A facile approach to spiro[dihydrofuran-2,3'-oxindoles] via formal [4 + 1] annulation reaction of fused 1H-pyrrole-2,3-diones with diazooxindoles

• Pavel A. Topanov,
• Anna A. Maslivets,
• Maksim V. Dmitriev,
• Irina V. Mashevskaya,
• Yurii V. Shklyaev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2022, 18, 1532–1538, doi:10.3762/bjoc.18.162

• heterocyclic systems are heteroanalogues of antimicrobial and antibiofilm fungal metabolites. The developed reaction represents the first example of involving 1H-pyrrole-2,3-diones fused at the [e]-side in a [4 + 1] annulation reaction. Keywords: [4 + 1] annulation; catalyst-free; diazooxindole; 1H-pyrrole

• constructing spirooxindole systems by employing different approaches [6][7][8][9][10][11][12]. Cyclopiazonic acid derivatives such as aspergillins A–E [13] (Figure 1) and speradines C and F [14][15] are secondary metabolites of fungi, and include a furan fragment spiro-fused with 2-oxindole. Cyclopiamides I

• first example of a catalyst-free formal [4 + 1] cycloaddition reaction of enones and complex diazo compounds. The synthesized compounds 3 have a pharmaceutically interesting fungal metabolites-like structure with a spiro[dihydrofuran-2,3'-oxindole] moiety. Selected examples of biologically active

Synthesis of the biologically important dideuterium-labelled adenosine triphosphate analogue ApppI(d₂)

• Petri A. Turhanen

Beilstein J. Org. Chem. 2022, 18, 1466–1470, doi:10.3762/bjoc.18.153

• known to be involved in the induction of cell death [14]. The mechanism of action related to the antiresorptive and anticancer effects of NBPs has been proposed to be attributable to the metabolites formed in the mevalonate pathway induced by NBPs [15]. In 2020 in Finland, the wholesaling of BPs has

Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants

• Karan Malhotra and
• Jakob Franke

Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135

• ], cosmetics [3] and pharmaceutical industries [4]. Plant triterpenoids include primary metabolites such as phytosterols or steroidal hormones such as brassinosteroids, but also specialised metabolites that convey diverse biological functions [5]. A key factor for the structural richness of triterpenoids and

Synthesis of tryptophan-dehydrobutyrine diketopiperazine and biological activity of hangtaimycin and its co-metabolites

• Houchao Xu,
• Anne Wochele,
• Minghe Luo,
• Gregor Schnakenburg,
• Yuhui Sun,
• Heike Brötz-Oesterhelt and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1159–1165, doi:10.3762/bjoc.18.120

• , growth control (no inhibitor), SC, sterile control (no bacteria), DMSO, culture medium supplemented with 1% DMSO, reflecting the DMSO concentrations in the hangtaimycin-containing samples. Structures of hangtaimycin (1) and its co-metabolites. First synthetic route towards TDD (4). Second synthetic route

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• isoflavone dimers derived from daidzein (4) During our effort of untargeted metabolomic screening of Streptomyces species, we identified several unknown isoflavone-like metabolites from S. cattleya NRRL8057 cultured on mannitol soya flour (MS) agar plates (Figure S2, Supporting Information File 1

• might provide an alternative pathway for antioxidant biosynthesis by using exogenous metabolites as substrates. The native substrate for CYP158C1, presumably produced by the clustered T3PKS, has yet to be identified. The broad substrate specificity of CYP158C1 towards plant polyphenols suggests a

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

• natural products, despite their notable biological activities. Reactivity-based screening is an emerging strategy in natural products discovery, in which chemical probes are used for the specific detection of the unique functionality of interest in crude metabolites [5][6]. The reactions usually

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

• antibiotic effects [3][5][6]. Acanthella sponges have thus attracted much attention from marine natural products chemists and pharmacologists. The title animal is the most chemically studied species among the Acanthella sponges. Till now, more than 100 secondary metabolites belonging to sesquiterpenoids and

• diterpenes [7][8], alkaloids [9], and steroids [10], have been isolated and characterized. In connection with our continuing studies of Chinese marine invertebrates to search for novel and bioactive secondary metabolites, we have recently studied the sponge A. cavernosa collected from Ximao Island of Hainan

Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity

• Jamshid Amiri Moghaddam,
• Huijuan Guo,
• Karsten Willing,
• Thomas Wichard and
• Christine Beemelmanns

Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72

• University, Johannisallee 21–23, 04103 Leipzig, Germany 10.3762/bjoc.18.72 Abstract Aromatic prenylated metabolites have important biological roles and activities in all living organisms. Compared to their importance in all domains of life, we know relatively little about their substrate scopes and

• prenyltransferase; Introduction Marine bacteria harbor an enormous potential to produce structurally diverse natural products, including prenylated aromatic metabolites [1][2]. Prenylation of metabolites most often confers increased biological activities due to enhanced lipophilicity, solubility, and improved

• spectrometer equipped with a Bruker Cryoplatform with chemical shifts given in ppm (δ). Prenylated aromatic metabolites are involved in cellular processes like cell respiration (coenzyme Q10), cell growth and survival (menaquinone MK-4), photosynthesis (chlorophyll a), oxygen reduction (heme O), and

Structural basis for endoperoxide-forming oxygenases

• Takahiro Mori and
• Ikuro Abe

Beilstein J. Org. Chem. 2022, 18, 707–721, doi:10.3762/bjoc.18.71

• Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan 10.3762/bjoc.18.71 Abstract Endoperoxide natural products are widely distributed in nature and exhibit various biological activities. Due to their chemical features, endoperoxide and endoperoxide-derived secondary metabolites have attracted keen

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

• -3α,12α,16α-triol (6) [15], 3-epimaslinic acid (7) [18], oleanolic acid (8) [19], and ursolic acid (9) [20]. To find potential antineuroinflammatory, neurotrophic, and cytotoxic secondary metabolites from G. hederacea var. longituba, the isolated compounds (1–9) were evaluated for these biological

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

• 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

• [7] activities. Based on these data, the investigation of secondary metabolites from this fungus is still limited. In our ongoing search for antimicrobial secondary metabolites from soil-derived fungi, T. citrinoviride PSU-SPSF346 was isolated from a soil sample collected from the Sirindhorn Peat

• configurations at C-5, C-6, C-7, and C-10 of compound 2 were proposed to be 5S, 6S, 7S, and 10R identical to those of the co-metabolites 4 and 5. The absolute configuration at C-4 was thus assigned to be R. Therefore, compound 2 is a rare bicyclic sesquiterpene. The isolated compounds 1 and 3–6 with sufficient

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• ; quinone; synthetic platform; vitamin K; Introduction Naphthoquinones belong to the chemical family of quinones and are widely present in synthetic and natural products (Figure 1). In nature, quinones are biosynthesized as secondary metabolites by various organisms, from simple single-celled

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

• metabolites with great variety and bioactivities. Previous chemical studies on soft corals Lobophytum, widely distributed in the world, resulted in the identification of lobane diterpene [1], cembranoids [2], and biscembranoids [3] with different bioactivities. Moreover, structurally specific steroids

Amamistatins isolated from Nocardia altamirensis

• Till Steinmetz,
• Wolf Hiller and
• Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

• iron-chelating properties of the retrieved metabolites were evaluated in a chrome azurol S assay. Keywords: actinomycete; amamistatin; Nocardia; siderophore; structure elucidation; Introduction Iron is known to easily interconvert between a reduced ferrous (Fe2+) and an oxidized ferric state (Fe3

• Nocardia as a whole is considered to be a rich source of bioactive secondary metabolites, including many structurally diverse siderophores [6]. Up to now, however, chemical studies in this taxonomic group mainly focused on pathogenic strains. In the present study we explored siderophore production in the

• fermentations of N. altamirensis DSM 44997 were then carried out to secure sufficient material of the responsible iron chelator(s) for isolation and structure elucidation. The metabolites secreted into the culture broth were recovered post fermentation with the adsorber resin XAD-7. After removal of the culture

Glycosylated coumarins, flavonoids, lignans and phenylpropanoids from Wikstroemia nutans and their biological activities

• Meifang Wu,
• Xiangdong Su,
• Yichuang Wu,
• Yuanjing Luo,
• Ying Guo and
• Yongbo Xue

Beilstein J. Org. Chem. 2022, 18, 200–207, doi:10.3762/bjoc.18.23

• diversity of the secondary metabolites from the genus Wikstroemia. Keywords: coumarin glucosides; flavonoids; lignans; structure elucidation; Wikstroemia nutans; Introduction The genus Wikstroemia (Thymelaeaceae) contains approximately 62 species, which are widespread throughout the subtropical regions of

• Asia and Oceania [1]. Nineteen species of the genus Wikstroemia are found to be domestic in China, such as W. nutans, W. indica, and W. canescens [2]. Previous investigations have not only reported diverse secondary metabolites from the genus, but also promising pharmacological activities of the

• ) [25] (Figure 1) by comparison to literature data. In addition, compounds 2, 3, 8, and 11 were isolated for the first time from the genus Wikstroemia. Biological activity Considered naturally occurring glycosides of phenolic metabolites usually exhibit anti-inflammatory activity in literature [26

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• metabolites for self-defense in different microorganisms, peptidic natural products are assembled either by ribosomal synthesis or by non-ribosomal peptide synthetases (NRPS) [2]. Macrocyclic peptides are pervasive throughout this class of natural products and often show improved stability against proteolytic

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

• . They instead harbour diverse and abundant microbes on their body surface or in the tissues [2][3] and are believed to utilize secondary metabolites from the symbionts as protectants from attacks by predators, competitors, or pathogens. The ecological functions as such make marine microorganisms an

• metabolites from Gram-negative bacteria are still quite limited, despite the predominance of this group in the marine environment [10][11]. The genus Tenacibaculum belongs to the family Flavobacteriaceae within the phylum Bacteroidetes. Members of this genus are Gram-negative, aerobic, motile by gliding, and

• 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

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

• enzyme human carboxylesterase (hCE1) that cleaves carboxylic esters. This enzyme functions in the detoxification metabolism of carcinogenic and mutagenic organic compounds, converting them into nontoxic metabolites. This compound served as inspiration for Hatfield and co-workers [84], who proposed the

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

• .17.203 Abstract A genome mining survey combined with metabolome analysis of publicly available strains identified Couchioplanes sp. RD010705, a strain belonging to an underexplored genus of rare actinomycetes, as a producer of new metabolites. HPLC-DAD-guided fractionation of its fermentation extracts

• Streptomyces, are especially noted, accounting for more than 800 metabolites of actinomycetes origin [11], which include the antiinfective aminoglycoside gentamicin [13], antidiabetic glycoside acarbose [14], glycopeptide antibiotic teicoplanin [15], enediyne antitumor component of drug-antibody conjugate

• metabolites of Pseudosporangium sp. RD062863, a strain available at the culture collection of the Biological Resource Center, National Institute of Technology and Evaluation (NBRC) [20], and discovered a novel cyclopeptide pseudosporamide along with three new oligomycin-class polyketide [21]. In addition, the

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet–Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

• Marco Keller,
• Karl Sauvageot-Witzku,
• Franz Geisslinger,
• Nicole Urban,
• Michael Schaefer,
• Karin Bartel and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2716–2725, doi:10.3762/bjoc.17.183

• relationships in this chemotype. Keywords: acyl Pictet–Spengler reaction; alkaloids; antiproliferative activity; benzyltetrahydroisoquinolines; ion channels; protective group; total synthesis; Introduction The benzylisoquinoline alkaloids are a large and diverse class of plant secondary metabolites including

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• hepatotoxicity and neurological effects on livestock and humans [1][2]. The less commonly encountered 2,3-dihydro-1H-pyrrolizine framework occurs in the butterfly metabolites danaidal (2) and hydroxydanaidal (3) [3], as well as in plant alkaloids such as loroquin (4) [4] and the recently characterized

Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B

• Emmanuel T. Oluwabusola,
• Olusoji O. Adebisi,
• Fernando Reyes,
• Kojo S. Acquah,
• Mercedes De La Cruz,
• Larry L. Mweetwa,
• Joy E. Rajakulendran,
• Digby F. Warner,
• Deng Hai,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2021, 17, 2390–2398, doi:10.3762/bjoc.17.156

• microbial sources led to the isolation of Pseudomonas sp. UIAU-6B from sediments collected from the Oyun river in North Central Nigeria. Herein, we report the isolation and structure elucidation of seven secondary metabolites including five new (1–5), and two known phenolic siderophores (6 and 7) [28][36

• secondary metabolites 1–5 including pseudomonin A–C (1–3) and pseudomobactins A and B (4 and 5). The two known compounds, pseudomonine (6) and salicylic acid (7) were also isolated as the major constituents of the extracts and their structures were determined by analysis of HRESIMS, 1D and 2D NMR data (see

Phenolic constituents from twigs of Aleurites fordii and their biological activities

• Kyoung Jin Park,
• Won Se Suh,
• Da Hye Yoon,
• Chung Sub Kim,
• Sun Yeou Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2021, 17, 2329–2339, doi:10.3762/bjoc.17.151

• A. fordii have shown Epstein–Barr virus activation effects and an enhancement of HTLV-I-induced colony formation of lymphocytes [8]. As an ongoing search for bioactive secondary metabolites from Korean medicinal sources, we investigated the methanolic extract of the twigs of A. fordii which resulted

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• marine environment is now attracting attention as a promising source for actinomycetes potentially producing new secondary metabolites [4][5]. Indeed, a large number of pharmaceutically worthy new compounds has been found from marine actinomycetes in various niches including sediments, sea water, marine

Natural products in the predatory defence of the filamentous fungal pathogen Aspergillus fumigatus

• Jana M. Boysen,
• Nauman Saeed and
• Falk Hillmann

Beilstein J. Org. Chem. 2021, 17, 1814–1827, doi:10.3762/bjoc.17.124

• metabolites. The genetic potential for the production of secondary metabolites in fungi is high and numerous potential secondary metabolite gene clusters have been identified in sequenced fungal genomes. Their production may well be regulated by specific ecological conditions, such as the presence of

• microbial competitors, symbionts or predators. Here we exemplarily summarize our current knowledge on identified secondary metabolites of the pathogenic fungus Aspergillus fumigatus and their defensive function against (microbial) predators. Keywords: amoeba predation; Aspergillus fumigatus; fungal ecology

• , physiological adaptations and chemical defence mechanisms to optimize their living conditions and resist competitors, parasites and predators [3][4][5]. These bioactive compounds are often considered as secondary metabolites (SM) which are involved in communication, symbiotic interactions, pathogenicity or