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

• experimental results indicated that the complexes have potential activities during the degradation of the azo dyes in the aqueous medium and in the presence of hydrogen peroxide. From the preliminary data, it was found that all the prepared complexes have demonstrated a promising catalytic activity at the same

• ) [33][34]. Effect of the hydrogen peroxide concentration As proved in the previous section, the action of H2O2 alone did not show any degradation capacity for the studied dye solution, although this agent is considered a relatively powerful oxidant. In this section, we examine the effect of H2O2 dose

• target removal of Eriochrome Blue Black B was reached within minutes, under some experimental conditions. These new complexes prove to be active and also to be a reusable catalyst for the decolorization of Erio solutions in the presence of hydrogen peroxide. Further work is ongoing to apply the same

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

• chemiluminescence experiment as a qualitative test. The known chemiluminescence reaction of the diaryl oxalate esters oxidized by hydrogen peroxide in the presence of rubrene was investigated (Scheme 2) [38][39][40]. Two solutions were prepared. One solution contained a mixture of diaryl oxalate and rubrene in

• dimethyl phthalate. The second solution was hydrogen peroxide dissolved in either water, or a water–organic solvent mixture. The solutions in the vial and delivery tube were alternated to ensure that the direction of diffusion was not gravity or density-dependent. We observed that the chemiluminescence

• 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

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

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

• numeral, but the acetylated derivative is amended by the letter “a”, e.g., cholesterol (1) and cholesteryl acetate (1a). Indirect electrochemical oxidation of cholesterol The selective oxidation of saturated hydrocarbons by dioxygen and hydrogen peroxide remains a challenging problem in chemistry and

• cholesterol took place in the cathodic compartment. The oxidation did not occur without the electrochemical reduction of Tl(III), which suggests that Tl(III) cannot activate dioxygen. In addition, the replacement of dioxygen by hydrogen peroxide gave a mixture of oxidation products. This indicates that

• dioxygen was not electrochemically reduced to hydrogen peroxide, which could act as an oxidant. It was also observed that the replacement of Tl(III) with Fe(III) caused a decrease in the reaction yield and the replacement of HMP with tetraphenylporphyrin or its derivatives resulted in product mixtures

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• antibacterial and antiviral activities, as well as inhibitory activity on thromboxane A2 and leukotriene D4 [4]. Acylphloroglucinols are known to act as anti-oxidants, by reducing hydroperoxides and hydrogen peroxide, thereby suppressing the formation of the reactive species [9]. The hyperaspidinols 1 and 2

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

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

• of both enantiomers of N-(4-hydroxyphenyl)mandelamide (1) were obtained though oxidative coupling with peroxidase and laccase and also via oligomerization with iron(II)-salen and hydrogen peroxide as a catalyzing system. In the presence of RAMEB-CD it was possible to oligomerize the poorly water

• oligo (N-(4-hydroxyphenyl)mandelamide) (2) Enzymatic oxidative oligomerization with peroxidase: A solution of 7.5 mg peroxidase dissolved in 10 ml pH 7 buffer was added to a solution of 1.22 g (5 mmol) N-(4-hydroxyphenyl)mandelamide (1) and 40 mL 1.4-dioxan. 510 µL of hydrogen peroxide (30%) were added

• reaction mixture. After addition of 510 µL of hydrogen peroxide (30%) in aliquots of 51 µL in 15 minutes intervals, the mixture was stirred for 2 h at room temperature. The precipitated product was isolated by filtration, washed with 0.5 M HCl, water and dried. Then the oligomer was dissolved in dioxan

Magnesium bis(monoperoxyphthalate) hexahydrate as mild and efficient oxidant for the synthesis of selenones

• Andrea Temperini,
• Massimo Curini,
• Ornelio Rosati and
• Lucio Minuti

Beilstein J. Org. Chem. 2014, 10, 1267–1271, doi:10.3762/bjoc.10.127

• efficient and mild methods for their synthesis is of considerable interest. A few previous papers report the synthesis of selenones 2 by oxidation of the corresponding selenides 1 with potassium permanganate [4], trifluoroacetic acid [4] and hydrogen peroxide in trifluoroethanol with stoichiometric amounts

Nonanebis(peroxoic acid): a stable peracid for oxidative bromination of aminoanthracene-9,10-dione

• Vilas Venunath Patil and
• Ganapati Subray Shankarling

Beilstein J. Org. Chem. 2014, 10, 921–928, doi:10.3762/bjoc.10.90

• , Oxone (Table 3, entry 2) shows 94% conversion of 1a in 2 h. In case of 50% Hydrogen peroxide (Table 3, entry 3), more than 7 equivalents of oxidant were required with successive addition. The urea hydrogen peroxide shows moderate conversion in 20 h (Table 3, entry 6). The other diperoxy acids like

• was surmised that in the presence of oxidant these substrates form a diimine type product (similar to oxidative hair dye mechanism) [33], which makes the ring unreactive towards electrophilic substitution. Since Oxone and 50% hydrogen peroxide showed good results with substrate 1a, we have checked the

• 50–55 °C. The N-alkylated substrates such as 1i, 1j and the substrate 1k showed poor conversion (product formed in tracess) even at a higher temperature when 50% hydrogen peroxide was used as an oxidant. This study demonstrates the superiority of nonanebis(peroxoic acid) under the present protocol

End-group-functionalized poly(N,N-diethylacrylamide) via free-radical chain transfer polymerization: Influence of sulfur oxidation and cyclodextrin on self-organization and cloud points in water

• Sebastian Reinelt,
• Daniel Steinke and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 680–691, doi:10.3762/bjoc.10.61

• accomplished by oxidation with hydrogen peroxide in analogy to literature [11]. As expected, the MALDI–TOF mass spectrum for 8bOx showed only one series of peaks, which was shifted by 16 Dalton in comparison to the origin series of peaks (see Figure 3). The FTIR spectrum showed a decrease of transmission at a

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• diastereomers (Scheme 25). No formation of products resulting from a first cycloaddition of the 1,3-butadienyl moiety was observed when these reactions were conducted in a tandem one-pot process. Various transformations were further carried out as oxidation with hydrogen peroxide or addition to aldehydes that

Synthesis and biological activity of N-substituted-tetrahydro-γ-carbolines containing peptide residues

• Nadezhda V. Sokolova,
• Valentine G. Nenajdenko,
• Vladimir B. Sokolov,
• Daria V. Vinogradova,
• Elena F. Shevtsova,
• Ludmila G. Dubova and
• Sergey O. Bachurin

Beilstein J. Org. Chem. 2014, 10, 155–162, doi:10.3762/bjoc.10.13

• ] (Figure 1). These peptides were found to scavenge hydrogen peroxide and peroxynitrite and inhibit lipid peroxidation in vitro. By reducing mitochondrial reactive oxygen species, they inhibit MPT and cytochrome c release, thus protecting cells from oxidative cell death [11]. We expected that the

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• peroxides are based on three key reagents: oxygen, ozone, and hydrogen peroxide. These reagents and their derivatives are used in the main methods for the introduction of the peroxide group, such as the singlet-oxygen ene reaction with alkenes, the [4 + 2]-cycloaddition of singlet oxygen to dienes, the

• Mukaiyama–Isayama peroxysilylation of unsaturated compounds, the Kobayashi cyclization, the nucleophilic addition of hydrogen peroxide to carbonyl compounds, the ozonolysis, and reactions with the involvement of peroxycarbenium ions. Each part of the review deals with a particular class of the above

• peroxide moiety, the Isayama–Mukaiyama peroxysilylation, and reactions involving peroxycarbenium ions. Syntheses employing hydrogen peroxide and the intramolecular Kobayashi cyclization are less frequently used. 1.1. Use of oxygen for the peroxide ring formation The singlet-oxygen ene reaction with alkenes

Biosynthesis of rare hexoses using microorganisms and related enzymes

• Zijie Li,
• Yahui Gao,
• Hideki Nakanishi,
• Xiaodong Gao and
• Li Cai

Beilstein J. Org. Chem. 2013, 9, 2434–2445, doi:10.3762/bjoc.9.281

• sanctum seeds) and investigated their synthetic application for L-glucose production from D-sorbitol (Scheme 13) [83][84]. Catalase could degrade the hydrogen peroxide byproduct and increase the conversion by removing the inhibition effect of hydrogen peroxide toward galactose oxidase and regenerating

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• -step sequence yielded azetidine 107. After oxidation with hydrogen peroxide, the resulting N-oxide cleanly underwent a [1,2]-Meisenheimer rearrangement upon heating in tetrahydrofuran. The so-formed azocine 108 was converted to amine 109 by hydrogenolysis of the N–O bond. Amide formation with acid

Integrating reaction and analysis: investigation of higher-order reactions by cryogenic trapping

• Skrollan Stockinger and
• Oliver Trapp

Beilstein J. Org. Chem. 2013, 9, 1837–1842, doi:10.3762/bjoc.9.214

• reactions, so that the reaction kinetics can be investigated under comparable reaction conditions. So far, we investigated only first-order or pseudo-first-order reactions, where, for example, one reactant is used as a carrier gas, i.e., hydrogen in hydrogenation reactions or hydrogen peroxide as oxidant

A practical synthesis of long-chain iso-fatty acids (iso-C₁₂–C₁₉) and related natural products

• Mark B. Richardson and
• Spencer J. Williams

Beilstein J. Org. Chem. 2013, 9, 1807–1812, doi:10.3762/bjoc.9.210

• triethylsilane and BF3·Et2O [53], affording 11. Oxidative cleavage of 11 with KMnO4/Bu4NBr [54] afforded iso-C12 acid 1. Alternatively, anti-Markovnikov hydration of 11, using I2/NaBH4 then hydrogen peroxide [55], afforded the alcohol 12, and oxidation of 12 with KMnO4/Bu4NBr afforded iso-C13 acid 2

Polymeric redox-responsive delivery systems bearing ammonium salts cross-linked via disulfides

• Christian Dollendorf,
• Martin Hetzer and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 1652–1662, doi:10.3762/bjoc.9.189

• hydrogels become soluble by reduction of disulfide to mercaptanes by use of dithiothreitol (DTT), tris(2-carboxyethyl)phosphine (TCEP) or cysteamine, respectively. The soluble polymeric system can be cross-linked again by using oxygen or hydrogen peroxide under basic conditions. The redox-responsive polymer

Re₂O₇-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles

• Wantanee Sittiwong,
• Michael W. Richardson,
• Charles E. Schiaffo,
• Thomas J. Fisher and
• Patrick H. Dussault

Beilstein J. Org. Chem. 2013, 9, 1526–1532, doi:10.3762/bjoc.9.174

• Brønsted or Lewis acid, or by conversion to an activated intermediate such as a haloacetal [1]. Perrhenates, best known as catalysts for large-scale alkene metathesis [2] and isomerization of allylic alcohols [3][4][5][6][7][8][9][10], have been shown to promote condensation of carbonyls with hydrogen

• peroxide or hydroperoxides [11][12], intramolecular displacements of reversibly formed hemiacetals and allylic alcohols [8][13], displacement of resonance-activated alcohols with electron-poor nitrogen nucleophiles [14], and a synthesis of homoallylated amines from condensation of carbonyl groups with an

Homolytic substitution at phosphorus for C–P bond formation in organic synthesis

• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 1269–1277, doi:10.3762/bjoc.9.143

•  15) [42]. Photolysis of the esters in the presence of white phosphorus followed by oxidation with hydrogen peroxide yields alkylphosphonic acid. The efficient phosphination would stem from the highly strained structure and the weak P–P bonds of white phosphorus. After 13 years of silence, radical

Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors

• Rahat Javaid,
• Shin-ichiro Kawasaki,
• Akira Suzuki and
• Toshishige M. Suzuki

Beilstein J. Org. Chem. 2013, 9, 1156–1163, doi:10.3762/bjoc.9.129

• have studied flow reactions, including the decomposition of hydrogen peroxide, oxidation of organic dyes, carbon–carbon coupling, and conversion of formic acid to hydrogen (H2) and carbon dioxide (CO2), using catalytic tubular reactors [10][11][12][13]. p-Aminophenol is an important intermediate

• acid (HNO3, 60%) and hydrogen peroxide (H2O2, 30%) were purchased from Wako Pure Chemical Industries Ltd. and were used without further purification. Fabrication of tubular reactors A double-layered tube (o.d. 1.6 mm, i.d. 0.5 mm, length 100 cm) composed of Inconel 625 and titanium (Ti) inner layer

Methylidynetrisphosphonates: Promising C₁ building block for the design of phosphate mimetics

• Vadim D. Romanenko and
• Valery P. Kukhar

Beilstein J. Org. Chem. 2013, 9, 991–1001, doi:10.3762/bjoc.9.114

• intermediate with hydrogen peroxide in tetrahydrofuran [26]. Mixed ethyl/isopropyl trisphosphonate ester 9 has been prepared by treatment of the bisphosphonate 7 with diethyl chlorophosphite and sodium hexamethyldisilazane, and subsequent oxidation of the phosphinate intermediate 8 with iodine in pyridine–THF

• treatment of trisphosphonate salt 38 with a mixture of hydrogen peroxide in trifluoroacetic acid (Scheme 22). An alternative and more efficient synthesis of methylidynetrisphosphonic acid uses a transsilylation of hexaalkyl trisphosphonate 9 followed by hydrolysis [27]. Synthesis of

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• phenols in water/organic-solvent systems in the presence of hydrogen peroxide. In recent studies it was demonstrated that several para-substituted phenols, i.e., 4-tert-butylphenol, can be polymerized with HRP in high yield and relatively high molecular weights [13]. Also several polyphenols with further

Reactions of nitroxides XIII: Synthesis of the Morita–Baylis–Hillman adducts bearing a nitroxyl moiety using 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl as a starting compound, and DABCO and quinuclidine as catalysts

• Jerzy Zakrzewski

Beilstein J. Org. Chem. 2012, 8, 1515–1522, doi:10.3762/bjoc.8.171

• of 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (3) on the reaction course was observed. Experimental General: 2,2,6,6-Tetramethyl-4-hydroxypiperidin-1-oxyl (1) was synthesized by the oxidation of 2,2,6,6-tetramethyl-4-piperidinol with 30% hydrogen peroxide (76.5% yield, mp 71–73 °C), according

Synthesis of compounds related to the anti-migraine drug eletriptan hydrobromide

• Suri Babu Madasu,
• Nagaji Ambabhai Vekariya,
• M. N. V. D. Hari Kiran,
• Badarinadh Gupta,
• Aminul Islam,
• Paul S. Douglas and
• Korupolu Raghu Babu

Beilstein J. Org. Chem. 2012, 8, 1400–1405, doi:10.3762/bjoc.8.162

• deacetylation reaction. Eletriptan N-oxide isomers 3 and 4 are possible contaminants that can be formed by oxidation in air. These compounds were prepared by oxidation of eletriptan (14) with aqueous hydrogen peroxide (~50%, w/w) in the presence of catalytic amounts of ammonium molybdate. The isomers 3 and 4

• (80–85 °C) in the presence of peroxide in aqueous acetonitrile. It was also observed that only 4.5% of this impurity was formed when 10% (w/w) hydrogen peroxide was used. However, this impurity was formed at 40–60%, when 30% (w/w) hydrogen peroxide used. This impurity was identified by LC–MS and

• [18]. This impurity is forming only in aprotic solvents, e.g., acetonitrile in the presence of peroxides at higher temperature. It was prepared by treating eletriptan hydrobromide (1) with aqueous hydrogen peroxide (30% w/w) in aqueous acetonitrile at 80–85 °C (Scheme 7). Formation of this impurity