A new and convenient synthetic way to 2-substituted thieno[2,3-b]indoles

• Roman A. Irgashev,
• Arseny A. Karmatsky,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2015, 11, 1000–1007, doi:10.3762/bjoc.11.112

• reagent under the current reaction conditions without displacement of CN- or NO2-groups (Table 1, entries 5 and 6). Additionally, compounds 12n,o bearing one or two bromine atoms at C-5 or C-5,7 of the thieno[2,3-b]indole scaffold have been prepared successfully from the corresponding isatins 7b,c and

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

• permeability and, therefore, bulk PTFE is impermeable to most solvents and reagents. However, bromine, which is soluble in liquid fluorous media, diffused through the bulk PTFE. A better understanding of the PTFE phase barrier will make it possible to further optimize the PV-PTFE reaction design. Keywords

• , such as on laboratory stir bars. Results and Discussion Solvent transport in the course of a simple PV-PTFE diffusion of bromine into solvent To better understand the solvent uptake phenomenon observed in PV-PTFE reactions with dichloromethane as a solvent [21] we investigated the addition of bromine

• through a PTFE-sealed delivery tube to a solvent that did not contain any substrate. In the delivery of bromine into dichloromethane, one may expect that the denser reagent in the delivery tube would simply diffuse downward into the less dense solvent. Indeed, when a delivery tube of bromine was placed in

Copper ion salts of arylthiotetrathiafulvalenes: synthesis, structure diversity and magnetic properties

• Longfei Ma,
• Jibin Sun,
• Xiaofeng Lu,
• Shangxi Zhang,
• Hui Qi,
• Lei Liu,
• Yongliang Shao and
• Xiangfeng Shao

Beilstein J. Org. Chem. 2015, 11, 850–859, doi:10.3762/bjoc.11.95

• two bromine bridges (Br–Cu bond length: 2.47 Å) to form a quasi-planar dianion [Cu2Br6]2−. Thus, the spin exchange interaction between these two Cu(II) would be significant, as discussed in the following section. Molecule 5 and the [Cu2Br6]2− ion form the mixed aggregation along the b-axis as shown in

• –Weiss law with C = 0.379 emu K mol−1 and θ = −4.6 K. As mentioned in the crystal structure section, two Cu(II) atoms in 5·Cu2Br6 are connected by two bromine bridges, which result in the strong spin interaction between Cu(II) atoms. The temperature-dependent magnetic susceptibility of 5·Cu2Br6 is shown

Discrete multiporphyrin pseudorotaxane assemblies from di- and tetravalent porphyrin building blocks

• Mirko Lohse,
• Larissa K. S. von Krbek,
• Sebastian Radunz,
• Suresh Moorthy,
• Christoph A. Schalley and
• Stefan Hecht

Beilstein J. Org. Chem. 2015, 11, 748–762, doi:10.3762/bjoc.11.85

• convergent by first preparing two different (zinc)porphyrin cores 1 and 2 (Scheme 1), which are equipped with two and four bromine atoms in the m-position of the meso-phenyl substituents, respectively, for further functionalization. Zinc porphyrins 1 and 2 have been synthesized following standard protocols

Direct access to pyrido/pyrrolo[2,1-b]quinazolin-9(1H)-ones through silver-mediated intramolecular alkyne hydroamination reactions

• Hengshuai Wang,
• Shengchao Jiao,
• Kerong Chen,
• Xu Zhang,
• Linxiang Zhao,
• Dan Liu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2015, 11, 416–424, doi:10.3762/bjoc.11.47

• –4). The introduction of a fluorine, a chlorine and a bromine atom at 5-, 6- and 7-positions resulted in a slight reduction of the yield of the products (Table 2, entries 5–9). However, a bulky phenyl group introduced at the 7-position led to a good yield (Table 2, entry 10). When the benzene ring of

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

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

• different solvents under constant current conditions. The supporting electrolyte tetraethylammonium bromide was used as a source of bromide ions, which were oxidized to give bromine. In aprotic solvents (dichloromethane, acetonitrile or acetic anhydride) only the corresponding 5α,6β-dibromocholestanes 13a–c

• of sensing, which have a distinct advantage over conventional enzymatic processes, have recently been developed. Some of these methods are based on the indirect electrochemical oxidation of cholesterol by using bromine species in organic media [69][70]. In a recent method, methylene blue formed an

Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

• Natalia A. Danilkina,
• Petr S. Vlasov,
• Semen M. Vodianik,
• Andrey A. Kruchinin,
• Yuri G. Vlasov and
• Irina A. Balova

Beilstein J. Org. Chem. 2015, 11, 373–384, doi:10.3762/bjoc.11.43

• could also be defined as a type of sila-Sonogashira coupling [47][48], which is an extremely convenient method for the one-step synthesis of non-symmetrically substituted diarylacetylenes [49][50]. Mild conditions allowed carrying out both reactions chemoselectively leaving the bromine atom for further

• reported [41][51], the double Sonogashira coupling for dibromocinnolines has not been investigated. To optimize the coupling conditions, several test experiments were carried out using the 4,6-dibromo-3-butylcinnoline (4a, Table 2). Taking into account that the substitution of a bromine atom in Pd

• unusual Hiyama coupling [52][53][54] of trimethylsilylacetylene with the more reactive C-4 carbon atom of the cinnoline ring. The substitution of the bromine atom at C-4 (not at C-6) of the cinnoline ring was proved by an 1H NMR NOESY experiment. Switching to Et3N as a solvent and a base as well as

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

• attacks the carbon atom bearing the bromine substituent to give epoxide 6a (Scheme 2). Presumably, the protonation of the alkoxide ion with MeOH is slower than the intramolecular nucleophilic attack. We could not exclude the possibility that a protonated DMSO molecule presumably generated by the reaction

• . Subsequently, DMSO attacks the bromonium ion from the more hindered face to form the corresponding β-haloalkoxysulfonium ion. The treatment of the β-haloalkoxysulfonium ion with NaOMe cleaves the O–S bond to generate the alkoxide ion, which attacks the carbon atom bearing bromine to give epoxide 6g. Therefore

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

• the halonium source. Several reactions using bromonium- and iodonium cations such as iodo-etherification, lactonisation or Friedel–Crafts alkylation reactions can be found in literature. However, these procedures often use expensive or toxic halonium sources like molecular bromine [10][28][29] or

Visible-light-induced bromoetherification of alkenols for the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans

• Run Lin,
• Hongnan Sun,
• Chao Yang,
• Youdong Yang,
• Xinxin Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2015, 11, 31–36, doi:10.3762/bjoc.11.5

• photoredox-catalyzed bromoetherification of alkenols is described. This approach, with CBr4 as the bromine source through generation of bromine in situ, provides a mild and operationally simple access to the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans with high efficiency and regioselectivity

• alkenes have received considerable attention from chemists, and various approaches have been made in this area. Initially, the classical synthetic pathway for bromocyclization proceeds utilizing bromine [10]. However, molecular bromine is hazardous and difficult to handle. Further research show that N

• investigations on the photoredox catalytic reactions [16][23][24][25][26][27], herein we report our preliminary studies on visible-light-induced photoredox-catalyzed bromoetherification of alkenols using CBr4 as the bromine source. Results and Discussion Our initial studies were focused on the reaction of

A carbohydrate approach for the formal total synthesis of (−)-aspergillide C

• Pabbaraja Srihari,
• Namballa Hari Krishna,
• Ydhyam Sridhar and
• Ahmed Kamal

Beilstein J. Org. Chem. 2014, 10, 3122–3126, doi:10.3762/bjoc.10.329

• rings) are unexpected, novel, secondary metabolites, isolated from the marine-derived fungus Aspergillus ostianus strain 01F313 in bromine-modified 1/2PD culture medium [1][2][3][4]. Interestingly, these compounds show cytotoxicity against mouse lymphocytic leukemia cells (L1210) with LD50 values of 2.1

Redox active dendronized polystyrenes equipped with peripheral triarylamines

• Toshiki Nokami,
• Naoki Musya,
• Tatsuya Morofuji,
• Keiji Takeda,
• Masahiro Takumi,
• Akihiro Shimizu and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2014, 10, 3097–3103, doi:10.3762/bjoc.10.326

• 4 (Eox = 1.17 V vs SCE) is slightly lower than that of the fluorine analogue (Eox = 1.25 V vs SCE) which was used as a precursor of the dendritic cation in our previous work [25], indicating that bromine analogue 4 can act as a precursor of the dendritic cation. The functionalization of 4 was

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• due to weakening of the carbon–bromine bond. Next, we aimed to investigate the amination of (±)-8 using Et2NH in toluene medium hoping that the employment of this aprotic and less polar solvent could shift the equilibrium toward the product formation if (±)-10 precipitated over the course of reaction

Synthesis and properties of novel star-shaped oligofluorene conjugated systems with BODIPY cores

• Clara Orofino-Pena,
• Diego Cortizo-Lacalle,
• Joseph Cameron,
• Muhammad T. Sajjad,
• Pavlos P. Manousiadis,
• Neil J. Findlay,
• Alexander L. Kanibolotsky,
• Dimali Amarasinghe,
• Peter J. Skabara,
• Tell Tuttle,
• Graham A. Turnbull and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2704–2714, doi:10.3762/bjoc.10.285

• coupling of the brominated core T-B0Br with trimethylsilylfluorenylboronic acid SiFB (68% yield). Subsequent electrophilic ipso-substitution of tris(trimethylsilylfluorenylBODIPY) T-B1Si by molecular bromine, in the presence of a weak base (KOAc) to avoid acidic conditions, gave T-B1Br in 55% yield

• molecular bromine which was used previously [33]. Thermal, electrochemical and optical properties TGA and DSC analyses All of the final target compounds showed good thermal stability. Thermogravimetric analysis (TGA) revealed decomposition temperatures in the range 396–442 °C (Table 1, Figure S1, Supporting

Selenium halide-induced bridge formation in [2.2]paracyclophanes

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

Beilstein J. Org. Chem. 2014, 10, 2550–2555, doi:10.3762/bjoc.10.266

• spectrometry analysis and a mutual NOE between H18 and H20. The relative Z stereochemistry of tetrabromo derivative 7 was unambiguously established by X-ray analysis; however, there is a disordered carbon–bromine bond and the structure could not be completely refined. The ratio of 5 and 6 was determined as 1

• :1.4. It is interesting to note that the synthesis of the [2.3.2](1,2,4)cyclophane derivative 5 has been previously reported as the result of bromine addition to bis(acetylene) 1, in 87% yield [13]. In both experiments, the formation of elemental red selenium was observed. The unexpected reaction

• selenium dihalides is used. Diselenium dihalides could be the source for the remaining two halogen atoms either by disproportionation, which generates molecular chlorine or bromine [30], or/and by decomposition (e.g., Se2Br2 + Br− → BrSeSe− + Br2). As mentioned before, we always noticed the formation of

Synthesis and biological evaluation of novel N-α-haloacylated homoserine lactones as quorum sensing modulators

• Michail Syrpas,
• Ewout Ruysbergh,
• Christian V. Stevens,
• Norbert De Kimpe and
• Sven Mangelinckx

Beilstein J. Org. Chem. 2014, 10, 2539–2549, doi:10.3762/bjoc.10.265

• compounds can be regarded as building blocks for further elaborations towards new analogues of AHLs. Therefore this study aimed towards the synthesis and biological evaluation of a series of novel halogenated analogues, in which a chlorine, bromine or iodine atom was introduced. To further evaluate the

• conditions were used for the preparation of AHLs with unfunctionalized acyl chains in a convenient way. The brominated fatty acids 5, except the commercially available α-bromohexanoic acid (5a), were prepared by a Hell–Volhard–Zelinsky bromination of the corresponding fatty acid 4 with molecular bromine and

• ). Synthesis of α-brominated fatty acids 5b–f To a flask equipped with a sodium hydroxide trap the corresponding fatty acid 4 (0.065 mol) and thionyl chloride (5 equiv, 40 mL, 0.325 mol) were added. The reaction mixture was stirred at 50 °C in a water bath. Then, liquid bromine (3 equiv, 5 mL, 0.195 mol) was

Superoxide chemistry revisited: synthesis of tetrachloro-substituted methylenenortricyclenes

• Basavaraj M. Budanur and
• Faiz Ahmed Khan

Beilstein J. Org. Chem. 2014, 10, 2531–2538, doi:10.3762/bjoc.10.264

• . Adducts 3k/4k containing bromine at ortho position, a relatively bulky substituent close to the reactive site, took a little longer time to afford the nortricyclene 5k. The 2,4-dichloro-substituted adduct 3l gave a good yield of the desired product 5m (78%) (Scheme 2). In order to explore this unexpected

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• ibuprofen. A nafion membrane is used, allowing a selective passage of protons and tetraalkylammonium cations from the anolyte to the catholyte. Cyclohexene is added to the anolyte to scavenge the anodically formed bromine. A current efficiency of up to 90% was reached with a copper cathode and graphite

• cell to capture the bromine generated at the anode, forming the reactant (Scheme 19). The low yields are caused by debromodimerization and oligomerization [144]. A significant effort has been devoted to efficiently produce cyanoacetic acid through CO2 fixation in chloroacetonitrile, as an alternative

• process provides a feasible route to methoxymethane-1,1,1’-tricarboxylate salts, which are excellent detergent builders. The reaction should be carried out in strictly anhydrous conditions, since water is a stronger acid than the weakly acidic hydrocarbons employed herein. Electrogenerated bromine is used

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

• synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy)-5-(4-bromophenyl)-2-(pyridin-2-yl)thiazole for fluorescence, UV and mass spectrometry (MS) detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of

• by introduction of charged species like ammonium or phosphonium for ionization in the positive mode [18][19][20]. Bromine [19][21][22] or chlorine [23] containing tags were also introduced as they generate a unique isotopic pattern and therefore enhance recognition and identification of labeled small

• to basic laboratory documentation equipment (365 nm UV-transilluminator, digital camera and a low cost commercial UV filter). Introduction of at least one atom with characteristic isotopic pattern like bromine or chlorine is necessary for a unique mass spectrometric detection of labeled substances

Loose-fit polypseudorotaxanes constructed from γ-CDs and PHEMA-PPG-PEG-PPG-PHEMA

• Tao Kong,
• Lin Ye,
• Ai-ying Zhang and
• Zeng-guo Feng

Beilstein J. Org. Chem. 2014, 10, 2461–2469, doi:10.3762/bjoc.10.257

• , 2-bromoisobutyryl group. Furthermore, there is a hydrolytic side reaction of end-capped bromine in the in situ aqueous ATRP of NIPAAm that can reduce the chain end functionality and the efficiency of future chain end modification. Thus, Cu(I)Cl/PMDETA was chosen as catalyst and DMF as solvent for

New highlights of the syntheses of pyrrolo[1,2-a]quinoxalin-4-ones

• Emilian Georgescu,
• Alina Nicolescu,
• Florentina Georgescu,
• Florina Teodorescu,
• Daniela Marinescu,
• Ana-Maria Macsim and
• Calin Deleanu

Beilstein J. Org. Chem. 2014, 10, 2377–2387, doi:10.3762/bjoc.10.248

• Table 1. The reaction pathway (Scheme 2) involves the quaternization of 1-substituted benzimidazoles 1 with ethyl bromoacetate (2) leading to corresponding benzimidazolium bromides 6. The attack of the bromine ion from the benzimidazolium bromide on the oxirane ring in 1,2-epoxybutane results in ring

N–O Cleavage reactions of heterobicycloalkene-fused 2-isoxazolines

• Jaipal R. Nagireddy,
• Geoffrey K. Tranmer,
• Emily Carlson and
• William Tam

Beilstein J. Org. Chem. 2014, 10, 2200–2205, doi:10.3762/bjoc.10.227

• mediation. These results are summarized in Table 2. Compared to the parent compound 10a which gave an appreciable 93% yield of the corresponding β-hydroxyketone (Table 2, entry 1), replacement of two of the arene hydrogens for bromine atoms in 10b resulted in a lower tendency toward N–O bond cleavage (Table

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• conditions providing diol 8 in excellent yield in multigram scale (up to 20 g). Attention should be paid to a possible reductive removal of the bromine substituent that can occur at higher temperature or longer reaction times as the resulting debrominated product is hard to remove from diol 8 by column

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• increase of reactivity by the easier nucleophilic attack of the dialkylphosphite salt on the bromine atom of CBrCl3 when compared to the reaction with CCl4. It is also noteworthy, that the use of bromotrichloromethane allowed the phosphorylation of ethanol. The formation of tetrabenzyl pyrophosphate

• - and bromophosphate intermediates were characterized by 31P NMR thus supporting the mechanism 2 (Scheme 2). In this study, Döring et al. reported that the shielding effect of bromine was also correlated to its higher reactivity (Scheme 5-ii) [22]. Feringa et al. developed a methodology for the