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Search for "oxidation" in Full Text gives 1439 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes
Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176
- is, therefore, urgently needed. Numerous techniques have been explored and used for the removal of dyes from water including coagulation, flocculation, adsorption, oxidation, electrolysis, biodegradation, and photocatalytic approaches [4][5]. Among these approaches, adsorption is most commonly used
Halogenated butyrolactones from the biomass-derived synthon levoglucosenone
Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175
- Baeyer–Villiger oxidation affording the fluorinated, chlorinated, and brominated dideoxyribonolactones. Keywords: butyrolactone; cyrene; fluorine; halogenation; levoglucosenone; Introduction The γ-butyrolactone ring is a privileged scaffold found in natural products and can be used as a valuable
- envisaged that halogenation could be combined with the Baeyer–Villiger oxidation which yields the butyrolactones by excision of C5, a reaction which is tolerant to substitution at C3 and can be carried out on a kilogram scale [30]. The present work was focussed on the development of additional halogenation
- reactions for 5 to give substrates for the Baeyer–Villiger oxidation resulting in halogenated butyrolactones, which is an unexplored chemical space for this biomass derivative. Results and Discussion The halogenated LGO derivatives 7a and 7b were prepared using literature procedures [22][23]. The reaction
Enantioselective radical chemistry: a bright future ahead
Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174
- are photoenzymatic catalysis and electrochemical oxidation or reduction. Free radicals can undergo several types of basic reactions (Figure 1B), including atom or group transfer, addition to a π-bond, and radical–radical combination. In an atom or group transfer reaction, an atom or group is
- oxidation or reduction of the radical yields a cationic or anionic intermediate that participates in a subsequent step through a polar mechanism. An important aspect of many of these radical reactions is that they can result in the formation of new carbon–carbon bonds, a fundamental goal in organic
- ]. MacMillan obtained chiral free radicals by stoichiometric single electron transfer (SET) oxidation of enamines, formed by the reaction between chiral secondary amines and aldehydes. This mode of activation was called SOMO (singly occupied molecular orbital) catalysis and was employed in several organic
Pathway economy in cyclization of 1,n-enynes
Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173
- ]. Similar to “atom and step economies”, this concept emphasizes prioritizing the minimization of redox manipulations during synthesis to achieve linear and stable progression of oxidation states in intermediates. In recent years, “pot economy” and “time economy” were proposed by Hayashi, underscoring the
- 2, path b). In the following years, Liu and co-workers discovered that the protonation of intermediate 2 triggered its conversion to intermediate 3, which subsequently underwent oxidation with oxygen, resulting in the generation of an indenone skeleton 6 [9]. This tunability achieved efficient and
- radical initiated intramolecular cascade cyclization of 1,n-enynes to provide structurally diverse heterocycles (Scheme 4) [11]. Solvent selection dictated divergent reaction pathways under I2/TBHP oxidation. When an acetonitrile/water mixed solvent was used, iodine radical addition to the alkyne
A chiral LC–MS strategy for stereochemical assignment of natural products sharing a 3-methylpent-4-en-2-ol moiety in their terminal structures
Beilstein J. Org. Chem. 2025, 21, 2243–2249, doi:10.3762/bjoc.21.171
- methods. We had also independently re-isolated compound 1 (1.2 mg) from the fungus Fusarium sp. (see Supporting Information File 1) and subsequently subjected 100 μg of 1 to the sequential degradation steps; (1) p-nitrobenzoylation of the two hydroxy groups, (2) RuO4 oxidation to cleave olefins including
Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates
Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169
- derivatives 10a,b exhibiting an extended aromatic ring system were isolated instead of the expected primarily formed congeners 11a,b, due to in situ oxidation of the C–C bond. Alternatively, when the one-pot method (method B, bismuth nitrate pentahydrate + PPA, MeOH, closed vial, 110 °C) was applied for the
Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings
Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166
- in 66%–87% yields. Boc-amino ester (2e), dipeptide (2f), apivalate ester (2g) and ethinyl estradiol (2h) skeletons were also tolerated well. According to the previous works [163] and the experimental results, the authors proposed a plausible mechanism. Firstly, the anodic oxidation of [Cp2Fe
- ][194][195][196][197][198][199][200], the authors proposed a possible reaction mechanism. For the synthesis of 11a in Pt plate electrodes, two-electron anodic oxidation of I− formed I+. Addition of I+ to C≡C in 10 resulted in the production of A. Meanwhile, continuous reduction of H2O at the cathode
- reaction also showed high compatibility with 2-naphthyl (15h), 2-thiophenyl (15i), ferrocenyl (15j), cyclohexenyl (15k) and tert-butyl (15l) incorporated at the ethynyl moiety. According to the results of control experiments, a plausible mechanism was presented. Firstly, one-electron oxidation of 14a
C2 to C6 biobased carbonyl platforms for fine chemistry
Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165
- promising strategy for sustainable energy development involves the electrochemical oxidation of biomass-derived feedstocks. Recent work by Shen et al. demonstrates that glycolic acid (GA), also referred to as hydroxyacetic acid, can be synthesized from glycerol (GLY) using a copper single-atom
- electrocatalyst supported on nitrogen-doped carbon nanosheets (Cu/NCNSs). This catalyst exhibits high activity for the oxidation of various substrates, including GLY, gluconic acid (GLU), 5-hydroxymethylfurfural (HMF), benzyl alcohol (BA), furfuryl alcohol (FA), and ethylene glycol (EG) (Scheme 7) [35]. Park et
- wettability (Scheme 11). The group of Gupta et al. investigated the kinetics of the oxidation by tetrachloroaurate(III) in acetic acid–sodium acetate buffer medium of some neutralized α-hydroxy acids, including glycolic acid (GA), lactic acid (LA), α-hydroxybutyric acid (IB), mandelic acid (MA), atrolactic
The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products
Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164
- modification of the terminal double bond afforded ketoaldehyde 31. The 2-bromoallylation [15] of 31 with boronic ester 32 stereoselectively constructed the C3–OH group to give homoallylic alcohol 33. Next, a successive manipulation by removal of TBS group, CSA-catalyzed ketalization, and DMP oxidation of the
- to ketone 48 via a seven-step transformation. Finally, removal of the TBS group in 48 followed by a sequential reduction and selective oxidation of allylic primary alcohol achieved the total synthesis of (−)-cyrneine A (7). The authors then moved forward to the synthesis of other target molecules
- (Scheme 3) [31][32]. Oxidation state adjustment of 48 led to the ketone 49. Starting from this common intermediate, firstly, base-promoted double bond migration and oxidation at the γ-position gave tertiary alcohol 50. Deprotection of acetyl in 50 followed by selective oxidation delivered (−)-cyrneine B
Further elaboration of the stereodivergent approach to chaetominine-type alkaloids: synthesis of the reported structures of aspera chaetominines A and B and revised structure of aspera chaetominine B
Beilstein J. Org. Chem. 2025, 21, 2072–2081, doi:10.3762/bjoc.21.162
- synthesis of natural products [10][55][56], in early 2009, our group disclosed a highly efficient four-step, enantioselective and diastereodivergent synthesis of (–)-chaetominine (1) and with one more step, of another diastereomer [57][58]. The strategy features a DMDO oxidation-triggered [59] double
- synthesis of diastereomers of versiquinazoline H: the fourth generation strategy In all our previous syntheses of chaetominine and isochaetominine alkaloids [57][58][60][61][62][63][64][65], the key DMDO-oxidation triggered double cyclization always accompanied with a monocyclization product. It was
- anticipated that if we run the work-up procedure under more basic conditions, one would be able to obtain solely double cyclization products. Indeed, alternation of the work-up protocol by employing an aged solution of K2CO3/MeOH (stood at rt overnight, pH 11) to quench the DMDO oxidation reaction of
Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design
Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161
- introduce the carboxylic acid group a sequence of formylation/oxidation reactions was used. Vilsmeier–Haack reaction of 1 afforded 6-oxoindolo[1,2-c]quinazoline-12-carbaldehyde (2) (Scheme 1). All attempts to oxidize the aldehyde group of 2 to the corresponding carboxylic acid were hampered by the oxidative
- sensitivity of the indole moiety, resulting in poor selectivity and formation of complex product mixtures. In particular, Jones oxidation of 2 gave the corresponding 6-oxoindolo[1,2-c]quinazoline-12-carboxylic acid (3) in a low yield (Scheme 1) making it necessary to look another synthetic pathway. Of
- interest, compound 2 applied as a useful substrate for a Baeyer–Villiger oxidation mediated by oxone, which selectively converted the aldehyde to the formate ester, yielding 6-oxo-5,6-dihydroindolo[1,2-c]quinazolin-12-yl formate (4). Subsequent hydrolysis of 4 furnished indolo[1,2-c]quinazoline-6,12-dione
Bioinspired total syntheses of natural products: a personal adventure
Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160
- TBS protection in one pot. Oxidation of the primary alcohol using Swern oxidation gave the hydroxy aldehyde 3, which was activated with a formal silicon cation to trigger the Prins cyclization terminated by the tertiary alcohol, affording silylated bicycle 9 directly through the designed bioinspired
- form a cis-substituted tetrahydrofuran (THF) moiety fused to the lactone with higher oxidation states. Notably, the phenyl ring contains three oxygen substituents in the form of alcohol and methoxy groups at different positions. Biosynthetically, the THF ring was supposed to be formed through a
- benzylic oxidation to generate a para-quinone methide (pQM) intermediate. Using fusarentin 6-methyl ether as an example, pQM intermediate 10 would be generated. The C10 alcohol should successively undergo an oxa-Michael addition reaction to close the THF ring, providing 7-O-demethylmonocerin. Similarly
Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis
Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154
- internal nucleophiles (Scheme 4), that could be used instead of the alcohol. The carboxylic acid-containing silane 7 (R = COOH), which was obtained by stepwise oxidation of the alcohol 7d, failed to give the desired lactone 8t product due to O-arylation of the carboxylic acid, leading to phenyl alkyl ester
Photochemical reduction of acylimidazolium salts
Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153
- suitably electrophilic substrate at the carboxylic acid oxidation level provides an acylazolium species B, which typically reacts directly with nucleophiles or may first be transformed into the corresponding enolate derivative. Regardless of the individual pathway, NHC-catalyzed reactions of this type
- acid derivative substrates [16]. Over the last few years, a wide range of valuable NHC-catalyzed transformations have also been developed that incorporate redox steps. As an enamine species, single-electron oxidation of a Breslow intermediate is comparatively favored with the resulting open shell
- synthesis with complete reduction to the alcohol followed by partial re-oxidation often being conducted. Conclusion In conclusion, we have developed novel light-driven methodologies for the reduction of acylazolium salts using benzoylimidazolium triflate as a model substrate. In the presence of a
Enantioselective desymmetrization strategy of prochiral 1,3-diols in natural product synthesis
Beilstein J. Org. Chem. 2025, 21, 1932–1963, doi:10.3762/bjoc.21.151
- sequence including oxidation and subsequent hydrogenation. The Huang group reported their synthesis of (+)-brazilin and its racemic form in 2022 (Scheme 5) [34]. They first evaluated the feasibility of the Prins/Friedel–Crafts tandem reaction in the construction of the 6/6/5/6 tetracyclic skeleton
- 139, epoxide 136 was first prepared from (R)-130 in two steps. Parikh–Doering oxidation of 136 followed by addition with Et2Zn in the presence of ligand 137 afforded alcohol 138, which was subsequently converted into amine 139 via a seven-step sequence. With the fragments 135 and 139 in hand
- ) and the following acid-mediated cyclization formed another tetrahydrofuran ring. The resulting compound was then converted into lactone 174 via 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO)-mediated oxidation. Lactone 174 was then converted into aldehyde 175 in three steps, which underwent Horner
Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs
Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148
- alkylating agents 1–3. The motivation behind these experiments was to explore whether these compounds, which individually exhibit no appreciable redox activity in the potential window applied, can chemically modify (alkylate) serum albumin and thus suppress its characteristic oxidation peaks. Human serum
- albumin was chosen as a model protein because of its well‐characterized structure and the presence of reactive sites that are known to be susceptible to alkylation. In standard aqueous media, the electrochemical oxidation of HSA can be observed via LSV as a broad wave, which is often attributed to the
- oxidation of amide and other amino acid side‐chain fragments. By tracking changes in this oxidation signal upon addition of an alkylating agent, we can infer whether the agent has effectively reacted with (and thus structurally altered) the protein. As illustrated by the black trace in the LSV plot, pure
Photoswitches beyond azobenzene: a beginner’s guide
Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143
- the photoswitch. Examples of photogenerated side reactions can be oxidation or irreversible rearrangements. In the following sections, seven classes of photoswitches beyond the classic azobenzene are introduced and discussed (Scheme 1). Each of them shows unique photophysical behaviour and has
- be synthesised through oxidation of aminoheteroarenes 12 (Scheme 4A) or reduction of nitroheteroarenes 13 (B). Bayer–Mills coupling (Scheme 4C) is suitable for both symmetric and asymmetric targets, usually in acidic conditions. Basic conditions [14] are more effective with very electron-poor
- , the synthesis can be directed towards the desired target with the use of protecting groups [41]. For the synthesis of azothiazoles 25, the addition of phenylhydrazine (22) to ammonium thiocyanate followed by ring closure and oxidation was recently proposed (Scheme 6A) [42]. Heteroarylazo-1,2,3
[3 + 2] Cycloaddition of thioformylium methylide with various arylidene-azolones in the synthesis of 7-thia-3-azaspiro[4.4]nonan-4-ones
Beilstein J. Org. Chem. 2025, 21, 1791–1798, doi:10.3762/bjoc.21.141
- (Supporting Information File 1, part 4). In contrast, compounds 8 and 6 quickly transformed into the single product (by TLC analysis) under the action of alkali, but this product was unstable in its individual form after evaporation from the solution (Supporting Information File 1, part 4). Oxidation, however
- , proved to be a more promising derivatization approach (Scheme 4). Thus, the short-term action of hydrogen peroxide successfully converted compounds 7e, 7c, and 9e to their corresponding sulfoxides 11e, 11c, and 13e. However, prolonged oxidation led not only to sulfone formation but also to deeper
- transformations. For example, compound 7e underwent both sulfone formation and S/O atoms exchange in the heterocyclic core. For derivatives 6 and 8, any oxidation conditions resulted in even more complex product mixtures (presumably due to the additional sulfur atom in the second ring), whose structures could not
Research progress on calixarene/pillararene-based controlled drug release systems
Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139
- destruction of aromatic macrocycles and their components. The external triggers include: pH [93], oxidation–reduction states [94], enzymatic actions [95], and light [96]. Specifically, within host–guest frameworks, the capability to meticulously regulate the assembly of complexes and synchronize them with
Preparation of a furfural-derived enantioenriched vinyloxazoline building block and exploring its reactivity
Beilstein J. Org. Chem. 2025, 21, 1737–1741, doi:10.3762/bjoc.21.136
- oxidation in methanol in batch electrolysis conditions, providing unsaturated esters S-3d and R-3d, respectively (Scheme 2). The previously used one-reactor two-step conditions were found to be productive for the electrosynthesis of S-3d, requiring the addition of acetic acid for the intermediate spiroketal
- 4d oxidation (Table 1, entry 1). We found that substrate S-2d can be transformed to ester S-3d in a single step with a reduced amount of HFIP as the only additive (Table 1, entries 2 and 3). Given the high cost of HFIP, we examined if it could be replaced with other proton donors for the cathode
- acetic acid or HFIP the electrochemical oxidation also provided the desired product 3d, although in reduced yield (Table 1, entry 7). An increased amount of acetic acid (1 mL or ≈ 18 equiv) also reduced the yield (Table 1, entry 8). The attempt to use LiOAc as electrolyte instead of LiClO4 was not
Approaches to stereoselective 1,1'-glycosylation
Beilstein J. Org. Chem. 2025, 21, 1700–1718, doi:10.3762/bjoc.21.133
- traceless hydrolysis of β-GlcN-derived allyl glycosides with retention of the anomeric configuration [102]. Anomeric deallylation was achieved through an initial double-bond isomerization to the propenyl moiety, followed by oxidation of the glycosidic prop-1-enyl group to a formyl group, as in 111, with
Continuous-flow-enabled intensification in nitration processes: a review of technological developments and practical applications over the past decade
Beilstein J. Org. Chem. 2025, 21, 1678–1699, doi:10.3762/bjoc.21.132
- -flow configurations demonstrate superior safety and efficiency. While the synthetic significance of nitration is underscored by the broad utility of nitro derivatives, persistent technical challenges including regioselectivity control, over-nitration phenomena, and substrate oxidation side reactions
- the material [70]. Oxygen balance (OB), a critical parameter quantifying how well an explosive provides its own oxidant, reveals potential safety risks when OB values exceed the threshold of −200. Since the energy release predominantly originates from oxidation reactions, the available oxygen content
Influence of the cation in hypophosphite-mediated catalyst-free reductive amination
Beilstein J. Org. Chem. 2025, 21, 1661–1670, doi:10.3762/bjoc.21.130
- pH 0) [19], and usage of an additional amount of base leads to stronger reductive properties. Moreover, the role of the cation could be critical for the thermal stability against disproportionation or aerobic oxidation of hypophosphite [38]; salts with larger cations are also more soluble in organic
Chemical synthesis of glycan motifs from the antitumor agent PI-88 through an orthogonal one-pot glycosylation strategy
Beilstein J. Org. Chem. 2025, 21, 1587–1594, doi:10.3762/bjoc.21.122
- over the following steps: 1) deprotection of the TBDPS group, 2) phosphitylation of the free alcohol with phosphoramidite 11 in the presence of 1H-tetrazole and 4 Å MS, and 3) oxidation of the phosphite by mCPBA. Hydrogenolysis of Bn and Cbz groups in 14 with Pd(OH)2/C and subsequent saponification of
Synthesis of an aza[5]helicene-incorporated macrocyclic heteroarene via oxidation of an o-phenylene-pyrrole-thiophene icosamer
Beilstein J. Org. Chem. 2025, 21, 1561–1567, doi:10.3762/bjoc.21.119
- macrocycle whose structure has been confirmed by X-ray diffraction analysis. Next, oxidation of 4 was attempted using [bis(trifluoroacetoxy)iodo]benzene (PIFA) in CH2Cl2 at −78 °C (Scheme 2). These reaction conditions had previously proven effective for the oxidation of 3 and other o-phenylene-bridged
- common organic solvents. Conclusion A novel o-phenylene-pyrrole-thiophene hybrid macrocycle (icosamer 4) was synthesized via Suzuki–Miyaura cross-coupling and isolated in 6% yield. Oxidation of 4 with PIFA produced a partially fused aza[5]helicene-containing macrocycle 5 in 58% yield, which was also
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