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Search for "isolation" in Full Text gives 946 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

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

Graphical Abstract
  • 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
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Published 06 Dec 2022

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

Graphical Abstract
  • 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
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Published 02 Dec 2022

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

Graphical Abstract
  • (+)-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
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Published 01 Dec 2022

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

Graphical Abstract
  • 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
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Published 28 Nov 2022

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

Graphical Abstract
  • , 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
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Published 23 Nov 2022

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

Graphical Abstract
  • 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
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Published 15 Nov 2022

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

Graphical Abstract
  • 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
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Published 14 Oct 2022

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

Graphical Abstract
  • 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
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Published 13 Oct 2022

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

Graphical Abstract
  • 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
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Published 07 Oct 2022

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

Graphical Abstract
  • , 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
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Published 05 Oct 2022

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

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  • 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
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Published 29 Sep 2022

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

Graphical Abstract
  • 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
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Published 19 Sep 2022

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

Graphical Abstract
  • 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
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Published 14 Sep 2022

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

Graphical Abstract
  • 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
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Published 30 Aug 2022

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

Graphical Abstract
  • ). 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
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Published 26 Aug 2022

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

Graphical Abstract
  • 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
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Published 17 Aug 2022

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

Graphical Abstract
  • 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
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Published 10 Aug 2022

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

Graphical Abstract
  • 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
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Published 09 Aug 2022

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

  • Daniele Rocco,
  • Ana A. Folgueiras-Amador,
  • Richard C. D. Brown and
  • Marta Feroci

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

Graphical Abstract
  • demonstrate for the first time the possibility to synthesize and accumulate N-heterocyclic carbene starting from BMImBF4 in a divided electrochemical flow cell. Although not fully optimized, the production of NHC was confirmed indirectly by isolation of its reaction product with elemental sulfur. A solution
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Published 05 Aug 2022

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

  • Valentin H. K. Fell,
  • Joseph Cameron,
  • Alexander L. Kanibolotsky,
  • Eman J. Hussien and
  • Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

Graphical Abstract
  • thiophene groups and has been applied in solution processed OFETs. A maximum hole mobility of 1.33 × 10−4 cm2 V−1 s−1 was measured for a single device. The isolation of the dibromide compound 29 provides the basis for the inclusion of this interesting molecule in larger conjugated structures or copolymers
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Published 01 Aug 2022

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

Graphical Abstract
  • Province, China, resulting in the isolation of fifteen new nitrogenous sesquiterpenoids, exemplified by (+)-ximaocavernosin A (8) (Figure 1) [11]. To accumulate more amounts of these sesquiterpenoids to perform more in-depth pharmacological screening, we carried out the chemical investigation of the same
  • with five related known ones [2, 3, (−)-4, 6, and 7] (Figure 1), were obtained. Herein, we report the isolation, chiral separation of racemic mixtures of 4 and 5, structural elucidation, plausible biosynthetic pathway, and biological evaluation of these isolated compounds. Results and Discussion By the
  • ratios of 74.1% in TNF-α and 64.1% in CCL2 at a concentration of 1 μM (Figure 6). Conclusion The continuous chemical investigation of the sponge A. cavernosa has resulted in the isolation of nine non-nitrogenous sesquiterpenoids, of which four optically pure compounds [(+)-1, (+)-4, (+)-5, and (−)-5] are
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Published 25 Jul 2022

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

Graphical Abstract
  • produced new peaks in the HPLC profiles after a 3-day fermentation. Larger scale (3 L) fermentations of DL10004 and DL10006 led to the isolation of 45 mg and 90 mg of terpentetriene and ent-kaurene, respectively, whose 1H and 13C NMR spectra supported their chemical structures (Figures S4–S7 in Supporting
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Published 21 Jul 2022

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

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  • pET28a(+) vectors were used, and E. coli BL21 was used as production host. Cultures were supplemented with ampicillin (100 µg mL−1) and kanamycin (60 µg mL−1) for the selection of plasmids. DNA isolation, PCR amplification, and cloning: gDNA of Maribacter sp. MS6 was extracted using DNeasy Blood & Tissue
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Published 22 Jun 2022

A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments

  • Constantine V. Milyutin,
  • Andrey N. Komogortsev,
  • Boris V. Lichitsky and
  • Valeriya G. Melekhina

Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61

Graphical Abstract
  • direction of the contraction of the pyranone ring leading to unstable α-hydroxydiketones. For the first time the possibility of isolation of the resulting α-hydroxydiketones in pure form was demonstrated. Wherein, it was shown that relatively low stable α-hydroxydiketones can be trapped by reaction with 1,2
  • solvents excluding acetic acid, DMSO and DMF. Initially, UV irradiation of compound 12a was carried out at a wavelength of 365 nm in a solution of DMSO in common glassware for 24 h. However, subsequent water treatment did not allow the isolation of the target product 14a. Due to the fact that aqueous
  • communication we have described for the first time the phototransformation of the 3-hydroxypyran-4-one fragment with the isolation of the resulting substituted α-hydroxy-1,2-diketone in pure form. The structure of the obtained compound 14a was confirmed using 1H, 13C NMR spectroscopy as well as 2D NMR
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Published 27 May 2022

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

Graphical Abstract
  • compounds (1–5) were isolated and characterized from G. hederacea var. longituba (Figure 1). Structures of these compounds were established by 1D and 2D NMR and HRESIMS, comparison of experimental and calculated ECD data, DP4+ analysis, and hydrolysis. Herein, the isolation and structural elucidation of the
  • School of Pharmacy, Sungkyunkwan University, Suwon, Korea. Extraction and isolation. The dried aerial parts of G. hederacea var. longituba (3.0 kg) were extracted with 80% MeOH (each 12.0 L × 1 day, 3 times) at room temperature and filtered. The filtrate was evaporated in vacuo to yield an 80% MeOH
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Published 17 May 2022
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