Search results

Search for "acid" in Full Text gives 2759 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

  • Manuel Pedrón,
  • Jana Sendra,
  • Irene Ginés,
  • Tomás Tejero,
  • Jose L. Vicario and
  • Pedro Merino

Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37

Graphical Abstract
  • and co-workers demonstrated for transannular Diels–Alder cycloaddition reactions of symmetrically tethered large systems (10–18-membered rings) [29]. In this context, we have recently reported the transannular enantioselective (3 + 2) cycloaddition of cycloalkenone hydrazones under Brønsted acid
  • alkenes under chiral BINOL-derived Brønsted acid catalysis has been studied by Houk and Rueping in 2014 [33]. These authors established the origin of the enantioselectivity and the differences between the catalyzed and uncatalyzed reactions, suggesting that the catalyzed reaction is, actually, a so-called
  • ), which are listed in Table 1. We used the phosphoric acid derived from 2,2'-biphenol as a model for the catalyst. The optimized geometries of the corresponding transition structures are given in Figure 1 (only those corresponding to fused cyclohexanes are shown, for the rest see Supporting Information
PDF
Album
Supp Info
Full Research Paper
Published 20 Apr 2023

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

  • Louis Monsigny,
  • Floriane Doche and
  • Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

Graphical Abstract
  • functionalization of other heteroaromatic derivatives (24j, 87% yield). It should be noted that the presence of zinc triflate, a Lewis acid, was used for the activation of the electrophilic source VI. Cobalt catalysis: In 2017, Wang described the Cp*Co(III)-catalyzed trifluoromethylthiolation of 2-phenylpyridine
  • approach. Of high interest, the modularity of the SCF2CO2Et was highlighted by its conversion into various other fluorinated residues (amide, carboxylic acid) and its selective oxidation into the corresponding sulfoxide and sulfone. I.5) Trifluoromethylselenolation of aromatic and vinylic C(sp2)–H bonds by
  • described the selective palladium-catalyzed ortho-2,2,2-trifluoroethoxylation of a series of benzaldehydes (Scheme 22, 35 examples) using the amino acid ʟ-valine in the presence of K2S2O8 and TFA at 80 °C [153]. This reaction proved to be highly tolerant to various substituents including a CF3 group at the
PDF
Album
Review
Published 17 Apr 2023

Mechanochemical solid state synthesis of copper(I)/NHC complexes with K3PO4

  • Ina Remy-Speckmann,
  • Birte M. Zimmermann,
  • Mahadeb Gorai,
  • Martin Lerch and
  • Johannes F. Teichert

Beilstein J. Org. Chem. 2023, 19, 440–447, doi:10.3762/bjoc.19.34

Graphical Abstract
  • approaches have in common that the conjugated acid of the added base is a liquid. In the literature, the improvement of mechanochemical syntheses by addition of small amounts of a liquid have been reported (LAG, liquid-assisted grinding) [43]. However, in our case, the formation of small amounts of liquid
PDF
Album
Supp Info
Letter
Published 14 Apr 2023

Dipeptide analogues of fluorinated aminophosphonic acid sodium salts as moderate competitive inhibitors of cathepsin C

  • Karolina Wątroba,
  • Małgorzata Pawełczak and
  • Marcin Kaźmierczak

Beilstein J. Org. Chem. 2023, 19, 434–439, doi:10.3762/bjoc.19.33

Graphical Abstract
  • analogues of fluorinated aminophosphonic acid sodium salts 9, 11 with phenylalanine at the N-terminus and evaluated their inhibitory activity against bovine cathepsin C. Inhibition kinetics were carried out at 37 °C for 10 minutes in acetate buffer at pH 5. Changes in product concentration versus time were
  • monitored spectrophotometrically at λ = 405 nm. Seven of the tested compounds were moderate competitive inhibitors with millimolar inhibitory activity (Table 2). Three of them at higher concentrations precipitated from 0.1 M acetate buffer at pH 5.0. Dipeptide analogues of α-fluorinated aminophosphonic acid
  • sodium salts 9 were more active against cathepsin C than β-fluorinated analogues 11. The dipeptide analogue of α-fluorinated aminophosphonic acid sodium salt bearing the valine residue as a second amino acid in the chain (9b) showed the greatest inhibitory power (Figure 1). The type of inhibition and the
PDF
Album
Supp Info
Full Research Paper
Published 12 Apr 2023

Asymmetric synthesis of a stereopentade fragment toward latrunculins

  • Benjamin Joyeux,
  • Antoine Gamet,
  • Nicolas Casaretto and
  • Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 428–433, doi:10.3762/bjoc.19.32

Graphical Abstract
  • ]2 (2.5 mol %), (S)-SEGPHOS (5 mol %), 3-nitrobenzoic acid (10 mol %), Cs2CO3 (20 mol %) in THF at 100 °C for 24 hours – we obtained homoallylic alcohol 12 in a good 86% yield, with a diastereomeric ratio (dr) of 93:7 deduced from the NMR analysis of the methyl substituent signals in CD3OD (NMR
  • secured by the NMR analysis of Mosher's esters made from (R)-(+)- and (S)-(−)-α-methoxy-α-trifluoromethylphenylacetic acid (MTPA) (see Supporting Information File 1) [23][24][25], confirming the installation of the C-11 stereocenter of latrunculins. The next steps consisted in the functionalization of 12
PDF
Album
Supp Info
Letter
Published 03 Apr 2023

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

  • Jorge de Lima Neto and
  • Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

Graphical Abstract
  • would give compounds 12 and 13. A coupling reaction would give the corresponding diaryl ether Int-2, in a similar way to that suggested by Pettit, which could be selectively reduced to afford the corresponding seco-acid (intermediates Int-3 and Int-4). Subsequent macrolactonization would give the
  • for synthesis. In general, the synthesis of these macrocyclic compounds can be accomplished by using two distinct disconnections (Scheme 3): one concerns the formation of the macrocycle through macrolactonization reaction from the former seco-acid formed from the Ar–O–Ar coupling from the aryl donor
  • Cham–Lam reactions [23][24][25][26]. However, it has been described that a Mitsunobu reaction of the seco-acid was particularly prone to an SN1 reaction, once the activated allylic alcohol yields an oxyphosphonium ion intermediate due to the conjugation to electron-rich aromatic ring, requiring some
PDF
Album
Review
Published 29 Mar 2023

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

  • Nicoleta G. Hădărugă,
  • Gabriela Popescu,
  • Dina Gligor (Pane),
  • Cristina L. Mitroi,
  • Sorin M. Stanciu and
  • Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

Graphical Abstract
  • principal component analysis (FTIR–PCA). These innovative complexes combine the characteristics of the three components and improve the properties of the resulting material such as the onsite protection against oxidative degradation of hazelnut oil unsaturated fatty acid glycerides. Also, the apparent water
  • solubility and bioaccessibility of the hazelnut oil components and antioxidants can be increased, as well as the controlled release of bioactive compounds (fatty acid glycerides and antioxidant flavonoids, namely hesperidin, naringin, rutin, and silymarin). The appropriate method for obtaining the ternary
  • and animal fat components that especially consist of fatty acid (FA) triglycerides are appropriate guest molecules for obtaining CD-based complexes. The hydrophobic long-chain moieties of the FA glycerides allow obtaining CD:FA glyceride complexes at various molar ratios [8][9], with increased
PDF
Album
Supp Info
Full Research Paper
Published 28 Mar 2023

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

  • Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

Graphical Abstract
  • ·5H2O and ascorbic acid as shown in Scheme 1. It was noted that an alkyne with an electron-withdrawing group 2c was found to be more reactive than an electron-donating group 2b in the formation of triazoloporphyrins. Similar to porphyrins, coumarin and its derivatives also possess diverse biological as
  • 6–10 in the presence of CuSO4·5H2O and ascorbic acid in DMF at 80 °C (Scheme 2). Further, the corresponding free-base porphyrins 11b–20b were obtained in good yields after demetallation of copper and zinc porphyrins under acidic conditions. Also, their zinc analogues 11c–15c were obtained by the
  • yields. Firstly, Zn(II) meso-phenyltriazole-linked porphyrin-coumarin conjugates 44a–48a were synthesized by using the “click reaction” between zinc(II) 5-(4-azidophenyl)-10,15,20-triphenylporphyrin (39a) and diverse alkyne-substituted coumarins 6–10 in DMF containing CuSO4·5H2O and ascorbic acid at 80
PDF
Album
Review
Published 22 Mar 2023

Group 13 exchange and transborylation in catalysis

  • Dominic R. Willcox and
  • Stephen P. Thomas

Beilstein J. Org. Chem. 2023, 19, 325–348, doi:10.3762/bjoc.19.28

Graphical Abstract
  • ‒H borylation, with an initial B‒Y/B‒H transborylation activating the precatalyst [62][63][64][65]. Zhang showed that benzoic acid decomposed HBpin to BH3 in situ to catalyse the C2‒H borylation of indoles (Scheme 4b) [66][67]. Gellrich reported the bis(pentafluorophenyl)borane-catalysed dimerisation
  • H-B-9-BBN, followed by B‒O/B‒H transborylation with HBpin to give the Bpin-enolate 52 and regenerate H-B-9-BBN (Scheme 12). Isotopic labelling with DBpin and H10Bpin supported this proposal. Fontaine reported that boric acid could be used as a precatalyst for the BH3-catalysed hydroboration of
  • esters, lactones, and carbonates with HBpin under microwave irradiation (Scheme 13) [57]. When HBpin and boric acid were reacted together, BH3-coordinated HBpin and O(Bpin)2 were detected by 11B NMR spectroscopy. Supported by computational analysis and single-turnover experiments, the reaction was
PDF
Album
Review
Published 21 Mar 2023

Synthesis and reactivity of azole-based iodazinium salts

  • Thomas J. Kuczmera,
  • Annalena Dietz,
  • Andreas Boelke and
  • Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

Graphical Abstract
  • -chloroperoxybenzoic acid (mCPBA) as the oxidant of choice in the presence of triflic acid (TfOH) [27][29]. Based on these promising results, the conditions were optimized using o-benzimidazole-substituted iodoarenes 4aa and 4ah (Table 1). While running the reaction in MeCN as solvent resulted in no product formation
  • , the reaction of 4aa in DCE at 50 °C gave the product 5aa in 23% yield (Table 1, entries 1 and 2). A larger amount of TfOH turned out to increase the solubility of the product and therefore impeded the purification process. However, an excess of acid is required for the electrophilic aromatic
  • substitution to take place. With 2.5 equivalents of TfOH as the optimum amount of acid the product 5aa was obtained in a yield of 69% (Table 1, entry 3). Similar results were observed with DCM at 40 °C (Table 1, entry 5). A higher amount of mCPBA did not lead to a better yield due to more washing required to
PDF
Album
Supp Info
Full Research Paper
Published 16 Mar 2023

Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements

  • Robert N. Goldberg,
  • Robert T. Giessmann,
  • Peter J. Halling,
  • Carsten Kettner and
  • Hans V. Westerhoff

Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26

Graphical Abstract
  • study should be clearly identified, e.g., by giving the UniProtKB [15] and/or Protein Data Bank [16] identifier(s) and origin (e.g., species, tissue). If the enzyme has not been registered, one should provide as much information as possible, i.e., the source and the amino acid sequence. Reporting an
  • Enzyme Commission number [17] is also helpful. If a recombinantly expressed enzyme is used, the intended amino acid sequence of the enzyme should be reported. Many biochemical substances exist as a multiplicity of species in aqueous solution (e.g., ATP is a mixture of ATP4−, HATP3−, H2ATP2−, MgATP2−, etc
PDF
Album
Perspective
Published 15 Mar 2023

Continuous flow synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin

  • János Máté Orosz,
  • Dóra Ujj,
  • Petr Kasal,
  • Gábor Benkovics and
  • Erika Bálint

Beilstein J. Org. Chem. 2023, 19, 294–302, doi:10.3762/bjoc.19.25

Graphical Abstract
  • corresponding carboxylic acid derivatives [20]. An alternative strategy to overcome the difficulties associated with the preparation of mono-6-O-tosyl-CD intermediates is the direct preparation of 6-monoaldehyde-CD with Dess–Martin periodinane in a fairly good yield of 85%, which can be considered the most
PDF
Album
Supp Info
Full Research Paper
Published 09 Mar 2023

Synthesis, α-mannosidase inhibition studies and molecular modeling of 1,4-imino-ᴅ-lyxitols and their C-5-altered N-arylalkyl derivatives

  • Martin Kalník,
  • Sergej Šesták,
  • Juraj Kóňa,
  • Maroš Bella and
  • Monika Poláková

Beilstein J. Org. Chem. 2023, 19, 282–293, doi:10.3762/bjoc.19.24

Graphical Abstract
  • : LManII from Drosophila melanogaster and JBMan from Canavalia ensiformis) were investigated. 6-Deoxy-DIM was found to be the most potent inhibitor of AMAN-2 (Ki = 0.19 μM), whose amino acid sequence and 3D structure of the active site are almost identical to the human α-mannosidase II (GMII). Although 6
  • model for structural and mechanistic inhibition studies [19][20][21]. On the other hand, Caenorhabditis elegans α-mannosidase II (AMAN-2) represents a Golgi-type α-mannosidase (GH38 family, E.C.3.2.1.114) and has the amino acid sequence and predicted 3D structure (based on a built homology model) of the
  • standards. The enzymes screened included two Golgi types (GMIIb and AMAN-2) and two lysosomal types (LManII and JBMan) (Table 1). As for the Golgi-type mannosidases, AMAN-2 is a more relevant enzyme because its amino acid sequence and the 3D structure of its active site are almost identical to those of
PDF
Album
Supp Info
Full Research Paper
Published 06 Mar 2023

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

  • Cécile Alleman,
  • Charlène Gadais,
  • Laurent Legentil and
  • François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

Graphical Abstract
  • construction of the 8-membered ring from an appropriate cyclopentane precursor. The proposed strategies include metathesis, Nozaki–Hiyama–Kishi (NHK) cyclization, Pd-mediated cyclization, radical cyclization, Pauson–Khand reaction, Lewis acid-promoted cyclization, rearrangement, cycloaddition and biocatalysis
  • precursor. The proposed strategies include metathesis, Nozaki–Hiyama–Kishi (NHK) cyclization, Pd-mediated cyclization, radical cyclization (including SmI2), Pauson–Khand reaction, Lewis acid-promoted cyclization, rearrangement, cycloaddition, and biocatalysis. In particular, the purpose will focus on the
  • formation of the fused cyclobutane acid 162 as the desired precursor for the cyclooctane formation. The ring expansion was achieved in the presence of an iridium catalyst and under blue LED irradiation, via the trapping by TEMPO or O2 of the cyclobutyl radical resulting from decarboxylation, which allowed a
PDF
Album
Review
Published 03 Mar 2023

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

  • Shubham Sharma,
  • Dharmender Singh,
  • Sunit Kumar,
  • Vaishali,
  • Rahul Jamra,
  • Naveen Banyal,
  • Deepika,
  • Chandi C. Malakar and
  • Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

Graphical Abstract
  • pharmaceutical ingredients [48] such as fenclosic acid, fentiazac, and febuxostate. Similarly, in contemporary chemistry, the amide functionality is one of the most studied functional groups. Specifically, this moiety is vital for the formation of the backbone of structural proteins and enzymes [49]. The amide
PDF
Album
Supp Info
Full Research Paper
Published 02 Mar 2023

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

  • Solomiia Borova and
  • Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

Graphical Abstract
  • acid polymer termini from the initiation were observed, and apparently only syntheses of polymers with a low molar mass could be achieved. In addition, the specific equipment necessary for supercritical CO2 applications will limit its widespread use. Dihydrolevoglucosenone (DLG) is a dipolar aprotic
  • typically set from 1000 m/z to 7000 m/z. After parameter optimization, the instrument was calibrated with PEG standards depending on the m/z range of the individual sample. Samples were prepared with sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid, SA) as matrices using the dried-droplet spotting
  • Dihydrolevoglucosenone (DLG) is prepared by hydrogenation of levoglucosenone in the presence of palladium as a catalyst. Recently, Debsharma et al. reported the CROP of levoglucosenyl alkyl ether in CH2Cl2 at 0 °C and at room temperature using triflic acid or boron trifluoride etherate as initiators [46][47][48]. The 1H
PDF
Album
Supp Info
Full Research Paper
Published 28 Feb 2023

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

  • Swantje Lerch,
  • Stefan Fritsch and
  • Thomas Strassner

Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20

Graphical Abstract
  • compounds, acylation is possible by an organic acid chloride/acid anhydride and a Lewis acid [6][7]. In the course of the development of ionic liquids (ILs) as a reaction medium for chemical reactions [8][9], the Friedel–Crafts reaction was also examined [10][11][12][13][14][15][16]. First protocols were
  • %, with minor formation of the ortho-isomer when using benzoic acid anhydride. Bromobenzene, which is electron poor and less reactive towards acylation, was also used as a substrate in the acylation reaction, but no product was observed. This indicates that the ionic liquid 6, having the same substituent
PDF
Album
Supp Info
Full Research Paper
Published 23 Feb 2023

Germacrene B – a central intermediate in sesquiterpene biosynthesis

  • Houchao Xu and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

Graphical Abstract
  • -selinene (10) (Scheme 4A) [43]. Interestingly, while racemic juniper camphor (11) is formed from 1 upon acid treatment [50], this reaction with diluted sulfuric acid in acetone results in (rac)-11 quantitatively. This observation is explained by a protonation-induced cyclisation, successive addition of
  • reports, so it remains unknown if the isolated materials arose from 1 by enzymatic or acid-catalysed reactions. The sesquiterpenes 9 and 10, besides several other products, were also prepared through pyrolysis of elemyl p-nitrobenzoate (23) (Scheme 8A) [56]. Because of the enantiomerically pure starting
  • was determined by NMR spectroscopy and verified by the acid-catalysed conversion into δ-selinene (26) (Scheme 9A) [72]. The same compound 18 was also reported from the closely related alga Laurencia nipponica [73] and from lime oil (Citrus aurantifolia) [74]. Fully assigned 1H and 13C NMR data were
PDF
Album
Review
Published 20 Feb 2023

Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones

  • Benedikt Kolb,
  • Daniela Silva dos Santos,
  • Sanja Krause,
  • Anna Zens and
  • Sabine Laschat

Beilstein J. Org. Chem. 2023, 19, 176–185, doi:10.3762/bjoc.19.17

Graphical Abstract
  • example, the sequential hydrozirconation/carbonylation of propargylic ethers 18 reported by Donato [58] yielded α,β-unsaturated lactones 19. Beside the hydrozirconation/acylation sequence of nitriles utilizing acid chlorides published by Majoral/Floreancig [59][60], Cox revealed that terminal alkynes 16
  • could be converted to enones 20 by hydrozirconation followed by Pd-catalyzed acylation with acyl chlorides 21 [61]. The substrate scope required aryl units at either alkyne or acid chloride unit. Recently, we could extend this method to alkyl-substituted alkynes 16 and acetyl chloride (22), providing
  • sequential reaction, different enynes 25 and acid chlorides 26 were studied (Table 4). Fortunately, all desired products 27 were formed in ≥95% (2E,4E)-configuration (via 1H NMR). First, phenylenyne 25a (R1 = Ph) was chosen as the starting material and reacted with different acid chlorides 26a–s (Table 4
PDF
Album
Supp Info
Full Research Paper
Published 17 Feb 2023
Graphical Abstract
  • scent gland macrolides can be biosynthesized by the frogs [7], although the macrolides are produced from the fatty acid biosynthetic pathway. The gas chromatographic separation obtained with the chiral phase also allowed the determination of the identity of the minor diastereomers formed during the
PDF
Album
Supp Info
Full Research Paper
Published 16 Feb 2023

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

  • Eric Gayon,
  • Guillaume Lefèvre,
  • Olivier Guerret,
  • Adrien Tintar and
  • Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

Graphical Abstract
  • -coupling systems involving this reagent are thus particularly scarce, and few examples are reported, using for some of them Ni-based catalysts [33]. 1-Bromopenta-1,3-diene used in the synthesis of 4 (Scheme 6) is not an exception. The expected (E,E) isomer was easily obtained from sorbic acid, a renewable
  • pheromone 4 can be obtained in a convergent total synthesis with a key iron-mediated cross coupling starting from sorbic acid and a commercially available α,ω-chloroalcohol in 4 steps, with an overall 38% yield. This method can also be used for the alkylation of dienyl bromides by classic aliphatic or
PDF
Album
Perspective
Published 14 Feb 2023

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

  • Sedat Ünal,
  • Gamze Varan,
  • Juan M. Benito,
  • Yeşim Aktaş and
  • Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

Graphical Abstract
  • also have increased. The 6-O-capro-β-CD and poly-β-CD-C6 derivatives used in the study are cyclodextrin derivatives with the same core structure. Heptakis(6-O-hexanoyl)-β-CD (6-O-capro-β-CD) is a primary face-modified amphiphilic CD derivative with a 6C fatty acid chain attached via an ester bond to
PDF
Album
Full Research Paper
Published 13 Feb 2023

Nostochopcerol, a new antibacterial monoacylglycerol from the edible cyanobacterium Nostochopsis lobatus

  • Naoya Oku,
  • Saki Hayashi,
  • Yuji Yamaguchi,
  • Hiroyuki Takenaka and
  • Yasuhiro Igarashi

Beilstein J. Org. Chem. 2023, 19, 133–138, doi:10.3762/bjoc.19.13

Graphical Abstract
  • limited number of attempts include an antifungal lipopeptide nostofungicidine [4] and an antioxidant nostocionone [5] from Nostoc commune, an unusual antibacterial n−1 fatty acid from N. verrucosum [2], and the sacrolides, antimicrobial oxylipin macrolactones from Aphanothece sacrum [6][7]. Nostochopsis
  • ear, and decrease writhing response induced by intraperitoneal injection of acetic acid in rodent models [11], thus supporting the ethnophamacological testimonies. Moreover, radical scavenging activity [11][12], hyaluronidase inhibitory activity [13], and tyrosinase inhibitory activity [14] were
  • , 129.1, and 128.9) observed in the 13C NMR spectrum (Table 1), revealing that compound 1 has a linear structure. The 1H NMR spectrum contained resonances typical of an unsaturated fatty acid, such as non-conjugated olefins with four-proton integration (δH ca. 5.34–5.32, 4H), a bisallylic methylene (δH
PDF
Album
Supp Info
Letter
Published 09 Feb 2023

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

Graphical Abstract
  • ) and the dimethylacetal derived from chloroacetaldehyde 11 affords the dithiolane 12. This 1,3-dithiolane spontaneously rearranges to the 1,4-dithiane with an elimination of hydrochloric acid by refluxing in a mixture of water and toluene. This two-step procedure constitutes a scalable and simple
  • excess of a perbenzoic acid, as shown for the oxidation of 6 to 7 [33][34]. Partial oxidations are also possible, but lead to mixtures of sulfoxides, including cis- and trans-sulfoxide stereoisomers (see also chapter 6). For a more detailed and extensive discussion of the synthesis of 1,4-dithiin
  • analog 26 should also be a reactive dienophile [51], but is a less useful building block, as it reacts twice and the adducts will not be as easily desulfonylated. The dienophile 7 reacts with a wide range of dienes at room temperature, without the need for a Lewis acid catalyst. This is particularly
PDF
Album
Review
Published 02 Feb 2023

Synthesis and characterisation of new antimalarial fluorinated triazolopyrazine compounds

  • Kah Yean Lum,
  • Jonathan M. White,
  • Daniel J. G. Johnson,
  • Vicky M. Avery and
  • Rohan A. Davis

Beilstein J. Org. Chem. 2023, 19, 107–114, doi:10.3762/bjoc.19.11

Graphical Abstract
  • ][8][9]. Interfering with this process means the parasite is unable to regulate Na+ [10], resulting in a significant increase in the acid load of the cell, which can lead to parasite growth inhibition and ultimately parasite death [8][9]. One of the current Series 4 aims includes lead optimisation to
PDF
Album
Supp Info
Full Research Paper
Published 31 Jan 2023
Other Beilstein-Institut Open Science Activities