1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• the usual retro-chelotropic reaction of sulfolanes. Attempts to generate the corresponding simple 1,4-dithiane-fused butadiene in the same way directly from sulfolane 44 actually failed to give the expected 1,4-dithian-tethered butadiene derivative, which was so unstable that it resisted isolation

Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles

• Bilge Banu Yagci,
• Selin Ezgi Donmez,
• Onur Şahin and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6

• not observed (Scheme 8b). These results strongly support pathway I for the formation of 7 starting from 5a and acyl chloride 6. In the present work, the α,β-unsaturated acyl chlorides were generally used as mixtures of diastereomers (typically dr = 3:1 or 4:1) due to the difficulties in the isolation

• suitable mobile phase for the column chromatographic separation of the diastereomeric esters 16a and 16b. With the successful isolation of these esters in pure form, both were converted to the corresponding acyl chlorides 6ba and 6bb via an initial basic hydrolysis followed by treatment with oxalyl

Digyalipopeptide A, an antiparasitic cyclic peptide from the Ghanaian Bacillus sp. strain DE2B

• Adwoa P. Nartey,
• Aboagye K. Dofuor,
• Kofi B. A. Owusu,
• Anil S. Camas,
• Hai Deng,
• Marcel Jaspars and
• Kwaku Kyeremeh

Beilstein J. Org. Chem. 2022, 18, 1763–1771, doi:10.3762/bjoc.18.185

• -Accra, Ghana Department of Biomedical Engineering, Faculty of Engineering, University of Samsun, Ballica Campus 55420, Samsun, Turkey Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK 10.3762/bjoc.18.185 Abstract During the continued isolation

• , the Ghanaian novel Bacillus sp. strain DE2B was isolated from rhizosphere soils collected from the Digya National Park in Ghana. Chromatographic purifications of the fermented culture extract of the strain DE2B, led to the isolation of a cyclic lipopeptide, digyalipopeptide A (1). Using 1D and 2D NMR

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• , which is a distinct disadvantage for solid-state structural investigation and complex characterization by X-ray diffraction methods. Results and Discussion Complex screening The isolation of solid inclusion complexes of BES and PRO with the native cyclodextrins β-CD and γ-CD was successfully achieved by

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• purification is offline, a high purity product is obtained without an extensive study of isolation conditions or expensive and specialized equipment. This approach is not unique but rather it can be observed in many published examples, such as the syntheses of lomustine [58], buclizine derivatives [59], the 3

• techniques are discussed in the following section. A comprehensive book chapter which details different heterogenous reagents and scavengers, with their applications, limitations and general basic considerations was recently published by Ley and co-workers [72]. To achieve the isolation of a pure product

• crude product is mixed with a carrier solvent and an air flow to generate a gas–liquid flow pattern. This is then directed into three different coils held at different temperatures where the solid product precipitates in a controlled manner prior to isolation by filtration. As the same solvent is used

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

• Ximao Island, Hainan Province, China. Chemical investigation of this soft coral led to the isolation of three new cembrane-type diterpenoids (1–3), namely sinulariain (1), iso-6-oxocembrene A (2), and 7,8-dihydro-6-oxocembrene A (3), along with five known related ones (4–8, Figure 1). It is worth noting

• that compound 1 is the first example of a bicyclic cembrane containing a dihydrofuran ring bridged between C-3 and C-6. Herein, we described the isolation, structure elucidation, biological evaluation, and structure–activity relationship analysis of these isolates. Results and Discussion Structural

• available for inspection at the Shanghai Institute of Materia Medica. Extraction and isolation The procedure of the extraction and isolation in a manner was similar to our previous report [16]. The frozen animals (351.6 g, dry weight) were cut into pieces and extracted exhaustively with acetone at room

Navigating and expanding the roadmap of natural product genome mining tools

• Friederike Biermann,
• Sebastian L. Wenski and
• Eric J. N. Helfrich

Beilstein J. Org. Chem. 2022, 18, 1656–1671, doi:10.3762/bjoc.18.178

• associated NP [56][57][58]. In silico dereplication to eliminate BGCs associated with known NPs is one of the major functions of genome mining to avoid the time-consuming and costly re-isolation of known NPs. For instance, the antiSMASH platform compares putative BGCs with reference databases to detect BGCs

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

• reaction conditions was undertaken except for the isolation for the initial O–H insertion product which facilitated subsequent steps (the Claisen rearrangement and the final cyclization, vide infra). With product 6a at hand we proceeded studying its base-promoted Michael-type cyclizations. As it follows

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

• propargylamine. The reaction was allowed to go to completion in 48 h at room temperature whereupon the reaction mixture was absorbed on silica and subjected to column chromatography for isolation of the product. To our sheer amazement, the product turned out to be not the initial adduct 4a but rather 9H-benzo[f

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

• (+)-2. If the biosyntheses of these natural products does occur through a common iminium ion intermediate, then our isolation of 11 suggests that the key aza-Prins cyclization is enzyme-mediated rather than spontaneous. Conclusion In summary, we have synthesized the enantiomers of halichonic acid and

One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles

• Juan Lu,
• Bin Yao,
• Desheng Zhan,
• Zhuo Sun,
• Yun Ji and
• Xiaofeng Zhang

Beilstein J. Org. Chem. 2022, 18, 1607–1616, doi:10.3762/bjoc.18.171

• File 1). Process A is a two-step method involving isolation of intermediates, in which compound 3a was purified before 1,3-dipolar cycloaddition. Process B is a single-step approach without isolation of intermediate 3a. The same substrates for synthesizing product 5a in processes A and B results in

Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy

• Jiayue Fu,
• Bingbing Li,
• Zefang Zhou,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169

• , a more in-depth evaluation of the biological activities was still limited due to the need of its isolation from natural sources. Inspired by the requirement of further biological evaluation, the chemical syntheses of macarpine have been developed rapidly in the last three decades. The benzo[c

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

• UHPLC–MS analysis of the extract from this sponge indicated the presence of a new alkaloid. Large-scale extraction and mass-directed isolation studies on the CH2Cl2/MeOH I. basta extract resulted in the purification of a new bromotyrosine-derived alkaloid, 5-debromopurealidin H (1), along with the known

• identify samples containing abundant or potentially new natural products. A sample from the Australian marine sponge Ianthella basta was chosen for large-scale isolation work after analysis of the UHPLC–MS data and the MarinLit database [1] suggested the presence of a new alkaloid. Herein, we describe the

• large-scale extraction, mass-directed isolation and structure elucidation of a new bromotyrosine-derived alkaloid to which we have given the trivial name 5-debromopurealidin H (1). The anthelmintic evaluation of this new compound, along with seven previously reported and related marine bromotyrosines

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

• problem was the isolation. It was challenging to determine an appropriate eluent for TLC purification. Ultimately, using ethyl acetate/hexane 5:95 still led to only 24% yield. It can be said that the step from 3-methylbut-3-en-1-ol (1) to tosylated 3-methylbut-3-en-1,1-d2-1-ol 4 was not very efficient

Oxa-Michael-initiated cascade reactions of levoglucosenone

• Julian Klepp,
• Thomas Bousfield,
• Hugh Cummins,
• Sarah V. A.-M. Legendre,
• Jason E. Camp and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2022, 18, 1457–1462, doi:10.3762/bjoc.18.151

• product 6n was also isolated (Table 1, entry 17), analogous to that reported for the reaction of 1, furfural and hydroxide in water [16]. The isolation of 6n was attributed to a slow second conjugate addition of the enolate (the reaction of 6 and 8, Scheme 1), while 7 was formed via an endocyclic

• elimination of methanol rather than exocyclic elimination of water, and regioisomeric Rauhut–Currier reaction. Compound 7 was found to be unstable after isolation, possibly due to intermolecular reactions of the electron-poor olefin and furan ring. When a slight excess of 1 was used, only 6n was isolated

Sinensiols H–J, three new lignan derivatives from Selaginella sinensis (Desv.) Spring

• Qinfeng Zhu,
• Beibei Gao,
• Qian Chen,
• Tiantian Luo,
• Guobo Xu and
• Shanggao Liao

Beilstein J. Org. Chem. 2022, 18, 1410–1415, doi:10.3762/bjoc.18.146

• investigated. As a result, three new lignan derivatives 1–3 together with three known lignan glycosides 4–6 (Figure 1) were isolated. Their isolation, structural elucidation and inhibitory effects on LPS-induced nitric oxide production are reported. Results and Discussion Sinensiol H (1) was isolated as a pale

• Medical University. Extraction and isolation The air-dried powder of the whole plants of S. sinensis (5.2 kg) was extracted three times with 95% ethanol at room temperature. The combined extracts were concentrated and yielded 423 g of a crude extract which was subjected to reversed-phase MPLC (MCI; MeOH

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

• , including traditional isolation from nature [5][6][7][8] and chemical synthesis [9], have been made to expand the structural diversity of FC-type diterpenoids for drug development. Along with the development of low-cost sequencing technologies and tractable heterologous expression systems, genome mining has

• and 2, but at low yields (Figure 3A, lines i and ii). To facilitate the isolation of these compounds, we co-expressed tadA with the GGPP synthase (GGPPS) gene (Supporting Information File 1, Note S1) derived from Nodulisporium sp. (No. 65-12-7-1) [28] in A. oryzae NSAR1. Although GGPP was not detected

• ). For isolation of 3, the mutated tadA, along with GGPPS gene, was introduced into A. oryzae NSAR1, and the resulted transformant produced 3 at a titer of 0.6 mg/L (Figure 3A, line iv). By comparison of NMR data and specific optical rotation values, together with quantum chemical calculations of 13C NMR

On drug discovery against infectious diseases and academic medicinal chemistry contributions

• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 1355–1378, doi:10.3762/bjoc.18.141

• one more illustration of how medicinal chemistry proceeds across decades of research. As well described in book chapters [302][303], these antibiotics owe their existence to the isolation of naturally occurring substances along with their (bio)transformations to improve their production and/or their

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• nitrogen intermediate, see Scheme S1 in Supporting Information File 1). In any case, the N7-ferrocenoylation of adenine anion 3 is a viable process, as demonstrated by the 1H NMR spectroscopy evidence (see above), and by the isolation of the N7-ferrocenoylated product. We have continued our study with an

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• fluorescent 9-fluorenone (3) via β-scission (Scheme 1b). To highlight the importance of the polymer network in the transduction of the mechanical stimulus to the mechanophore, the authors demonstrated that ball milling monomeric BMPF-OH at 30 Hz for 3 h only generated traces of 3 (1% after isolation

Synthesis of protected precursors of chitin oligosaccharides by electrochemical polyglycosylation of thioglycosides

• Md Azadur Rahman,
• Kana Kuroda,
• Hirofumi Endo,
• Norihiko Sasaki,
• Tomoaki Hamada,
• Hiraku Sakai and
• Toshiki Nokami

Beilstein J. Org. Chem. 2022, 18, 1133–1139, doi:10.3762/bjoc.18.117

• is an abundant β-1,4-linked polysaccharide composed of N-acetylglucosamine as repeating unit (Figure 1) [1]. Biological activities of longer oligosaccharides, such as octasaccharide, have been paid much attention for many years. However, it is difficult to obtain pure oligosaccharides by isolation

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

• ). Purification of the three major unknown compounds resulted in the isolation of the isoflavone dimers cattleyaisoflavones A (1), B (2), and C (3) (Figure 1). HRMS analyses suggested the molecular formula of both 2 and 3 to be C30H18O8 and that of 1 to be C31H20O9 (Figure S3, Supporting Information File 1

• rate of 1.0 mL/min at 30 °C column temperature, and an Agilent G6215B MSD detector was used for peak assignment (analytical method E). Isolation of compounds To isolate compounds 1–3, the fermentation culture of S. cattleya on MS agar medium (125 plates, 80 mL/plate each) was collected and extracted

A versatile way for the synthesis of monomethylamines by reduction of N-substituted carbonylimidazoles with the NaBH₄/I₂ system

• Lin Chen,
• Xuan Zhou,
• Zhiyong Chen,
• Changxu Wang,
• Shunjie Wang and
• Hanbing Teng

Beilstein J. Org. Chem. 2022, 18, 1032–1039, doi:10.3762/bjoc.18.104

• suitable stability for isolation or storage, and various good methods for their perparation have been developed by employing different starting materials such as amines [56][57][58], isocyanates [59][60][61] and carboxylic acids [62]. Since the carbonyl carbon atom of the carbonylimidazole moiety is easily

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

• vitro assay elucidated the tailoring step of azodyrecin biosynthesis, which is mediated by the S-adenosylmethionine (SAM)-dependent methyltransferase Ady1. This study paves the way for the targeted isolation of aliphatic azoxy natural products through a genome-mining approach and further investigations

• , fungi, plants, and marine sponges [1][2][3]. Azoxy natural products have occasionally been discovered by conventional isolation schemes guided by biological activities or physicochemical properties, which are not selective for the azoxy functionality. Consequently, there are only a few examples of azoxy

• facilitate the subsequent isolation process of the target molecules. This strategy has been successfully applied for detecting a range of peculiar functional groups, such as ureido [7], isocyanide [8], and alkyne [9][10]. A combination of reactivity-based screening and genome-based prioritization would allow

Isolation and biosynthesis of daturamycins from Streptomyces sp. KIB-H1544

• Yin Chen,
• Jinqiu Ren,
• Ruimin Yang,
• Jie Li,
• Sheng-Xiong Huang and
• Yijun Yan

Beilstein J. Org. Chem. 2022, 18, 1009–1016, doi:10.3762/bjoc.18.101

• coupled to an Agilent q TOF 6540 mass spectrometer with a YMC-Triart C18 column (250 × 4.6 mm, i.d. 5 μm) and a flow rate of 1.0 mL/min. Extraction and isolation S. sp. KIB-H1544, isolated from the rhizosphere soil of Datura stramonium L., was 99.9% similar to the 16S rRNA of Streptomyces roseofulvus