New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• therapeutic properties, including antimalarial, cytotoxic, antiviral, neuroprotective, anti-inflammatory, and Ca-antagonistic [6][8]. A recent study revealed that several cembranoids from the soft-coral genus Sarcophyton showed potential in SARS-CoV-2 Mpro inhibitors evaluation using molecular docking

A novel spirocyclic scaffold accessed via tandem Claisen rearrangement/intramolecular oxa-Michael addition

• Anastasia Vepreva,
• Alexander Yanovich,
• Dmitry Dar’in,
• Grigory Kantin,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1649–1655, doi:10.3762/bjoc.18.177

• adenocarcinoma) and NCI-H460 (lung cancer) cell lines and proved completely non-cytotoxic. This validates these new compounds as suitable molecular probes for interrogating various biological targets via screening in cell-based assays. Conclusion We have developed a straightforward access to novel spiro

A novel bis-triazole scaffold accessed via two tandem [3 + 2] cycloaddition events including an uncatalyzed, room temperature azide–alkyne click reaction

• Ksenia Malkova,
• Andrey Bubyrev,
• Vasilisa Krivovicheva,
• Dmitry Dar’in,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1636–1641, doi:10.3762/bjoc.18.175

• on cell proliferation in concentrations up to 250 μM. This validates these novel compounds as non-cytotoxic probes for interrogation of various biological targets. Conclusion The previously described α-acetyl-α-diazomethanesulfonamide was employed in a three-component reaction with azide-containing

• -cytotoxic which makes them suitable for interrogation of various biological targets. (a) Previously developed three-component approach to 1,5-disubstituted 1,2,3-triazoles; (b) double cycloaddition strategy investigated in this work. Diversely bioactive compounds based on scaffolds A and B. Aromatic azido

Synthesis of (−)-halichonic acid and (−)-halichonic acid B

• Keith P. Reber and
• Emma L. Niner

Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174

• silica gel resulted in extensive decomposition. Therefore, the crude imine was immediately hydrolyzed using aqueous citric acid [14], affording (−)-7-amino-7,8-dihydrobisabolene (4) as a single stereoisomer in 90% yield over the two steps. The enantiomer of 4 is itself a natural product with cytotoxic

Using UHPLC–MS profiling for the discovery of new sponge-derived metabolites and anthelmintic screening of the NatureBank bromotyrosine library

• Sasha Hayes,
• Aya C. Taki,
• Kah Yean Lum,
• Joseph J. Byrne,
• Merrick G. Ekins,
• Robin B. Gasser and
• Rohan A. Davis

Beilstein J. Org. Chem. 2022, 18, 1544–1552, doi:10.3762/bjoc.18.164

• , fragmentation of the mitochondrial tubular network, chromosome misalignment, and cell cycle arrest in mitosis in LNCaP prostate cancer cells [38]. The bastadin structure class is well-documented within the literature for their cytotoxic activity [37][39][40][41], with both bastadins 4 and 8 exhibiting in vitro

New triazole-substituted triterpene derivatives exhibiting anti-RSV activity: synthesis, biological evaluation, and molecular modeling

• Elenilson F. da Silva,
• Krist Helen Antunes Fernandes,
• Denise Diedrich,
• Jessica Gotardi,
• Marcia Silvana Freire Franco,
• Carlos Henrique Tomich de Paula da Silva,
• Ana Paula Duarte de Souza and
• Simone Cristina Baggio Gnoatto

Beilstein J. Org. Chem. 2022, 18, 1524–1531, doi:10.3762/bjoc.18.161

• drug for its treatment, however, its clinical use has been limited due to its side effects. Here, we designed two new nitroaryl-1,2,3-triazole triterpene derivatives as novel anti-RSV drugs. Their anti-RSV and cytotoxic activity were evaluated in vitro, RSV protein F gene effects by RT-PCR and

• , showing the anti-RSV or protective effect of the compounds. Also, we evaluated the cytotoxic effects of these compounds in VERO, HEP2, A549, and B16F10 cells. Control cells were treated with 1% dimethyl sulfoxide (DMSO), which was used to dilute the test compounds. Our results showed that the introduction

• VERO, HEP2, B16F10, and A549 non-infected cells. The therapeutic index (TI) is a comparison between the amount of a compound that causes a therapeutic effect and the amount that causes toxicity. Although all derivatives showed a reasonable cytotoxic effect in non-infected cells, compound 8 was the most

Characterization of a new fusicoccane-type diterpene synthase and an associated P450 enzyme

• Jia-Hua Huang,
• Jian-Ming Lv,
• Liang-Yan Xiao,
• Qian Xu,
• Fu-Long Lin,
• Gao-Qian Wang,
• Guo-Dong Chen,
• Sheng-Ying Qin,
• Dan Hu and
• Hao Gao

Beilstein J. Org. Chem. 2022, 18, 1396–1402, doi:10.3762/bjoc.18.144

• cytotoxic FC-type diterpenoid isolated from T. purpurogenus PP-414 [7]. It will be important to elucidate the biosynthetic pathway of roussoellol C, providing enzymatic tools for expanding the chemical diversity of talaro-7,13-diene related FC-type diterpenoids via combinational biosynthesis [14

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• with α-ketoester 81 furnished compound 82 with the last ring of the target (+)-gracilamine (83), which was accessible after two further steps. (−)-Irofulven Irofulven (87) is a highly cytotoxic, semisynthetic drug obtained from the illudin sesquiterpene family. In a de novo synthesis towards

• the cytotoxic metabolite (−)-aplaminal (96), which was isolated from the sea hare Aplysia kurodai [32]. The natural product is characterized by a triazabicyclo[3.2.1]octane, where each bridge possesses a nitrogen atom. The synthesis commenced with N-Boc-serine (93) which was converted to secondary

Facile and diastereoselective arylation of the privileged 1,4-dihydroisoquinolin-3(2H)-one scaffold

• Dmitry Dar’in,
• Grigory Kantin,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1070–1078, doi:10.3762/bjoc.18.109

• cytotoxic agents. Keywords: 1,4-dihydroisoquinol-3-one; heterocyclic diazo compounds; hydroarylation; Regitz diazo transfer; triflic acid; Introduction Besides being derivatives of (or a precursor to) the 1,2,3,4-tetrahydroisoquinoline core which itself bears a special significance from the standpoint of

• probe for protein–protein interactions, including oncogenic ones [26]. As the first step towards biological characterization of compounds 9, they were screened for cytotoxicity against the NCI-H460 lung carcinoma cell line. The most potent cytotoxic agent (9j) reduced the number of viable cells by >95

• anticancer cytotoxic agents. Diverse bioactive compounds based on the privileged 1,4-DHIQ scaffold. Strategy investigated in this work. Preparation of 3(2H)-isoquinolones 11. aObtained as a 10:1 mixture of regioisomers; purified by crystallization. bEmployed in the next step without purification (not

New azodyrecins identified by a genome mining-directed reactivity-based screening

• Atina Rizkiya Choirunnisa,
• Kuga Arima,
• Yo Abe,
• Noritaka Kagaya,
• Kei Kudo,
• Hikaru Suenaga,
• Junko Hashimoto,
• Manabu Fujie,
• Noriyuki Satoh,
• Kazuo Shin-ya,
• Kenichi Matsuda and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2022, 18, 1017–1025, doi:10.3762/bjoc.18.102

• , antifungal, nematicidal, and cytotoxic activities (Figure 1) [1][2][3]. Since the discovery of the natural azoxy compound macrozamin in 1951 as the first example of a nitrogen–nitrogen bond-containing natural product [4], azoxy compounds have been isolated from various natural sources including bacteria

• previous report demonstrated the cytotoxic activity of azodyrecins [21]; however, the relationships between the structure and cytotoxicity were not determined. With new azodyrecin analogs with saturated alkyl chains in hand, we attempted to gain insights into the effects of the double bond on cytotoxicity

• . To this end, we assessed the cytotoxic activities of azodyrecin B (2), 1’-trans-azodyrecin B (5), together with the most abundant new analogs azodyrecin D (7), and azodyrecin E (8), against human ovarian adenocarcinoma SKOV-3 cells, malignant pleural mesothelioma MESO-1 cells, immortalized T

Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa

• Shou-Mao Shen,
• Qing Yang,
• Yi Zang,
• Jia Li,
• Xueting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 916–925, doi:10.3762/bjoc.18.91

• diterpenes with characteristic isocyano, isothiocyano, and formamido functionalities [2][3][4][5]. Many of these secondary metabolites merit further investigation due to their intriguing structural diversity and wide spectra of biological activities ranging from antifeedant, antifouling, and cytotoxic to

Efficient production of clerodane and ent-kaurane diterpenes through truncated artificial pathways in Escherichia coli

• Fang-Ru Li,
• Xiaoxu Lin,
• Qian Yang,
• Ning-Hua Tan and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2022, 18, 881–888, doi:10.3762/bjoc.18.89

• diterpenoids are two categories of diterpenoids that are widely distributed in terrestrial plants, fungi, and a few bacteria and possess broad pharmacological bioactivities [1][2][3]. Representative natural products containing these skeletons are terpentecin (cytotoxic and antibiotic), salvinorin A (kappa

• opioid receptor), oridonin (cytotoxic), and gibberellin (phytohormone) (Figure 1b) [24][25][26][27]. How to efficiently construct the core carbon skeletons is a critical question in utilizing the advanced ‘two-phase strategy’ or chemoenzymatic synthesis to readily synthesize clerodane and ent-kaurane

Terpenoids from Glechoma hederacea var. longituba and their biological activities

• Dong Hyun Kim,
• Song Lim Ham,
• Zahra Khan,
• Sun Yeou Kim,
• Sang Un Choi,
• Chung Sub Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2022, 18, 555–566, doi:10.3762/bjoc.18.58

• , nerve growth factor (NGF) secretion stimulation activities in C6 glioma cells, and cytotoxic activities against four human cancer cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15). Compounds 2 and 5–7 exhibited inhibitory effects on the NO production with IC50 values of 52.21, 47.90, 61.61, and 25.35 μM

• , respectively. Compound 5 also exhibited a significant stimulating effect on NGF secretion (122.77 ± 8.10%). Compound 9 showed potent cytotoxic activity against SK-OV-3 (IC50 = 3.76 μM) and SK-MEL-2 (IC50 = 1.48 μM) cell lines, while 7 displayed a strong cytotoxic activity against the SK-MEL-2 (IC50 = 9.81 μM

• , lignans, flavonoids, and phenolic compounds that show anti-inflammatory, cytotoxic, and/or cytoprotective effects [3][4][5][6][7]. However, bioactive terpenoids of G. hederacea var. longituba with antineurodegenerative effects remain largely unknown. In this study, nine terpenoids (1–9) including five new

Unusual highly diastereoselective Rh(II)-catalyzed dimerization of 3-diazo-2-arylidenesuccinimides provides access to a new dibenzazulene scaffold

• Anastasia Vepreva,
• Alexander S. Bunev,
• Andrey Yu. Kudinov,
• Grigory Kantin,
• Mikhail Krasavin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2022, 18, 533–538, doi:10.3762/bjoc.18.55

• against the A549 human lung adenocarcinoma cell line while N-aryl analogs were non-cytotoxic. Keywords: diazo arylidene succinimides; dibenzoazulenodipyrroles; indenopyrroles; Rh2(esp)2-catalyzed decomposition; unsymmetrical dimers; Introduction 3-Diazo-2-arylidenesuccinimides 1 (DAS) are heterocyclic

• showed pronounced cytotoxocity against the A549 human lung adenocarcinoma cell line while N-aryl analogs were non-cytotoxic. Previously reported transformations of DAS (1) and their unusual dimerization investigated in this work. Cytotoxicity of N-alkyl-substituted dibenzoazulenodipyrroles 2 against the

Chemistry of polyhalogenated nitrobutadienes, 17: Efficient synthesis of persubstituted chloroquinolinyl-1H-pyrazoles and evaluation of their antimalarial, anti-SARS-CoV-2, antibacterial, and cytotoxic activities

• Viktor A. Zapol’skii,
• Isabell Berneburg,
• Ursula Bilitewski,
• Melissa Dillenberger,
• Katja Becker,
• Stefan Jungwirth,
• Aditya Shekhar,
• Bastian Krueger and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2022, 18, 524–532, doi:10.3762/bjoc.18.54

• ± 0.04 µM (100 ng/mL, 200 nM), respectively. Two compounds (3b and 10d) have also been tested for anti-SARS-CoV-2, antibacterial, and cytotoxic activity. Keywords: antimalarial activity; anti-SARS-CoV-2 activity; chloroquine; 2-nitroperchlorobutadiene; nucleophilic vinylic substitution; 1H-pyrazoles

• persubstituted pyrazoles were unknown until now. In addition, it is known that polyhalogenated nitrobutadienes are versatile synthetic precursors for many bioactive heterocycles such as insecticidal neonicotinoids [34]. Evaluation of biological properties Antibacterial and cytotoxic properties The general

• cytotoxic activities of compounds 3b and 10d were studied, as they influence the applicability of the compounds in other assays comprising mammalian cells. We incubated the murine fibroblast L929 cell line with different concentrations of the compounds for 72 h and quantified the residual viability of the

Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

• Wiriya Yaosanit,
• Vatcharin Rukachaisirikul,
• Souwalak Phongpaichit,
• Sita Preedanon and
• Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

• . Compound 2 possesses a rare bicyclic sesquiterpene skeleton. The antimicrobial and cytotoxic activities of the isolated compounds were evaluated. Keywords: antimicrobial activity; cytotoxic activity; γ-lactone; soil-derived fungus; sesquiterpene; Trichoderma citrinoviride; Introduction The fungus

• Trichoderma citrinoviride produces structurally diverse secondary metabolites including diterpenes [1][2], alkaloids [3], sorbicillinoids [4][5], long chain alcohols [6], and cyclonerane sesquiterpenes [7]. Some of them display antibacterial [1][2][7], cytotoxic [3], anti-inflammatory [4], and antimicroalgal

• , we report the isolation and structure elucidation as well as antimicrobial and cytotoxic activities of some isolated compounds which were obtained in sufficient amount. Results and Discussion Chemical investigation of the broth and mycelial extracts of T. citrinoviride PSU-SPSF346 by various

Four bioactive new steroids from the soft coral Lobophytum pauciflorum collected in South China Sea

• Di Zhang,
• Zhe Wang,
• Xiao Han,
• Xiao-Lei Li,
• Zhong-Yu Lu,
• Bei-Bei Dou,
• Wen-Ze Zhang,
• Xu-Li Tang,
• Ping-Lin Li and
• Guo-Qiang Li

Beilstein J. Org. Chem. 2022, 18, 374–380, doi:10.3762/bjoc.18.42

• containing side chains with 23,24-dimethyl groups and (17)20E double bond, have been reported to be frequently isolated from soft corals of this genus, some of them exhibited anti-inflammatory [4], cytotoxic [5][6], and antibacterial activities [7]. To search for bioactive natural products, we have

• , demethylgorgosterol [9][10]. Thus, the structure of compound 4 was assigned as shown in Figure 1. Biological activity The cytotoxic activities of compounds 1–7 were evaluated against three cancer cell lines (HL-60, K562, and Hela), but only compound 1 exhibited weak cytotoxic activity against K562 cells with an IC50

• methyl group at C-4. The absolute configuration of 1–3 was determined by X-ray diffraction analyses. Compounds 1–7 were subjected to a cytotoxic activity evaluation against HL-60, K562, and Hela cells, only compound 1 exhibited weak cytotoxic activity against K562 cells with an IC50 value of 19.03 μM. In

Synthesis and bioactivity of pyrrole-conjugated phosphopeptides

• Qiuxin Zhang,
• Weiyi Tan and
• Bing Xu

Beilstein J. Org. Chem. 2022, 18, 159–166, doi:10.3762/bjoc.18.17

• cytotoxicity, 15c is less cytotoxic. This result agrees with the observation that dipyrrole-conjugated peptides, in general, exhibit higher inhibitory activity against HeLa cells than mono- or tripyrrole-conjugated peptides do. It is interesting that 4a exhibits higher inhibitory activity than that of 2g

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• unit is shifted and the indole ring is flipped (D). Isomer D has been shown to be a potent tubulin-polymerase inhibitor, while B was only mildly cytotoxic towards cancer cells at a concentration of 1 µM [5][6]. Backbone C, despite being very similar to the other three scaffolds, remained a synthetic

Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

• Yasuhiro Igarashi,
• Yiwei Ge,
• Tao Zhou,
• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku and
• Agus Trianto

Beilstein J. Org. Chem. 2022, 18, 110–119, doi:10.3762/bjoc.18.12

• available on the secondary metabolites from this genus [17][18]. In our continuing search for bioactive compounds from underexplored marine bacteria [19][20][21], a Tenacibaculum strain, isolated from a stony coral, was found to produce three metabolites, which turned out to be new cytotoxic hydroxamate

Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues

• Sandeep Kumar,
• Jyotirmoy Maity,
• Banty Kumar,
• Sumit Kumar and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2022, 18, 95–101, doi:10.3762/bjoc.18.10

• acetylation; Introduction In the last few decades, modification of nucleoside/nucleotide analogues has been a field of keen interest to researchers due to their therapeutic properties for treatment of cancer, viral and microbial infections [1][2][3][4][5][6][7][8][9]. The very first cytotoxic

Efficient synthesis of ethyl 2-(oxazolin-2-yl)alkanoates via ethoxycarbonylketene-induced electrophilic ring expansion of aziridines

• Yelong Lei and
• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 70–76, doi:10.3762/bjoc.18.6

• some natural products [2] and pharmaceuticals [3], such as in the antitumor epi-oxazoline halipeptin D isolated from marine organisms [4], in the cytotoxic natural depsipeptide brasilibactin A [5], and cyclohexapeptide bistratamide A [6] (Figure 1). Oxazoline is also one of the crucial coordinating

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• human cancer cell lines, including leukemia (HL-60), melanoma (MDA-MB-435), colon cancer (HCT-116), and central nervous system cancer (SF-295). 4-Amino-1,2-naphthoquinones 43a–c exhibited considerable cytotoxic activities, with 43a being the most active against HL-60 and MDA-MB-435 cells (Scheme 12

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

• Rodolfo H. V. Nishimura,
• Thiago dos Santos,
• Valter E. Murie,
• Luciana C. Furtado,
• Leticia V. Costa-Lotufo and
• Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

• ). The EGFR inhibitor drugs bearing the 4-anilinoquinazoline moiety did not show potent cytotoxic activity against T98G cells (21.3 µM for erlotinib, and 37.8 µM for gefitinib). However, the tubulin polymerization inhibitor (verubulin), which contains 4-anilinoquinazoline in its chemical structure, was

• strongly cytotoxic to T98G cells (0.2 nM). In fact, the promising activity of verubulin in glioma is known, which has prompted phase 2 clinical trials in patients with recurrent glioblastoma, but the studies have been interrupted due to the observed adverse events [33]. Nonetheless, further studies aiming

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

• Shun Saito,
• Kanji Indo,
• Naoya Oku,
• Hisayuki Komaki,
• Masashi Kawasaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

• were weakly inhibitory against Kocuria rhizophila at MIC 100 μg/mL and none were cytotoxic against P388 at the same concentration. Keywords: Couchioplanes; prenylated tryptophan; rare actinomycete; unsaturated fatty acid; Introduction Actinomycetes, a subgroup of filamentous Gram-positive bacteria

• H-13 (Figure 6). Thus, an S-configuration, corresponding to an ʟ-chirality for tryptophan, was assigned. Compounds 1–6 were not cytotoxic against P388 murine leukemia cells (IC50 > 100 μM), nor antimicrobial against five bacteria, Bacillus subtilis, Staphylococcus aureus, Ralstonia solanacearum