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

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• > perbenzoic acid > peracetic acid >> H2O2 > t-BuOOH [196]. The migratory ability of substituents in the Criegee intermediate decreases in the following series: tertiary alkyl > cyclohexyl > secondary alkyl > benzyl > phenyl > primary alkyl > cyclopentyl, cyclopropyl > methyl. In some cases, stereoelectronical

• hydrogen peroxide. Oxidizing systems containing hydrogen peroxide as the oxidizing agent allow the usual and asymmetric oxidation of the substrate to the target product with high conversion and yield. In recent years, the inexpensive, commercially available, and environmentally friendly H2O2 was utilized

• theoretically studied mechanism of the oxidation reaction promoted by H2O2 and the Lewis acid BF3 [217][219]. In the first step, the hydrogen peroxide–boron trifluoride complex 8 reacts with ketone 9 to form adduct 10. The latter intermediate rearranges through transition state 11 into the tetrahedral

Automated glycan assembly of a S. pneumoniae serotype 3 CPS antigen

• Markus W. Weishaupt,
• Stefan Matthies,
• Mattan Hurevich,
• Claney L. Pereira,
• Heung Sik Hahm and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2016, 12, 1440–1446, doi:10.3762/bjoc.12.139

• trisaccharide 5. Reagents and conditions: a) LiOH, H2O2, THF, −5 °C to rt; b) NaOH, MeOH, 0 °C to rt; c) Pd(OH)2/C, MeOH/H2O/AcOH (50:25:1 v/v/v), 71% over 3 steps. Supporting Information Supporting Information File 184: Experimental details as well as full characterization of all new compounds

Nucleic acids through condensation of nucleosides and phosphorous acid in the presence of sulfur

• Tuomas Lönnberg

Beilstein J. Org. Chem. 2016, 12, 670–673, doi:10.3762/bjoc.12.67

• polymerization. Proposed oxidants for prebiotic phosphite chemistry include H2O2 and Fe(III). The present paper describes the polymerization of thymidine and triethylammonium phosphite, with elemental sulfur acting as the oxidant. Up to pentameric oligonucleotides with internucleosidic phosphorothioate linkages

Aluminacyclopentanes in the synthesis of 3-substituted phospholanes and α,ω-bisphospholanes

• Vladimir A. D’yakonov,
• Alevtina L. Makhamatkhanova,
• Rina A. Agliullina,
• Leisan K. Dilmukhametova,
• Tat’yana V. Tyumkina and
• Usein M. Dzhemilev

Beilstein J. Org. Chem. 2016, 12, 406–412, doi:10.3762/bjoc.12.43

• additional asymmetric centre С(1′) in the substituent, and the total yield of these compounds is 90–93%. Phospholanes 2а–h readily react with H2O2 in chloroform, owing to the presence of a lone electron pair at phosphorus to give phospholane 1-oxides 3а–h in quantitative yields. The reaction of 2а–h with S8

• (10d), 1,4-bis(1-methylphospholan-3-yl)butane (10e), and 1,6-bis(1-phenylphospholan-3-yl)hexane (10с) in 85 % yields. Similarly to phospholanes 2a–h, the resulting bisphospholanes 10a–c readily react with H2O2 in chloroform or with elemental sulfur to furnish the corresponding bisphospholane 1,1

Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues

• Charlotte Collet,
• Françoise Chrétien,
• Yves Chapleur and
• Sandrine Lamandé-Langle

Beilstein J. Org. Chem. 2016, 12, 353–361, doi:10.3762/bjoc.12.39

• bromide under classical conditions in the presence of NaH at reflux [44] to afford myo-9 and scyllo-9 in good yield of 80% and 82%, respectively. The hydroxylated arm was obtained by hydroboration using BH3 on the unsaturated compounds myo-9 and scyllo-9 followed by an oxidation with H2O2/NaOH allowing

• , after hydroboration using BH3 in THF at 0 °C followed by conventional oxidation using H2O2/NaOH, in 70–80% yield. Subsequent catalytic hydrogenation under pressure with Pd(OH)2 as the catalyst [45] allowed to obtaining quantitatively the fully hydroxylated inositols myo-3, scyllo-3, myo-4 and scyllo-4

• , iPrOH, rt, 2 h, 58 and 30%; b) allyl bromide, NaH, 70 °C, 2 h, 80–82%; c) BH3, THF, rt, 6 h then H2O2, NaOH, rt, 12 h, 75–78%; d) Pd(OH)2, MeOH/CH2Cl2/H2O 10:10:1 (v/v/v), 45 psi, 18 h, quantitative. Synthesis of O-alkylated fluorinated inositol derivatives 2. Synthesis of C-alkenylated inositol

Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes

• Norbert Vida,
• Jiří Václavík and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 110–116, doi:10.3762/bjoc.12.12

• maleic acid derivative 4 in the product mixture. Control experiments in which 8 or 3 were reacted with H2O2/H2SO4 did not provide 4. This suggests that 4 may be formed by a second hydroxylation of 6 to 9. The second electrophilic aromatic hydroxylation is a favorable process because 6 is a more activated

• 12. To test this hypothesis, both 10 and 11 were subjected to oxidation by H2O2/H2SO4 mixture. Indeed, the yield of 3 decreased considerably while the yield of 4 increased somewhat but still remains low (Scheme 3). The presumed intermediate 2-(pentafluorosulfanyl)-1,4-benzoquinone (12) in the pathway

• substituents ortho to the SF5 group are relatively uncommon [21]. Reduction with sodium dithionite [20] provided aminophenol 14 in good overall yield and oxidation with MnO2 [22] gave benzoquinone 12 also in a good yield. Further oxidation with H2O2/H2SO4 resulted in a mixture of four SF5-containing products

Photoinduced 1,2,3,4-tetrahydropyridine ring conversions

• Baiba Turovska,
• Henning Lund,
• Viesturs Lūsis,
• Anna Lielpētere,
• Edvards Liepiņš,
• Sergejs Beljakovs,
• Inguna Goba and
• Jānis Stradiņš

Beilstein J. Org. Chem. 2015, 11, 2166–2170, doi:10.3762/bjoc.11.234

• contains the mixture of 3, 4 and 5. The same product mixture was obtained if the solution of 1 is treated with concentrated H2O2 or Fenton reagent. The reaction starts even if the irradiation wavelengths only partially cover the absorption band of 1. It explains also the observed fact that during the

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• quantitative yield (Scheme 3). However, any attempt of isolating each isomer of peroxylippidulcine by column chromatography technique failed. In addition, the singlet dark oxidation (H2O2 with a catalytic amount of Na2MoO4 at 55 °C) was tested, but without success [33]. Then, we tried to separate 2a–c by means

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea

• Mohammad Abbasi and
• Reza Khalifeh

Beilstein J. Org. Chem. 2015, 11, 1265–1273, doi:10.3762/bjoc.11.141

• containing Et3N and a thick brick-red liquid was formed. Next, H2O (1 mL) and H2O2 (1.2 mmol) were added to the reaction mixture and the resulting solution was stirred for 1 h at room temperature. Extractive work-up with EtOAc followed by silica gel column chromatography afforded benzoyl disulfide in 91

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• gap energy values (Eg) ranging between 2.34 and 3.21 eV. Their catalytic activities were tested for the degradation of Eriochrome Blue Black B (a model of azo dyes) in the presence of an ecological oxidant (H2O2). The efficiency of the decolorization has been confirmed via UV–visible spectroscopic

• analysis and the factors affecting the degradation phenomenon have been studied. The removal of the Eriochrome reached high yields. We have found that the complex 9 promoted 84% of color elimination within 5 min (C0 = 30 mg/L, T = 22 °C, pH 7, H2O2 = 0.5 mL) and the energetic parameters have been also

• conditions (t = 10 min, C0 = 30 mg/L, 10 mg of the catalyst, amount of H2O2 = 0.5 mL). Among the six compounds, catalyst 9 was found to be the most active during this study because the corresponding solution became almost colorless within five minutes (Figure 4). As also clearly depicted in Figure 5, the

Properties of PTFE tape as a semipermeable membrane in fluorous reactions

• Brendon A. Parsons,
• Olivia Lin Smith,
• Myeong Chae and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2015, 11, 980–993, doi:10.3762/bjoc.11.110

• height of the oxalate–rubrene solution in the delivery tube (Figure 12), even over an extended period of time. This indicates that solvent transport was not necessarily a requirement for the delivery of the H2O2 reagent. From the directionality of the PV-PTFE chemiluminescence reaction and lack of change

• in solvent volume in the delivery tube, we conclude that PTFE tape is permeable to small H2O2 molecules but not to the considerably larger oxalate or rubrene molecules. In the reactions where hydrogen peroxide was dissolved in acetonitrile/water (2:1) or tert-butanol/water (2:1) mixtures, the column

• on the left and (b) in the vial in the experiment on the right. (c) The experimental set up with the lights on and (d) lights off. The orange solution contains an oxalate/rubrene mixture in dimethyl phthalate and the clear solution is 10% aqueous H2O2. Progression of PV-PTFE chemiluminescence with

Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

• Stephan Schmidt,
• Hanqing Wang,
• Daniel Pussak,
• Simone Mosca and
• Laura Hartmann

Beilstein J. Org. Chem. 2015, 11, 720–729, doi:10.3762/bjoc.11.82

• (96% H2SO4 and 30% H2O2, 3:1). The coverslips were rinsed with ultra-pure water and dried in a nitrogen stream. Amine surfaces were prepared via chemical vapor deposition of 3-aminopropyltriethoxysilane (APTES) (50 µL) on a freshly cleaned coverslip were placed in a desiccator and vacuum was applied

Eosin Y-catalyzed visible-light-mediated aerobic oxidative cyclization of N,N-dimethylanilines with maleimides

• Zhongwei Liang,
• Song Xu,
• Wenyan Tian and
• Ronghua Zhang

Beilstein J. Org. Chem. 2015, 11, 425–430, doi:10.3762/bjoc.11.48

• −. The HOO− will be subsequently protonated to yield H2O2 as the by-product. H2O2 was detected after the reaction was completed by using KI/starch indicator (see the Supporting Information File 1). The involvement of radical pathway was supported by experimental result that the reaction was suppressed in

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• compounds 11 (20%) and 12 (43%) were formed. Second, during the reaction with hydrogen peroxide as an oxidant under non-electrochemical conditions no products were detected, which indicates that the role of dioxygen is not the source of electrochemically generated H2O2. Furthermore, the epoxide 10 was not

Switching the reaction pathways of electrochemically generated β-haloalkoxysulfonium ions – synthesis of halohydrins and epoxides

• Akihiro Shimizu,
• Ryutaro Hayashi,
• Yosuke Ashikari,
• Toshiki Nokami and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2015, 11, 242–248, doi:10.3762/bjoc.11.27

• -I was synthesized using I2 and H2O2; see Supporting Information File 1) indicated that the addition of I+ and DMSO across the C–C double bond was anti-selective as anticipated. Synthesis of halohydrins and epoxides from various alkenes The present method was successfully applied to the synthesis of

Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes

• Philipp Röse,
• Steffen Emge,
• Jun-ichi Yoshida and
• Gerhard Hilt

Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18

• (IV), mCPBA, FeCl3 or H2O2 have been reported [40][41][42][43][44][45]. A more efficient and versatile method is the electrochemical generation of halonium ions. Thereby, it is possible to accumulate the halonium ions in solution and to add those to a substrate in a separated process (“pool” method

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• -immobilized manganese phthalocyanine/H2O2aq [166], a Ni(II) complex/H2O2aq [167], and ZnBr2/H2O2 [168]. The oxidative C–O coupling of aromatic aldehydes 181 with cycloalkanes 182 was accomplished in the presence of the Cu(OAc)2/t-BuOOH system to prepare products 183. This reaction is unusual in that it

Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols

• Bianca Rossi,
• Nadia Pastori,
• Simona Prosperini and
• Carlo Punta

Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10

• aldehyde or ketone, and a suitable source of nucleophilic radicals (Nu–H = formamide [24][25], methanol [26][27], ethers [28]), in the presence of titanium chlorides, and slowly dropping a solution of hydroperoxide (H2O2 or tert-butyl hydroperoxide (t-BuOOH)) into the reaction medium (Scheme 1). Aqueous

Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

• László Tóth,
• Yan Fu,
• Hai Yan Zhang,
• Attila Mándi,
• Katalin E. Kövér,
• Tünde-Zita Illyés,
• Attila Kiss-Szikszai,
• Balázs Balogh,
• Tibor Kurtán,
• Sándor Antus and
• Péter Mátyus

Beilstein J. Org. Chem. 2014, 10, 2594–2602, doi:10.3762/bjoc.10.272

• . Separated enantiomers of the products were characterized by HPLC-ECD data, which allowed their configurational assignment on the basis of TDDFT-ECD calculation of the solution conformers. Two compounds showed neuroprotective activities against hydrogen peroxide (H2O2) or β-amyloid25–35 (Aβ25–35)-induced

• preparation of condensed O,N-heterocycles with the 1,2,8,9-tetrahydro-7bH-quinolino[1,2-d][1,4]benzoxazepine skeleton, the neuroprotective activities of which were tested against hydrogen peroxide (H2O2), Alzheimer's amyloid β-peptide fragment Aβ25–35 and oxygen–glucose deprivation (OGD)-induced neurotoxicity

• rac-5 were tested against hydrogen peroxide (H2O2), β-amyloid-25-35 (Aβ25–35) and oxygen–glucose deprivation (OGD)-induced neurotoxicity in human neuroblastoma SH-SY5Y cells [22]. The preliminary screenings showed that rac-7a at 10 µM concentration displayed neuroprotective activity against H2O2

Oligomerization of optically active N-(4-hydroxyphenyl)mandelamide in the presence of β-cyclodextrin and the minor role of chirality

• Helmut Ritter,
• Antonia Stöhr and
• Philippe Favresse

Beilstein J. Org. Chem. 2014, 10, 2361–2366, doi:10.3762/bjoc.10.246

• monomeric residual of each oligomerization was measured twice. The obtained enantiomeric excess (ee) values of the monomeric residual are given in Table 1. Because of the rapid conversion of the monomer 1 during the oligomerization with highly active peroxidase–H2O2 system at room temperature, the reaction

Indium-mediated allylation in carbohydrate synthesis: A short and efficient approach towards higher 2-acetamido-2-deoxy sugars

• Christopher Albler,
• Ralph Hollaus,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2014, 10, 2230–2234, doi:10.3762/bjoc.10.231

• , rt, 16 h, then TEA, rt, 30–50 min, quant.; (c) H2O2, cat., CH2Cl2, −20 °C, 16 h, then Ph3P(CHCO2Me), CH2Cl2, rt, 1 h, 72–75%, 2 steps; (d) TMSN3, Pd(PPh3)4, THF, rt, 1 h, 76–85%. Deprotection sequence; reagents and conditions: (a): HCl/MeOH, rt, 16–24 h, then MeOH, CH2Cl2, O3, −78 °C then PPh3, rt

Rasta resin–triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions

• Xuanshu Xia and
• Patrick H. Toy

Beilstein J. Org. Chem. 2014, 10, 1397–1405, doi:10.3762/bjoc.10.143

• alcohol, aziridine, aldehyde and epoxide halogenation reactions from which the desired products are easily isolated and the phosphine oxide byproduct is readily recycled. Results and Discussion Rasta resin 16 was prepared by oxidation of 14, which was prepared as previously reported [28], using H2O2

• 1.06 mmol/g, respectively. It should be noted that a test reaction between N,N-diisopropylbenzylamine and H2O2 under similar reaction conditions does not result in amine oxidation, and this seems to indicate that only the phosphine groups of 19 are oxidized during its conversion to 18. Having

Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin

• Melanie Rauschenberg,
• Eva-Corrina Fritz,
• Christian Schulz,
• Tobias Kaufmann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 1354–1364, doi:10.3762/bjoc.10.138

• small pieces of around 1.6 × 2.6 cm2, cleaned with detergent and dried. After sonification in pentane, acetone and Milli-Q water, the slides were put into a freshly prepared piranha solution (H2O2/H2SO4 = 1:3) for 30 min. The wafers were then thoroughly washed with water, dried and immersed in a 0.3 vol