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Regular & Special Issues

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Published online: 30th November, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-944
Highly Oxidized γ-Lactam-Containing Natural Products: Total Synthesis and Biological Evaluation

Kosaku Tanaka III,* Hiroshi Kogen, and Kenichi Kobayashi*

*Graduate School of Pharmaceutical Sciences, Health Sciences University of Hokkaido; 1757 Kanazawa, Tobetsu-cho, Ishikari-gun, Hokkaido 061-0293, Japan

Abstract

γ-Lactam is a ubiquitous structure found in the natural products. A number of highly oxidized γ-lactam-containing natural products are produced by various fungi. These compounds often show a wide range of biological activities because their multiple internal reaction sites, which arise from the high oxidation state of the compounds, can react with biological nucleophiles. Due to their high reactivity and dense functionality, total syntheses of these molecules require strict control of the inherent reactivity and the appropriate design of synthetic intermediates. This review focuses on the recent total syntheses of some highly oxidized γ-lactam-containing natural products, including fused bicyclic (epolactaene, NG-391, lucilactaene, L-755,807), spirocyclic (azaspirene, pseurotin A, E, and F2, cephalimysin A–C, FD-838, and berkeleyamide D), and tricyclic (rubrobramide and talaramide A) skeletons, and on the structure-activity relationship studies of related molecules.

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Published online: 27th November, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)39
Intramolecular Transamidation-Cyclization of N-(α-Oxoacetyl) Diamine: Influence of Solvent, Acidity and Substituents

Takashi Kouko, Hiroaki Miyazawa, Hideki Hikita, Hiromi Totsuka, Kazuhiro Higuchi,* and Tomomi Kawasaki*

*Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan

Abstract

We studied the selective formation of 3,5- and 2,5-pyrazinone via a transamidation-cyclization reaction. The equilibrium between acyl amides changed depending on the solvent, acidity, and substituents. Furthermore, selective transformation of 2,5-pyrazinone was accomplished by using a substrate with a secondary amine.

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Published online: 26th November, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)37
Synthesis, Structure, and π-Donor Properties of Tris(Ethyleledioxy)Benzene and Bis(Ethyleledioxy)Thiophene

Ryoji Watanabe, Tohru Nishinaga,* Yoshiyuki Kuwatani, and Masahiko Iyoda*

*Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan

Abstract

Tris(ethylenedioxy)benzene 3 and bis(ethylenedioxy)thiophene 4 have been synthesized starting from 2,3-dibromo-1,4-dioxene in 25 and 38% overall yields, respectively. These ethylenedioxy-fused benzene and thiophene can be easily oxidized to produce the corresponding radical cations 3•+ and 4•+ because of their high-lying HOMO levels. Interestingly, the radical cation 3•+ exhibits a fairly strong fluorescent emission at λmax 602 and 590 nm (φF = 0.40 in MeCN and 0.50 in H2SO4).

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Published online: 24th November, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14365
Liquid-Assisted Mechanosynthesis of trans-2,3-Dihydropyrroles from Chalcones and Enaminones

Ming-Yue Weng, Hui Xu,* Hong Chen, and Ze Zhang*

*Anhui Province Key Laboratory of Functional Coordinated Complexes for Materials Chemistry and Application, and School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu 241000, P. R. China

Abstract

An efficient synthesis of a variety of trans-2,3-dihydropyrroles via iodine-promoted cyclization between chalcones and enaminones has been demonstrated under liquid-assisted grinding conditions. The present protocol provides a practical, fast and green alternative to traditional solvent-based methods due to its notable advantages such as significantly higher yield, much shorter reaction time, good functional group tolerance and mild reaction conditions.

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Published online: 20th November, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)34
Synthesis and Blue Dyeing Ability for Polypropylene Fabrics of Various 3,7-Bis(Dialkylamino)Phenoxazin-5-Ium Salts and the Sulfur and Selenium Analogs

Takumi Yoshida* and Masahito Segi*

*Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan

Abstract

3,7-Bis(dialkylamino)phenoxazin-5-ium salts having different amino groups (dimethylamino, diethylamino, dipropylamino, dibutylamino, and pyrrolidyl) and counter anions (chloride, bromide, iodide, hydrogensulfate, and nitrate) were synthesized in up to 80% isolated yield as blue cationic dyes. In addition, 3,7-bis(diethylamino)phenothiazin-5-ium and 3,7-bis(diethylamino)phenoselenazin-5-ium iodides were also synthesized in 20% and 17% isolated yields, respectively. Polypropylene fabrics were dyed with the above synthesized blue cationic dyes. As an evaluation result, it has been found that the moderate size such as diethylamino groups at the 3 and 7 positions of phenoxazinium salts is suitable for the dyeing ability.

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Published online: 20th November, 2020

Review | Special issue | Prepress
DOI: 10.3987/REV-20-SR(K)3
Recent Advances in Synthetic Strategies for The C4a,C9a-Fused Tetracyclic Hydrocarbazole Core Structure of Minfiensine and Related Akuammiline Alkaloids

Keisuke Hosoya, Keita Iida, Minami Odagi,* and Kazuo Nagasawa*

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

Abstract

The Strychnos alkaloid minfiensine and its analogs among the akuammiline alkaloids have a variety of biological activities, including anti-tumor and analgesic activities, and have therefore attracted considerable synthetic interest. Here we provide an overview of recent advances in methodologies for the construction of the characteristic tetracyclic hydrocarbazole core structure containing a fused pyrrolidine ring at C4a and C9a.

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Published online: 18th November, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14363
Probing the Reaction of N,N-Dimethyformamide Dimethyl Acetal with p-tert-Butylthiacalix[4]arene Tetrahydrazides: A Facile Approach for the Synthesis and Application of Novel Metal Receptors

Omran A. Omran and Ayman Nafady*

*Chemistry Department, Faculty of Science, Sohag University, 82524, Sohag, Egypt

Abstract

Recent developments in the field of sensing and recognition revealed that artificial receptors based on calix[4]arenes with π-conjugated fluorophoric or chromophoric moieties are efficient in enhancing selectivity/sensitivity as well as the binding affinity for ionic or molecular recognition. Herein, via studying the reaction of dimethylformamide dimethyl acetal (DMF–DMA) with p-tert-butylthiacalix[4]arene tetrahydrazides in three different conformers (i.e., cone, partial-cone, and 1,3-alternate), the formation of novel lower rim p-tert-butylthiacalix[4]arene derivative (cone, partial-cone, and 1,3-alternate) conformers in high yields (80, 95, and 85%, respectively) was achieved. The structure of isolated products was confirmed using different spectroscopic and analytical techniques such as FT-IR, 1H NMR, 13C NMR, and elemental analysis. Importantly, the synthesized receptors showed preferential uptakes of alkali (Na+, K+ and Cs+), heavy (Pb2+, Cd2+, Hg2+, and Ag+) and transition (Ni2+, Co2+, and Cu2+) metal ions via liquid–liquid extraction method. The finding of this work adds new compounds to the growing family of thiacalix[4]arenes and validates their high sensitivity and selectivity in detection of heavy metal ions.

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Published online: 13th November, 2020

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)38
De Novo Approach to Izidines via a Gold-Catalyzed Hydroamination–N-acyliminium Ion Cyclization of Acyclic Ynamides

Kenji Sugimoto,* Shota Mizuno, Misaki Shirato, Kosuke Tanabe, and Yuji Matsuya*

*Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.

Abstract

A gold(I)-catalyzed novel domino reaction of acyclic ynamides yielding nitrogen-fused bicyclic skeletons was described. The reaction with 10 mol% JohnPhosAuNTf2 and stoichiometric amount of PhCO2H enables constructions of quinolizidine and indolizidine skeleton having tetrasubstituted carbon center. Especially in the case of quinolizidine synthesis, the quaternary stereogenic center could be furnished under highly diastereoselective manner.

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Published online: 13th November, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14355
Synthesis, Structures and Interactions with Ct-DNA/BSA of Three New Acylhydrazones Containing Oxazole Ring

Lingling Chang, Xiangrong Liu,* Zaiwen Yang, Shunsheng Zhao, Xinjuan Chen, and Bosen Dai

*College of Chemistry and Chemical Engineering, Xi’an University of Science and Technology, Xi’an 710054, China

Abstract

Three new acylhydrazones containing oxazole ring C11H8N3O2X (X = F, 1; Br, 2; I, 3) have been synthesized. The single crystal XRD presented that 1 belonged to the monoclinic system, while 2 and 3 belonged to the triclinic systems. TG-DTG results showed that the maximum thermal decomposition temperatures of 1-3 were more than 260 °C. The UV-vis spectra, fluorescence spectra and microcalorimetry measurements indicated that each acylhydrazone bound to calf thymus DNA (CT-DNA) via groove binding mode and interacted with bovine serum albumin (BSA) by static quenching effect and the corresponding interaction processes were all exothermic. The molecular docking showed that each acylhydrazone bound to CT-DNA and BSA mainly through hydrogen bonding. The minimum inhibitory concentrations of 1-3 against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa were all about 0.25 mg·mL-1.

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Published online: 13th November, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14356
Practical Synthesis of 1-Substituted 5-Aminopyrazolo[4,3-d]pyrimidin-7-ones Using Intramolecular Friedel–Crafts Type Cyclization and Its Application to the Synthesis of Pharmaceutically Active Compounds

Takashi Goi,* Tetsuji Matsudaira, and Koichi Fukase*

*Sohyaku. Innovative Research Division, Mitsubishi Tanabe Pharma Corporation, 1000, Kamoshida-cho, Aobaku, Yokohama, 227-0033, Japan

Abstract

Intramolecular Friedel–Crafts type cyclization is known as an efficient method of synthesizing fused bicyclic pyrimidones. However, the synthesis of 1-substituted pyrazolo[4,3-d]pyrimidin-7-ones using this cyclization method has not been achieved. Herein, we describe the synthesis of various 1-substituted pyrazolo[4,3-d]pyrimidin-7-ones using practical intramolecular Friedel–Crafts type cyclization, which was carried out in N, N-dimethylformamide in the presence of chlorotrimethylsilane. A hypoxia-inducible factor prolyl hydroxylase domain (HIF-PHD) inhibitor was efficiently synthesized by this method.

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Published online: 12th November, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14362
A Simple Route for Synthesis and Evaluation of Antioxidant Activity of (Guaiazulen-1-Yl)Furans

Si-Tong Guo, Jiao Xu, Xiao-Liang Zhang, Xin-Shuang Xiong, Lu Zhang, Dao-Lin Wang,* and Shu-Quan Zhang*

*College of Chemistry and Material Science, Bohai University, Jinzhou, China

Abstract

An effective protocol for the synthesis of guaiazulene substituted furan derivatives via three-component reactions of guaiazulene, α-ketoaldehyde, and 1,3-dicarbonyl compound under mild conditions in good yield is reported. All of these compounds were evaluated for their antioxidant properties in vitro against lipid peroxidation and several compounds were found to have good activities.

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Published online: 9th November, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-943
Systematic Search for Transition States in Complex Molecules: Computational Analyses of the Regio- and Stereoselective Interflavan Bond Formation in Flavan-3-Ols

Daisuke Urabe* and Keisuke Fukaya

*Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan

Abstract

This review describes our recent work on a systematic search for transition states in transformations of complex molecules. The method features a combination of a conformational search method using constrained models to create a large library of transition-state candidates, and subsequent density functional theory (DTF)-based transition state calculations for the candidates. The method is applicable to calculation of transition states for inter- and intramolecular interflavan bond formation in flavan-3-ols to reproduce experimental results for highly regio- and stereoselective C-C bond formation. The specific roles of van der Waals interactions in the transition states can be visualized by NCIPLOT mapping to show the importance of weak but attractive interactions for selective interflavan bond formation.

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Published online: 9th November, 2020

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)35
Design, Synthesis, Physical Properties and Indoleamine 2, 3-Dioxygenase 1 Inhibitory Activity of Substitued Indole Derivatives with N-H, N-Metohymethyl, or N-Mehylthiomethyl Group toward Fragment-Based Drug Discovery

Kenta Hayami, Yuichi Kuboki, Katsumi Ohta, Bangzhong Lin, Megumi Fumimoto, Kazuto Nunomura, Jun-Ichi Haruta , Kenichi Murai, Hiromichi Fujioka, Akira Asai, and Mitsuhiro Arisawa*

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

Abstract

We designed and prepared N-H, N-CH2OMe(MOM), and N-CH2SMe (MTM) forms of various substituted indoles, using a docking study, as a small fragment library toward fragment-based drug discovery (FBDD) and evaluated their indoleamine 2, 3-dioxygenase 1 (IDO1) inhibitory activities and physical properties.

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Published online: 29th October, 2020

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)32
Hybrid Catalysis of 8-Quinolinecarboxaldehyde and Brønsted Acid for Efficient Racemization of α-Amino Amides and Its Application in Chemoenzymatic Dynamic Kinetic Resolution

Kohsuke Ohmatsu, Mari Kiyokawa, Yuto Shirai, Yuya Nagato, and Takashi Ooi*

*Institute of Transformative Bio-Molecules (WPI-ITbM), and Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan

Abstract

The combination of 8-quinolinecarboxaldehyde and benzoic acid proved to be an effective catalyst system for the racemization of N-unprotected α-aryl- or α-alkyl-substituted α-amino amides. Application of this system to chemoenzymatic dynamic kinetic resolution provided an efficient access to enantiomerically pure N-acetyl-α-amino amides in good to high yields.

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Published online: 29th October, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)28
Synthesis of 1-Methoxy-1H-Indoles with a Heterocyclic Moiety via Unstable Indole Isothiocyanate by Using Enzyme from Brassicaceae Plant

Kaori Ryu, Seikou Nakamura,* Koya Miyagawa, Souichi Nakashima, and Hisashi Matsuda*

*Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan

Abstract

A synthesis of five 1-methoxy-1H-indole derivatives with imidazole, pyrazole, 1H-1,2,3-triazole, and 1H-1,2,4-triazole moieties was achieved by focusing on the formation mechanism of plant constituents. The objective 1-methoxy-1H-indole derivatives were obtained in situ (in one step) through the reaction of an unstable 3-(isothiocyanatomethyl)-1-methoxy-1H-indole, which was derived from neoglucobrassicin and plant enzyme myrosinase, and a heterocyclic compound. We have great hopes that this method would be useful for the development of medicinal seeds.

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Published online: 28th October, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)29
Stereoselective Alkylation of Oxathiazinane N,O-Ketals for the Construction of Aza-Quaternary Carbon Centers

Hisanori Nambu, Eri Tanaka, Mai Okada, Chiaki Hirosawa, Narumi Noda, Tomoya Fujiwara, and Takayuki Yakura*

*Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan

Abstract

Stereoselective construction of aza-quaternary carbon centers was achieved using the alkylation of oxathiazinane N,O-ketals prepared by Rh(II)-catalyzed C–H amination of sulfamates. The addition of alkyl Grignard reagents into N,O-ketals in the absence of any Lewis acid proceeded stereoselectively to provide the corresponding alkylated products with an aza-quaternary carbon center in high yields. The obtained product could be converted into an α-amino alcohol derivative, which is a potential synthetic intermediate for sphingofungin F and its derivatives.

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Published online: 27th October, 2020

Review | Special issue | Prepress
DOI: 10.3987/REV-20-SR(K)1
Recent Advances in the Microwave Assisted Synthesis of Benzofuran and Indole Derivatives

Thaipparambil Aneeja, Sankaran Radhika, C M A Afsina, and Gopinathan Anilkumar*

*School of Chemical Sciences, Mahatma Gandhi University, Priyadarsini Hills, Kottayam, Kerala , India

Abstract


Abstract – Microwave (MW) assisted syntheses are environment friendly, efficient, rapid and convenient methodology for the synthesis of organic compounds. Benzene ring fused to a five membered ring containing N or O atom exhibits wide range of biological activities. Benzofuran is present in polymers, pharmaceuticals, and bioactive natural products. Benzofuran is significant as insecticides, herbicides, anti-inflammatory and anti-viral agents. Indoles are well known scaffold showing noteworthy activities like anti-tumor, anti-viral, anti-microbial and anti-oxidant. Indole derivatives are valuable moiety in different therapeutically active drug molecules. On account of the biological significance of benzofuran and indole scaffold, this review describes the recent advances in microwave assisted synthesis of benzofurans and indoles, and covers literature from 2012-2020.

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Published online: 27th October, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-939
Attractive Organic Cocrystal Materials in Optics

Xiao Han,* Linyu Wang, and Gaiqing Xi

*College of Chemical Engineering & Material, Hebei Key Laboratory of Heterocyclic Compounds, Handan University, Handan 056005, Hebei, China

Abstract

Since the beginning of this century, organic molecule solid material, one of favorable choices for constructing high-performance optoelectronic devices/circuits, has showed the impressive perspective in organic optoelectronics. Especially, because of the long-range order, absent grain boundary and extremely low defect density, organic single-crystal material support a great platform for fundament and application researches. Herein, cocrystal engineering, one simply collaborative strategy, shows offers the unique advantages, involving facile and low-cost synthesis procedure, easily achieving rare and multifunctional properties, tunable structure, morphology and size. It is extremely suitable to construct functional organic molecule solid material, especially novel multifunctional organic single-crystal materials. In this mini review, a overview of organic cocrystal is presented to introduce its attractive future in optics, such as OFET, lasing, nonlinear optics, optical waveguide material, stimuli-responsive material and other potential applications.

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Published online: 26th October, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)30
Synthesis and Structure-Activity Relationship Study of 1,12-Dicarba-closo-dodecaborane-based Triol Derivatives as Nonsecosteroidal Vitamin D Analogs

Shinya Fujii, Ryota Sekine, Atsushi Kano, Hiroyuki Masuno, Emiko Kawachi, Tomoya Hirano, and Hiroyuki Kagechika*

*Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10, Surugadai, Kanda, Chiyoda-ku 101-0062, Japan

Abstract

The secosteroidal hormone 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] is a specific ligand of nuclear vitamin D receptor (VDR), and novel vitamin D analogs are promising candidates for multiple clinical applications. We previously developed a series of 1,12-dicarba-closo-dodecaborane (p-carborane) derivatives as nonsecosteroidal VDR agonists. Here, we report the synthesis and structure-activity relationship of p-carborane-based nonsecosteroidal vitamin D analogs bearing a nitrogen or a sulfur atom in the linker structure. Biological evaluation revealed that the structure–activity relationships of amine derivatives and sulfide derivatives are different, and therefore the choice of the linker structure significantly affects the activity. We also found that benzylamine structure could be a lead scaffold for novel vitamin D analogs. The structure–activity relationships presented here should be helpful in further development of nonsecosteroidal vitamin D analogs.

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Published online: 26th October, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14347
Reactivity of 4,9-Dimethoxy-5-oxo-5H-furo[3,2-g]chromene-6-carbonitrile towards Some Nitrogen Nucleophilic Reagents

Magdy A. Ibrahim* and Esam S. Allehyani

*Department of Chemistry, Faculty of Education, Ain Shams University, Cairo, Egypt

Abstract

The chemical behavior of 4,9-dimethoxy-5-oxo-5H-furo[3,2-g]chromene-6-carbonitrile (khellin-6-carbonitrile) (1) was examined towards a variety of nitrogen nucleophiles. Some novel Schiff bases 5-7 were prepared from reaction of carbonitrile 1 with some heterocyclic amines. Treatment of carbonitrile 1 with some hydrazine derivatives in boiling ethanol afforded pyrazole derivatives 8-13. Khellin-6-carbonitrile (1) reacted with hydrazine hydrate and phenylhydrazine in acetic acid to afford angular heteroannulated furo[3`,2`:6,7]chromeno[4,3-c]pyrazol-4(1H)-one derivatives 14 and 15. Triazolo[1,5-a]pyrimidine 16 and pyrimido[1,2-a]benzimidazole 17 were synthesized through ring opening and recyclization reactions of compound 1 with 3-amino-1,2,4-triazole and 2-aminobenzimidazole, respectively. Reaction of compound 1 with guanidine and cyanoguanidine in ethanolic potassium hydroxide solution resulted in ring conversion giving the novel angular furo[3`,2`:6,7]chromeno[4,3-d]pyrimidin-5-ones 18 and 19. The antimicrobial activity of the prepared compounds appeared distinguish activity against the selected microorganisms.

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Published online: 26th October, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14350
Montmorillonite K-10 Catalyzed Microwave-Assisted Synthesis of Pyrroles in Solvent Free Conditions

Chaowei Ma* and Guosheng Huang

*College of Chemistry and Environmental Engineering, Xinjiang Institute of Engineering, Xinjiang Wulumuqi Nanchang Road 830091, china

Abstract

An effective microwave-induced, montmorillonite K-10 catalyzed, environmentally benign synthesis of substituted pyrroles from α‑amino carbonyl compounds and aldehydes under solvent-free conditions is described. The reaction involving various substituted substrates proceeds smoothly, and substituted pyrroles are synthesized in moderate to excellent yields within minutes. The developed method offers advantages such as operational simplicity, solvent-free, rapid reaction rate and use of a commercially recyclable catalyst.

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Published online: 22nd October, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)36
Preparation of 2-Aryl-3-Silyl- and 2-Aryl-3-Germyl-1,3-Butadienes via Arylnickelation and Zinciomethylation

Nana Yoshino, Betemariam Sharewa, Zenichi Ikeda, and Seijiro Matsubara*

*Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigaku-Katsura, Nishikyo, Kyoto 615-8510, Japan

Abstract

Benzyl 3-silyl(or germyl)propargyl ether, aryl iodide, and bis(iodozincio)methane were assembled in the presence of a nickel catalyst to efficiently give 2-aryl-3-silyl(germyl)-1,3-butadienes via arylnickelation, zinciomethylation, and 1,4-elimination of zinc benzyloxide. As a ligand, an electron-deficient phospine such as tris(2-furyl)phosphine was effective.

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Published online: 22nd October, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-940
Synthetic Approaches for Heteroannulated Chromones Fused Various Heterocyclic Systems

Salsabeel H. Hashiem, Magdy A. Ibrahim, Al-Shimaa Badran,* Nasser M. El-Gohary, and Hassan A. Allimony

*Department of Chemistry, Faculty of Education, Ain Shams University, Roxy 11711, Cairo, Egypt

Abstract

The main focus of this review summarized the different methods utilized for the synthesis of chromone annulated with different heterocyclic rings such as pyrroles, furans, pyrazole, imidazole, benzene, naphthalene, quinolone……and others.

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Published online: 21st October, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-935
The Interrupted Pummerer Reaction: Design of Sulfoxides and Their Utility in Organic Synthesis

Kazuhiro Higuchi* and Masanori Tayu

*Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan

Abstract

Acid anhydride-activated sulfoxides can undergo a variety of cascade reactions after reacting with nucleophiles on its sulfur atom. Originally regarded as an abnormal phenomenon that occurs under Pummerer reaction conditions, the reports of the reaction increased gradually, and research regarding sulfoxide reactivity has advanced. In recent years, the term ‘interrupted Pummerer reaction’ has been introduced, and the transformation has been actively incorporated into the development of new research areas. Such studies have yielded numerous valuable sulfoxides, which contribute to the precise reaction control and to the generation of practical products. Notably, the outcome of the interrupted Pummerer reaction is characteristic for each nucleophile.

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Published online: 20th October, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)31
Mn(III)-Based Oxidative Cyclization of 2-((2-Arylamino)Ethyl)Malonates: Synthesis of Quinolines via Dihydroquinolinedicarboxylates

Takayuki Nagashimada, Masahiro Morikawa, Kengo Ohki, and Hiroshi Nishino*

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

Abstract

The synthesis of quinolines from aniline derivatives via the Mn(III)-based oxidative cyclization of 2-(2-(arylamino)ethyl)malonates is described. The 2-(2-(arylamino)ethyl)malonates were prepared in two steps from the substituted anilines. The cyclization of nineteen arylaminoethylmalonates protected by the N-acyl and N-alkoxycarbonyl groups easily proceeded in the formal 6-endo mode regardless of the presence of halo, methyl, and methoxy groups on the aromatic ring, and the corresponding tetrahydroquinolinedicarboxylates were produced in high yields except for the 2,4-dimethoxyphenyl-substituted aminoethylmalonate which occurred by ipso-cyclization. The tetrahydroquinolinedicarboxylate could be transformed into quinoline via decarboxylation and deprotective hydrolysis. The characteristic phenomenon in the NMR spectrum of the tetrahydroquinolinedicarboxylates is also discussed.

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Published online: 20th October, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-942
Mini Review: Antioxidant Application of Metal-Organic Frameworks and Their Composites

Shaikha S. Alneyadi*

*Department of Chemistry, College of Science, UAE University Al-Ain, 15551 UAE

Abstract

Metal–organic frameworks (MOFs) are porous coordination materials composed of multidentate organic ligands and metal ions or metal clusters. MOFs have great potential as medical materials for biological, environmental, and food antimicrobial fields. In recent years, MOFs have been applied to various antioxidant fields due to their continued release capability, porosity, and structural flexibility in combination with many chemicals and/or materials such as nanoparticles, antioxidant, and polymers. This review offers a detailed summary of the antioxidant applications of MOFs and their composites, focusing on the combination types of MOF composites and their antioxidant effects in different applications described in 2015-2020. These applications are illustrated by the examples discussed in this review.

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Published online: 19th October, 2020

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)24
Rhodium-Catalyzed Crossed [2+2+2] Cycloaddition with Ynamides: Key-Strategy for The Concise Total Synthesis of 3-Oxygenated Carbazole Alkaloids

Carole Alayrac* and Bernhard Witulski*

*Laboratoire de Chimie Molèculaire et Thioorganique (LCMT)
, National Graduate School of Engineering and Research Center, , France

Abstract

Total syntheses of a set of naturally occurring 3-oxygenated carbazole alkaloids - 6-chlorohyellazole, carazostatin, carbazomycins A and B - are described. The key-strategy underlines a highly chemo- and regioselective rhodium-catalyzed [2+2+2] cyclotrimerization between appropriately tailored yne-ynamides and 1-methoxypropyne that is stirred by the interplay of stereoelectronic and steric effects allowing the introduction of four ring substituents of the natural carbazoles within a single step and making the overall syntheses short and efficient.

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Published online: 16th October, 2020

Communication | Regular issue | Prepress
DOI: 10.3987/COM-20-14346
Rhodium-Catalyzed Oxidative Olefination of N-(2-(4,5-Dihydrooxazol-2-yl)phenyl)amides with Arylethenes via Extraordinary N-Aryl C-H Bond Functionalization

Hao Yan,* Fang-Peng Hu, Xiao-Qiang Zhou, Zhi Li, and Guosheng Huang*

*College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, 712046, P. R. of China

Abstract

Amide-tethered aryloxazoline motifs are important structural moiety because of ubiquity in medicinal chemistry, functional materials and pincer ligands. In recent years, much attention about N-(2-(4,5-dihydrooxazol-2-yl)phenyl)amides has been focused on ortho C−H functionalization of amides. Herein a highly efficient rhodium(III) catalyzed oxidative olefination of N-(2-(4,5-dihydrooxazol-2-yl)phenyl)amides with arylethenes via extraordinary N-aryl C-H bond functionalization was developed.

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Published online: 15th October, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14342
Five New Highly Oxidized Neoclerodane Diterpenes, Salvileucalins E-I from Salvia leucantha

Yutaka Aoyagi,* Yutaka Nakazato, Akira Yamazaki, Haruna Kondo, Ayana Ninomiya, Mari Tokuda, Haruhiko Fukaya, Reiko Yano, Koichi Takeya, and Yukio Hitotsuyanagi*

*College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya 463-8521, Japan

Abstract

Five new rearranged neoclerodane diterpenes (salvileucalins E-I) were isolated from Salvia leucantha (Lamiaceae), whose structures were elucidated by spectroscopic analysis and X-ray crystallographic analysis.

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Published online: 15th October, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14349
Synthesis of Novel Thienopyrimidines and Thienodiazepines from Ethyl 2,4-Diamino-5-{[(2E)-2-(1-phenylethylidene)hydrazino]carbonyl}thiophene-3-carboxylate

Osama Farouk and Kamelia M. El-mahdy*

*Department of Chemistry, Faculty of Education, Ain Shams University, Roxy, 11711, Cairo, Egypt

Abstract

Ethyl 2,4-diamino-5-{[(2E)-2-(1-phenylethylidene)hydrazino]-carbonyl}thiophene-3-carboxylate (3) was synthesized via Gewald reaction that can be readily used as precursor to potentially interesting thiophenes. Compound 3 reacted with cyanoacetamide and/or malononitrile producing thienopyrimidines 4 and 5, respectively. Reaction of compound 3 with hydrazinecarbodithioic acid afforded pyrimidothienotriazepine 6. Treatment of compound 3 with ethylenediamine and carbon disulfide gave (imidazolinyl)thiophene 7. The latter compound can be used as building blocks for the synthesis of various heterocycles. Structures of the newly synthesized compounds were deduced based on their analytical and spectral data.

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