Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

• Maurizio Selva,
• Alvise Perosa,
• Sandro Guidi and
• Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

• ]. Again, in this case, the investigation proved that the activity of the organic salt was higher than that of sulfuric acid. The use of ionic liquids for the catalytic production of biodiesel was recently reviewed by Fauzi and Amin [51], who focused on the improvements made possible by organocatalysts

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

• -oxabicycloalkanes 147a–d in formic or acetic acid containing catalytic amounts of sulfuric acid affords ω-alkoxy-(ω-3)-hydroxyalkanoic acid lactones 148a–d and 149a–d (Table 10) [297]. The transformation of 1-hydroperoxy-2-oxabicycloalkanones 147a–d into ω-alkoxy-(ω-3)-hydroxyalkanoic acid lactones 148a–d and 149a

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• H2SO4 or Lewis acids such as SnCl2, FeCl3 and VCl3, as well as heterogeneous catalysts including silica gel supported sulfuric acid and sodium hydrogen sulfate did not affect this reaction. Also, the reaction in the presence of p-toluenesulfonic acid (TsOH), in aprotic solvents proceeded with much

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• , acetonitrile, or ether at 0 °C or −78 °C. To each was added nitric acid (16 M) and concentrated sulfuric acid (18 M), a biphasic organic/inorganic reaction mixture formed [25]. Unfortunately after work-up all of these reactions afforded complex mixtures. Thus although the 1H NMR and mass spectrometry indicated

• identify individual components. In summary, the seemingly straightforward combination of nitric and sulfuric acid was unsuited to the efficient synthesis of IPNs. Although generating a mixture of rac-17 and rac-18 was broadly acceptable due to their ease of synthesis, our inability to effectively separate

• of mercury(I) chloride (0.06 mol %) and sulfuric acid (0.35 mol %) in water following the procedure of Boger et al. [51]. 63 was afforded in an unoptimized 78% yield. Employing the conditions outlined in Scheme 10 63 reacted with the stabilized ylide generated from the deprotonation of triethyl

Synthesis and in vitro cytotoxicity of acetylated 3-fluoro, 4-fluoro and 3,4-difluoro analogs of D-glucosamine and D-galactosamine

• Štěpán Horník,
• Lucie Červenková Šťastná,
• Petra Cuřínová,
• Jan Sýkora,
• Kateřina Káňová,
• Roman Hrstka,
• Ivana Císařová,
• Martin Dračínský and
• Jindřich Karban

Beilstein J. Org. Chem. 2016, 12, 750–759, doi:10.3762/bjoc.12.75

• deoxofluoro derivatives of 2-azido-1,6-anhydrohexopyranoses in hand, we examined their conversion to the target acetylated hexosamine analogs. Initially, compound 19 was hydrogenated (Pd/C) and acetylated to afford acetamide 40 in modest yield (37%). Sulfuric acid-catalyzed [35] cleavage of the internal

• oxazoline formation, the order of reactions was reversed, and triethylsilyl triflate (TESOTf)-catalyzed [58] acetolysis of the 1,6-anhydro bridge in 19 gave 42 (Table 1) as a mixture of anomers from which the α-anomer crystallized. TESOTf as a catalyst for acetolysis gave better results than sulfuric acid

Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

• Helmut Ritter,
• Monir Tabatabai and
• Markus Herrmann

Beilstein J. Org. Chem. 2016, 12, 245–252, doi:10.3762/bjoc.12.26

• heated under reflux. A second 500 mL single-necked flask was equipped with N-bromosuccinimide (NBS, 50 g 0.28 mol) in a mixture of THF/H2O 1:2. To the boiling tert-butanol 5 portions of 5 mL each concentrated sulfuric acid were added dropwise every 15 min. The forming isobutene was bubbled into the NBS

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

• the Czech Republic, Vídeňská 1083, 142 20 Prague, Czech Republic 10.3762/bjoc.12.12 Abstract Oxidation of 3- and 4-pentafluorosulfanyl-substituted anisoles and phenols with hydrogen peroxide and sulfuric acid provided a mixture of SF5-substituted muconolactone, maleic, and succinic acids. A plausible

• -(pentafluorosulfanyl)anisole (1) or 4-(pentafluorosulfanyl)phenol (2) by a mixture of aqueous hydrogen peroxide and concentrated sulfuric acid (Scheme 1). The major product was muconolactone 3 while maleic acid 4 and succinic acid 5 were formed in small amounts. Herein we report a full account of this oxidation

• )anisole and 4-(pentafluorosulfanyl)phenol the meta-derivatives 10 and 11 underwent oxidation with aqueous hydrogen peroxide in sulfuric acid to provide SF5-muconolactone and SF5-maleic acid as main products. Improved conversion of SF5-maleic acid was rationalized by preferential formation of SF5

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• the generation of active layers in organic electronic devices. Experimental Materials and methods 1, 2, tetrakis(triphenylphosphine)palladium(0) [Pd(PPh3)4], β- and γCD, bromobenzene (Br–Ph), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and quinine sulfate dehydrate in 0.5 M sulfuric acid were

• ]. The PLQE was estimated by comparison with a solution of quinine sulfate dehydrate in 0.5 M sulfuric acid of known quantum efficiency, 56 ± 5%. CVs were carried out in a three-electrode cell in which Pt (1 mm diameter) was used as a working electrode, a Pt wire as counter-electrode and an Ag wire as

Versatile synthesis and biological evaluation of novel 3’-fluorinated purine nucleosides

• Hang Ren,
• Haoyun An,
• Paul J. Hatala,
• William C. Stevens Jr,
• Jingchao Tao and
• Baicheng He

Beilstein J. Org. Chem. 2015, 11, 2509–2520, doi:10.3762/bjoc.11.272

• -ribofuranose (25) was then obtained in 33.13% overall yield after further treatment with acetic anhydride–acetic acid–sulfuric acid system. More than 200 g scale was achieved for the synthesis, and high purity (98%) product was obtained. This key intermediate 25 can be used to synthesize a variety of 3’-fluoro

[2.2]Paracyclophane derivatives containing tetrathiafulvalene moieties

• Laura G. Sarbu,
• Lucian G. Bahrin,
• Peter G. Jones,
• Lucian M. Birsa and
• Henning Hopf

Beilstein J. Org. Chem. 2015, 11, 1917–1921, doi:10.3762/bjoc.11.207

• salts, consists of an acid-catalyzed cyclocondensation of phenacyl carbodithioates 4. Using a concentrated sulfuric acid–glacial acetic acid mixture (1:3, v/v) [20], the cyclization of carbodithioates 4a–c takes place under mild reaction conditions. After 10 min at 80 °C the homogeneous reaction mixture

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• efficient than the first. Other differences have been noted such as Friedel–Craft acylation in sulfuric acid that led to one product after chromatographic column purification, while in the second preparation, a mixture of two adducts was obtained after an absorbent-free purification. This may explain why

• by treating the binicotinic acid with methanol and sulfuric acid. The resulting product was transformed into a 2-haloanilide under Weinreb conditions, namely trimethylaluminium and 2-haloaniline. Subarine (37) was subsequently obtained from the radical cyclization of the haloanilide derivative in the

Are D-manno-configured Amadori products ligands of the bacterial lectin FimH?

• Tobias-Elias Gloe,
• Insa Stamer,
• Cornelia Hojnik,
• Tanja M. Wrodnigg and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 1096–1104, doi:10.3762/bjoc.11.123

• performed on precoated silica gel plates on aluminum 60 F254 (E. Merck 5554). Detection was effected by UV and/or charring with 10% sulfuric acid in EtOH and/or with ceric ammonium molybdate (100 g ammonium molybdate/8 g ceric sulfate in 1 L 10% H2SO4) followed by heat treatment at ≈180 °C. Flash

Synthesis of multivalent carbohydrate mimetics with aminopolyol end groups and their evaluation as L-selectin inhibitors

• Joana Salta,
• Jens Dernedde and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2015, 11, 638–646, doi:10.3762/bjoc.11.72

• reasonably reproducible procedure. Since other sulfation methods such as SO3∙pyridine [35] provided unsatisfactory results an excess of SO3∙DMF [13][36] was used as sulfating agent and the resulting sulfuric acid monoesters (in a mixture with an excess of the sulfating reagent) were directly converted into

• exchange DOWEX® Na+ (50WX8-200) column to assure that all sulfuric acid monoesters as well as the excess of the sulfating agent were converted into the corresponding sodium salts. After this filtration a dialysis of the mixture generally afforded pure products. The modified procedure was applied to the O

Ruthenium-catalyzed C–H activation of thioxanthones

• Danny Wagner and
• Stefan Bräse

Beilstein J. Org. Chem. 2015, 11, 431–436, doi:10.3762/bjoc.11.49

• cleavage catalyzed by hot sulfuric acid. In this case, methylation (Me2SO4, K2CO3) of the hydroxythioxanthones 1c, 1e and 1g provided the required methyl ethers 1d, 1f and 1h, respectively in good yields (80, 85 and 95%), Scheme 1. Ru-catalyzed C–H activation Following the precedence for other carbonyl

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

• the reaction of alkenes with Br2 and I2 [2]. However, the most straightforward method is the reaction of alkenes with halogen cations such as Br+ and I+. The I+ cation pool exists as reported by Filimonov et al. [3], although the used solvent is concentrated sulfuric acid which is therefore not

Synthesis and characterization of pH responsive D-glucosamine based molecular gelators

• Navneet Goyal,
• Hari P. R. Mangunuru,
• Bargav Parikh,
• Sonu Shrestha and
• Guijun Wang

Beilstein J. Org. Chem. 2014, 10, 3111–3121, doi:10.3762/bjoc.10.328

• compared to the non-substituted series, which may be useful for a triggered release of entrapped agents under an acidic environment. We tested the stability of two aqueous gels formed by compounds 23 [36] and 21 by using diluted sulfuric acid solution (pH 1). As shown in Figure 6, the stability of two gels

• mixture was recorded. Acid stability study Two gels were prepared in DMSO/H2O from compounds 21 and 23 at 5 mg/mL and 1 mL total volume in a small vial. To this gel, 1 mL of sulfuric acid solution (pH 1) was carefully added to the top the gel. This mixture was then monitored at 25 °C to observe the

• test results under acidic conditions. a) A gel formed by compound 23 in DMSO/H2O (1:2) at 5 mg/mL. b) A gel formed by compound 21 in DMSO/H2O (1:2) at 5 mg/mL. The photos show the gels treated with 1 mL of sulfuric acid solution (pH 1) at different time periods. Release of naproxen sodium from the gel

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• simple filtration and washing. It was also found that compared to thermal treatment, the rearrangement of 73 to 76 proceeds by far more efficiently in the presence of sulfuric acid (Scheme 29, top right). In a follow-up study, the elaborated electrolysis protocol served as a key-step for the generation

Detonation nanodiamonds biofunctionalization and immobilization to titanium alloy surfaces as first steps towards medical application

• Juliana P. L. Gonçalves,
• Afnan Q. Shaikh,
• Manuela Reitzig,
• Daria A. Kovalenko,
• Jan Michael,
• René Beutner,
• Gianaurelio Cuniberti,
• Dieter Scharnweber and
• Jörg Opitz

Beilstein J. Org. Chem. 2014, 10, 2765–2773, doi:10.3762/bjoc.10.293

• aminosilanized DND 6 adsorbed to the air-formed passive layer of Ti6Al7Nb sample followed by anodic polarization (60 V, 50 mA/cm2). Overview on applied modification techniques to obtain DND with phosphate groups; conditions and reagents: (i) Sulfuric acid and nitric acid solution (9:1), 80 °C, 24 h (ii) O

A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

• Stefanie Wolfram,
• Hendryk Würfel,
• Stefanie H. Habenicht,
• Christine Lembke,
• Phillipp Richter,
• Eckhard Birckner,
• Rainer Beckert and
• Georg Pohnert

Beilstein J. Org. Chem. 2014, 10, 2470–2479, doi:10.3762/bjoc.10.258

• with a GENESYS™ 10 S spectrophotometer (Thermo Fischer Scientific Inc., Waltham, MA, USA) with 10 mm quartz cells. Quantum yields were obtained as described in [43] using quinine sulfate in 0.05 M sulfuric acid as fluorescent standard with a Varian Cary 500 spectrophotometer (Varian Inc., Palo Alto, CA

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• , hydrochloric and sulfuric acid in aqueous RF solutions are also known to decrease the photodestruction rate of RF by 1.5–2.5 times. This could be due to protonation and formation of a complex between metal ions and oxygen atoms of hydroxy groups of RF [162]. Although RF is a thermostable substance, the

Expedient synthesis of 1,6-anhydro-α-D-galactofuranose, a useful intermediate for glycobiological tools

• Luciana Baldoni and
• Carla Marino

Beilstein J. Org. Chem. 2014, 10, 1651–1656, doi:10.3762/bjoc.10.172

• (layer thickness 0.2 mm) with solvent systems given in the text. Visualization of the spots was effected by exposure to UV light and charring with a solution of 10% (v/v) sulfuric acid in EtOH containing 0.5% p-anisaldehyde. Column chromatography was carried out with Silica Gel 60 (230–400 mesh, Merck

Multichromophoric sugar for fluorescence photoswitching

• Stéphane Maisonneuve,
• Rémi Métivier,
• Pei Yu,
• Keitaro Nakatani and
• Juan Xie

Beilstein J. Org. Chem. 2014, 10, 1471–1481, doi:10.3762/bjoc.10.151

• fluorescence quantum yields were determined by using quinine sulfate dihydrate in sulfuric acid (0.5 N) as a standard at λexc = 325 nm (ΦF = 0.546) and coumarin 540A in ethanol as a standard at λexc = 450 nm (ΦF = 0.544). Photochromic reactions were induced in situ by a continuous irradiation Hg–Xe lamp

Human dendritic cell activation induced by a permannosylated dendron containing an antigenic GM₃-lactone mimetic

• Renato Ribeiro-Viana,
• Elena Bonechi,
• Javier Rojo,
• Clara Ballerini,
• Giuseppina Comito,
• Barbara Richichi and
• Cristina Nativi

Beilstein J. Org. Chem. 2014, 10, 1317–1324, doi:10.3762/bjoc.10.133

• without purification. Synthetic compounds were purified by Sephadex (LH20). Thin-layer chromatography (TLC) was carried out with pre-coated Merck F254 silica gel plates. Reaction completion was observed by TLC with phosphomolibdic acid, 10% sulfuric acid in methanol or anisaldehyde as development reagents

Solid-phase-supported synthesis of morpholinoglycine oligonucleotide mimics

• Tatyana V. Abramova,
• Sergey S. Belov,
• Yulia V. Tarasenko and
• Vladimir N. Silnikov

Beilstein J. Org. Chem. 2014, 10, 1151–1158, doi:10.3762/bjoc.10.115

• plates (Merck, Germany) in the proper solvent systems (see below) and visualized by UV irradiation, ninhydrin (amine groups) or cystein/aqueous sulfuric acid (nucleoside and trityl groups). Preparative silica gel column chromatography, RPC, and cation exchange chromatography were performed using silica

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

• aminoanthracene-9,10-dione deactivate the ring towards electrophilic substitution [11]. Generally, the bromination of aminoanthracene-9,10-dione is carried out in sulfuric acid [12][13][14][15] (20 to 98%) and nitrobenzene [16][17] at a high temperature (80 to 120 °C) with or without a catalyst (like Cu or CuSO4

• ) [18][19][20][21]. In all processes, hazardous molecular bromine is used as a bromine source [11][12][13][14][15][16][17][18][19][20][21]. Ghaieni et. al. [22][23] have reported bromination of aminoanthracene-9,10-dione in a mixture of conc sulfuric acid with chlorobenzene, glacial acetic acid

• (Universal V4.5A TA Instrument), ramp 10.00 °C/min to 300.00 °C, flow rate: 50.0 mL/min. Procedure for the preparation of nonanebis(peroxoic acid): In 250 mL round bottomed flask equipped with a mercury sealed stirrer, 10 g of nonanedioic acid (0.0531 mol) was dissolved in 95% sulfuric acid (25 g, 0.255 mol