Mn-mediated sequential three-component domino Knoevenagel/cyclization/Michael addition/oxidative cyclization reaction towards annulated imidazo[1,2-a]pyridines

• Olga A. Storozhenko,
• Alexey A. Festa,
• Delphine R. Bella Ndoutoume,
• Alexander V. Aksenov,
• Alexey V. Varlamov and
• Leonid G. Voskressensky

Beilstein J. Org. Chem. 2018, 14, 3078–3087, doi:10.3762/bjoc.14.287

• screening of the oxidants revealed, that the use of molecular iodine gave the desired product with 27% yield (Table 1, entry 4), while employment of NaOCl, NaIO4, MnO2, H2O2, or CuI/TBHP was not effective and led to the formation of complex mixtures (Table 1, entries 5–9), and use of CAN did not promote the

DABCO- and DBU-promoted one-pot reaction of N-sulfonyl ketimines with Morita–Baylis–Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives

• Soumitra Guin,
• Raman Gupta,
• Debashis Majee and
• Sampak Samanta

Beilstein J. Org. Chem. 2018, 14, 2771–2778, doi:10.3762/bjoc.14.254

• as the requirement of high temperatures or use of strong oxidants (H2O2, oxone, K2S2O8, TBHP, PIDA, NHPI etc.) that are not much compatible with functionality, precluding late-stage functionalization. Moreover, the scope of substitution on the pyridine ring is limited which in turn hampers the

A general and atom-efficient continuous-flow approach to prepare amines, amides and imines via reactive N-chloramines

• Katherine E. Jolley,
• Michael R. Chapman and
• A. John Blacker

Beilstein J. Org. Chem. 2018, 14, 2220–2228, doi:10.3762/bjoc.14.196

• equivalents of aldehyde 17 led to 30% product formation (Table 3, entry 6). Notably, other oxidants such as H2O2 and NaOCl failed to produce any amide product. Likewise, attempts to couple morpholine in place of its N-chloro derivative reached only 19% conversion. Following the investigation of the batch

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• comportment of G-1 piperazine dendron D-N

  NH being not entirely ruled out [68]. In line with this hypothesis, we recently described [35] the aptitude of the non-O-n-octylated analogue of G-2 dendrimer 4 (Scheme 3) to deprotonate Hemin completely (1:5 molar ratio), thus generating a new MOF for H2O2

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

• catalytic amounts only) causes additional costs. Therefore, we concentrated on alcohol oxidase-catalysed reaction schemes (Scheme 1B. Oxidases utilise O2 as terminal electron acceptor for the oxidation reaction yielding H2O2 as sole byproduct. The latter can be disproportionated easily by using catalase

• of trans-hex-2-enal. B: Envisioned aerobic oxidation using alcohol oxidases (AOx). H2O2 is formed as byproduct and dismutated by catalase into H2O and O2. Effect of variation of the gas-to-liquid ratio on the rate of the PeAAOx-catalysed aerobic oxidation of trans-hex-2-enol. Supporting Information

Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications

• Mattias Bood,
• Sangamesh Sarangamath,
• Moa S. Wranne,
• Morten Grøtli and
• L. Marcus Wilhelmsson

Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7

• , where R = H, 7-MeO or 8-MeO [47]. a) H2NNH2 followed by H2O2, 20 h, 100 °C, 60–98%; b) PEt3, H2O, diglyme, then Na2CO3 and 5-bromouracil, rt to 120 °C, 2 h, 24–86%; c) HCl, butanol, 120 °C, 24–72 h, 27–86%; d) BSA (bis(trimethylsilyl)acetamide), Hoeffer´s α-chloro sugar, SnCl4, 0 °C to rt, 2 h, 12–41

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

• simple alkenes, sodium triflinate and diazonium salts. The CF3 radical was produced from CF3SO2Na by oxidation with H2O2 in the presence of silver nitrate. Then, CF3• was added to the terminal position of the alkene to give radical 26 that was trapped by the arenediazonium salt to form the radical cation

Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity

• Tathagata Mukherjee,
• Soumik Biswas,
• Andreas Ehnbom,
• Subrata K. Ghosh,
• Ibrahim El-Zoghbi,
• Nattamai Bhuvanesh,
• Hassan S. Bazzi and
• John A. Gladysz

Beilstein J. Org. Chem. 2017, 13, 2486–2501, doi:10.3762/bjoc.13.246

• degradation under free radical chlorination conditions. However, no reactions were observed when RfnI were treated with Cl2 or NaOCl/HCl. Nonetheless, perfluoroalkyl iodides RfnI (n = 6–8, 10, 12) can be oxidized using various recipes (e.g., 80% H2O2 in trifluoroacetic acid anhydride) to the iodine(III) bis

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• aromatic systems. Miscellaneous reactions The oxidation of E-1a with H2O2 in acetonitrile gave oxirane 101, which subsequently was used for reactions with diverse nucleophiles [80] (Scheme 32). Upon treatment with diheptyl sulfide, 101 was transformed into ethoxalyl cyanide (102) [81]. The aziridination of

• ). Formation of disulfides through reaction of thiols with E-1a. Formation of CT salts of E-1 with Mn2+ and Cr2+ metallocenes through one-electron transfer. Oxidation of diethyl dicyanofumarate (E-1a) with H2O2 to give oxirane 101. The aziridination of E-1b through nitrene addition. Acknowledgements The

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• esterified with N-hydroxy-2-thiopyridone in the presence of DCC to produce 134 (Figure 37). This compound 134 was added to P4 solubilized in THF and was stirred for 30 minutes before replacing THF by DME. Then, H2O2 was added portion-wise and the solution was heated at reflux to produce the phosphonic acid

• 135. For some compounds, the reaction with H2O2 occurred at rt and then SO2 is added to complete the oxidation reaction. The work-up is, however, tedious because some excess of P4 must be removed without any contact with oxygen. This procedure was applied to natural compounds including lipophilic

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

• 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

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• -transfer reactions is hydrogen peroxide (H2O2). Unfortunately, the direct use of this base-chemical under asymmetric organocatalysis turned out to be rather tricky for α-hydroxylation reactions. One recent report by the Ooi group overcame some of the limitations by using H2O2 in combination with

• cycloetherification reactions based on the use of in situ-generated chiral quaternary ammonium hypoiodite species. By using Maruoka-type catalysts B, which contain an iodide counter anion, in the presence of a simple oxidant like H2O2 they were able to generate a chiral hypoiodite species in situ, which then

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

• Ana Franco,
• Sudipta De,
• Alina M. Balu,
• Araceli Garcia and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1439–1445, doi:10.3762/bjoc.13.141

• this work, new transition metal-based catalysts were proposed to investigate their efficiency in vanillin production. Reduced graphene oxide supported Fe and Co catalysts showed high conversion of isoeugenol under mild reaction conditions using H2O2 as oxidizing agent. Fe catalysts were more selective

• as compared to Co catalysts, providing a 63% vanillin selectivity at 61% conversion in 2 h. The mechanochemical process was demonstrated as an effective approach to prepare supported metal catalysts that exhibited high activity for the production of vanillin from isoeugenol. Keywords: H2O2

• employed [14][19][20][21]. However, the selectivity of vanillin still remains an important issue. In this work, we report the mechanochemical design of transition-metal-based catalysts supported on reduced graphene oxide support for the oxidation of isoeugenol into vanillin using H2O2 as oxidant. The

Total synthesis of elansolids B1 and B2

• Liang-Liang Wang and
• Andreas Kirschning

Beilstein J. Org. Chem. 2017, 13, 1280–1287, doi:10.3762/bjoc.13.124

• alcohol described above (124.0 mg, 0.21 mmol, 1.0 equiv) in THF (0.75 mL) was added a solution of TBAF (c = 1.0 M in THF, 0.84 mL, 4.0 equiv) and the mixture was stirred for 15 min. Methanol (2.23 mL), KHCO3 (41.85 mg, 0.42 mmol, 2.0 equiv) and H2O2 (35% in H2O, 0.36 mL, 4.18 mmol, 20 equiv) were

Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

• Adrián A. Heredia and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92

• confirmed the presence of H2O2 [43] resulting from the superoxide radical anion (O2·−) generated during reaction under oxygen atmosphere. It is also possible that the superoxide radical anion oxidizes the alkyl selenide anion (11) to the corresponding alkyl selenide radical and the formed O22− affords H2O2

• air atmosphere, the presence of oxygen promotes the oxidation of anion 11 to 8 [45], continuing the cycle until complete consumption of 11. Due to the aerobic conditions and the presence of oxidative species such as O2·−, O22− or H2O2, the oxidative retro-alkylation is favored [46][47][48][49

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

• reactive oxygen species (ROS) production in plant tissues. Usually, NO and ROS, such as O2−, OH· and H2O2, together are required to induce the activation of various defense-related enzymes in plants [55]. Plant cells contain oxygen radical detoxifying enzymes and nonenzymatic antioxidants which have an

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

• they used a stoichiometric amount of reactive iron complex [Fe(II)(BPMEN)(CH3CN)2](ClO4)2 to achieve ortho-hydroxylation of benzoic acid in the presence of H2O2, affording salicylic acid in low yields [52]. In the past decade, the selectivity and yield of C–H hydroxylation of arenes were highly

• °C (Scheme 31). In 2015, Itoh and co-workers employed PdCl2 as catalyst and the hydroxylation of arylpyridines was carried out in 4-methyl-2-pentanone at 100 °C in the presence of H2O2 (Scheme 32) [61]. In terms of reactivity, substituent at the para-position of the phenyl ring is more favored than

• (Scheme 51). 1.2.4 Vanadium mediated C–H hydroxylation of arenes: In 2012, Mizuno employed divanadium-substituted phosphotungstate, and accomplished the direct hydroxylation of structurally simple arenes to phenols in the presence of H2O2 [84]. The reaction occurred at 60 °C in CH3CN/t-BuOH (1:1) and

Studies directed toward the exploitation of vicinal diols in the synthesis of (+)-nebivolol intermediates

• Runjun Devi and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2017, 13, 571–578, doi:10.3762/bjoc.13.56

• of the allyl group in 16 with 9-BBN and the oxidation of the resulting organoborane with NaOH and H2O2 furnished alcohol 17 in 96% yield. A one-pot PCC oxidation–Wittig olefination (with Ph3P=CHCO2Et) of 17 provided (E)-α,β-unsaturated ester 18 in 85% yield over 2 steps. Compound 18 was then

Adsorption of RNA on mineral surfaces and mineral precipitates

• Elisa Biondi,
• Yoshihiro Furukawa,
• Jun Kawai and
• Steven A. Benner

Beilstein J. Org. Chem. 2017, 13, 393–404, doi:10.3762/bjoc.13.42

• washed with (in this order) tap water, ddH2O, 30% H2O2, ddH2O, EtOH 99%. Minerals were then air-dried for about 30 min in a sterile environment. For each mineral, droplets (2 μL) containing ≈100 fmol of radiolabeled RNA were spotted on the surface and let adsorb for 45 min at room temperature. Macro

• extensively washed with tap water, ddH2O, 30% H2O2, ddH2O, and then EtOH (99%) to remove all organic species. The specimens were then air-dried under cover for about 30 min. Droplets (2 μL) containing ≈100 fmol of radiolabeled RNA were spotted on the surface of each crystal. The material was allowed to adsorb

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• a mixture of AcOH/H2O/t-BuOH prior to ester hydrolysis using LiOH/H2O2 enabled the hexasaccharide 1 to be obtained in 37% yield (Scheme 9). Conclusion The first total synthesis of the S. pneumoniae serotype 12F capsular polysaccharide repeating unit hexasaccharide 1 was achieved by means of a linear

• (0.5 M in MeOH) in MeOH, ii. NaOH (4 M, 2 M, 1 M, 0.5 M, 0.1 M) solution in THF, iii. H2O2, LiOH, THF, H2O; successful sequence (d) Pd/C, AcOH, H2O, t-BuOH (e) H2O2, LiOH, THF, H2O, 37% over two steps. Supporting Information Supporting Information File 44: Experimental details and full

Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

• Tamás Zoltán Agócs,
• István Puskás,
• Erzsébet Varga,
• Mónika Molnár and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2016, 12, 2873–2882, doi:10.3762/bjoc.12.286

• environments, can set up a photo-Fenton system with H2O2 produced in situ generating OH radicals of high oxidizing capacity [42][43]. Nitrate could also produce OH radicals when absorbing UV light, but the low concentration of nitrate in tap water can insignificantly contribute to enhancing photodegradation

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

• Donghui Pan,
• Yanbin Wang and
• Guomin Xiao

Beilstein J. Org. Chem. 2016, 12, 2443–2449, doi:10.3762/bjoc.12.237

• precursor of parylene D, from 2,5-dichloro-p-xylene. In the first bromination step, with H2O2–HBr as a bromide source, this procedure becomes organic-waste-free and organic-solvent-free and can appropriately replace the existing bromination methods. The Winberg elimination–dimerization step, using aqueous

• sodium hydroxide solution instead of silver oxide for anion exchange, results in a significant improvement in product yield. Furthermore, four substituted [2.2]paracyclophanes were also prepared in this convenient way. Keywords: bromination; dimerization; H2O2–HBr system; paracyclophane; polymerization

• drawbacks such as low atom efficiency and the requirement of reagent residue elimination [14]. In contrast to traditional brominating reagents, the H2O2–HBr system, which generates active bromine in situ, is a convenient and green brominating agent [15]. Furthermore, the use of the H2O2–HBr couple improves

Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

• Raimondo Maggi,
• N. Raveendran Shiju,
• Veronica Santacroce,
• Giovanni Maestri,
• Franca Bigi and
• Gadi Rothenberg

Beilstein J. Org. Chem. 2016, 12, 2173–2180, doi:10.3762/bjoc.12.207

• toluene (120 mL) and the resulting supported propylmercaptane has been oxidized to propanesulfonic acid by treatment with 30% aq H2O2 (100 mL; 1 mol) for 24 h under stirring at rt, adding a few drops of concentrated sulfuric acid after 12 h. Acidity has been measured via the titration method [35] (0.51

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

• TiO2 nanoparticle assemblies using H2O2 [51]. Geminal chloronitroso compounds are synthesized or in situ generated from their corresponding oximes by chlorination. As halogen source elemental chlorine [52][53][54], nitrosyl chloride [55], alkyl hypochlorites [56], N-chlorourea [57], tert-butyl