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Search for "catalytic" in Full Text gives 1500 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics
Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91
- viruses and plays a crucial role in viral RNA replication. In the proteome of SARS-CoV-2, the catalytic subunit nsp12, expressed together with the cofactors nsp7 and nsp8, constitutes the RdRp [8]. RdRp is usually targeted by nucleotide analogue inhibitors (NAIs) [9]. This class of antivirals can inhibit
Carbonylative synthesis and functionalization of indoles
Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87
- years later, they performed, using the same catalytic and oxidative conditions, another oxidative heterocyclization/alkoxycarbonylation process for the synthesis of N-substituted indole-3-carboxylic esters and N–H free indole-3-carboxylic esters from N-substituted 2-alkynylanilines and 2-alkynylanilines
- , Davies et al. published a paper presenting a new method for the synthesis of indoles from o-nitrostyrenes by using a different catalyst system and performing the reaction under mild conditions [27]. At first they decided to change the catalytic system applied by Söderberg using 1,10-phen instead of PPh3
- as ligand, because it was already known that catalysts derived from palladium(II) salts and bidentate nitrogen ligands were highly reactive systems for the reduction of o-nitrostyrenes [28][29][30]. The catalytic system Pd(OAc)2/1,10-phen worked better than Söderberg´s one (Pd(OAc)2/PPh3) under mild
Enhancing structural diversity of terpenoids by multisubstrate terpene synthases
Beilstein J. Org. Chem. 2024, 20, 959–972, doi:10.3762/bjoc.20.86
- , that bind trinuclear magnesium clusters for diphosphate abstraction, whereas class II TSs have a DXDD motif that acts as the catalytic acid. Recently, several novel unconventional TSs that share low sequence and structural similarities with classical TSs have been discovered and comprehensively
- cyclization reactions to form pre-sodorifen (103, Figure 8b), which was subsequently converted to 102 by TS [57]. Key residues lining the catalytic cavity of SpSodMT, Q57, F58, N219, V273, and L302, were found to affect product outcomes, and mutagenesis of these residues resulted in new C16-prenyl substrates
Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles
Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84
- conditions: b) 4de (0.105 mmol, 1.0 equiv), PhSH (0.16 mmol, 1.5 equiv), K2CO3 (0.21 mmol, 2 equiv), MeCN (1 mL), DMSO (0.4 mL), 25 °C, 2 h. Enantiomeric ratio (er) determined by high-performance liquid chromatography (HPLC) analysis of the purified compounds. A rationale for the catalytic cycle for the Heck
(Bio)isosteres of ortho- and meta-substituted benzenes
Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78
- catalytic system of B2cat2 and 4-phenylpyridine to form pyridine-boryl radicals which initiated ring expansion. The method was shown to be similarly tolerable of functional groups as Procter’s synthesis. Intramolecular crossed [2 + 2] cycloadditions offer an alternative approach to 1,2-disubstituted BCHs
Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria
Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75
- and kinetic experiments or crystallization of the active homodimer will be required to resolve the catalytic mechanism. If NnlA is specific for NNG as suggested by these results, it is worth speculating about potential functions of NNG and other nitramine natural products. Bacterial natural products
Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions
Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74
- the byproduct triphenylphosphine oxide, necessitating chromatography which resulted in some hydrolysis. There are a number of catalytic activation strategies for Appel or Mitsunobu reactions such as those described by the Denton group [30], and Rutjes and co-workers [31], and while these may prove
Advancements in hydrochlorination of alkenes
Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72
- ]. It is important to note that we are not aware of any catalytic enantioselective hydrochlorination reactions of alkenes. Conjugate additions of HCl to a complex of α,β-unsaturated acids, incorporated in an α-cyclodextrin, which corresponds to a formal hydrochlorination was reported by Tanaka and co
- only 10–25% of the primary chloride for the reaction of tert-butylethylene with HCl in the presence of benzoyl peroxide [33]. c) Several metal halides such as AlCl3, SnCl4, FeCl3, and CuCl exhibit catalytic activities for the hydrochlorination of alkenes. The enthalpy of formation for the hydrogen
- Syntheses [83]. The proposed catalytic cycle is shown in Figure 7 and involves the following steps. First, a cobalt hydride complex A is formed in situ from Co(II) complex and the silane. Then, regioselective alkene hydrocobaltation takes place. This step is highly regioselective, placing the cobalt atom on
Research progress on the pharmacological activity, biosynthetic pathways, and biosynthesis of crocins
Beilstein J. Org. Chem. 2024, 20, 741–752, doi:10.3762/bjoc.20.68
- enzymes in crocin biosynthetic pathways CCDs: Crocin biosynthesis initiates with the catalytic cleavage of the C‒C double bond by CCDs at various sites of the carotenoid skeleton. The cleavage generates a carbonyl group at the end of the formed carotenoid derivatives [88]. The CCD family can be
- CsCCD2 that exhibits broader substrate specificity and higher catalytic efficiency through computational modeling. Heterologous expression of the S323A mutant of CsCCD2 in yeast led to a 4-fold enhancement in the production of 1, with a crocetin (1) titer of 107 mg/L in a 5-liter fed-batch fermentation
- supply, overexpressing PsBCH-CsCCD2, and optimizing the fermentation medium, the yield of crocetin (1) reached 12.43 ± 0.62 mg/L in a 5 L bioreactor [115]. While CCD has a higher catalytic activity at low temperature, the biosynthesis of zeaxanthin (7) is more suited to a higher temperature. As such, Liu
Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis
Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67
- only for the incorporation of one extender unit [2][3]. Although enzyme domains with various specialised catalytic functions can be found as integral part of polyketide synthases, three domain types are fundamental to their biosynthesis, resembling the same logic as observed for fatty acid biosynthesis
- ester 5 was coupled with the carboxylic acid (S)-8, derived from ʟ-leucine ((S)-6) via hydroxyacid (S)-7, to yield the amide (S)-9. Deprotection through catalytic hydrogenation to (S)-10, saponification of the acetate ester and Steglich esterification with N-acetylcysteamine gave access to the desired
Genome mining of labdane-related diterpenoids: Discovery of the two-enzyme pathway leading to (−)-sandaracopimaradiene in the fungus Arthrinium sacchari
Beilstein J. Org. Chem. 2024, 20, 714–720, doi:10.3762/bjoc.20.65
- AsCPS synthesized copalyl diphosphate and that AsPS then converted it to (−)-sandaracopimaradiene. Since AsPS and AsCPS have distinct domain organizations from those of known fungal TCs and are likely generated through fusion or loss of catalytic domains, our findings provide insight into the evolution
- gene (AsGGS), suggesting that they are related to the biosynthesis of diterpenes (Figure 2A). AsPS and AsCPS consist of αβ and αβγ domains, respectively. Further sequence analysis revealed that the β domain of AsPS contains a mutation at the catalytic aspartic acid residue, indicating that this enzyme
SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes
Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64
- since it is known to be reduced by photocatalysts such as Cu(dap)2Cl [17]. This perfectly fits a catalytic cycle involving the reduction of Ts-ABZ (3) followed by oxidation of the carbon radical to form a carbocation and regenerate the ground state catalyst. Styrene (1a) was used as model substrate
Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives
Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62
- based on derivatives of imidazolidin-4-one were synthesised and characterised. The catalytic activity and enantioselectivity of their corresponding copper(II) complexes were studied in asymmetric Henry reactions. It was found that the enantioselectivity of these catalysts is overall very high and
- itself constitutes a stereocentre [4]. The specific pairing of a chiral ligand and a metal ion is essential for the catalytic characteristics and its effectiveness of the complex in asymmetric syntheses [1][2][3]. In recent years, our research group has synthesised a series of chiral ligands based on 2
- catalytic arrangements of the most enantioselective catalysts, including anchoring on polystyrene beads [8][9], magnetic nanoparticles [10], or block copolymers composed of PEG-poly(Glu) [11]. These modifications have facilitated the recycling of the catalysts, offering numerous advantages, including
Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines
Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59
- (PPh3)2Cl as catalyst, the model reaction also afforded the corresponding product 4a in 31% yield, demonstrating the H–Pd(II)–X species could be a possible catalytic species (Scheme 4d). According to the UV–visible spectra, the only absorbing species at 467 nm consists in the pre-catalytic system Pd(OAc
- subsequent attack of amine 3 at the latter stage would afford the unsaturated ε-AA derivative 4 and regenerates the Pd(0)Ln to close the catalytic cycle. Different from the reactive site of 1,3-diene, the hybrid alkylPd radical I selectively adds to the central position of the allenyl group of allene 5a
A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts
Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54
- sphere, accessing more diverse fused imidazolium frameworks and different peripheral functionality offers significant scope to influence catalytic properties. Few studies into L-shaped imidazolylidines have explored core motifs beyond ImPy, with NHCs derived from two π-rich rings fused together
A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A
Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51
- is relatively high. However, this is similar to other myo-inositol dehydrogenases whose KM values are also in the mM range [12][16]. Hyg17 showed a higher catalytic efficiency of 366.7 ± 46.96 M−1 s−1 with myo-inositol as compared to the 29.6 ± 5.28 M−1 s−1 for scyllo-inositol. This reduced catalytic
- efficiency can be attributed to the reduced kcat and increased KM for scyllo-inositol over myo-inositol. We also found that the catalytic efficiency for NAD+ was 452.4 ± 54.49 M−1 s−1 (Table 1 and Figure 2f). Sequence similarity network We generated a sequence similarity network (SSN) for the protein family
Recent developments in the engineered biosynthesis of fungal meroterpenoids
Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50
- analyses of these enzymes and the invention of AlphaFold2 have facilitated access to their structures. Structure-based mutagenesis combined with applications of unnatural substrates has further diversified the catalytic repertoire of these enzymes. The information in this review provides useful knowledge
- residues, the catalytic activities of these enzymes were exchanged [34]. From 24, PrhA V150L/A232S produced 27, and AusE L150V/S232A produced 28. Surprisingly, PrhA V150L/A232S/M241V catalyzed additional oxidations of 27 to produce compounds 29 and 30, as unnatural products. As demonstrated in these
- compounds (40, 43, 44, 47, 48, 50, 51, and 53–55) (Figure 7A). In addition, a structure-based mutagenesis study of SptF was performed to further amplify its catalytic potential. Firstly, the hydrophobic residues Ile63, Phe133, and Ile231, which compose the substrate binding site of SptF, were mutated. As a
Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group
Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47
- in acetonitrile. However, the simplest and most effective method was the addition of a catalytic amount of HClO4 [14]. Although studies on photoacylotropic systems have been carried out for some time [14][16], only within the framework of this work, a method for the preparative synthesis of
Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors
Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46
- quinolines and indoles [24], pyridines [25], and imines [26], the reactions of 5 and 15c with ammonia borane (3 equiv) in the presence of a catalytic amount of B(C6F5)3 in toluene as an aprotic solvent at a temperature of 80 °C afforded aminoboranes 17b (R1 = F) and 17c (R1 = CH3) as main products along with
- accordance with the results obtained for dimethylated [1,3]thiazolo[4,5-b]pyridine 15c, the corresponding aminoboranes 17d and 17e were formed when 6-bromo[1,3]thiazolo[4,5-b]pyridine 12c was treated with ammonia borane in toluene at 45 °C in the presence of a catalytic amount of B(C6F5)3 (Scheme 3). Whilst
Switchable molecular tweezers: design and applications
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
- : (i) metal coordination for closing/opening of the tweezers, (ii) reversible oxidation, (iii) pyrazine guest binding in the oxidized state. Such an example demonstrates the potential of the molecular tweezers architecture to go beyond simple two-level switches and access multilevel systems. Catalytic
- tweezers 16 were then synthetized by Vives and co-workers using a 6,6”-substituted terpyridine this time bearing zinc(II)–salphen complexes [47]. The catalytic activity was evaluated in an acetyl transfer reaction between pyridinemethanol derivatives and anhydrides. For the ortho derivative, a rate
- substrate-dependent allosteric with potential applications for regulating cooperative catalytic reactions. Terpyridine-based tweezers have also been developed by Bencini, Lippolis, and co-workers for the selective recognition of diphosphate with [9]aneN3 unit 17 [48]. When closed with Zn(ClO4)2, the anion
Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination
Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43
- protodeauration was not confirmed [27]. Follow-up studies in our lab revealed that the alkylgold intermediate (2a, Scheme 1) reacts significantly slower than observed rates for catalytic hydroamination, suggesting it is not a viable intermediate in the catalytic cycle [28]. It has been shown that C(sp2)-vinylgold
- were shown to proceed with anti-selectivity and that was used as support for gold catalysis [15], but mechanism studies of triflic acid catalysis showed a preference for anti-selectivity as well [31]. Despite similarities, control studies indicate meaningful differences in catalytic activity between
- generally acidic conditions that initiate cyclization [34][35]. These observations are critical for informing future discussion and experiments related to this important reaction. Results Ligand effect To examine the catalytic activity of gold with ligands of different electronic properties, we used our
Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells
Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39
- modular synthases [5]. They used the inhibitors of individual domains to investigate the biosynthetic pathway of blue pigment synthetase A, which produces the blue pigment indigoidine, and demonstrated that their results complement the proposed biosynthetic pathway. Furthermore, among the catalytic domain
Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives
Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37
- (Table 1, entries 14–16). The decisive influence of the base for this reaction is probably due to a concerted metalation–deprotonation mechanism [27][28][29][30]. Then, the scope of the Pd-catalyzed direct arylation for access to fluoranthenes was investigated (Scheme 2). The first step of the catalytic
- -aryl-8-bromonaphthalene A (Scheme 2). This catalytic cycle is followed by a second involving oxidative addition of 1-aryl-8-bromonaphthalene A, followed by intramolecular C–H coupling of the two aryl rings to give the fluoranthene derivative. Consequently, the use of arenes bearing substituents at the
Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
- counterparts, due to their recyclability, ease of handling, and low cost [40]. Carbon-based solid acid catalysts especially are an interesting catalyst class, because they display low corrosiveness, toxicity, and higher catalytic activity, while also being insoluble in most organic solvents. The large amount
- of strong acidic sites that are on the carbon-based solid acids enhance their catalytic ability, compared to traditional Lewis and protic acids [41][42][43]. The most common examples in literature for the reaction of the synthesis of BIMs under solvent-free conditions utilize either protic acids
- . Finally, another nucleophilic attack by a second molecule of indole to IV is occurring, forming the desired BIM 12, while simultaneously releasing the catalyst, rendering it available for another catalytic cycle [80]. Halogen bonding processes Recently, halogen bonding (XB) interactions have emerged as an
Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters
Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35
- (3.15 to 2.06 × 105 s−1) [34] when employing catalytic IrIII excited state reductants with moderate reducing potentials (E1/2red[IrIV/*IrIII] ≈ −1.13 V vs Fc0/Fc+ in MeCN) [35]. This suggests that in the absence of a sufficiently strong driving force, BET and fragmentation compete to influence the
- resulting concentration of radicals. In such instances, opting for a stronger catalytic reductant or utilizing a stoichiometric electron donor can greatly improve the efficiency of radical generation. On the other hand, additional factors such as the ability of Brønsted and Lewis acid additives to promote
- hydrogen atom transfer (HAT) or sequential electron transfer and proton transfer (ET/PT) steps. Alternatively, redox-neutral transformations can be envisioned using catalytic reductants, which can enable a complementary scope of downstream functionalizations (Scheme 2B). In this perspective, we present an
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