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

Cuevaenes C–E: Three new triene carboxylic derivatives from Streptomyces sp. LZ35ΔgdmAI

• Jing-Jing Deng,
• Chun-Hua Lu,
• Yao-Yao Li,
• Shan-Ren Li and
• Yue-Mao Shen

Beilstein J. Org. Chem. 2014, 10, 858–862, doi:10.3762/bjoc.10.82

• was added to 5 mL of 1.7% (w/v) bismuth nitrate solution in 20% (v/v) acetic acid, and the mixture was diluted to 100 mL with 10% (w/v) sulfuric acid). Material. Strain LZ35 was isolated from the intertidal soil collected at Jimei, Xiamen, China. It was identified as a Streptomyces species according

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• reaction resulted in the desired oxazoles (Scheme 44). Herein, dimethoxybenzylamine, several isocyanides, aryl-glyoxals and (hetero)-aryl carboxylic acids afforded the desired corresponding Ugi-products 144 in reasonable to good yields (42–65%). Subsequent exposure to concentrated sulfuric acid at 60 °C

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• organic compound [1]. Among the earliest reports are those of Faraday nitrating benzene, the synthesis of nitrobenzene by Mitscherlich [2] using benzene and fuming nitric acid, and the use of mixed acids (nitric acid and sulfuric acid) for aromatic nitration by Mansfield [3]. In general, nitration

• nitrations of organic substrates with sulfuric acid and nitric acid as the nitrating agents. However, the use of other activating agents (e.g., acetic anhydride) is not uncommon. Typically, nitrations with undiluted nitric acid generate water that leads to the dilution of the nitric acid, so that the

• and it can form a complex with the organic products, so that only after reaction, significant dilution with water allows separating the organic phase from the diluted nitric acid. The sulfuric acid in so-called “mixed acid”, i.e., a mixture of HNO3 and H2SO4, catalyzes the generation of nitronium ions

Carbenoid-mediated nucleophilic “hydrolysis” of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants^§

• Rudolf Knorr,
• Thomas Menke,
• Johannes Freudenreich and
• Claudio Pires

Beilstein J. Org. Chem. 2014, 10, 307–315, doi:10.3762/bjoc.10.28

• The carboxylic acid 10 (Scheme 2) would normally (and more expediently than before [15]) be accessible through a simple hydrolysis reaction [16][17] of 6 with concentrated (80–100%) sulfuric acid. Our in situ 1H NMR spectra showed that 6 was insoluble in D2SO4 (97%) at rt and that two promising

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

• hydroperoxy acetals 61a,b (Scheme 19) [250]. The ozonolysis of 9-methyleneheptadecane-7,11-diyl-bis(methanesulfonate) (63) gave 9-oxoheptadecane-7,11-diyl-bis(methanesulfonate) (64). The latter reacted with H2O2 in the presence of sulfuric acid (or iodine) as the catalyst to form 9,9-dihydroperoxyheptadecane

Synthesis of nucleotide–amino acid conjugates designed for photo-CIDNP experiments by a phosphotriester approach

• Tatyana V. Abramova,
• Olga B. Morozova,
• Vladimir N. Silnikov and
• Alexandra V. Yurkovskaya

Beilstein J. Org. Chem. 2013, 9, 2898–2909, doi:10.3762/bjoc.9.326

• solvent systems (see below) and spots were visualized by UV irradiation, ninhydrin (for amine groups) or cysteine/aqueous sulfuric acid (for nucleosides and tryptophan) solution. Evaporations were performed under reduced pressure at 40 °C. The preparative silica gel column chromatography was performed

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• ) sulfate and ferrocene were used alternately as catalysts in the presence or not of sulfuric acid, but other metals proved inactive. The procedures could be adapted to larger-scale synthesis (10 g). 3.3.5 Fe-catalyzed trifluoromethylation of arylboron reagents. S. L. Buchwald et al. developed an iron(II

Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

• Sudipta Pathak,
• Kamalesh Debnath and
• Animesh Pramanik

Beilstein J. Org. Chem. 2013, 9, 2344–2353, doi:10.3762/bjoc.9.269

• pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA) as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused

• starting materials, and the excellent yields of products. Keywords: green chemistry; pyrrole-fused isocoumarin; reusable solid support; silica sulfuric acid; solvent-free condition; Introduction Isocoumarins are an important class of naturally occurring lactones [1][2][3], which has attracted the

• reactions in solution because of simple work-up procedures, improved product yields, greater ease of purification, shorter reaction times, milder reaction conditions, and recyclability of the catalyst [24]. In the recent years, silica sulfuric acid (SSA) has shown immense potentiality as an efficient and

Raman spectroscopy as a tool for monitoring mesoscale continuous-flow organic synthesis: Equipment interface and assessment in four medicinally-relevant reactions

• Trevor A. Hamlin and
• Nicholas E. Leadbeater

Beilstein J. Org. Chem. 2013, 9, 1843–1852, doi:10.3762/bjoc.9.215

• reaction of benzaldehyde, ethyl acetoacetate and urea catalyzed by sulfuric acid (Figure 8). The calculated Raman spectrum of the product, 4a, shows a strong signal at 1598 cm−1 which was selected for monitoring. Using a catalyst loading of 10 mol % and a flow rate of 1 mL/min, we monitored the reaction

The first example of the Fischer–Hepp type rearrangement in pyrimidines

• Inga Cikotiene,
• Mantas Jonusis and
• Virginija Jakubkiene

Beilstein J. Org. Chem. 2013, 9, 1819–1825, doi:10.3762/bjoc.9.212

• recognized that a 6-chloro substituent is activated by the N-nitroso moiety in position 4 of the pyrimidine ring which facilitates nucleophilic substitutions. Moreover, after completion of the substitution reaction, N-nitroso moieties can be easily removed by short heating in diluted sulfuric acid [16]. When

• are presented in Scheme 4 and Table 1. As it was shown by us earlier, N-nitrosated compounds 4, bearing hydrogen or methyl groups in position 2 of the pyrimidine ring undergo a smooth denitrosation reaction during heating in 10% sulfuric acid at 120 °C (Table 1, entries 1 and 4–9). After the work-up

• during heating of the suspension of 4ea, bearing a methylthio group in position 2 of the pyrimidine ring, in 10% sulfuric acid at 120 °C (Table 1, entry 11). After the classical work-up of the reaction mixture, two products were isolated. One of these products was proved to be N-benzyl-2-methylthio-6

Anionic cascade reactions. One-pot assembly of (Z)-chloro-exo-methylenetetrahydrofurans from β-hydroxyketones

• István E. Markó and
• Florian T. Schevenels

Beilstein J. Org. Chem. 2013, 9, 1319–1325, doi:10.3762/bjoc.9.148

• potassium tert-butoxide were added. After 15 minutes, 700 mg (6.0 mmol, 1 equiv) of hydroxyketone in 1 mL of THF were added. After one hour, 20 mL of water was added and the mixture was neutralized with diluted sulfuric acid. The aqueous layer was extracted with 2 × 20 mL of DCM. The organic layer was dried

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• initiators. Azo-initiators were mainly employed for the synthesis of phenol derivatives by aerobic oxidation of isopropyl aromatics. For example, the oxidation of 2,6-diisopropylnaphthalene with air in the presence of α,α’-azobisisobutyronitrile (AIBN) and NHPI, followed by decomposition with sulfuric acid

An aniline dication-like transition state in the Bamberger rearrangement

• Shinichi Yamabe,
• Guixiang Zeng,
• Wei Guan and
• Shigeyoshi Sakaki

Beilstein J. Org. Chem. 2013, 9, 1073–1082, doi:10.3762/bjoc.9.119

• ; Introduction The fundamental Bamberger rearrangement is defined in Scheme 1 [1][2]. In the aqueous sulfuric acid, 4-aminophenol was afforded exclusively by the rearrangement. On the other hand, the 2- and 4-chloro-amino derivatives were afforded when hydrochloric acid was used. In spite of the classic and well

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• 29a–c was built by acylating 2-hydroxy-5-methoxyacetophenone (34) with 4-nitrobenzoyl chloride (35) and subjecting the resulting 2-acyloxyacetophenone (36) to Baker–Venkataraman rearrangement [17] to afford the 1,3-diarylpropane-1,3-dione 37, which was dehydrated with sulfuric acid to give 38

3-Pyridylnitrene, 2- and 4-pyrimidinylcarbenes, 3-quinolylnitrenes, and 4-quinazolinylcarbenes. Interconversion, ring expansion to diazacycloheptatetraenes, ring opening to nitrile ylides, and ring contraction to cyanopyrroles and cyanoindoles

• Curt Wentrup,
• Nguyen Mong Lan,
• Adelheid Lukosch,
• Pawel Bednarek and
• David Kvaskoff

Beilstein J. Org. Chem. 2013, 9, 743–753, doi:10.3762/bjoc.9.84

• -Azido-2-phenylquinoline (44): This compound was prepared according to a standard literature procedure [40]. A sample of 2.54 g (11.5 mmol) of 3-amino-2-phenylquinoline [41] was dissolved in a mixture of 2 mL of conc. sulfuric acid (d = 1.84) and 13 mL water at 40 °C and then cooled to 0 °C. A solution

A new intermediate in the Prins reaction

• Shinichi Yamabe,
• Takeshi Fukuda and
• Shoko Yamazaki

Beilstein J. Org. Chem. 2013, 9, 476–485, doi:10.3762/bjoc.9.51

• produced when pinene (a bicyclic monoterpene) was heated with paraformaldehyde. However, Prins performed the first rather comprehensive study of the reactions between formaldehyde and hydrocarbons with C=C double bonds [2][3]. These were styrene, pinene, camphene and anethole. As a catalyst, sulfuric acid

• hydrolyzed to form the 1,3-diol by stirring the former in a 2% (or lower) sulfuric acid solution under reflux [4]. However, the hydrolysis yield on the dioxane charged is only 8–17% depending on the alkene reactants. The result was interpreted in terms of a reversible reaction shown in Scheme 3. On the other

• regarded as products of the styrene Prins reaction. In this respect, the equilibrium depicted in Scheme 3 is not for the (dioxane–diol) pair but for the (dioxane–ether) pair. The product 1,3-dioxane may be obtained with aid of the hygroscopy of the 45−55% sulfuric acid. The water is taken off by H2SO4, and

De novo synthesis of D- and L-fucosamine containing disaccharides

• Daniele Leonori and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 332–341, doi:10.3762/bjoc.9.38

• aqueous sulfuric acid) or potassium permanganate solution (potassium permanganate in basic aqueous solution). Column chromatography was performed by using Kieselgel 60 (230–400 mesh) silica gel with a typical 50–100:1 weight ratio of silica gel to crude product. For the preparation and characterization of

Synthesis and testing of the first azobenzene mannobioside as photoswitchable ligand for the bacterial lectin FimH

• Vijayanand Chandrasekaran,
• Katharina Kolbe,
• Femke Beiroth and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2013, 9, 223–233, doi:10.3762/bjoc.9.26

• charring with 10% sulfuric acid in EtOH followed by heat treatment at ~180 °C. Flash chromatography was performed on silica gel 60 (Merck, 230–400 mesh, particle size 0.040–0.063 mm) by using distilled solvents. Optical rotations were measured with a Perkin-Elmer 241 polarimeter (sodium D-line: 589 nm

Amino-substituted diazocines as pincer-type photochromic switches

• Hanno Sell,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2013, 9, 1–7, doi:10.3762/bjoc.9.1

• Loriot-Oriel. Melting points were taken without correction. UV–vis spectra were recorded on a Perkin-Elmer Lambda 14 spectrometer. Synthesis 1,2-Bis(2-nitro-4-aminophenyl)ethane (3): A solution of 5.0 g 1,2-bis(4-aminophenyl)ethane (24.0 mmol) in 40 mL of sulfuric acid was warmed up to 60 °C and a

• solution of 4.4 g (52.0 mmol) finely grounded sodium nitrate in 45 mL of sulfuric acid was added dropwise. The mixture was stirred at 60 °C for 6 h and afterwards poured into 200 mL of ice–water. The resulting suspension was neutralised by the addition of an aqueous ammonia solution (32%). The red

Hydrophobic analogues of rhodamine B and rhodamine 101: potent fluorescent probes of mitochondria in living C. elegans

• Laurie F. Mottram,
• Safiyyah Forbes,
• Brian D. Ackley and
• Blake R. Peterson

Beilstein J. Org. Chem. 2012, 8, 2156–2165, doi:10.3762/bjoc.8.243

• Science). TLC plates were visualized by UV irradiation (254 nm) or stained with a solution of phosphomolybdic acid and sulfuric acid in ethanol (1:1:20). Flash column chromatography employed ICN SiliTech Silica Gel (32–63 μm). Melting points were measured with a Thomas Hoover capillary melting point

S-Fluorenylmethyl protection of the cysteine side chain upon N^α-Fmoc deprotection

• Johannes W. Wehner and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2012, 8, 2149–2155, doi:10.3762/bjoc.8.242

• , Merck). Detection was effected by UV irradiation and subsequent charring with 10% sulfuric acid in EtOH followed by heat treatment. Flash chromatography was performed on silica gel 60 (230–400 mesh, particle size 0.040–0.063 mm, Merck). Preparative MPLC was performed on a Büchi apparatus by using a

Synthesis of a derivative of α-D-Glcp(1->2)-D-Galf suitable for further glycosylation and of α-D-Glcp(1->2)-D-Gal, a disaccharide fragment obtained from varianose

• Carla Marino,
• Carlos Lima,
• Karina Mariño and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2012, 8, 2142–2148, doi:10.3762/bjoc.8.241

• . Visualization of the spots was effected by exposure to UV light or dipping in 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). Optical rotations were measured with a Perkin-Elmer 343 digital polarimeter

Tricyclic flavonoids with 1,3-dithiolium substructure

• Lucian G. Bahrin,
• Peter G. Jones and
• Henning Hopf

Beilstein J. Org. Chem. 2012, 8, 1999–2003, doi:10.3762/bjoc.8.226

• heterocyclization of compounds 6 should, hence, provide new tricyclic fused flavonoids 7 by using an appropriate mixture of acids, as described above (Scheme 1, Table 1). Using a concentrated sulfuric acid/glacial acetic acid (1:3 v/v) mixture [22][23][24] the cyclization of dithiocarbamates 6a–f takes place under

Peptides presenting the binding site of human CD4 for the HIV-1 envelope glycoprotein gp120

• Julia Meier,
• Kristin Kassler,
• Heinrich Sticht and
• Jutta Eichler

Beilstein J. Org. Chem. 2012, 8, 1858–1866, doi:10.3762/bjoc.8.214

• peroxidase conjugate from Dianova (diluted 1:5000 with antibody buffer), and washed four times with washing buffer. Plates were developed with 100 µL/well substrate solution (1 mg/mL OPD in 0.03% H2O2/H2O) in the dark (approx. 20 min), and the reaction was stopped by addition of 2 M sulfuric acid (50 µL/well