawa, Kosuke Yamamoto, and Osamu Onomura*

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

Abstract

β-Trichloroacetylation of cyclic amines was developed under mild reaction conditions, and the desired trichloroacetylated products were obtained in good yields. This method was applied to the preparation of optically active azabicyclo compounds, which were converted to chiral azabicyclo-N-oxyls.

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Published online: 7th December, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-13978
Facile and Solvent-Free Synthesis of Quinazolin-4(3H)-ones under Microwave Condition Promoted by SbCl3

Jun Li, Weili Wang,* Xinglin Su, Xiaoling Zhang, Yan Zhang, Xuewen Zhang, Mengmeng Cai, Yuqian Cao, Juan Jin, and Yanbin Xu*

*School of chemistry and material science, Ludong University, No. 186 Hongqi Middle Road, Zhifu District, 264025, China

Abstract

Antimony trichloride (SbCl3) was found to be an effective catalyst (1 mol%) for one-pot synthesis of quinazolin-4(3H)-ones in good to excellent yields using anthranilamide and acyl chlorides under microwave irradiation. This method has the advantages of simplicity, mild reaction conditions, highly tolerant to several functional groups, as well as the avoidance of hazardous solvents.

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Published online: 7th December, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14003
Three New Limonoids from the Fruits of Melia toosendan

Qiong Zhang,* Min Li, Qing-Hong Zheng, and Zhi-Da Min

*Department of Pharmaceutical Science, Shanxi Medical University, 56 Xinjian South Road, Taiyuan, Shanxi Province 030001, China

Abstract

Three new limonoids, 12-ethoxynimbolinins I-K (1-3) were isolated from the fruits of Melia toosendan. Their structures were established on the basis of spectroscopic methods. In addition, Compounds 1-3 were evaluated for their antibacterial activities.

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