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Search for "oxidation" in Full Text gives 1397 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Reactivity of hypervalent iodine(III) reagents bearing a benzylamine with sulfenate salts
Beilstein J. Org. Chem. 2024, 20, 3281–3289, doi:10.3762/bjoc.20.272
- lengths and angles fall within the expected range for similar compounds [31]. Later, the β-sulfinyl esters 4 were prepared by Michael addition reaction of thiols and α,β-unsaturated esters [32], followed by oxidation of the corresponding sulfides 3 using two different oxidizing agents (oxone and m-CPBA
- 5aa (Table 1, entry 2) but with prior degassed solvent (DMF), to prevent potential oxidation of the sulfenate to sulfinate anions. Indeed, the oxidation of the unstable sulfenate intermediates has been previously reported by Waser when using EBX – an HIR applied in the transfer of alkynes to sulfenate
- oxidation of sulfinamide 6aa by dissolved oxygen molecules in the media. Therefore, an additional experiment was conducted using sodium benzenesulfinate to simulate the potential in situ oxidation of the sulfenate anion before the addition of BBX 2a, but only trace amounts of sulfonamide 5ea were observed
Synthesis of 2H-azirine-2,2-dicarboxylic acids and their derivatives
Beilstein J. Org. Chem. 2024, 20, 3191–3197, doi:10.3762/bjoc.20.264
- included oxidation of aldehydes 4 with Oxone to acids 5 and the conversion of the latter into acid chlorides with thionyl chloride. The first reaction sequence was suitable for obtaining compounds 1a–c,e,f with substituents tolerant to radical reaction conditions. A significant advantage of the method is
- separate impurities. In these cases, as well as in reactions giving low aldehyde yields in the first step (4b,d), the second developed reaction sequence turned out to be more effective. In the second approach, the oxidation of aldehydes 4 with Oxone to acids 5 occurs with yields close to quantitative, and
Direct trifluoroethylation of carbonyl sulfoxonium ylides using hypervalent iodine compounds
Beilstein J. Org. Chem. 2024, 20, 3182–3190, doi:10.3762/bjoc.20.263
- [28]. In 2017, the Aϊssa group described a procedure to better synthesize such α-alkyl-substituted carbonyl sulfoxonium ylides [29]. This protocol involved the alkylation of a dialkyl thioether, counterion exchange, oxidation, and eventual acylation (Scheme 1a). More recently, the Burtoloso group
Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold
Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262
- lead to the corresponding hydrazones 6a–d in good yields (69–80%). Surprisingly, these conditions were unsuitable for compounds 5e and 5f and led to the formation of numerous byproducts. Fortunately, the replacement of iodine with N-bromosuccinimide (NBS), previously reported for the oxidation of
- hydrazine [36], allowed the expected compounds 6e and 6f to be obtained in good yields. This methodology was applied to the previous hydrazides 5a–d giving the corresponding compounds 6a–d in similar yields. As expected, no isomerization occurred during the oxidation, leading exclusively to the imine and
- . Allylation of fluorinated hydrazones 3a–f to obtain 5a–f. Oxidation of hydrazines 5a–f to obtain hydrazones 6a–f. Intramolecular cyclization of compounds 6a–f to obtain tetrahydropyridazines 7a–f. Preparation of tripeptides 8e, 8e’, 8f, and 8f’. Yields refer to the yield over 2 steps. Supporting Information
Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies
Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261
- biomolecules like DNA and lipids. Lipid peroxidation and membrane disruption can cause random cross-linking, resulting in cell death and the fragmentation of proteins and enzymes. Elevated concentrations of reactive oxygen species (ROS) from various molecular processes contribute to the oxidation of proteins
Hypervalent iodine-mediated intramolecular alkene halocyclisation
Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258
- ; heterocycles; hypervalent iodine; oxidation; Introduction Halogenated carbocyclic and heterocyclic compounds are present in many active pharmaceutical ingredients [1][2]. The intramolecular halocyclisation of alkenes mediated by HVI(III) reagents allow access to a range of halogenated cyclic scaffolds in a
- fluorinated oxazolines 32 was also reported using an electrochemical approach in 2019 by Waldvogel and co-workers (Scheme 17) [40]. The authors used electrochemical oxidation to form p-tolyl-difluoro-λ3-iodane 10 on the anode using an undivided cell with platinium electrodes in a 1:1 solution of CH2Cl2 and
- electrochemical oxidation of the substrate. A range of N-allylcarboxamides 31 were cyclised to fluorinated oxazolines 32 in moderate to very good yields. Poor yields, however, were reported with electron-withdrawing aryl groups on the substrate. Intramolecular nucleophilic attack from oxygen onto the activated
Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts
Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257
- at β- and meso-positions, N-alkylation, arylation or protonation, interruption of the conjugated system, reduction/oxidation of the macrocycle and/or strapping of the macrocycle via covalent linkage of the meso- or β-pyrrole positions [22][53][54][55][56][57]. These alternations can significantly
- . Changes in the reduction or oxidation state can alter redox behavior, thereby affecting catalytic activity. For example, it has been reported that 2,3,5,7,8,10,12,13,15,17,18,20-dodecasubstituted free-base porphyrins and their mono/diprotonated derivatives are highly distorted with a good access to the
- the UV–vis spectrum revealed a red shift, indicating the presence of diprotonated H4TPP2+ macrocycle (Figure 21a). Fc addition into an air-saturated DCE solution containing 18 (H2TPP) and HTB led to oxidation of Fc to Fc+ and initiated the ORR process (Figure 20b). The rate of ferrocene oxidation (Fc
Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond
Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253
- ], requires the presence of a nucleophile at the β-position of the amino acid and occurs exclusively on select amino acids. Specifically, cyclodehydration of a serine or threonine (followed by oxidation or reduction) generates an oxazole, oxazoline, or oxazolidine moiety in the NRP backbone, and the analogous
Advances in radical peroxidation with hydroperoxides
Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249
- . Keywords: C–H functionalization; oxidation; peroxidation; radical reactions; TBHP; Introduction Organic peroxides are used in many different areas of human activities. The traditional and most developed field is the use of peroxides as initiators in the polymerization process for the production of a wide
- formation of peroxide 9. The enantioselective peroxidation of alkenes 10 with TBHP with the formation of the optically active products 11 was carried out in good yields and low ee by the use of in situ-generated chiral bisoxazoline–copper(I) complexes (Scheme 7) [43]. Studying the oxidation of α-pinene (12
- then reacts with tert-butylperoxy radical B to form the target peroxide 20 and Cu(I). Cu(I) is oxidized by TBHP to form Cu(II) and tert-butoxy radical C, which abstracts a hydrogen atom from TBHP to form tert-butylperoxy radical B. Radical B can also be formed via oxidation of TBHP by complex A or the
Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins
Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248
- ]. Beyond their essential biological roles, porphyrins and their derivatives are employed in a number of applications, acting as catalysts in numerous reactions, including oxidation, reduction, and cycloaddition [6][7][8][9][10]. Particularly when electron-rich porphyrins act as reducing agents, e.g. in
- to serve as a proton source for redox reactions at the metal. 3. The electronic properties of the porphyrin, especially the low oxidation potential, should not be increased. We have chosen four-fold meso-3,4,5-trimethoxyphenyl-substituted Ni porphyrin as the electron-rich system, however, the post
- carboxylic acids [10]. It was therefore obvious to use a perfluoroalkyl chain as a tether. However, a perfluoroalkyl chain as a substituent on the porphyrin has an electron-withdrawing effect and thus a negative influence on the oxidation potential. We have therefore inserted an O–CH2 group between the
The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives
Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244
- reversible oxidation waves as shown from the CV data (Figure 6 and Table 1). This reversibility is crucial for the regeneration of dyes following redox processes. The compounds display ionisation energies (IEs) of −5.38 eV, −5.34 eV, and −5.40 eV for 3a, 3b, and 3c, respectively, with electron affinities
- exhibit a narrow HOMO–LUMO gap (1.46–1.47 eV), with a wide absorption range exceeding 800 nm compared to their previously reported precursors [30]. The electrochemical studies of the three materials show reversible oxidation and reduction waves with EA values that are in a similar range (from −3.70 to
Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts
Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243
- state, eosin Y*. This excited state further undergoes oxidation via a single-electron-transfer (SET) reaction with Ar2IBF4 26, producing eosin Y+ and a phenyl radical 30 (Scheme 10). The radical intermediate 30 selectively binds to the C2 position of either quinoline or pyridine N-oxide, forming
- assist in the deprotonation of intermediate II to produce final products 27, while K2S2O8 aids in the oxidation of the photocatalyst in the case of pyridine N-oxide. In another photoinduced reaction procedure, Murarka et al. reported the formation of aryl radicals from a tetrameric electron donor
- 62. Acetonitrile was identified as a suitable solvent for this reaction, resulting in moderate to good yields of the products. The three main steps in the reaction were oxidation of the aryl iodide, addition of the TMP auxiliary, and C–O coupling reaction. Olofsson et al. worked towards the synthesis
N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity
Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240
- oxidation with CrO3. Although this approach allowed for the synthesis of acceptor-substituted isatin-N-glycosides, it proved to be tedious and the yields were low. In a similar way, acetyl-protected isoindigo-N-glycosides were prepared. In addition, benzyl-protected isoindigo-N-glycoside β-58d, containing a
- of rhamnose with indoline (66) afforded β-67a which was transformed to indol-N-rhamnoside β-68a (Scheme 39) [59]. Benzylation and subsequent oxidation gave isatin-N-rhamnoside β-70a, albeit, in low yield. Condensation with 2-coumaranone (63) afforded the benzylated oxoisoindigo-N-rhamnoside β-71a
Interaction of a pyrene derivative with cationic [60]fullerene in phospholipid membranes and its effects on photodynamic actions
Beilstein J. Org. Chem. 2024, 20, 2732–2738, doi:10.3762/bjoc.20.231
- in Vm was caused by some modification – most likely oxidation – of the plasma membrane by the photoexcited triad molecule. Taken together, for the realization of rapid control of Vm using such C60-based molecules in the membrane, the suppression of ROS generation is an important consideration. In
Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light
Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230
- indole alkaloids. Here, we develop a novel approach for the one-pot multistep synthesis of different spiro[indole-isoquinolines]. The protocol proposed involves the visible light mediated oxidation of N-aryl tertiary amines using bromochloroform with the generation of a reactive iminium species, which
- reacts with an isocyanide and an electron-rich aniline in a three-component Ugi-type reaction to give an α-aminoamidine. This compound might undergo an additional visible light-mediated oxidation to furnish a second iminium intermediate, which acts as electrophile in an intramolecular electrophilic
- : isocyanide; multicomponent reactions; one-pot reaction; oxidation; spiroindolenine; Ugi reaction; visible light; Introduction Diversity-oriented synthesis (DOS) is a successful approach to biologically active scaffolds directed to create an enormous exploratory space in pharmaceutical hit discovery [1][2
5th International Symposium on Synthesis and Catalysis (ISySyCat2023)
Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227
- -dihydro-1H-pyrroles using aryldiazonium salts and (S)-PyraBox, followed by sequential Jones oxidation. They showcased their methodology by preparing both (R)-rolipram and (R)-baclofen hydrochloride. Tóth et al. reported the design and synthesis of new analogues of HeE1-2Tyr, a nonnucleoside SARS-CoV-2
Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones
Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223
- , Trombay, Mumbai-400085, India Homi Bhabha National Institute, Anushaktinagar, Mumbai, PIN-400094, India 10.3762/bjoc.20.223 Abstract A transition-metal-free decarbonylation–oxidation protocol for the conversion of 3-arylbenzofuran-2(3H)-ones to 2-hydroxybenzophenones under mild conditions has been
- abilities has been verified by mathematical calculations. Keywords: decarbonylation–oxidation; hydroperoxide; 2-hydroxybenzophenone; transition-metal-free; UV-protection; Introduction Benzophenone compounds are ubiquitous in nature, and show biological activities such as anti-inflammatory, antiviral, and
- oxidative coupling of salicylaldehyde with arylboronic acids to successfully produce 2-hydroxybenzophenones [14]. Recently, a Ni-catalyzed decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones emerged as an innovative route to access 2-hydroxybenzophenones [2]. The use of transition metals poses
Deciphering the mechanism of γ-cyclodextrin’s hydrophobic cavity hydration: an integrated experimental and theoretical study
Beilstein J. Org. Chem. 2024, 20, 2635–2643, doi:10.3762/bjoc.20.221
- hydrogen bonding, although generally not dominant, can influence the complex formation as well [5]. Cyclodextrins form inclusion complexes with polar and non-polar substances of various aggregate states. This incredible versatility, combined with the enhanced stability against oxidation, as well as
Efficient modification of peroxydisulfate oxidation reactions of nitrogen-containing heterocycles 6-methyluracil and pyridine
Beilstein J. Org. Chem. 2024, 20, 2599–2607, doi:10.3762/bjoc.20.219
- -hydroxy-6-methyluracil, etc.). One of the successful methods for hydroxylation is peroxydisulfate oxidation. By modifying the Elbs reaction through catalysis and the introduction of additional oxidants, we have been able to significantly increase the yields of practically useful compounds. Keywords
- : oxidation; 6-methyluracil; peroxydisulfate; phthalocyanine catalysts; pyridine; Introduction The Elbs and Boyland–Sims peroxydisulfate oxidation reactions offer a convenient means of introducing the hydroxy function into phenols and aromatic amines [1]. The oxidation of phenol using peroxydisulfate was
- first demonstrated by Karl Elbs in 1893 [2], with E. Boyland later expanding this reaction to include aromatic amines [3]. Concurrently, the successful oxidation of several pyrimidine derivatives was also reported [4]. Since then, the reaction has been extensively researched on various classes of
A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis
Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214
- pharmaceutical drugs and natural products. We classify these advancements into three types: anodic oxidation, cathodic reduction, and paired electrolysis (Figure 1). This review considers direct electrolysis (oxidation or reduction), mediator-induced electrolysis, and metal-catalyzed and photocatalyzed
- . Review 1 LSF via anodic oxidation To date, the majority of electrosynthetic methods in organic chemistry consists of anodic oxidations. These techniques are generally more robust and can often be performed outside of a glovebox, making them particularly attractive for larger scale applications in
- industrial settings. An anodic oxidation is frequently employed for C–H functionalization, which can simplify late-stage functionalization strategies. Additionally, many of these synthetic methods do not require precious metals, enhancing their appeal in terms of sustainability and cost-effectiveness
Visible-light-mediated flow protocol for Achmatowicz rearrangement
Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213
- ], spirulina [16], Ti(OiPr)4/t-BuOOH [17], VO(acac)2)/t-BuOOH [18], and enzymatic oxidation [19] etc., which may compromise the environmental benefits (Scheme 1a,b) and take longer reaction times. Alternatively, a new green pathway is necessary for the Achmatowicz reaction to be performed in a faster and safer
- et al. [22] have demonstrated a combined use of flow and batch processes involving an electrochemical flow cell for the oxidation of furfuryl alcohols and subsequently utilizing the crude electrolysis mixture for hydrolysis in a traditional batch process to get the rearranged Achmatowicz product. As
HFIP as a versatile solvent in resorcin[n]arene synthesis
Beilstein J. Org. Chem. 2024, 20, 2469–2475, doi:10.3762/bjoc.20.211
- ]. In contrast, the protocol reported herein provides 94–98% yield when employing longer chain-containing aldehydes (1c–e). In addition to resorcinol, 2-methylresorcinol is commonly used in resorcin[n]arene synthesis as radical oxidation of the methyl unit in the ArCH3 fragments provides a benzyl
Photoredox-catalyzed intramolecular nucleophilic amidation of alkenes with β-lactams
Beilstein J. Org. Chem. 2024, 20, 2461–2468, doi:10.3762/bjoc.20.210
- functionalization of amides with alkenes under photoredox conditions. Another viable approach for amide functionalization through photoredox catalysis involves the nucleophilic addition, in the presence of base, of an amide to a radical cation obtained by oxidation of an unfunctionalized alkene moiety (Figure 1A
- ) [23][24][25]. The nucleophilic attack of the nitrogen atom on the oxidized C=C double bond results in the formation of a radical intermediate after deprotonation. This radical intermediate can proceed through various pathways (e.g., HAT, oxidation) to yield the desired final product. In the
- functionalization of amides with alkenes under oxidative conditions, the oxidation potential of the alkene plays a pivotal role in the oxidation to a radical cation through photoredox catalysis [26]. Alkenes that are less functionalized possess a higher oxidation potential, necessitating the use of potent
Hypervalent iodine-mediated cyclization of bishomoallylamides to prolinols
Beilstein J. Org. Chem. 2024, 20, 2455–2460, doi:10.3762/bjoc.20.209
- ]. Iodoethane was also shown to be an effective reagent furnishing the product in up to 56% upon heating to 40 °C (Table 1, entries 11 and 12). It was envisaged that oxidation of iodoethane led to formation of oxidized forms of iodide by C–I-bond cleavage, therefore tetrabutylammonium iodide was utilized to see
Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles
Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206
- detection of benzaldehyde which was considered to be formed by the NaClO-mediated oxidation of benzyl alcohol generated by hydrolysis. Changing the oxidizing reagent to crystalline NaClO·5H2O nicely solved the problem with the realization of 86% isolated yield of 2b by the utilization of this oxidant (2
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