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Published online: 28th May, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14264
Synthesis, Characterization and Antimicrobial Evaluation of Some Novel Chromenopyridine, Pyranochromene and 3-Hetarylcoumarin Derivatives

Khaled S. Mohamed* and Engy E. Elbialy

*Engineering Chemistry Department, Higher Institute for Engineering and Technology, New Damietta, New Damietta 34518, Egypt

Abstract

3-Acetylcoumarin was used as a precursor for the synthesis of novel fused heterocyclic compounds as chromeno[3,4-c]pyridine, chromeno[4,3-b]pyridine and pyrano[3,4-c]chromene derivatives in addition to the synthesis of 3-hetarylchromene derivatives. The chemical structures of newly synthesized compounds were avowed by means of spectral and analysis data. The novel synthesized compounds were estimated as antibacterial agents against Staphylococcus aureus and Escherichia coli bacteria.

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Published online: 25th May, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14262
Synthesis of Lesinurad via a Multicomponent Reaction with Isocyanides and Disulfides

Yaoqi Li and Zhihua Sun*

*College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Longteng Rd., Songjiang, Shanghai, 201620, China

Abstract

An efficient synthesis of Lesinurad, a selective uric acid reabsorption (URAT1) inhibitor, is described in this article. The route to synthesis of Lesinurad avoids the use of thiophosgene and the formation of thiols. The key reaction in this synthesis is construction of the 1,2,4-triazole ring in 72% yield. The title product is obtained in 45% yield over 5 steps.

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Published online: 25th May, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14255
Insertion Reaction of Chalcogens into an Al–P Bond

Tatsuya Yanagisawa, Yoshiyuki Mizuhata,* and Norihiro Tokitoh*

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

Abstract

We examined the reactions of a phosphanylalumane (>Al–P<) with chalcogen sources as a part of our investigation of the reactivity of the Al–P bonds. In the case of sulfur source, two S atoms were inserted into the Al–P bond to afford an [Al–S–P–S] heterocycle. Structural analysis and theoretical calculations revealed a charge-separated structure between the [Al]+ and [S2P] moieties of the [Al–S–P–S] 4-membered ring, which is different from the [B–S–P–S] ring having concrete B–S σ-bonds in the 4-membered ring.

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Published online: 25th May, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14260
Synthesis and Characterization of Pd(II) And Ru(II) Complexes of Tetradentate N,N,N,N-(Diphosphinomethyl)amine Ligands: Catalytic Properties in Transfer Hydrogenation and Heck Coupling Reactions

Serhan Uruş,* Mustafa Keleş, and Seda Köşker Akkaya

*Chemistry Department, Faculty of Science and Letters, Kahramanmaras¸ Sütçü İmam University, 46100, Kahramanmaraş¸ Turkey

Abstract

Tetradentate N,N,N,N-(diphosphinomethyl)amine ligands and their Pd(II) and Ru(II) complexes were synthesized under a nitrogen atmosphere using Schlenk technique. The synthesized ligands and the complexes were characterized with 1H- and 31P-NMR, FT-IR, TG/DTA, and elemental analysis techniques. Pd(II) Complexes were used as catalysts in Heck coupling reactions and Ru(II) complexes were tried in transfer hydrogenation reactions of acetophenone derivatives. According to the results, L4-Pd(II) complex showed the best catalytic activity in the Heck coupling reaction of p-methylbromobenzene with o-chlorostyrene. It was confirmed that the reduction of bromo and chloroacetophenones in all catalysts the conversions were higher. The results showed that Ru(II) complexes as efficient catalysts and up to 99% conversions was occurred with bromo and chloro acetophenones in K2CO3/isopropyl alcohol media at 80 °C.

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Published online: 22nd May, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-929
Chemical Syntheses and Biological Studies of Agelastatin A, A Bioactive Marine Heterocycle Gifted from Nature

Takehiko Yoshimitsu*

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

Abstract

Agelastatin A, an alkaloid originally isolated from the marine sponge Agelas dendromorpha, has long been an attractive target of chemical synthesis due to its significant biological activity and unique chemical structure. The synthetic approaches to the agelastatin alkaloid have demonstrated the advances of new methodologies and strategies for accessing a highly functionalized polycyclic nitrogen heterocycle. The present article reviews synthetic endeavors on agelastatin A that have been made by various synthetic chemists as well as biological studies on the natural product and its analogues aimed at the development of medicinal resources.

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Published online: 22nd May, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)13
3-Trifluoromethanesulfonyloxy-4,7-Dihydro-Pyrazolo[1,5-a]Pyridine Via Ring-Closing Metathesis: Synthesis and Transformation to Withasomnine Homologs

Yoshihide Usami,* Yuya Tatsui, Kodai Sumimoto, Ayami Miyamoto, Nanase Koito, Hiroki Yoneyama, and Shinya Harusawa

*Laboratory of Pharmaceutical Organic Chemistry, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan

Abstract

3-Trifluoromethanesulfonyloxy-4,7-dihydropyrazolo[1,5-a]pyridine (9) was successfully synthesized from the starting material, pyrazole, via a sequence of reactions containing ring-closing metathesis as a key step. Suzuki-Miyaura coupling of 9 with various arylboronic acids, followed by oxidation or hydrogenation, readily afforded pyrazolo[1,5-a]pyridines (11) or 3-aryl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridines (12), respectively. Compounds 12 were found to be withasomnine homologs

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Published online: 21st May, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)7
Synthesis of 5-H Thiazoles via Thioamide Dianions with Thioformamides: Pyridylmethyl Group on The Nitrogen Atom of Thiazole Promotes The Formation of 5-H Thiazoles

Khurnia Krisna Puji Pamungkas , Shizuka Hattori, Toshifumi Maruyama, Masahiro Ebihara, and Toshiaki Murai*

*Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University , 1-1 Yanagido, Gifu, Gifu 501-1193, Japan

Abstract

The reaction of in situ-generated thioamide dianions having a pyridylmethyl group on the nitrogen atom with thioformamides resulted in the formation of 5-H thiazoles as major products along with 5-N,N-dimethylaminothiazoles. The presence of a pyridylmethyl group plays an important role in the formation of 5-H thiazoles. A wide range of substituents at the 2-position of a thiazole ring tolerated the reaction conditions, and the intramolecular cyclization reaction proceeded smoothly. However, a phenyl substituent at the 4-position of a thiazole ring significantly reduced the yields of 5-H thiazoles.

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Published online: 19th May, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14270
Reactivity of 6-Ethyl-4,5-dioxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carboxaldehyde towards Some Nucleophilic Reagents

Magdy A. Ibrahim,* Mohamed Abass, Hany M. Hassanin, and Al-Shimaa Badran

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

Abstract

6-Ethyl-4,5-dioxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbox-aldehyde (1) was prepared and utilized as a starting material. Carboxaldehyde 1 was subjected to react with a diversity of carbon nucleophiles producing a variety of condensation products as well as heterocyclic rings linked pyrano[3,2-c]quinolines. Also, reaction of carboxaldehyde 1 with p-toluidine, heterocyclic amines and some hydrazine derivatives produced a variety of products. The structures of the new synthesized products were deduced on the basis of their analytical and spectral data.

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Published online: 18th May, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14196
Recyclable Triphenylbismuth (V) Bisperfluorooctanesulfonate Catalyzed Synthesis of Dihydropyrimidinones

Ablimit Abdukader,* Rong Wang,* and Marhaba Mamat

*School of Chemistry and Chemical Engineering, Xinjiang University, Shengli Road 666,Urumqi,China, 8300046, China

Abstract

Triphenylbismuth(V) bisperfluorooctanesulfonate Ph3Bi(OSO2C8F17)2 was successfully synthesized by treatment of Ph3BiCl2 with C8Fl7SO2OAg, and was found to have the nature of air-stability, water tolerance, high thermal stability and strong Lewis acidity. This complex showed high catalytic efficiency for the synthesis of dihydropyrimidinones (DHPMs) via three-component reaction of aromatic aldehydes, 1,3-dicarbonyl compound and urea under mild conditions. Furthermore, it can be reused without loss of activity in a test of five cycles. Hence, here we provide a convenient and efficient method for preparation of dihydropyrimidinones.

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Published online: 14th May, 2020

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)9
Synthesis of A Pentacoordinate Germanium Compound Possessing A γ-Lactone And A Dative-Bonding Carboxylic Acid

Hiroki Tanimoto,* Daiki Toumori, Tsumoru Morimoto, and Kiyomi Kakiuchi*

*Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan

Abstract

A pentacoordinate germanium compound consisting of a spirocyclic dilactone-like structure was synthesized. Both radical and oxidation synthetic routes afforded the diphenylgermanium dicarboxylic acid compound. Then, mono-dearylation by acid treatment successfully delivered a hypercoordinate germane product. X-Ray crystallographic analysis revealed that the product adopted trigonal bipyramidal geometry in which a γ-lactone ring and a dative-bonding carboxylic acid moiety were incorporated.

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Published online: 13th May, 2020

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)11
Synthesis of Pyrrolo[1,2-c]Pyrimidines

Easha Narayan, Liangfeng Fu, and Gordon W. Gribble*

*6128 Burke Laboratory, Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, U.S.A.

Abstract

The synthesis of several new pyrrolo[1,2-c]pyrimidines from the base-induced condensation of pyrrolo-2-carbaldehydes with either TosMIC (toluenesulfonylmethyl isocyanide) or ethyl isocyanoacetate is described, along with the preparation of novel bis(pyrrolo[1,2-c]pyrimidines).

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Published online: 13th May, 2020

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)5
Conjugate Addition Reaction of Indole to Protected 2-Amino-1-Nitroethenes Mediated by Silica Gel

Kenichi Murai,* Shuji Miyazaki, and Hiromichi Fujioka*

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

Abstract

We have developed a silica-gel-mediated route for the conjugate addition of indole to protected 2-amino-1-nitroethenes for the synthesis of 1-indolyl-1,2-ethanediamines. This is the first demonstration of indole as the nucleophile for addition to protected 2-amino-1-nitroethenes.

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Published online: 13th May, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14258
Ruthenium(II)-Catalyzed Regioselective C-H Hydroxymethylation of N-Aryl-azaindoles with Paraformaldehyde

Siqi Li, Yang Yu,* Yaxi Yang, and Bing Zhou*

*Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR, China

Abstract

A facile synthesis of hydroxymethylated N-aryl-azaindoles was developed via a Ru(II)-catalyzed regioselective C-H addition to paraformaldehyde. The reaction is compatible with air, shows high functional group tolerance and regioselectivity, and is an environmentally benign method without any undesired byproduct.

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Published online: 12th May, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)8
Concise Preparation and Biological Evaluations of 9-cis-Retinoic Acid Analogues Having an Aromatic Ring

Takashi Okitsu,* Kinya Iwatsuka, Kimie Nakagawa, Toshio Okano, and Akimori Wada*

*Faculty of Pharmaceutical Science, Kobe Pharmaceutical University, 4-19-1, Motoyamakita, Higashinada, Kobe 658-8558, Japan

Abstract

A series of 9-cis-retinoic acid analogues having an aromatic ring were prepared in only two steps, and were evaluated for transcriptional activities with retinoic acid response element (RARE) and retinoid X response element (RXRE). Among them, compound 6c, bearing a 2-naphthyl substituent, exhibited the highest transcriptional activity with RXR selectivity.

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Published online: 12th May, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14257
HBTU-Catalyzed Simple and Mild Protocol for the Synthesis of Quinoxaline Derivatives

Bhushan B. Popatkar* and Gangadhar A. Meshram

*Department of Chemistry, University of Mumbai, Vidyanagari, Kalina, Santacruz (E), Mumbai, India

Abstract

HBTU-catalyzed, simple, mild, and effective protocol for the synthesis of quinoxalines has been established. The reaction between 1,2-diamines, benzil, and catalytic amount of HBTU in ethanol resulted into quinoxalines. Various aliphatic, aromatic and heterocyclic 1,2-diamines reacted smoothly with benzil to obtained the title compounds in moderate to high overall yield. Use of environmentally benign solvent, high yield of the product, comparably less reaction time and mild reaction condition are advantages of this method.

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Published online: 8th May, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-19-924
New and Practical Applications of Functionalized Cyclotriphosphazene Core-Based Materials

Manabu Kuroboshi* and Hideo Tanaka

*Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 3-1-1, Kita-ku, Okayama, 700-7530, Japan.

Abstract

Hexachlorocyclotriphosphazene (HCCP) is a very old compound, and used as a starring material of a variety of cyclotriphosphazene derivatives. Some of them have unique properties, and have been used in not only frame retardants but also functional materials and biomaterials. To develop cyclotriphosphazene derivatives having a desired function, numbers of substituents, regio-, and stereochemistry should be controlled in the reaction between HCCP and nucleophiles. In this review, selectivity in the reaction between HCCP and nucleophiles as well as application of the cyclotriphosphazene derivatives are summarized.

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Published online: 8th May, 2020

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)6
Synthesis of Lactone-Fused Cyclopropanes by Ring Contractive α-Ketol Rearrangement of Ketal-Fused Cyclobutanones

Kiyosei Takasu,* Koichi Shigenaga, Kazuma Shimoda, Hiroshi Takikawa, and Yousuke Yamaoka

*Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-shimoadachi-machi, Sakyo-ku, Kyoto 606-8501, Japan

Abstract

Ring contraction of cyclic silyl ketal-fused cyclobutanones into lactone-fused cyclopropanes under desilylative conditions is described. The reaction affords 1-hydroxy- and 1-amino-1-cyclopropanecarboxylic acid derivatives from cyclobutanone substrates and their imine congeners, respectively.

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Published online: 7th May, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14254
Convenient Methods for the Synthesis of Novel Thiadiazoles and Polythiadiazoles

Abedlwahed R. Sayed* and Yasair S. Al-Faiyz

*Department of Chemistry, Faculty of Science, King Faisal University, Hofuf 31982, Saudi Arabia

Abstract

In this study, the novel thiadiazoles were formed via the reaction of hydrazonoyl halides with methyl 2-(adamantan-2-ylidene)hydrazinecarbodithioate. Also, the reaction of 2,5-dihydrazinyl-1,3,4-thiadiazoles with 2-adamantanone or acetylferrocene produced the 2,5-bis(2-(adamantan-2-ylidene)hydrazinyl)-1,3,4-thiadiazole or 2,5-bis(2-(1-(ferrocenylidene)hydrazinyl)-1,3,4-thiadiazole, respectively. Analogously, treatment of terephthalaldehyde with 2,5-dihydrazinyl-1,3,4-thiadiazole afforded new poly(benzylidenehydrazinyl-1,3,4-thiadiazole). Finally, the reaction of bishydrazonoyl halides with 2,5-dihydrazinyl-1,3,4-thiadiazole afforded new poly(1,3,4-thiadiazolo[2,3-c][1,2,4]triazine). The synthetic structures for the final products are suggested and discussed. The compound structures of the products were recognized by different spectroscopic analyses.

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Published online: 30th April, 2020

Communication | Regular issue | Prepress
DOI: 10.3987/COM-20-14253
Sulfamic Acid-Catalyzed Conversion of o-Aminothiophenol and Aromatic Aldehydes to 2-Arylbenzothiazoles

Xiaofeng Yu,* Renyuan Song, Chunjie Shi, and Guangrong Wang

*School of Materials and Chemical Engineering, Bengbu University, Bengbu, Anhui 233030, P. R. China

Abstract

Non-metallic, non-toxic, and cheap sulfamic acid was used as a catalyst for the synthesis of 2-arylbenzothiazole from o-aminothiophenol and aromatic aldehydes bearing electron-donating or electron-withdrawing groups. The sulfamic acid catalyst can be reused without any change in catalytic effect. The drug GW610 was successfully synthesized on a hundred-gram scale using this synthetic route.

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Published online: 28th April, 2020

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14210
Facile Synthesis of 2-Aryl(guaiazulen-1-yl)methylkojic Acid Derivatives via Benzylation

Xin-Shuang Xiong, Dao-Lin Wang,* Si-Tong Guo, and Xiao-Liang Zhang

*College of Chemistry and Chemical Engineering, Bohai University, 19, Keji Rd., New Songshan District, Jinzhou City, Liaoning Province 121001, China

Abstract

A facile and efficient one-pot procedure for the preparation of 2-aryl(guaiazulen-1-yl)methylkojic acid derivatives by a catalyst-free, benzylation of guaiazulene with kojic acid-substituted benzylic alcohols under mild conditions in good yield is reported.

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Published online: 28th April, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)3
Thermally-Induced Doping of The Regioregular Polythiophene Bearing Alkylene Spacered Benzene Sulfonate Group at The Side Chain

Chihiro Kubota, Daisuke Morita, Keisuke Fujita, Sonoka Yamamoto, Toyoko Suzuki, Kentaro Okano, Masahiro Funahashi, Masaki Horie, and Atsunori Mori*

*Department of Chemical Science and Engineering, Kobe University, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan

Abstract

Regioregular polythiophene bearing a benzenesulfonate group, which involved an alkylene spacer between thiophene and benzene ring, was synthesized. The obtained polythiophene was shown to improve its conductivity by heating the polymer thin film through the transformation of the ester group into the corresponding sulfonic acid.

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Published online: 28th April, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14244
Convenient Synthesis of 2,3-Dihydro-1,2,4-thiadiazoles, 4,5-Dihydro-1,3-thiazoles, and 1,3-Thiazoles through a [4+1]-Type Oxidative Ring Closure of 1,3-Thiaza-1,3-butadienes

Kazuaki Shimada,* Megumi Isogami, Kitami Maeda, Rei Nishinomiya, and Toshinobu Korenaga

*Department of Chemistry and Biosciences, Faculty of Science and Engineering, Iwate University, Morioka, Iwate 020-8551, Japan

Abstract

1,3-Thiaza-1,3-butadienes bearing an N,N-dimethylamino group at the C-2 position were efficiently converted into 5H-1,2,4-oxathiazoles, 2,3-dihydro-1,2,4-thiadiazoles, 4,5-dihydro-1,3-thiazoles, and 1,3-thiazoles through an oxidative ring closure by treating with mCPBA, chloramine-T, metal carbenoids, or dichlorocarbene, respectively, via the ring closure of in situ generated heterocumulene-type reactive species involving thione S-oxides, thione S-imides, and thiocarbonyl ylides.

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Published online: 28th April, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14251
Highly Regioselective Synthesis of 1-Acyl-5-hydroxypyrazolines or Synthesis of 3,5-Disubstituted Pyrazoles from (E)-β-Chlorovinyl Ketones and Benzohydrazides or Hydrazine Hydrate

Haotian Wu, Rongrong Hou, Ye Yuan, Jingli Zhang,* Bifeng Chen, and Taolei Sun*

*School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, 122 Luoshi Road,Wuhan,Hubei 430070, China

Abstract

Highly regioselective synthesis of 1-acyl-5-hydroxypyrazolines or synthesis of 3,5-disubstituted pyrazoles have been achieved through the cyclocondensation of (E)-β-chlorovinyl ketones with benzohydrazides/hydrazine hydrate under extremely mild reaction conditions. The mechanistic studies showed that diverse electrophilic pathways of (E)-β-chlorovinyl ketones could be observed by using different nucelophilic species. Moreover, the utility of the tandem reaction is further illustrated by the concise synthesis of 1-acyl-pyrazole and 3-pentyl-5-phenyl-1H-pyrazole.

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Published online: 27th April, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-928
Recent Advances in the Total Synthesis of Clavilactones

Akihiro Ogura and Ken-ichi Takao*

*Department of Applied Chemistry, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, Japan

Abstract

Clavilactones are meroterpenoids containing a 10-membered carbocycle fused to an α,β-epoxy-γ-lactone and a hydroquinone or benzoquinone. This review describes the total synthesis of clavilactones achieved by four research groups, focusing on their innovative synthetic strategies.

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Published online: 17th April, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)1
Synthesis of Probe Molecules, 6-(Dimethylamino)-2-Phenylisoindolin-1-Ones, for Mechanistic Studies of Firefly Luciferase Inhibition

Medha J. Gunaratna, Bo Hao, Man Zhang, Madoka Nakagomi, Ai Ito, Takeo Iwamoto, and Duy H. Hua*

*Department of Chemistry, Kansas State University, Manhattan, KS 66506, U.S.A.

Abstract

Firefly luciferase is used in high-throughput screening based on the detection of chemiluminescence. It catalyzes an esterification reaction of luciferin with adenosine 5’-triphosphate (ATP) followed by decarbonylation with oxygen and concomitance of light. Previously, we reported that firefly luciferase also possesses acyl-CoA synthetase activity and catalyzes an aromatic carboxylic acid group of F-53, using ATP, Mg2+ and coenzyme A (CoA), to produce F-53 covalently attached to active-site lysine-529 residue of firefly luciferase through the formation of an amide group. The amidation of lysine-529 resulted in a deactivation of luciferase. In order to probe firefly luciferase inhibition’s mechanism, we synthesized two probe molecules 1 and 2, mimicking F-53. Molecule 1 contains an azido-appended side chain in the aromatic ring of F-53, while 2 possesses an azido and a carboxylic acid group appended side chains. Both synthetic schemes are readily amenable to large-scale syntheses. Molecule 1 was made from 2-allylaniline, which was derived from a thermal-induced aromatic-Claisen rearrangement of N-allylaniline. The azido-appended side chain of 2 was installed from a Horner-Wadsworth-Emmons reaction and the carboxylic acid side chain from a Sonogashira reaction.

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Published online: 16th April, 2020

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)4
Synthetic Studies on Densanins: Stereoselective Construction of A Pyrrolidine Ring Containing a Quaternary Carbon

Kyosuke Ueda and Satoshi Yokoshima*

*Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan

Abstract

We disclose our synthetic studies on densanins, which feature the stereoselective cycloaddition of a cycloheptenone and an azomethine ylide to construct a pyrrolidine ring containing a quaternary carbon

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Published online: 10th April, 2020

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14245
Facile and Convenient Synthesis of New Isoxazolo[5,4-b]pyridine, Pyrrolo[3,2-d]isoxazole, Isoxazolo[5,4-b]azepine-4,7-dione and Isoxazole Derivatives with Potential Anticancer Activity

Ahmed El-Mekabaty* and Mona E. Ibrahim

*Chemistry Department, Faculty of Science, Mansoura University, El-Gomhoria Street, ET-35516 Mansoura, Egypt

Abstract

The readily available 3-methylisoxazol-5-amine (1) has been used as a key intermediate for the synthesis of isoxazolo[5,4-b]pyridine, pyrrolo[3,2-d]isoxazole, isoxazolo[5,4-b]azepine-4,7-dione and isoxazole derivatives via its reactions with some chemical reagents. Sixteen compounds were designed to study their cytotoxic properties against three human cell lines: colorectal carcinoma (HCT-116), prostate cancer (PC3) and normal lung fibroblast (WI-38), using the MTT colorimetric assay. 5-Fluorouracil, a well-known anticancer drug, was used for comparison. Among the tested candidates, pyrrolo[3,2-d]isoxazole 5 and isoxazole derivatives 11-14 showed the highest activity against the tested cancer cell lines with good selectivity by their lower toxicity against normal cells.

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Published online: 9th April, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-927
5,15-Diheteroporphyrins Synthesized from α,α'-Dihalodipyrrin as a Key Building Block

Soji Shimizu*

*Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan

Abstract

A facile synthesis of meso-aryl-substituted α,α'-dihalodipyrrins and their use as starting materials in the porphyrin synthesis have enabled creation of various porphyrin analogues containing heteroatoms at two opposite meso-positions, namely 5,15-positions. Incorporation of lone pair electrons into the 18π-electron aromatic conjugated system of porphyrin allows the system to attain antiaromaticity with unique optical and electrochemical properties. This review summarizes the recent development in the chemistry of 5,15-diheteroporphyrins synthesized from meso-aryl-substituted α,α'-dihalodipyrrins.

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Published online: 27th March, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-926
The Synthesis of Heterocyclic Compounds Based on 3-Formylchromone via Organic Reactions

Ghodsi Mohammadi Ziarani,* Parisa Mofatehnia, Fatemeh Mohajer, and Razieh Moradi

*Department of Chemistry, Alzahra University, Vanak Square, Tehran, P.O. Box 1993891176, Iran

Abstract

3-Formylchromones are known as key heterocyclic scaffolds for the synthesis of various important organic compounds. The compounds with 3-formylchromone have attracted much attention among heterocyclic structures. This review article aims to provide an overview of multi-component reactions related to 3-formylchromone derivatives in the synthesis of various heterocyclic compounds covering the literature going back to 2015 until 2019.

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Published online: 16th March, 2020

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)2
5-Arylidenetetronate as A Versatile Electrophore for Pi-Extended Electron Acceptors

Yuki Hayashi, Yusuke Ishigaki, Jérémy Merad, Takanori Suzuki,* and Maurice Médebielle*

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

Abstract

Bis[4-methoxy-5-methylenefuran-2(5H)-one]-type electron acceptors with anthracene-9,10-diyl and thiophene-2,5-diyl spacer were prepared by one-pot condensation of methyl tetronate with the corresponding dialdehydes. They undergo reversible electrochemical reduction, thus showing the potential utility of 5-arylidenetetronate as an electrophore for developing novel electron acceptors.

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