Synthesis of legonmycins A and B, C(7a)-hydroxylated bacterial pyrrolizidines

• Wilfred J. M. Lewis,
• David M. Shaw and
• Jeremy Robertson

Beilstein J. Org. Chem. 2021, 17, 334–342, doi:10.3762/bjoc.17.31

• and B, are related as 7a-epimers that interconvert in aqueous solution to form a pH-dependent equilibrium ratio of the two [9]; they are weakly antibacterial and were shown to prolong “the survival period of mice inoculated with leukaemia L-120 cells” [7][8]. Although the clazamycins are not

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• studies on this plant have reported triterpenoids [2][3][4][5][6][7][8] and phenolic compounds [2][9][10][11][12], and some of them showed anti-inflammatory and neuroprotective [13][14][15], antitumor [2], tissue factor inhibitory [5][9], antibacterial [8], antihemolytic [8], or antipruritic activities

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• Pseudomonas aeruginosa, a Gram-negative rod-shaped bacterium [5][6][7][8]. RL are built up by one or two rhamnose sugar units as well as one to three β-hydroxy fatty acids, which can also be unsaturated. These highly functional biomolecules exhibit interesting biological and antibacterial properties, as

Synthesis and investigation of quadruplex-DNA-binding, 9-O-substituted berberine derivatives

• Jonas Becher,
• Daria V. Berdnikova,
• Heiko Ihmels and
• Christopher Stremmel

Beilstein J. Org. Chem. 2020, 16, 2795–2806, doi:10.3762/bjoc.16.230

• -inflammatory [25], antibacterial [26][27], and anticancer reagents [28][29]. The latter property is mainly based on the binding interaction of berberine with nucleic acids and the resulting inhibition of topoisomerase and telomerase [2][30]. Most notably, berberine (1a) induces a strong growth inhibition in

Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of ¹J_C,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites

• Md. Rokon Ul Karim,
• Enjuro Harunari,
• Amit Raj Sharma,
• Naoya Oku,
• Kazuaki Akasaka,
• Daisuke Urabe,
• Mada Triandala Sibero and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 2719–2727, doi:10.3762/bjoc.16.222

• actinomycete origin. For example, salinosporamide A, an antitumor drug candidate in clinical trials, is a proteasome inhibitor with an unusual γ-lactam-β-lactone bicyclic core produced by marine Salinospora tropica [10]. Abyssomicin, another example of uncommon polycyclic frameworks, is an antibacterial

Enzyme-instructed morphological transition of the supramolecular assemblies of branched peptides

• Dongsik Yang,
• Hongjian He and
• Bing Xu

Beilstein J. Org. Chem. 2020, 16, 2709–2718, doi:10.3762/bjoc.16.221

• , peptide assemblies are being explored for a wide range of applications, including cell cultures [6], tissue engineering [7], drug delivery [8][9][10][11], antibacterial agents [12][13], regarding biomineralization [14][15], as collagen mimics [16], anisotropic hydrogels [17][18], for cancer therapy [19

Selective and reversible 1,3-dipolar cycloaddition of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with 1,3-diphenylprop-2-en-1-ones under microwave irradiation

• Alexander P. Molchanov,
• Mariia M. Efremova,
• Mariya A. Kryukova and
• Mikhail A. Kuznetsov

Beilstein J. Org. Chem. 2020, 16, 2679–2686, doi:10.3762/bjoc.16.218

• pyrazolidinone derivatives like LY186826 and its analogues with antibacterial activity [8][9][10][11][12]. The chemistry of azomethine imines has been actively investigated since the second half of the last century but their reactivity is still far less studied compared with nitrones or azomethine ylides – other

Host–guest interaction of cucurbit[8]uril with oroxin A and its effect on the properties of oroxin A

• Zhishu Zeng,
• Jun Xie,
• Guangyan Luo,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 2332–2337, doi:10.3762/bjoc.16.194

• beneficial biological effects of OA, which include antioxidant, antidiabetic, anticancer, antibacterial, anti-inflammatory and antiviral properties [25][26][27][28][29][30]. Herein, we selected Q[8] as a host molecule and investigated its host–guest interactions with OA, as well as its effect on the

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

• Ken-ichi Nakashima,
• Junko Tomida,
• Tomoe Tsuboi,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 2100–2107, doi:10.3762/bjoc.16.177

• configurations were determined using the modified Mosher’s method and through comparisons of experimental and calculated electronic circular dichroism data. In addition, muyocopronone B (2) was found to exhibit a weak antibacterial activity against some Gram-positive bacteria. Keywords: azaphilones; endophytic

• ,10R,11R) stereoisomer. Finally, since a number of azaphilones have been reported to exhibit antimicrobial activity [5][23], muyocopronones A (1) and B (2) were screened for their antibacterial activity against five strains of Gram-positive bacteria, namely Staphylococcus aureus (PAGU 273T

• ), methicillin-resistant S. aureus (PAGU 841, MRSA), S. epidermidis (PAGU 283T), Enterococcus faecalis (PAGU 102T), and vancomycin-resistant E. faecalis (PAGU 100). Although muyocopronone B (2) exhibited an antibacterial activity against both antibiotic-resistant and antibiotic-susceptible strains, with minimum

pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

• Goutam Ghosh and
• Gustavo Fernández

Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168

• , as mentioned above. The pH-responsive self-assembling behavior of peptides has a great importance in drug delivery, and since PEP-1 contains rich cationic residues, such as Arg, this system can be an interesting potential candidate for DDS and as an antibacterial agent [71]. Biocompatibility, drug

• delivery, and antibacterial studies are underway in our laboratory. Concentration-dependent secondary structure formation Apart from the pH-dependent self-assembly, we also investigated the role of the concentration on the self-assembly and secondary structure. As shown previously, the CD spectra at

Stereoselective Biginelli-like reaction catalyzed by a chiral phosphoric acid bearing two hydroxy groups

• Xiaoyun Hu,
• Jianxin Guo,
• Cui Wang,
• Rui Zhang and
• Victor Borovkov

Beilstein J. Org. Chem. 2020, 16, 1875–1880, doi:10.3762/bjoc.16.155

• ][2][3][4]. In the last decade, chiral DHPMs showed valuable pharmacological properties such as antiviral, antitumor, antibacterial, anti-inflammatory, and antihypertensive effects [5][6]. However, the individual enantiomers of DHPMs were found to exhibit different or even opposite pharmaceutical

Three new O-isocrotonyl-3-hydroxybutyric acid congeners produced by a sea anemone-derived marine bacterium of the genus Vibrio

• Dandan Li,
• Enjuro Harunari,
• Tao Zhou,
• Naoya Oku and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1869–1874, doi:10.3762/bjoc.16.154

• )-configuration of the 3-hydroxy acid components in 1–4. These compounds showed no cytotoxicity but were weakly antibacterial against a fish ulcer pathogen, Tenacibaculum maritimum. The (2Z)-enoic acyl termini in 1–4 are precedented by 5, discovered from another Vibrio bacterium, and the (R)-configured short

• . Antibacterial assay The antibacterial activity was evaluated by a microculture technique described previously [20], except for a 1:100 reduction of the seeding density of T. maritimum NBRC16015. Cytotoxicity assay 3Y1 rat embryonic fibroblastic cells were maintained in low-glucose DMEM medium containing ʟ

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

• Dalel El-Marrouki,
• Sabrina Touchet,
• Abderrahmen Abdelli,
• Hédi M’Rabet,
• Mohamed Lotfi Efrit and
• Philippe C. Gros

Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144

• antibacterial, antifungal, anticancer, or anti-inflammatory agents or even on the central nervous system [7][12][13]. Several routes have been reported to access these key compounds, the most developed being for the indole [14] derivatives using the Fischer indole synthesis involving sigmatropic rearrangements

Microwave-assisted efficient one-pot synthesis of N²-(tetrazol-5-yl)-6-aryl/heteroaryl-5,6-dihydro-1,3,5-triazine-2,4-diamines

• Moustafa Sherief Moustafa,
• Ramadan Ahmed Mekheimer,
• Saleh Mohammed Al-Mousawi,
• Mohamed Abd-Elmonem,
• Hesham El-Zorba,
• Afaf Mohamed Abdel Hameed,
• Tahany Mahmoud Mohamed and
• Kamal Usef Sadek

Beilstein J. Org. Chem. 2020, 16, 1706–1712, doi:10.3762/bjoc.16.142

• -2,4-diamines; one-pot synthesis; X-ray crystallography; Introduction The family of triazines is of considerable interest in fields related to organic and medicinal chemistry. 2,4-Diaminotriazines are privileged scaffolds exhibiting diverse biological activities such as antibacterial [1], anti-HSV-1

• ]. Tetrazole derivatives exhibit a wide spectrum of biological activities as antibacterial [14], anticancer [15], anti-inflammatory [16], antidiabetic [17], antitubercular [18], and analgesic [19] agents. It is well established that many medical disorders can be caused as a result of defects at more than one

Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)

• Cora Hertzer,
• Stefan Kehraus,
• Nils Böhringer,
• Fontje Kaligis,
• Robert Bara,
• Dirk Erpenbeck,
• Gert Wörheide,
• Till F. Schäberle,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132

• the genus Doriprismatica and scalarane-containing dictyoceratid sponges of the Spongiidae family. The results also indicate that D. stellata passes the scalarane metabolite on to its egg ribbons, most likely for protective purposes. The scalarane showed antibacterial activity against the Gram-positive

• bacteria Arthrobacter crystallopoietes (DSM 20117) and Bacillus megaterium (DSM 32). Keywords: antibacterial; Dictyoceratida; Nudibranchia; scalarane; sesterterpene; Introduction In habitats with intense competition and feeding pressure, such as coral reefs, sessile or slow-moving organisms commonly

• sesterterpene reported with a cyclopropane ring bridging the carbons C-3, C-22 and C-4 in ring A, and an acetoxy group at C-11 instead of C-12 in ring C (Figure 2). All ethyl acetate extracts, as well as the isolated new scalarane, showed antibacterial activity against the Gram-positive bacteria Arthrobacter

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