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28 data found. 1 - 28 listed

Published online: 3rd March, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14426
One-Pot and Three-Component Synthesis of Some Novel Functionalized Chromonyl Pyrido[2,3-d]pyrimidines as Anticancer Agents

Tarik E. Ali,* Mohammed A. Assiri, Ali A. Shati, Mohammad Y. Alfaifi, Serag Eldin I. Elbehairi, and Attalla F. El-Kott

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

Abstract

A facile and efficient method for the construction of functionalized chromonyl pyrido[2,3-d]pyrimidines via a one-pot, three-component reaction of 6-aminothiouracil and 4,6-diaminopyrimidine-2(1H)-thione with 4-oxo-4H-chromene-3-carboxaldehyde in the presence of different nitrile active methylene compounds in distillated water at 70 oC without using a catalyst was achieved. The methodology displayed excellent yields and simple workup procedure. The targeted compounds were assessed for their in vitro anticancer activity against mammary gland breast cancer cell line (MCF-7), liver cancer (HepG-2), and human colon cancer (HCT-116) by using sulphorhodamine B assay (SRB) method, while doxorubicin, was utilized as standard reference drug. Compounds 4b and 6a were the best potent cytotoxic agents towards liver (HepG-2) and colon (HCT-116) compared with doxorubicin as a reference drug with IC50 values ranging from 1.1 to 1.8 μg/mL.

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Published online: 26th February, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14414
Synthesis of Anti-Insomnia Drug Suvorexant

Hongshun Yuan, Lei Guo,* and Xianhua Pan*

*School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, China.

Abstract

Suvorexant is the first dual orexin receptor antagonist for treating insomnia. Although numerous methods have been developed to construct suvorexant, a generally efficient, mild, facile synthesis platform for the conversion of simple starting material to this highly enantioselective scaffold via successive C–N bond forming steps remains in high demand. Here we report an efficient synthetic route without using chiral HPLC separation, resolution, enzyme catalysis or transition metal catalysis, and the total yield is up to 37%.

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Published online: 24th February, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14402
3,5-Disubstituted Tetrahydro-2H-1,3,5-thiadiazine-thiones Ester Derivatives and Their Antimicrobial Evaluation

Irfan Ullah, Jamshed Hashim,* Nuzhat Arshad,* Muhammad Yaseen, Rasool Khan, Tahseen Iqbal, Syeda Zehra Hamid, Afshan Kanwal, and Iqbal Safi

*H.E.J. Research Institute of Chemistry, ICCBS, University of Karachi, Karachi-75270, Pakistan

Abstract

A diverse set of 3,5-disubstitited tetrahydro-2H-1,3,5-thiadiazine-thiones (THTT) and their ester derivatives were synthesized in good to excellent yields. The ester derivatives were screened for their antibacterial and antifungal potential and compared with their acidic counterparts. Structure-activity relationship revealed that the THTTs with N-3 carboxylic functionality have very promising potential against all tested pathogens in general. However, ester analogues showed suppressed or no activities against the same pathogens thus indicate that these compounds can be used as a template study for the development of improved antimicrobial agents/prodrugs.

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Published online: 18th February, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14398
Synthesis of 4-Hydroxyaurones and Their Herbicidal Activities

Mei Xia, Min Zhang,* Jianfen Ding, Jiankai Hong, Yuting Shen, and Liuqing Yang*

*School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China

Abstract

A series of 4-hydroxyaurone derivatives 4a-4v were synthesized and characterized by 1H NMR, 13C NMR, and elemental analysis. Their herbicidal activities against four species of plants were evaluated in a greenhouse by both pre- and post-emergence treatments at a dosage of 750 g a.i. ha-1. The bioassay revealed that 4-hydroxyaurones exhibited moderate to good herbicidal activities against dicotyledons plants for post-emergence treatment. For instance, (Z)-4-hydroxy-2-(4-nitrobenzylidene)benzofuran-3(2H)-one (4m), demonstrated 74.5% inhibitory activity against Amaranthus retroflexus L., higher than that of the positive control herbicide acetochlor. Thus, compound 4m may serve as a new possible leading compound for the discovery of post-emergence herbicide.

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Published online: 18th February, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14409
A Simple Synthesis and Antimicrobial Activity of Some New 1,2,4-Triazolopyrimidine Derivatives

Kamelia M. El-mahdy* and Azza M. El-kazak

*Department of Chemistry, Faculty of Education, Ain Shams University, Roxy 11757, Cairo, Egypt

Abstract

The synthesis of new 1-(7-oxo-5-phenyl-1,7-dihydro[1,2,4]triazolo-[1,5-a]pyrimidin-2-yl)guanidine (2) by reaction 2,3-diamino-6-phenylpyrimidin-4(3H)-one (1) with cyanoguanidine was achieved. Compound 2 reacted with malononitrile to produce diaminopyrimidine derivative 3 which upon treatment with CS2 resulted in the formation of 1,3,5-triazine 4. Cyclization of compound 1 with either benz[c]acridine-7-carboxylic acid or mandelic acid in presence of phosphoryl chloride was investigated. Moreover, 2-[chloro(phenyl)methyl]-5-phenyl[1,2,4]triazolo[1,5-a]pyrimidin-7(1H)-one (6) was used as a valuable scaffold to construct various fused and attached heterocyclic rings via simple reactions. The antimicrobial activity of the synthesized compounds were tested. Spectral and analytical data of the newly synthesized compounds were all in good agreement with the proposed chemical structures.

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Published online: 9th February, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14411
Synthesis of Some Macrocyclic Diimines from Mono-, Di-, Tri-, and Tetra-Indolyl Dialdehydes

Kittya Somphol, Naresh Kumar, and David StC. Black*

*School of Chemistry, The University of New South Wales, Sydney 2052, Australia

Abstract

Reactions of a range of diamines with a variety of dialdehydes containing one, two, three, or four indole rings are described. In certain cases, high yields can be obtained to deliver macrocyclic diimines containing one, two, three, or four indole rings. The range of macrocyclic diimines incorporates compounds with 15-, 17-, 18-, 19-, 20-, 21-, 22-, 23-, 24-, 25-, 28-, 30-, 31-, and 32-membered rings. A feature of most of these successful reactions is the use of isopropanol as the solvent.

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Published online: 8th February, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-21-14404
Catalytic and Diastereoselective Cascade Reaction for the Preparation of cis-1,3-Disubstituted Isoindoline-Aminal Hybrid Compounds

Tetsuya Tsujihara,* Takeyuki Suzuki, and Tomikazu Kawano*

*School of Pharmacy, Iwate Medical University, 1-1-1 Idaidori, Yahaba, Iwate 028-3694, Japan

Abstract

A convenient and catalytic method for the diastereoselective construction of cis-1,3-disubstituted isoindoline skeletons is described. In the presence of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene as a base catalyst and under mild conditions, the direct aminalization of N-protected imines bearing a Michael acceptor using the aniline derivatives and the subsequent intramolecular aza-Michael reaction proceeded successfully in a short reaction time. A series of cis-1,3-disubstituted isoindoline-aminal hybrid compounds are obtained in moderate to good yield (44%–93%) with complete diastereocontrol.

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Published online: 4th February, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14384
Microwave-Assisted and Solvent-Free Synthesis of Quinoline Derivatives and Their Fluorescence Properties

Xiaobin Zhang, Xiumei Ma, Yun Ai, Yuanyuan Ren, Xiao Bai, Huan Chen, Ying Zhou, Wenyu Li, Cuiling Wang,* and Yifeng Liu

*College of Life Sciences, Northwest University, No. 229, Taibai North Road, Xi'an, Shaanxi 710069, China

Abstract

A protocol for the microwave-assisted Friedländer synthesis of quinoline derivatives under solvent-free conditions has been developed. According to this modified method, quinoline derivatives were synthesized by condensation of 2-aminobenzophenone with the corresponding carbonyl compounds in the presence of phosphomolybdic acid for 8 min in a 320 W microwave with yields ranging from 61% to 90%. The fluorescence properties of the synthesized compounds were studied, and all compounds showed good fluorescence properties. The substituted groups and the concentrations of quinolines and solvents had significant effects on the compounds’ fluorescence properties. This method provides a convenient way to obtain quinolines, and is beneficial to the application of these compounds.

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Published online: 3rd February, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14400
Efficient Synthesis of Acrylates Bearing an Aryl or Heteroaryl Moiety: One-Pot Method from Aromatics and Heteroaromatics Using Formylation and the Horner-Wadsworth-Emmons Reaction

Tatsuro Yasukata* and Takaharu Matsuura

*API R&D Laboratory, CMC R&D Division, Shionogi & Co., Ltd., 1-3 Kuise Terajima 2-chome, Amagasaki, Hyogo 660-0813, Japan

Abstract

Acrylates bearing an aryl or heteroaryl moiety were efficiently prepared by a one-pot process employing a sequence of lithiation, formylation and the Horner-Wadsworth-Emmons reaction starting from aromatic and heteroaromatic compounds. This method can efficiently introduce an acrylate moiety into aromatic and heteroaromatic compounds.

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Published online: 1st February, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14396
Acetate/Acetic Acid-Assisted One-Pot Synthesis of (Diarylmethylene)imidazolone from Amide or Thioamide

Masahiro Ikejiri,* Atsufumi Watanabe, Mari Katsuda, Mayu Funakoshi, Aki Fujisaka, and Kazuyuki Miyashita*

*Faculty of Pharmacy, Osaka Ohtani University, Nishikiori-Kita 3-11-1, Tondabayashi, Osaka 584-8540, Japan

Abstract

With the aim of extending the library of green fluorescent protein chromophore analogs, a facile one-pot synthesis of 5-(diarylmethylene)imidazolones from the corresponding amide or thioamide is described. Isolation of unstable imidate intermediates is not required, thereby circumventing the drawback of previous approaches. A reaction mechanism in which both acetate and acetic acid promote the imidazolone formation is proposed.

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Published online: 29th January, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14388
Construction and Biological Evaluations of Some Novel Chromeno[2,3-b]pyridines and Chromeno[2,3-b]quinolines Using 6-Methylchromone-3-carbonitrile

Magdy A. Ibrahim* and Nasser M. El-Gohary

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

Abstract

Reaction of 6-methylchromone-3-carbonitrile (1) with acetylacetone under basic conditions afforded 3-acetyl-2,7-dimethyl-5H-chromeno[2,3-b]pyridin-5-one (2) which utilized as a starting substrate. Condensation of compound 2 with a variety of amines and hydrazines produced chromeno[2,3-b]pyridines linked variable compounds in the same molecular frame. Condensation reaction of compound 2 with variable carbon nucleophilic reagents namely; malononitrile, ethyl cyanoacetate, malononitrile dimer, 1H-benzimidazol-2-ylacetonitrile and dimedone produced heteroannulated chromeno[2,3-b]quinolines 18-22. The synthesized compounds were screened in vitro for their antimicrobial activity and revealed remarkable inhibitory effects against the selected microorganisms. Structures of the newly synthesized products have been deduced upon the help of elemental analysis and spectral data (IR, 1H NMR, 13C NMR and mass spectra).

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Published online: 29th January, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14401
Stepwise Reactions between Cyclic 1,4-Diazadienes and Ketenes: Characteristics and Mechanism

Kazuhide Nakahara,* Koki Yamaguchi, and Hisao Kansui

*Department of Integrative Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan

Abstract

The reaction of unsymmetrical monophenyl cyclic 1,4-diazadienes with ketene derivatives yields new structures via 1,5-sigmatropic reactions. These structures were determined and confirmed by single-crystal X-ray analysis. The reaction mechanism was investigated by density functional theory calculations. The result of the calculation indicated whether the reaction was a cyclization reaction or a 1,5-shift rearrangement based on the stability of the intermediate conformation.

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Published online: 29th January, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14403
Synthesis of Pyrazolo[4,3-c]quinolines and the C-C Bond Cleavage during Reductive Cyclization

Nisha Devi, Antriksh Gupta, Raghuram Gujjarappa, Chandi C. Malakar,* and Virender Singh*

*Department of Chemistry, National Institute of Technology Manipur, Langol, Imphal-795004, Manipur, India

Abstract

An efficient synthesis of o-nitrophenyl tethered pyrazole-4-carbaldehydes was achieved via Vilsmeier-Haack formylation of hydrazone derivatives which were subjected to Claisen-Schmidt condensation and Morita-Baylis-Hillman (MBH) reaction with various methyl ketones and activated alkenes respectively to generate the corresponding chalcones and MBH adducts. However, successive Fe-mediated reductive cyclization was followed by an unusual C-C bond cleavage which afforded the pyrazolo[4,3-c]quinolines devoid of diverse substituents at C-4 position.

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Published online: 28th January, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14382
DBU-Catalyzed Highly Efficient Synthesis of 1,4-Dihydropyridine Derivatives from Arylidenemalononitriles and β-Enamino Imides

Wei Han, Kazuya Nakajima, Masashi Kajitani, and Takeshi Oriyama*

*Department of Chemistry, Faculty of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan

Abstract

Various 1,4-dihydropyridine derivatives were efficiently synthesized from arylidenemalononitriles and β-enamino imides using DBU (3 mol%) as the catalyst at room temperature. This mild, straightforward high-yielding protocol was atom-economy, time-economy, with a low catalyst load, and without the need for reflux.

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Published online: 28th January, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14383
Efficient Approach towards the Polysubstituted 4H-Pyran Hybrid Quinolone Derivatives and Subsequent Copper-Catalyzed Hydroxylation of Haloarenes

Vipin Kumar, Dharmender Singh, Raghuram Gujjarappa, Chandi C. Malakar,* and Virender Singh*

*Department of Chemistry, National Institute of Technology Manipur, Langol, Imphal-795004, Manipur, India

Abstract

A proficient and feasible approach towards polysubstituted quinolone conjugated 4H-pyrans has been elucidated. The illustrated phenomenon concern with the base-mediated multicomponent reaction and subsequent copper-catalyzed hydroxylation of C-X bond emerging in an amide functionality. The developed reaction conditions showcased considerable substrate scope and functional group tolerance by giving the desired products in good yields.

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Published online: 27th January, 2021

Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14372
The Electronic Structure of Thioxanthylium Scaffolds

Koki Hirano, Akira Yasuda, Takahiro Sasamori, Kosei Shioji, Kentaro Okuma, and Noriyoshi Nagahora*

*Department of Chemistry, Faculty of Science, Fukuoka University, Nanakuma 8-19-1, Jonan-ku, Fukuoka, Fukuoka 814-0180, Japan

Abstract

A new series of thioxanthylium trifluoromethanesulfonates has been synthesized via a trifluoromethanesulfonic-acid-induced cyclization of thioether precursors. The electronic structure of these thioxanthylium salts were determined by UV−vis absorption spectroscopy, and theoretically investigated by density functional theory calculations.

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Published online: 27th January, 2021

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-20-14394
Synthesis and in vitro Biological Evaluation of Cananodine

Abdullah Yusuf,* Paruke Aibibula, Ju-Bao Zhang, Guo-Zheng Huang, Haji Akber Aisa, and Jiang-Yu Zhao*

*College of Chemistry and Environmental Science, Laboratory of Xinjiang Native Medicinal and Edible Plant Resources Chemistry, Kashgar University, Xueyuan Road 29, Kashgar 844000, P. R. China

Abstract

(±)-Cananodine was obtained by common reactions from (±)-rupestine G and was isolated and synthesized by our group. (+)-Cananodine and its enantiomer were obtained by chiral separation and their absolute configurations were determined by high-resolution mass spectrometry, nuclear magnetic resonance, and electronic circular dichroism spectroscopy. The optical rotation of both cananodine and its enantiomer were re-treated. Biological activity against Hep G2, Hela, and MDA-MB-231 were also investigated.

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Published online: 23rd December, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-948
Imidazole Chemistry in Crop Protection

Clemens Lamberth*

*Syngenta Crop Protection AG, Research Chemistry, Schaffhauserstrasse 101, CH-4332 Stein, Switzerland

Abstract

An overview is given of the significance of the imidazole scaffold in crop protection chemistry. The main herbicidally, fungicidally and insecticidally active imidazole classes are presented, together with their synthesis routes, modes of action and biological efficacies. Also, partially and fully saturated imidazole derivatives, such as imidazolines and imidazolidines, oxygenated derivatives, such as imidazolinones and hydantoins as well as annulated derivatives, such as benzimidazoles, are covered. In addition, also the role of imidazoles as intermediates or reagents in the synthesis of other agrochemicals is reported.

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Published online: 21st December, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-949
Recent Advances in Synthetic Transformations with Robust Yet Reactive B(Dan) Moiety

Jialun Li and Hiroto Yoshida*

*Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.

Abstract

Recent advances in the direct B(dan)-installing reactions (dan = naphthalene-1,8-diaminato) into organic frameworks by utilizing (pin)B–B(dan) or H–B(dan) as a B(dan) source, and the direct cross-coupling of dan-substituted organoboron compounds therefrom are described.

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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: 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: 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: 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

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: 6th October, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-941
Synthetic Methods for Phosphorus Compounds Containing Chromone and Thiochromone Rings

Tarik E. Ali,* Mohammed A. Assiri, Somaia M. Abdel-Kariem, and Ibrahim S. Yahia

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

Abstract

The chromone and thiochromone rings are prominent heterocyclic substructures present in numerous natural and pharmacologically active compounds. To date, many chromone analogues containing phosphorus compounds are interest in several laboratories due to their potent pharmacological activities. This review compiles all the available literature data on the synthesis of phosphorus compounds containing chromone and thiochromone rings as well as their available biological properties starting from their appearance up to the end of 2019.

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Published online: 8th September, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-938
9,9'-Bi(xanthene)-Type Hexaphenylethane Derivatives as Advanced Organic Electrochromic Systems

Takanori Suzuki,* Yusuke Ishigaki, Masaki Takata, Jun-ichi Nishida, and Takanori Fukushima

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

Abstract

9-Phenylxanthenyl radical can undergo facile C-C bond formation at C9-position when the two units of the radical are connected at C2'-positions to give stable intramolecular dimer (1), which is a clamped hexaphenylethane derivative with an elongated C-C bond. The newly formed bond in 1 can be cleaved easily upon two-electron oxidation to give bis(9-xanthenylium)-type dication (22+), from which the diradical is generated upon two-electron reduction. This review account describes the dynamic redox ("dyrex") pair of colorless 1 and yellow-orange 22+, which provides a versatile scaffold to develop multi-functional electrochromic systems. Both of 1 and 22+ are sterically challenged molecules and thus adopt characteristic skewed geometries. Electrochiroptical response was realized by suppressing the chiral inversion of helicity in 1 and axial chirality in 22+ whereas redox-induced fluorescence switching was attained by attaching the fluorophore whose emission is quenched by xanthenylium in 22+ but not by spiro(xanthene) unit in 1. By the molecular design that allows intramolecular chiral transmission, the spectral changes were also induced by the external stimuli (e.g. heat, pH) other than redox input, which made it possible to construct less well-explored multi-input-multi-output response systems. More advanced functions could be endowed, such as chiral redox memory or reversible O2-storage, by further modification of the prototype.

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Published online: 20th August, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-937
Pyrrolotetrazoles and Ring-Fused Derivatives

Dietrich Moderhack*

*Institute of Medicinal and Pharmaceutical Chemistry, Technical University, Braunschweig, Beethovenstrasse 55, D-38106, Germany

Abstract

The preparative chemistry of seven types of pyrrolotetrazoles (formally: pyrrolo[1,2-d]tetrazoles) AG including five ring-fused derivatives such as B', B'', C', C'', and E' is surveyed in this article. Theoretical work on annular tautomerism and pyrrolotetrazole–azidopyrrole isomerism is dealt with complementarily.

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28 data found. 1 - 28 listed