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Published online: 14th May, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14456
■ Synthesis and Biological Activities of Selenium/Thioether Quinazoline Compounds

Canjun Yan, Yuchun Zhang, Guihan Zhao, Xiaohong Jin, Wuwei Yang, Pengpeng Niu, Haojie Wang, and Gang Liu*

*School of Chemistry and Materials Science, Ludong University, Yantai 264025 China

Abstract

In view of the important role of quinazoline skeletons in anti-cancer drugs like Gefitinib and the vital importance of organoselenium compounds in biomedicine field, in this protocol, twenty quinazoline selenium derivatives were designed and synthesized with the aim to develop new anti-cancer drugs by utilizing the synergistic effects of quinazoline skeleton and selenium. In addition, the synthetic method of thioether substituted quinazolines was improved. The biological activities of title compounds were determined against A549 cancer cells in vitro by using MTT assay at 1 μM and 10 μM concentrations. The results showed that most of the title compounds had good anticancer activities. Of note, 6-chloro-4-benzylselenoquinazoline (G5) exhibited better inhibitory activity (67.8% inhibition ratio) than the positive control drug Gefitinib (62.9% inhibition ratio) at the concentration of 10 μM. These findings will provide some clues for further research of anticancer drugs.

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Published online: 14th May, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14480
■ Total Synthesis of Hyalodendriol C

Ishtiaq Jeelani,* Katsunori Itaya, and Hitoshi Abe

*Graduate School of Innovative Life Science, University of Toyama, 3190 Gofuku 930-8555, Japan

Abstract

We present a total synthesis of hyalodendriol C, a fungal natural product. We have focused on the use of palladium-catalyzed intramolecular biaryl coupling reaction of phenyl benzoate derivatives to synthesize hyalodendriol C. Keeping in view, the indispensable biological values of this compound, we took the advantage of our established strategy to chemically synthesize hyalodendriol C. The total synthesis of hyalodendriol C got accomplished in 10 steps beginning with the preparation of phenol derivative from the commercially available 5-methylbenzene-1,3-diol and synthesis of the corresponding benzoic acid derivative.

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Published online: 10th May, 2021

Review | Regular issue | Prepress
DOI: 10.3987/REV-21-956
■ Synthetic Approaches toward Certain Structurally Related Antimicrobial Thiazole Derivatives (2010-2020)

Abdelfattah Hassan, Heba A. Hassan, Dalia Abdelhamid, and Gamal El-Din A. Abuo-Rahma*

*Medicinal Chemistry Department, Faculty of Pharmacy, Minia University, Minia, Egypt & Pharmaceutical Chemistry Department, Faculty of Pharmacy, Deraya University, New Minia, Minia, Egypt

Abstract

In the present literature review, we comprehensively discuss different methods of synthesis of published antimicrobial thiazole derivatives in the last decade mainly those which showed antibacterial, antimycobacterial and/or antifungal activity. Owing to the great diversity of thiazole-derived antimicrobial agents, we organized most of them chemically in stipulated classes. In each class, we mentioned common methods of thiazole ring closure and indicated antimicrobial activity of the most active derivatives in clear and simple way.

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Published online: 28th April, 2021

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-953
■ Recent Achievements in the Synthesis of Heterocyclic Compounds by Phthalhydrazide-Based Multicomponent Reactions

Ghodsi Mohammadi Ziarani,* Negar Jamasbi, and Fatemeh Mohajer

*Department of Chemistry, Faculty of Physic and Chemistry, Alzahra University, Tehran, Iran. P. O. Box 1993893973

Abstract

Phthalhydrazide is one of the useful starting material toward the synthesis of heterocyclic compounds, and considered as a valuable structural unit in organic synthesis due to its significant pharmacological and biological activities. There are many multicomponent reactions using phthalhydrazide under different conditions. This review article aims to give an overview of recent applications of phthalhydrazide in the multicomponent reactions during the period of 2006 to 2021.

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Published online: 20th April, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14446
■ Recyclable Heterogeneous Nanocrystal Promoted Cascade Reaction in Water: An Access to Green Synthesis of Highly Functionalized 4H-pyrans Containing Phosphonate Motif

Yong-Hong Cai, Ya-Sa Xie, Ran Li, Ming-Mei Fan, Jing-Jing Li, Chuan-Bao Zhang,* and Jin-Fang Yuan*

*College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China.

Abstract

A green and environmentally friendly cascade reaction of diethyl (2-phenylacetyl)phosphonate with benzylidenemalononitrile promoted by Zr-Ce-SBA-15-NH2 in water was developed, and a wide range of highly functionalized 4H-pyrans containing phosphonate motif were obtained in up to 89% yield. Moreover, SBA-15-NH2 also showed good catalytic activity for this transformation in acetonitrile.

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Published online: 15th April, 2021

Review | Regular issue | Prepress
DOI: 10.3987/REV-21-958
■ Recent Advances in 1,2,4-Triazole Ring Construction via Cycloaddition Reactions

Nataliya Korol,* Mikhailo Slivka, and Oksana Holovko-Kamoshenkova

*Organic synthesis laboratory, Faculty of Chemistry, Uzhhorod National University, Uzhhorod 88000, Ukraine

Abstract

The sources, describing cycloaddition reactions that lead to obtaining of substituted 1,2,4-triazoles and their fused derivatives were reviewed. The review article covers the literature data published in the period 2011-2021. Synthetic particularities of cycloaddition products, the optimization of reaction conditions, factors that influence on the direction of the reaction are reasonably mentioned. Cycloaddition reactions are presented as convenient method for obtaining of as functional 1,2,4-triazoles, as well as their fused derivatives.

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Published online: 14th April, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14460
■ Metal-Free sp3 C-H Bond Oxidation and Functionalization of α-Bromoketones to Quinoxalinone, Benzoxazinone, and Benzothiazinone Heterocyclic Compounds

Tianlong Wei, Haiying Tian, Fang Guo,* Hongxue Qi, and Xiuling Chen*

*School of Nuclear Technology and Chemistry & Biology, Hubei University of Science and Technology, Xianning 437100, China

Abstract

A series of heterocyclic compounds (benzothiazinones, benzoxazinones and quinoxalinones) were efficiently synthesized in excellent yields via α-bromoketones with o-substituted aniline (2-aminothiophenol, aryl-1,2-diamines and 2-aminophenol). This protocol accomplishes sp3 C-H bond oxidation and functionalization in one-pot without any metal catalyst.

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Published online: 12th April, 2021

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-950
■ Iodine-Containing 4,7-Dihalobenzo[b]thiophene Building Blocks and Related Iodobenzo[b]thiophenes: Promising Molecular Scaffolds for Bio-Inspired Molecular Architecture

Kozo Toyota* and Shinichi Mikami

*Department of Chemistry, Graduate School of Science, Tohoku University, Aoba, Sendai, Miyagi 980-8578, Japan

Abstract

This review describes preparations and reactions of 4,7-dihalobenzo[b]thiophenes bearing iodine atom(s). A short survey of typical preparative methods for iodobenzo[b]thiophenes and relatively simple benzo[b]thiophenes is included. Reactions of the iodine-containing 4,7-dihalobenzo[b]thiophenes are shown and their application to α helix-inspired artificial molecular architecture is referred.

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Published online: 12th April, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14459
■ A One-Pot Approach to Construct 3-(2-Methoxypyridin-3-yl)-4H-chromen-4-ones via Meinwald Rearrangement/Intramolecular Demethylation Annulation of Epoxides

Min-Qi Hu, Ying Zhang, Kai-Li Dai, Li-Fang Yu, Ting Liu, Jie Tang, and Fan Yang*

*Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, PR China

Abstract

A convenient and practical approach for construction of 3-(2-methoxypyridin-3-yl)-4H-chromen-4-ones has been successfully developed by a one-pot Meinwald rearrangement/intramolecular demethylation annulation reaction sequence with easily accessible epoxides as the starting material. The synthetic protocol is of excellent functional group compatibility under mild reaction conditions, and 3-(2-methoxypyridin-3-yl)-4H-chromen-4-ones were obtained in high yields. Moreover, further derivation successfully furnished more complicated derivatives by Suzuki-Miyaura cross-coupling reaction which may provide a promising potential application in exploring biological activity of 3-aryl-4H-chromen-4-ones.

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Published online: 12th April, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14461
■ Three-Component Reaction of Arynes, Quinolines, and Chloroform: Two-Step Synthesis of 2-Quinolinones from Quinolines

Kentaro Okuma,* Shiho Inomata, Yuxuan Qu, and Noriyoshi Nagahora

*Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka 814-0180, Japan

Abstract

Reaction of quinoline with benzyne prepared from benzenediazonium-2-carboxylate and chloroform gave 1-phenyl-2-trichloromethyl-1,2-dihydroquinoline in 79% yield. Basic hydrolysis of dihydroquinoline by KOH resulted in the formation of 2-quinolinone in 85% yield.

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Published online: 6th April, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14448
■ Synthesis and Biological Activities of Some New Phosphorus Compounds Containing Pyranopyrazole Moiety

Tarik E. Ali,* Mohammed A. Assiri, Hafez M. El-Shaaer, Somaia M. Abed-Kariem, Wafaa R. Abdel-Monem, Somaya M. El-Edfawy, Noha M. Hassanin, Ali A. Shati, Mohammad Y. Alfaifi, and Serag Eldin I. Elbehairi

*Department of Chemistry, Faculty of Science, King Khalid University, Abha, Saudi Arabia.

Abstract

A simple method for construction of functionalized pyranopyrazoles containing phosphoramide and phosphonate groups via one-pot reaction was achieved. The methodology depended on the reaction of 6-amino-3-methyl-1,4-diphenyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (3) with triethyl phosphite and hexaethylphosphoramide and so with diethyl phosphite in the presence of chloroacetyl chloride or carbon disulfide. The products were screened for their antimicrobial, antioxidant and antiproliferative properties. Compound 7 displayed promising antimicrobial and antioxidative properties. Also, compound 8 showed potent cytotoxic effects against MCF-7, HepG-2 and HCT-116 cancer cells with IC50 values in range 5.3 ± 0.9 to 7.5 ± 0.6 μg/mL. Acridine orange and ethidium bromide were used for the detection of viable, apoptotic, and necrotic cells. The early apoptotic cell death was observed by the compounds in all types of the treated cells. Compounds 5, 7 and 8 induced high percentage of necrosis towards all treated cells. The late apoptosis was recorded as a high rate after treatment with compound 3 in HepG-2 cells.

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Published online: 5th April, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14450
■ Facile Access to Highly-Substituted Dihydrofurans Using Resonated Vinylpentanedione Radicals Generated by Mn(III)-Based Oxidation

Sousuke Oka, Shintaro Hashimoto, Kazuki Hisano, and Hiroshi Nishino*

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

Abstract

Useful and easy access to highly-substituted dihydrofurans, which convert into various acetals, was established using the common Mn(III) oxidation. The key point is to use resonated vinylpentanedione radicals that cyclize to produce the desired acetoxydihydrofurans which are transformed into the hemiacetals and acetals in good yields under very mild conditions.

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Published online: 2nd April, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14423
■ An Efficient SeO2/FeCl3 Promoted Acylation:Intramolecular Friedel-Crafts Reaction Leading to a One-Pot Synthesis of Wrightiadione and Its Derivatives

Huan Zhang, Qi Wang, Lu Huang, Ziye Tian, Shunguang Zhang,* and Youlai Zhang*

*Tianjin Key Laboratory of Drug Targeting and Bioimaging, School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384, P.R. China.

Abstract

Wrightiadione has been shown to exhibit a broad range of biological activities. An efficient and straightforward synthetic method for generating wrightiadione and its derivatives which contain a unique tetracyclic isoflavone moiety was developed. This unprecedented one-pot route utilizes a wide spread of substrates through three-step tandem Riley oxidation/Friedel-Crafts reaction/oxidation with SeO2/FeCl3 in moderate yield.

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Published online: 30th March, 2021

Review | Regular issue | Prepress
DOI: 10.3987/REV-21-955
■ The Fascinating Chemistry of Mesoionic 4-Trifluoroacetyl-1,3-oxazolium-5-olates and Related Compounds

Ryosuke Saijo and Masami Kawase*

*Faculty of Pharmaceutical Sciences, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama, Ehime 790-8578, Japan

Abstract

This review illustrates the unexpected and unique transformation of mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates (4-TFMK-münchnones) on treatment with different nucleophiles. A trifluoromethyl group that cannot be synthesized by the usual methods is incorporated in the products. The research discussed in this review is focused on the rich chemistry of 4-TFMK-münchnones. In particular, we highlight the recent advances in their use in contemporary organic synthesis, primarily of trifluoromethyl-substituted heterocycles. The chemistry of related mesoionic compounds is also discussed.

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Published online: 30th March, 2021

Communication | Regular issue | Prepress
DOI: 10.3987/COM-21-14433
■ Acylative Desymmetrization of Glycerol Derivatives by Chiral DMAP Derivatives

Hiroki Mandai,* Kosuke Ashihara, Koichi Mitsudo, and Seiji Suga*

*Department of Pharmacy, Faculty of Pharmacy, Gifu University of Medical Science, 4-3-3 Nijigaoka, Kani, Gifu, 509-0293

Abstract

An efficient enantioselective acylative desymmetrization of glycerol was developed by using a chiral DMAP derivatives 1e having a 1,1ʹ-binaphthyl unit. The reactions required only 0.1 mol% of the catalyst and showed moderate to good enantioselectivity (up to 94:6 er). Control experiments revealed that the first acylation of a glycerol derivative proceeded selectively rather than the second acylation to give diacylate.

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Published online: 30th March, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14443
■ Facile Preparation of 2-Aryl-3-iodopyrroles with N-Tosyl 4-Aryl-3-butyn-1-ylamines, I2, and tBuOK

Kaho Shibasaki, Hiroki Naruto, and Hideo Togo*

*Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan

Abstract

Treatment of N-tosyl 4-aryl-3-butyn-1-ylamines with I2 and K2CO3, followed by the reaction with tBuOK under mild conditions gave 2-aryl-3-iodopyrroles in good yields. The present approach is a one-pot method for the preparation of 2-aryl-3-iodopyrroles from N-tosyl 4-aryl-3-butyn-1-ylamines, which could be easily prepared from aryl iodides, N-(3-butyn-1-yl)phthalimides, and p-toluenesulfonyl chloride.

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Published online: 29th March, 2021

Review | Special issue | Prepress
DOI: 10.3987/REV-20-SR(K)8
■ Recent Development on the Ring Transformation Reactions: Synthesis of Functionalized Benzenes, N-Heterocycles and Fused Ring Systems

Priyanka B. Kole and Fateh V. Singh*

*Chemistry Division (SAS), VIT Chennai, Vandalur-Kelambakkam Road, Chennai, Tamil Nadu, India

Abstract

Ring transformation reactions using 2H-pyran-2-ones as valuable synthetic precursor with several nucleophiles for designing numerous interesting scaffolds is a growing field in synthetic organic chemistry. 2H-Pyran-2-ones has tendency to act as very good Michael acceptor and hence functions as good electrophile. The scope of 2H-pyran-2-ones has been explored for the synthesis of various molecules owning significant biological importance. Additionally, their synthetic potential has been discovered for the construction of interesting photophysically active molecules. From this point of view, the development of simple and environmental benign ring transformation strategy is a dynamic research field until today. This short review describes an overview of the most recent advances in ring transformation of functionalized 2H-pyran-2-ones into valuable aromatic scaffolds like functionalized benzenes, N-heterocycles and fused ring systems.

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Published online: 26th March, 2021

Paper | Special issue | Prepress
DOI: 10.3987/COM-21-S(K)74
■ Decisive Effects of C-N Axial Chirality of Intermediary Enolates on the Stereochemical Course of β-Lactam Formation from β-Branched α-Amino Acid Derivatives via Memory of Chirality

Ryuichi Hyakutake, Tomoyuki Yoshimura, Takahiro Sasamori, Norihiro Tokitoh, Kazuhiro Morisaki, and Takeo Kawabata*

*Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan

Abstract

Stereochemistry of β-lactam formation of β-branched β-amino acid derivatives via a MOC strategy was investigated. The 4-exo-trig cyclization of axially chiral enolates generated from l-threonine and l-allo-threonine derivatives proceeded predominately with inversion of the configuration at the newly formed tetrasubstituted carbon, irrespective of the chirality at the β-carbon of the β-lactam precursors. These results indicated that C–N axial chirality of the intermediary enolates generated from the α-amino acid derivatives has decisive effects on the stereochemical course of β-lactam formation even in the presence of an sp3-chiral center at the β-carbon.

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Published online: 26th March, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14435
■ Anti-Tobacco Mosaic Virus Isoindolin-1-ones from the Stems of Nicotiana tabacum

Jian-Duo Zhang, Xin Liu, Li Xu, Jia-Rui Jiang, Le-Le Deng, Wen-Wu Yang, Xue-Mei Li, Guang-Yu Yang, Tao Zhou,* and Feng-Xian Yang*

*Technology Center, China Tobacco Yunnan Industrial Co., Ltd., Kunming, Yunnan 650231, China

Abstract

Three new (1-3) and three known (4-6) isoindolin-1-ones were isolated from the stems of Nicotiana tabacum. Their structures were determined by means of HRESIMS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1-3 were tested for their anti-tobacco mosaic virus (anti-TMV) activitiy. The results showed that compounds 1-3 showed high anti-TMV activity with inhibition rates of 42.6, 46.7 and 38.5% at the concentration of 20 μM, respectively. These rates are higher than that of ningnanmycin, a positive control.

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Published online: 23rd March, 2021

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)72
■ Claisen Rearrangement of 4-Allyloxy-1-p-methoxy benzylpyrazole and Synthesis of Pyrazole-Fused 7-Membered Lactones

Hayato Ichikawa,* Hiroki Takashima, and Shoichi Shimizu

*College of Industrial Technology, Nihon University, 1-2-1, Izumi-cho, Narashino, Chiba 275-8575, Japan

Abstract

Allyl 4-pyrazolyl ethers were subjected to the Claisen rearrangement that involved heating under microwave condition to prepare the corresponding products with regioselective allylation at 5-position of the pyrazoles in good yields. The rearrangement products were converted into 7-membered pyrazololactones having an oxygen atom at 4-position of pyrazole, via a hydroesterification reaction with Pd(OAc)2 and DPE-phos as ligand under 40 atm of CO/H2 (6:34) in moderate to excellent yields.

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Published online: 23rd March, 2021

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)68
■ Chloroamidation of Alkenes Using Sodium Hypochlorite Pentahydrate and Its Application to Synthesis of Aziridines

Masayuki Kirihara,* Kouta Adachi, Yugo Sakamoto, Kazuki Tujimoto, Sho Yamahara, Ryoji Matsushima, Yukou Namba, Kosuke Sato, Takashi Kamada, Yoshikazu Kimura, and Shinobu Takizawa*

*The Institute of Scientific and Industrial Research, Osaka University, 8-1, Mihogaoka, Ibaraki, Osaka 567-0047, Japan

Abstract

The reaction of alkenes with sodium hypochlorite pentahydrate (NaOCl·5H2O) and phosphoric acid (H3PO4) in nitrile solvents resulted in a chloroamidation reaction, producing -chloroamide derivatives in good yields without the use of a transition metal catalyst (up to 90%). N-Pivalazirizines were readily obtained from the resulting -chloroamide derivatives when they were reacted with lithium hexamethyldisilazide (LiHMDS).

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Published online: 23rd March, 2021

Review | Regular issue | Prepress
DOI: 10.3987/REV-21-957
■ Synthesis and Structure−Activity Relationship Study of Intervenolin, an Antitumor and Anti-Helicobacter Pylori Quinolone Natural Product

Takumi Watanabe*

*Institute of Microbial Chemistry, Tokyo (BIKAKEN), 3-14-23 Kamiosaki Shinagawa-ku, Tokyo 141-0021, Japan

Abstract

This review article overviews the chemistry and biology of intervenolin, a quinolone natural product bearing unusual substituents. Intervenolin was isolated as a modulator of tumor–stroma interactions, communication between tumor cells and surrounding normal cells to regulate tumor-associated events including proliferation. The synthesis of intervenolin by the author employs thiocyanate–isothiocyanate rearrangement and Suzuki–Miyaura cross coupling as key reactions, which was utilized in structure–activity relationship studies. The SAR studies generated analogs that are effective in vivo. Moreover, several intervenolin and analogs also showed anti-Helicobacter pylori activity. Mechanistic aspects of these biological activities, and synthetic study on structurally related natural products by Spring and co-workers are also discussed.

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Published online: 18th March, 2021

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)55
■ Stereoselectivity of the Biginelli Reaction Catalyzed by Chiral Primary Amine: A Computational Study

Takayoshi Yoshimura, Maneeporn Puripat, Vudhichai Parasuk, and Miho Hatanaka*

*Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan

Abstract

The Biginelli reaction catalyzed by a chiral compound is one of the most effective ways to form bioactive heterocycle compounds. High enantioselectivity was obtained using primary amine with a chiral diamine backbone as a chiral catalyst. To elucidate the origin of the enantioselectivity, we investigated the reaction pathways of this catalytic reaction using the density functional theory. We also focused on the transition states of the rate-determining step leading different stereoisomers. The rate-determining step was the proton transfer process accompanying the cyclization of the substrate, which was mediated by the amide moiety of the catalyst, and the orientation of the amide moiety was the reason for the enantioselectivity.

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Published online: 15th March, 2021

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)50
■ Fasciospyrinadinone and Fasciospyrinadinol, Novel 3-Alkylpyridine Sesquiterpenoids from an Indonesian Marine Sponge, as Selective Growth Inhibitors of the Cancer Cells Under Nutrient Starvation

Hirokazu Matsumoto, Tomoya Hisa, Kazunari Toda, Ryosuke Ishida, Andi Setiawan, Masayoshi Arai, and Naoyuki Kotoku*

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

Abstract

On the guidance of the bioassay using PANC-1 cells adapted to the glucose starvation, two novel pyridine sesquiterpenoids named fasciospyrinadinone (1) and fasciospyrinadinol (2) were isolated from the Indonesian marine sponge of Petrosaspongia sp. The chemical structures of the compounds were established on the basis of the 1D and 2D NMR spectra data. Then, we accomplished the first total syntheses of 1 and 2. Compound 1 showed selective growth inhibitory activity against PANC-1 cells adapted to glucose starvation, with IC50 value of 13 µM.

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Published online: 15th March, 2021

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)73
■ Large-Scale Synthesis of Thio-glucose-Conjugated Chlorin e6 for Photodynamic Therapy

Akihiro Nomoto,* Hiroaki Yamaguchi, Masato Masuda, Keisuke Hyakumura, Shintaro Kodama, Tomohiro Osaki, Yoshiharu Okamoto, Mamoru Tanaka, Hiromi Kataoka, Atsushi Narumi, Tomokazu Yoshimura, Shigenobu Yano, and Akiya Ogawa

*Engineering, Department of Applied chemistry, Osaka Prefecture University, Sakai, Osaka 593-8531, Japan

Abstract

Chlorin e6 is a heterocycle exhibiting spectral absorption in the 600–700 nm wavelength range used for photodynamic therapy (PDT). Herein, a sugar-conjugated chlorin e6 derivative was synthesized on a large scale. An alkyl spacer was fabricated by controlling the alkylation conditions between the thio-sugar and chlorin e6 and thio-glucose-conjugated chlorin e6 was successfully synthesized.

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Published online: 12th March, 2021

Review | Special issue | Prepress
DOI: 10.3987/REV-20-SR(K)6
■ Combined Brønsted-Base-Mediated Direct C-H Carboxylation of Heteroarenes with CO2

Masanori Shigeno,* Keita Sasaki, Kazuya Hanasaka, Itsuki Tohara, Kanako Nozawa-Kumada, and Yoshinori Kondo*

*Graduate School of Pharmaceutical Science, Tohoku University, 6-3 Aobayama, Sendai 980-8578, Japan

Abstract

This review article summarizes that the combined Brønsted-base system comprising LiO-t-Bu, CsF, and 18-crown-6 efficiently proceeds the direct carboxylation of electron-rich heteroarenes, such as benzothiophene and benzofuran, with CO2. Good functional group compatibility is displayed, allowing the use of Me, MeO, halogen, CN, ketone, and amide moieties. 3-Substituted indoles are also used for C-2 carboxylation, while double-carboxylation of 2-alkylheteroarenes is achieved by LiO-t-Bu and CsF.

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Published online: 12th March, 2021

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)71
■ Gold-Catalyzed Formal [3+2]Cycloaddition of p-Quinones and 1-Phenylpropenes in Ionic Liquid: Environmentally Friendly and Stereoselective Synthesis of 2,3-Dihydrobenzofuran Neolignans

Nobuyoshi Morita,* Kanae Ikeda, Hitomi Chiaki, Ryuto Araki, Kosaku Tanaka III, Yoshimitsu Hashimoto, and Osamu Tamura*

*Laboratory of Organic Chemistry, Pharmaceutical Sciences, Showa Pharmaceutical University, 3-3165, Higashi-tamagawagakuen, Machida, Tokyo 194-8543, Japan

Abstract

Gold(III)-catalyzed formal [3+2] cycloaddition of p-quinones with 1-phenylpropenes in an ionic liquid, [EMIM][NTf2], enabled environmentally friendly, stereoselective synthesis of 2,3-dihydrobenzofuran neolignans in good yields. Moreover, the recycle of tThe gold catalyst in /ionic liquid was achievedcould be recycled at least five times, affording 2,3-dihydrobenzofuran in good yields.

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Published online: 9th March, 2021

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)70
■ Stereoselective Synthesis of (2S,3R)- and (2S,3S)- 2-Amino-3-(3,4-dihydroxyphenyl)-3-hydroxypropanoic Acid

Yoko Yasuno, Shunsuke Yamaguchi, Yuma Karita, Kenta Sakai, Hironori Okamura, Atsushi Nakayama, and Tetsuro Shinada*

*Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan

Abstract

(2S,3R)- and (2S,3S)-2-amino-3-(3,4-dihydroxyphenyl)-3-
hydroxypropanoic acids (ADHP) are often found in an unusual amino acid component of phomopsin B, ustiloxins, RA-IV, and MPC1001B. Herein, we would like to report stereoselective synthesis of (2S,3R)- and (2S,3S)-ADHP equivalents for the synthesis of ADHP containing natural products. The synthesis is characterized by the stereocontrolled construction of the (2S,3R)- and (2S,3S)-stereocenters starting from Garner’s aldehyde as a common starting material.

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Published online: 5th March, 2021

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)59
■ On the Order of Addition of Sodium Dispersion in Reductive Diborations of Stilbene and 1,2-Diphenylcyclopropane

Shuo Wang, Atsushi Kaga, and Hideki Yorimitsu*

*Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan

Abstract

Two extreme methods to add sodium dispersion were investigated in the 1,2-diboration of stilbene and the ring-opening 1,3-diboration of 1,2-diphenylcyclopropane on a 20-mmol scale. Method 1 denotes that a substrate is added to a mixture of sodium dispersion and a boron electrophile. Method 2 denotes that sodium dispersion is slowly added to a mixture of a substrate and a boron electrophile. In these four cases, no significant differences were observed in the yields of the products and their syn/anti ratios, except for the diboration of stilbene by Method 1, wherein aggregation of sodium dispersion in the flask and 5% recovery of stilbene were observed. This information would be helpful in performing sodium-dispersion-mediated transformations on a large scale.

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Published online: 1st March, 2021

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)63
■ Design and Synthesis of Novel Orexin Antagonists via Structural Simplification of the Morphinan Skeleton

Sayaka Ohrui,* Yoko Irukayama-Tomobe, Yukiko Ishikawa, Masashi Yanagisawa, and Hiroshi Nagase

*C1232 Kanagawa Science Park R & D Building, Research Foundation ITSUU Laboratory, 3-2-1 Sakado, Takatsu-ku, 213-0012 Kawasaki, Kanagawa, Japan

Abstract

Herein, we report novel orexin antagonists with a spiro-type piperidine skeleton designed and synthesized via removal of the unnecessary sites of orexin 1 receptor (OX1R) antagonists with a morphinan skeleton for binding to OX1R. In addition, while decahydroisoquinoline compounds with an A-ring did not show antagonistic activity for OX1R, spiro-type piperidine compounds with a dihydroindene structure showed antagonistic activities. This suggests that the lipophilic site corresponding to the A-ring of the morphinan skeleton is important for determining the antagonistic activity toward OX1R.

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