One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol

• Aleksandar Pashev,
• Nikola Burdzhiev and
• Elena Stanoeva

Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121

• ]isoquinoline skeleton is incorporated in a large group of natural compounds such as crispines, trolline, and lamellarins, which are interesting due to their anticancer, antiviral, and antibacterial activities [7][8]. In the light of this broad array of biological activities, the development of novel methods

Synthesis of pyrrolidinedione-fused hexahydropyrrolo[2,1-a]isoquinolines via three-component [3 + 2] cycloaddition followed by one-pot N-allylation and intramolecular Heck reactions

• Xiaoming Ma,
• Suzhi Meng,
• Xiaofeng Zhang,
• Qiang Zhang,
• Shenghu Yan,
• Yue Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2020, 16, 1225–1233, doi:10.3762/bjoc.16.106

• ; Introduction Pyrrolo[2,1-a]isoquinoline and hexahydropyrrolo[2,1-a]isoquinoline are privileged heterocyclic rings existing in many natural products and synthetic compounds possessing antitumor, antibacterial, antiviral, antioxidizing, and other biological activities (Figure 1) [1][2]. For example, the alkaloid

Efficient synthesis of piperazinyl amides of 18β-glycyrrhetinic acid

• Dong Cai,
• ZhiHua Zhang,
• Yufan Meng,
• KaiLi Zhu,
• LiYi Chen,
• ChangXiang Yu,
• ChangWei Yu,
• ZiYi Fu,
• DianShen Yang and
• YiXia Gong

Beilstein J. Org. Chem. 2020, 16, 798–808, doi:10.3762/bjoc.16.73

• [3], antitumor [4], and antibacterial [5] activity and their proberties as hepatic protective agents [6]. Over the past few decades, the emphasis was placed primarily on explaining structure–activity relationships of 18β-glycyrrhetinic acid derivatives to enhance their biological activity. The

Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

• Marcin Kaźmierczak and
• Henryk Koroniak

Beilstein J. Org. Chem. 2020, 16, 756–762, doi:10.3762/bjoc.16.69

• applications of fluorinated aminophosphonates and aminophosphonic acid derivatives, they exhibit antiviral [4][5], antibacterial [6] and antifungal [7] activities. Moreover, α-fluorinated phosphonates can be considered as hydrolytically stable mimics of naturally occurring phosphates [8]. Due to the fact that

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• catalysts; Sharpless–Meldal C–N bond-forming reaction; silica/carbon/magnetic materials; Introduction Heterocycles are a class of organic compounds with significant biological activities [1][2][3][4][5][6][7][8][9][10], including antimicrobial [2], antibacterial [3], anti-HIV [4], antiviral [5

• ], antiparkinsonian [6], and anticancer [10] properties. Particularly, triazoles illustrate distinguished moieties well distributed in natural products with biological properties [2][3][4][9][10], including antimicrobial [2], antibacterial [3], antifungal [3], anti-HIV [4], and anticancer [10] activities. One of the

Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku,
• Nobuyasu Matsuura,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 297–304, doi:10.3762/bjoc.16.29

• assignment of an E geometry at C8 in 2. As metabolites of microbes, compounds 1 and 2 are unprecedented in terms of bearing a 2,4-dienone system. Both 1 and 2 showed antibacterial activity against the plant pathogen Rhizobium radiobacter and the fish pathogen Tenacibaculum maritimum, with a contrasting

• preference that 1 is more effective to the former strain while 2 is so to the latter. In addition, compounds 1 and 2 displayed agonistic activity against peroxisome proliferator-activated receptors (PPARs) with an isoform specificity towards PPARα and PPARγ. Keywords: antibacterial; coral; keto fatty acid

• and 2 showed selective antibacterial activity against the plant pathogen R. radiobacter and the fish pathogen T. maritimum, respectively. In addition, both 1 and 2 displayed agonistic activity against PPARα and PPARγ. Experimental General experimental procedure UV and IR spectra were recorded on a

Absolute configurations of talaromycones A and B, α-diversonolic ester, and aspergillusone B from endophytic Talaromyces sp. ECN211

• Ken-ichi Nakashima,
• Junko Tomida,
• Takao Hirai,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 290–296, doi:10.3762/bjoc.16.28

• : secalonic acids, ergoflavins, and ergochrysins), which are well-known mycotoxins that exhibit toxic, antibacterial, and mutagenic properties [1]. On the other hand, a limited number of monomeric tetrahydroxanthones has been reported as fungal metabolites to date, including the blennolides [2], diversonolic

Ultrasonic-assisted unusual four-component synthesis of 7-azolylamino-4,5,6,7-tetrahydroazolo[1,5-a]pyrimidines

• Yana I. Sakhno,
• Maryna V. Murlykina,
• Oleksandr I. Zbruyev,
• Anton V. Kozyryev,
• Svetlana V. Shishkina,
• Dmytro Sysoiev,
• Vladimir I. Musatov,
• Sergey M. Desenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2020, 16, 281–289, doi:10.3762/bjoc.16.27

• importance, and they have attracted the attention of medicinal chemists because of their various biological activities [1]. Furthermore, tetrahydropyrimidines containing fused azole rings are a privileged class of heterocycles due to their antiviral [2], antitubercular, antitumor [3], antibacterial [4][5

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• ], anti-oxidant [7], antibacterial [8], hepatoprotective, anticoagulant, antiviral and antithrombotic activities [9]. The variety of uses of these compounds resulted in an increase in demand for large quantities of coumarins. Due to an insufficient natural supply to meet this demand for these compounds

Understanding the role of active site residues in CotB2 catalysis using a cluster model

• Keren Raz,
• Ronja Driller,
• Thomas Brück,
• Bernhard Loll and
• Dan T. Major

Beilstein J. Org. Chem. 2020, 16, 50–59, doi:10.3762/bjoc.16.7

• by featuring anticancer, antibacterial, anti-inflammatory, and antiretroviral activities [37]. Moreover, they are applied in the food industry as antioxidants and sweeteners [4]. CotB2 is a bacterial diterpene cyclase from S. melanosporofaciens, which catalyzes the formation of cyclooctat-9-en-7-ol

Light-controllable dithienylethene-modified cyclic peptides: photoswitching the in vivo toxicity in zebrafish embryos

• Sergii Afonin,
• Oleg Babii,
• Aline Reuter,
• Volker Middel,
• Masanari Takamiya,
• Uwe Strähle,
• Igor V. Komarov and
• Anne S. Ulrich

Beilstein J. Org. Chem. 2020, 16, 39–49, doi:10.3762/bjoc.16.6

• , we noticed that there was generally a poor correlation between the antibacterial activity on the one side, and the cytotoxicity against HeLa cells on the other side, and erythrocytes as a third scenario. Different compounds could thus be regarded as potential leads for chemotherapy of either

Construction of trisubstituted chromone skeletons carrying electron-withdrawing groups via PhIO-mediated dehydrogenation and its application to the synthesis of frutinone A

• Qiao Li,
• Chen Zhuang,
• Donghua Wang,
• Wei Zhang,
• Rongxuan Jia,
• Fengxia Sun,
• Yilin Zhang and
• Yunfei Du

Beilstein J. Org. Chem. 2019, 15, 2958–2965, doi:10.3762/bjoc.15.291

• of the obtained chromone derivatives was their conversion to chromone-derived natural products. Frutinone A, isolated from the leaves and root bark of Polygala fruticosa, shows various biological activities, including antibacterial, antioxidant, and potent cytochrome P450 1A2 inhibition (CYP1A2, IC50

Two new aromatic polyketides from a sponge-derived Fusarium

• Mada Triandala Sibero,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Ocky K. Karna Radjasa,
• Agus Sabdono,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2941–2947, doi:10.3762/bjoc.15.289

• of NMR and MS spectroscopic data. The NMR assignment of 1 was assisted by DFT-based theoretical chemical shift calculation. Compound 2 showed antibacterial activity against multidrug resistant Salmonella enterica ser. Typhi with a MIC of 125 µg/mL while 1 was not active. Keywords: aromatic

• ). Antibacterial activities of compounds 1–7 were tested against clinical pathogen Salmonella enterica ser. Typhi strain MDR from General Hospital Dr. Kariadi, Semarang, Indonesia. Compounds 2–7 were weakly active with MIC values of 125 µg/mL, while 1 was not active in the same concentration range. Conclusion In

Chemical synthesis of tripeptide thioesters for the biotechnological incorporation into the myxobacterial secondary metabolite argyrin via mutasynthesis

• David C. B. Siebert,
• Roman Sommer,
• Domen Pogorevc,
• Michael Hoffmann,
• Silke C. Wenzel,
• Rolf Müller and
• Alexander Titz

Beilstein J. Org. Chem. 2019, 15, 2922–2929, doi:10.3762/bjoc.15.286

• ’-methoxy group to halogens or other substituents in different positions led to a loss of antibacterial activity, whereas the 5’-methoxytryptophan regioisomer largely retained activity against P. aeruginosa PAO1. Inspection of the crystal structure of argyrin in complex with the bacterial elongation factor

Diversity-oriented synthesis of spirothiazolidinediones and their biological evaluation

• Sambasivarao Kotha,
• Gaddamedi Sreevani,
• Lilya U. Dzhemileva,
• Milyausha M. Yunusbaeva,
• Usein M. Dzhemilev and
• Vladimir A. D’yakonov

Beilstein J. Org. Chem. 2019, 15, 2774–2781, doi:10.3762/bjoc.15.269

• represent an important class of nitrogen-containing biologically active compounds which exhibit various biological properties, such as antiviral, antibacterial and anticancer, etc. [55][56][57][58]. Recently, the use of 1,2,3-triazole derivatives as drug candidates has been increased for clinical therapy of

Fluorinated maleimide-substituted porphyrins and chlorins: synthesis and characterization

• Valentina A. Ol’shevskaya,
• Elena G. Kononova and
• Andrei V. Zaitsev

Beilstein J. Org. Chem. 2019, 15, 2704–2709, doi:10.3762/bjoc.15.263

• . Maleimides are considered as a biologically important scaffold that possess almost all types of biological activities including antibacterial and antifungal activity [24], anticancer activity [25], cox-2 inhibitor and anti-inflammatory, antidiabetic activity [26] and photodynamic activity [27]. Attaching of

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• cell lines, two bacteria, one fungus and one plant (Table 4). Compound 1 was inactive up to 100 μg mL−1 in all of the assays performed, suggesting acylation at 6-OH is important for biological activity. Compounds 4, 5 and 7 showed moderate antibacterial activity against B. subtilis, with weaker

Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides

• José Brango-Vanegas,
• Luan A. Martinho,
• Lucinda J. Bessa,
• Andreanne G. Vasconcelos,
• Alexandra Plácido,
• Alex L. Pereira,
• José R. S. A. Leite and
• Angelo H. L. Machado

Beilstein J. Org. Chem. 2019, 15, 2544–2551, doi:10.3762/bjoc.15.247

• wavenumber values for the lactone C=O stretch was also observed for bands assigned to the C=C bonds as consequence of their conjugation. Evaluation of the growth inhibition and hemolytic activity of S. aureus for the solonamide analogues Initially, the antibacterial activity of all analogues 9 was tested by

• range of 300–0.3 µM. None of the compounds presented antibacterial activity against S. aureus, since no MIC value could be obtained in the range of concentrations tested (MIC > 300 µM). Subsequently, a screening assay was carried out to evaluate the effect of these compounds on the hemolysis of

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• presence of acetic anhydride produced a crude acetamido ester (R)-132 which was transformed into the final N-benzyl amide (R)-130 with of 99.9% ee after crystallization. ʟ-(+)-Furanomycin (Scheme 35) is a natural nonproteinogenic amino acid which showed pronounced antibacterial activity. From several

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• ., anti-inflammatory, anticancer, antibacterial, anxioselective and antiprotozoal [3][4][5]. Furthermore, a number of drugs embracing the imidazopyridine (IP) skeleton have been commercially marketed with their trade names as minodronic acid (for the treatment of osteoporosis), olprinone (for acute heart

Synthesis of 9-O-arylated berberines via copper-catalyzed C_Ar–O coupling reactions

• Qiaoqiao Teng,
• Xinhui Zhu,
• Qianqian Guo,
• Weihua Jiang,
• Jiang Liu and
• Qi Meng

Beilstein J. Org. Chem. 2019, 15, 1575–1580, doi:10.3762/bjoc.15.161

• natural alkaloid extracted from ranunculaceae, rutaceae and berberidaceae, which features a tetracyclic isoquinoline core unit. It was widely used as antibacterial agent [1] and has shown myriad therapeutic potencies in tumor cell suppression [2][3] and various chronic disease management [4]. In most

Synthesis of ([1,2,4]triazolo[4,3-a]pyridin-3-ylmethyl)phosphonates and their benzo derivatives via 5-exo-dig cyclization

• Aleksandr S. Krylov,
• Artem A. Petrosian,
• Julia L. Piterskaya,
• Nataly I. Svintsitskaya and
• Albina V. Dogadina

Beilstein J. Org. Chem. 2019, 15, 1563–1568, doi:10.3762/bjoc.15.159

• number of drugs and [1,2,4]triazolo[4,3-a]pyridines were shown to have herbicidal [5][6], antifungal [7], neuroprotective [8][9] and antibacterial activity [10]. In addition, [1,2,4]triazolopyridine has been used as electron-acceptor unit in the synthesis of organic light emitting diodes (OLED) [11]. 2

Molecular basis for the plasticity of aromatic prenyltransferases in hapalindole biosynthesis

• Takayoshi Awakawa and
• Ikuro Abe

Beilstein J. Org. Chem. 2019, 15, 1545–1551, doi:10.3762/bjoc.15.157

• beneficial bioactivities, exemplified by 12-epi-hapalindole E isonitrile, which exhibits antibacterial, antifungal, and antimycobacterial activities [16], and ambiguine I, which induces apoptosis and cell-cycle arrest through the inhibition of an NF-κB-related regulation pathway [17]. To investigate their

Synthesis of pyrrolo[1,2-a]quinolines by formal 1,3-dipolar cycloaddition reactions of quinolinium salts

• Anthony Choi,
• Rebecca M. Morley and
• Iain Coldham

Beilstein J. Org. Chem. 2019, 15, 1480–1484, doi:10.3762/bjoc.15.149

• with a quinoline. Pyrroloquinolines have been found to show antibacterial and antifungal activity, to be ligands for the NK1 receptor, and to be effective against the Hif hypoxia pathway in cancer cell lines [36][37][38]. Almost all of the examples of dipolar cycloaddition reactions involving

Synthesis and biological evaluation of truncated derivatives of abyssomicin C as antibacterial agents

• Leticia Monjas,
• Peter Fodran,
• Johanna Kollback,
• Carlo Cassani,
• Thomas Olsson,
• Maja Genheden,
• D. G. Joakim Larsson and
• Carl-Johan Wallentin

Beilstein J. Org. Chem. 2019, 15, 1468–1474, doi:10.3762/bjoc.15.147

• , Gothenburg, Sweden 10.3762/bjoc.15.147 Abstract The synthesis and antibacterial activity of two new highly truncated derivatives of the natural product abyssomicin C are reported. This work outlines the limits of structural truncation of the natural product and consequently provides insights for further

• physicochemical properties that NPs typically show [3]. Abyssomicin C (AbC) is an NP with antibacterial activity that was isolated from the marine actinomycete strain Verrucosispora AB-18-032 in 2004 [4][5]. It shows antibacterial activity against Gram-positive bacteria, including resistant pathogens such as

• the same time, and these compounds did not show any antibacterial activity (Figure 1). Consequently, the enone moiety of AbC was proposed to play an essential role in the antibiotic activity. Indeed, in a subsequent study it was shown that AbC has a unique mechanism of action amongst NPs: it is a