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Search for "oxidants" in Full Text gives 216 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

2-Iodo-N-isopropyl-5-methoxybenzamide as a highly reactive and environmentally benign catalyst for alcohol oxidation

  • Takayuki Yakura,
  • Tomoya Fujiwara,
  • Akihiro Yamada and
  • Hisanori Nambu

Beilstein J. Org. Chem. 2018, 14, 971–978, doi:10.3762/bjoc.14.82

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  • fundamental and frequently used transformation in organic synthesis. Heavy metal-based oxidants such as chromium(VI), lead(IV), and mercury(II) have been extensively used for this purpose for a long time. However, these oxidants are highly toxic and produce hazardous waste. Recently, hypervalent iodine
  • oxidants have been widely employed for oxidation in organic synthesis [1][2][3][4][5][6][7][8][9] because they are nonmetallic, less toxic, and easy to handle, and they allow mild reaction conditions in most cases. Pentavalent iodine reagents such as Dess–Martin periodinane (DMP, 1) [10] and 2
  • -iodoxybenzoic acid (IBX, 2) [11] are well known as representative environmentally benign oxidants for alcohol oxidation (Figure 1). However, despite the utility and versatility of these oxidants, they still have several drawbacks: both are potentially explosive, DMP is moisture-sensitive, and IBX is insoluble
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Published 30 Apr 2018

One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

  • Natalia Soldatova,
  • Pavel Postnikov,
  • Olga Kukurina,
  • Viktor V. Zhdankin,
  • Akira Yoshimura,
  • Thomas Wirth and
  • Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 849–855, doi:10.3762/bjoc.14.70

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  • based on the use of inexpensive, commercially available oxidants is an important and challenging goal. A vast majority of existing procedures involve the interaction of electrophilic hypervalent iodine(III) species with suitable arenes through ligand exchange processes [16][17][18][19][20]. The reactive
  • ][27][28][29]. However, these now well-established processes involve oxidations using mCPBA in the presence of strong organic acids [30][31][32][33][34][35]. Therefore, the development of new, convenient and inexpensive methods utilizing readily available and easy-to-handle oxidants still remains a
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Published 12 Apr 2018

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

  • Morten M. C. H. van Schie,
  • Tiago Pedroso de Almeida,
  • Gabriele Laudadio,
  • Florian Tieves,
  • Elena Fernández-Fueyo,
  • Timothy Noël,
  • Isabel W. C. E. Arends and
  • Frank Hollmann

Beilstein J. Org. Chem. 2018, 14, 697–703, doi:10.3762/bjoc.14.58

Graphical Abstract
  • by undesired side reactions [1]. Also some of the stoichiometric oxidants used are questionable from an environmental and/or toxicological point of view and therefore are not compatible with consumer products such as Green Notes. Therefore, we turned our attention to biocatalytic oxidation methods
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Published 26 Mar 2018

Oxidative cycloaddition of hydroxamic acids with dienes or guaiacols mediated by iodine(III) reagents

  • Hisato Shimizu,
  • Akira Yoshimura,
  • Keiichi Noguchi,
  • Victor N. Nemykin,
  • Viktor V. Zhdankin and
  • Akio Saito

Beilstein J. Org. Chem. 2018, 14, 531–536, doi:10.3762/bjoc.14.39

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  • generated from hydroxamic acids with oxidants due to their instabilities (Scheme 1, route a). Among the oxidants, tetra-n-alkylammonium periodates are commonly employed for these HDA reactions, however, the removal of the tetra-n-alkylammonium salts, massively generated in these reactions, is often
  • groups have developed the DA reactions with MOBs as dienes [30][31][32][33], which recently were employed in the HDA reactions of acylnitroso species [34]. However, in the HDA reactions with MOBs, the oxidation of the hydroxamic acids to the acylnitroso species requires other oxidants such as tetra-n
  • reaction involving the generation of MOBs by the dearomatization of guaiacols followed by the HDA reactions of acylnitroso species with MOBs as dienes. Our findings provide an extended scope of dienes for the HDA reactions and HDA reactions of acylnitroso species with MOBs using single oxidants. Hetero
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Published 28 Feb 2018

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu4NI

  • Mi-Hai Luo,
  • Yang-Ye Jiang,
  • Kun Xu,
  • Yong-Guo Liu,
  • Bao-Guo Sun and
  • Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

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  • terminal oxidants [14]. The protocol was also extended to reactions with 2-alkylquinoline [15] and phenols [16] using O2 and di-tert-butyl peroxide (DTBP) as oxidant, respectively (Scheme 1). A CuCl-catalyzed oxidative cross coupling of glycine derivatives with indoles has been developed by Hou et al
  • stoichiometric or excess amounts of chemical oxidants and transition metal (photo)catalysts. The utilization of stoichiometric or excess amounts of chemical oxidants results in producing waste, which is not atomic economically and environmentally benign. In addition, over-oxidation of products likely occurs in
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Published 22 Feb 2018

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

  • Fabio Tonin and
  • Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

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  • ] (yield 90%) and subsequently reduced with metallic sodium in presence of imidazole and 1-propanol (yield 80%) yielding the 7β-OH epimer (UDCA) as imidazole salt. Notably, the regiospecific oxidoreduction of the 7α-OH group is achieved using weak oxidants: this behavior can be explained by the peculiar
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Published 20 Feb 2018

Photocatalytic formation of carbon–sulfur bonds

  • Alexander Wimmer and
  • Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

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  • later, Lei and co-workers reported a photocatalyzed oxidant-free method for the preparation of allyl sulfones from sulfinic acids and α-methylsytrenes, applying Eosin Y as organic photocatalyst and avoiding any sacrificial additives or oxidants (Scheme 45) [82]. They successfully applied the proton
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Published 05 Jan 2018

Quinone-catalyzed oxidative deformylation: synthesis of imines from amino alcohols

  • Xinyun Liu,
  • Johnny H. Phan,
  • Benjamin J. Haugeberg,
  • Shrikant S. Londhe and
  • Michael D. Clift

Beilstein J. Org. Chem. 2017, 13, 2895–2901, doi:10.3762/bjoc.13.282

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  • stoichiometric oxidants, such as NaIO4 and Pb(OAc)4, must be employed to enable the desired transformations. Given that 1,2-amino alcohols are readily accessible from feedstock chemicals such as styrenes [36][37][38] and amino acids [39], the development of a new methodology to transform these materials into
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Published 28 Dec 2017

CF3SO2X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF3SO2Na

  • Hélène Guyon,
  • Hélène Chachignon and
  • Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

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  • metal catalysts and/or a large excess of organic oxidants can be obstacles to production. In a quest for ideal conditions, Lei and co-workers exposed heteroatom-functionalised alkenes 14 to aerobic Cvinyl–heteroatom bond oxygenation under metal-free conditions, where oxygen from air worked in concert
  • persulfate by hypervalent iodine oxidants such as iodobenzene diacetate (PIDA, Scheme 28) [49], or iodobenzene bis(trifluoroacetate) (PIFA) [50]. Fu and co-workers proposed the reaction mechanism depicted in Scheme 28. PIDA reacted with CF3SO2Na under heating conditions to produce two radicals: CF3• along
  • groups were tolerated (Scheme 38). Zou and co-workers applied the conditions described by Langlois or Baran (CF3SO2Na/t-BuOOH/cat. Cu(II) or CF3SO2Na/t-BuOOH, respectively) for the trifluoromethylation of coumarins but no reaction was observed. By testing other oxidants, they found that Mn(OAc)3 was a
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Published 19 Dec 2017

Mechanically induced oxidation of alcohols to aldehydes and ketones in ambient air: Revisiting TEMPO-assisted oxidations

  • Andrea Porcheddu,
  • Evelina Colacino,
  • Giancarlo Cravotto,
  • Francesco Delogu and
  • Lidia De Luca

Beilstein J. Org. Chem. 2017, 13, 2049–2055, doi:10.3762/bjoc.13.202

Graphical Abstract
  • -phase system buffered at pH 8.5–9.5 [20]. Over the years, bleach has been replaced with an impressively long list of other co-oxidants [21], which are sometimes very expensive, and exhibit a wide spectrum of effectiveness (Scheme 1) [22][23]. Recently, Stahl [24] developed a practical CuI/TEMPO-based
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Published 02 Oct 2017

Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes

  • Hao Wang,
  • Cui Chen,
  • Weibing Liu and
  • Zhibo Zhu

Beilstein J. Org. Chem. 2017, 13, 2023–2027, doi:10.3762/bjoc.13.200

Graphical Abstract
  • and biological properties [26][27]. Organoperoxides have wide applications in the field of organic synthesis, as radical initiators, oxidants that replace transition metal oxidants, and key reactive intermediates in diverse organic synthesis reactions [28][29][30], as well as in medicinal chemistry
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Published 28 Sep 2017

Transition-metal-free synthesis of 3-sulfenylated chromones via KIO3-catalyzed radical C(sp2)–H sulfenylation

  • Yanhui Guo,
  • Shanshan Zhong,
  • Li Wei and
  • Jie-Ping Wan

Beilstein J. Org. Chem. 2017, 13, 2017–2022, doi:10.3762/bjoc.13.199

Graphical Abstract
  • , free of any strong oxidants and neutral reaction conditions. Methods on the synthesis of 3-sulfenylchromones. Scope of the 3-sulfenylated chromone synthesis. General conditions: 1 (0.3 mmol), 2 (0.36 mmol), KIO3 (0.15 mmol) in 2 mL DMF, stirred at 130 °C for 24 h; yield of isolated product based on 1
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Published 27 Sep 2017

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

  • Daily Rodríguez-Padrón,
  • Alina M. Balu,
  • Antonio A. Romero and
  • Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

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  • require stoichiometric amounts of inorganic oxidants, which are highly toxic and polluting. Aiming to minimize chemical waste in these catalytic processes, the scientific community is moving towards the use of clean oxidants ("green oxidants"), such as molecular oxygen or H2O2 [39]. Thus, the use of clean
  • oxidants with heterogeneous catalysts such as Fe2O3 nanoparticles, Ag nanoparticles supported on hydrotalcites, Au nanoparticles supported on metal oxides, and Pd nanoparticles supported on SBA-15 has been developed [41][42][43][44]. In this regard, both unsupported “free” iron oxide nanoparticles [45] and
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Published 21 Sep 2017

Iodoarene-catalyzed cyclizations of N-propargylamides and β-amidoketones: synthesis of 2-oxazolines

  • Somaia Kamouka and
  • Wesley J. Moran

Beilstein J. Org. Chem. 2017, 13, 1823–1827, doi:10.3762/bjoc.13.177

Graphical Abstract
  • propargylamides 4 (Scheme 5). In line with the results for the propargylamides, iodobenzene was an inferior pre-catalyst to 2-iodoanisole and other oxidants, acids and solvents led to lower yields of 6. The scope of this cyclization process was explored and different aromatic amide and ketone groups were well
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Published 31 Aug 2017

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

  • Santanu Hati,
  • Ulrike Holzgrabe and
  • Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

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  • acceptor) or via oxidative dehydrogenation in the presence of appropriate oxidants. In absence of hydrogen acceptors, post dehydrogenation the hydrogen is released as H2↑. Catalysts such as iridium pincer complexes, CuAl2O3, hydroxyapatite bound palladium and ruthenium hydride complexes have been harnessed
  • dehydrogenation strategies have been reported lately. This review will discuss various techniques of oxidative dehydrogenation of nitrogen heterocycles via reagents, catalysts and also in the presence of stoichiometric oxidants or under aerobic conditions. Review Reagent-based approaches For the reagent-based
  • oxidative dehydrogenation, a stoichiometric amount of oxidant is applied in the reaction that gets associated with the nitrogen and facilitates subsequent proton abstraction and elimination in the ring to afford the desired heteroaromatics. Various organic oxidants such as 2-iodoxybenzoic acid (IBX), 2,3
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Published 15 Aug 2017

Development of a method for the synthesis of 2,4,5-trisubstituted oxazoles composed of carboxylic acid, amino acid, and boronic acid

  • Kohei Yamada,
  • Naoto Kamimura and
  • Munetaka Kunishima

Beilstein J. Org. Chem. 2017, 13, 1478–1485, doi:10.3762/bjoc.13.146

Graphical Abstract
  • , provided the corresponding 2,4,5-trisubstituted oxazoles in good yields. Furthermore, several functionalities, such as ethoxycarbonyl, formyl, and methylsulfanyl groups, which are sensitive to acids, bases, nucleophiles, electrophiles and oxidants, were able to tolerate these reaction conditions (Table 1
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Published 27 Jul 2017

Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

  • Adesh Kumar Singh,
  • Varsha Tiwari,
  • Kunj Bihari Mishra,
  • Surabhi Gupta and
  • Jeyakumar Kandasamy

Beilstein J. Org. Chem. 2017, 13, 1139–1144, doi:10.3762/bjoc.13.113

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  • controlled oxidation of thioglycosides to glycosyl sulfoxides and sulfones selectively by altering the reaction conditions. It is also observed that thioglycoside oxidation suffers from low yields, poor selectivity (i.e., sulfoxide vs sulfone), use of inconvenient reaction conditions and expensive oxidants
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Published 13 Jun 2017

Isoxazole derivatives as new nitric oxide elicitors in plants

  • Anca Oancea,
  • Emilian Georgescu,
  • Florentina Georgescu,
  • Alina Nicolescu,
  • Elena Iulia Oprita,
  • Catalina Tudora,
  • Lucian Vladulescu,
  • Marius-Constantin Vladulescu,
  • Florin Oancea and
  • Calin Deleanu

Beilstein J. Org. Chem. 2017, 13, 659–664, doi:10.3762/bjoc.13.65

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  • situ by the oxidative dehydrogenation of aldoximes in the presence of various oxidants [26][27][28][29], or by the dehydrohalogenation of hydroxyiminoyl halides promoted by organic or inorganic bases [30][31][32]. A less used synthetic procedure involves the oxidative dehydration of primary nitro
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Published 06 Apr 2017

Transition-metal-catalyzed synthesis of phenols and aryl thiols

  • Yajun Liu,
  • Shasha Liu and
  • Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

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  • ]. Rao and co-workers found that both biaryl ketone and aryl alkyl ketones could be regioselectively hydroxylated in satisfying yields. The reaction proceeded in TFA/TFAA in the presence of Pd(OAc)2 as catalyst and several type of oxidants including selectfluor, PhI(OAc)2 and K2S2O8, respectively (Scheme
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Published 23 Mar 2017

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

  • Flavio Fanelli,
  • Giovanna Parisi,
  • Leonardo Degennaro and
  • Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

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  • reported a metal-free photocatalytic aerobic oxidation of thiols to disulfides under continuous-flow conditions [64]. Disulfides are useful molecules employed as drugs, anti-oxidants or pesticides as well as rubber vulcanizating agents [65]. Symmetric disulfides are generally obtained by oxidative coupling
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Published 14 Mar 2017

Synthesis and evaluation of anti-oxidant and cytotoxic activities of novel 10-undecenoic acid methyl ester based lipoconjugates of phenolic acids

  • Naganna Narra,
  • Shiva Shanker Kaki,
  • Rachapudi Badari Narayana Prasad,
  • Sunil Misra,
  • Koude Dhevendar,
  • Venkateshwarlu Kontham and
  • Padmaja V. Korlipara

Beilstein J. Org. Chem. 2017, 13, 26–32, doi:10.3762/bjoc.13.4

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  • derivatives have been assessed by their IC50 inhibitory values in the proliferation of MDA-MB231, SKOV3, MCF7, DU 145 and HepG2 cancer cell lines. Keywords: anticancer; anti-oxidants; caffeic acid; coumaric acid; ferulic acid; phenolic lipids; sinapic acid; undecenoic acid; Introduction Phenolic compounds
  • potential of compounds. The results for the ability of the prepared compounds to scavenge the DPPH radical are shown in Table 1 along with reference anti-oxidants α-tocopherol (α-TP) and tert-butylhydroquinone (TBHQ). As can be seen, all synthesized derivatives exhibit radical scavenging ability except the
  • , pure linoleic acid and linoleic acid containing the synthesized compounds were subjected to DSC analysis. The results of the assay are shown in Table 2 and α-TP and TBHQ were included as standard anti-oxidants. Pure linoleic acid showed an oxidative induction temperature (OIT) of 116 °C which was found
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Published 04 Jan 2017

Copper-catalyzed asymmetric sp3 C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

  • Pierre Querard,
  • Inna Perepichka,
  • Eli Zysman-Colman and
  • Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

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  • developed the first direct sp3 C–H arylation of THIQ with arylboronic acids using a copper catalyst (Scheme 1) [30]. Oxygen gas and tert-butyl hydroperoxide (TBHP) were used as external oxidants, which gave moderate to good isolated yields (up to 75%). In addition, we demonstrated the first enantioselective
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Published 06 Dec 2016

Diels–Alder reactions in confined spaces: the influence of catalyst structure and the nature of active sites for the retro-Diels–Alder reaction

  • Ángel Cantín,
  • M. Victoria Gomez and
  • Antonio de la Hoz

Beilstein J. Org. Chem. 2016, 12, 2181–2188, doi:10.3762/bjoc.12.208

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  • are improved and selectivity is enhanced or modified [13]. In this regard, heterogeneous catalysis in general and zeolites in particular are remarkably efficient since they permit the replacement of toxic mineral acids and oxidants by easily recyclable catalysts [14]. One approach to improve yields
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Published 13 Oct 2016

The direct oxidative diene cyclization and related reactions in natural product synthesis

  • Juliane Adrian,
  • Leona J. Gross and
  • Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

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  • fact, in these cases, mostly a trans-selectivity for the cyclization event is observed, due to the loose coordination. The most prominent oxidants to promote such type C reactions are Co(II) and Re(VII) complexes [27][28][29]. Reactions where a 5- and/or 6-(di)hydroxy group directs an oxidizing reagent
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Published 30 Sep 2016

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

  • Lucie Brulíková,
  • Aidan Harrison,
  • Marvin J. Miller and
  • Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

Graphical Abstract
  • ) [36]. The introduction of the nitroso group through the transformation of pendant functional groups includes the oxidation of primary amines [37][38][39][40][41] (Scheme 4) and hydroxamic acids [42][43][44] (Scheme 5) and the reduction of nitro compounds [45][46][47]. As oxidants for the amino group
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Published 01 Sep 2016
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