Synthesis, dynamic NMR characterization and XRD studies of novel N,N’-substituted piperazines for bioorthogonal labeling

• Constantin Mamat,
• Marc Pretze,
• Matthew Gott and
• Martin Köckerling

Beilstein J. Org. Chem. 2016, 12, 2478–2489, doi:10.3762/bjoc.12.242

• benzoyl moiety. Furthermore, a proof of concept was accomplished with a pharmacologically active peptide using the Huisgen-click reaction and compound 4b. Additionally, 5b was introduced in a small molecule using the traceless Staudinger ligation. The synthesis of the 18F-labeled building blocks [18F]4b

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• devices with PTB7-Th resulting in high-performance OPV devices with up to 10.7% PCE. Keywords: molecular materials; nematic liquid crystal; organic solar cells; organic synthesis; p-type organic semiconductors; small molecule; Introduction Bulk heterojunction (BHJ) organic solar cells (OSC), a blend of

Effect of the π-conjugation length on the properties and photovoltaic performance of A–π–D–π–A type oligothiophenes with a 4,8-bis(thienyl)benzo[1,2-b:4,5-b′]dithiophene core

• Ni Yin,
• Lilei Wang,
• Yi Lin,
• Jinduo Yi,
• Lingpeng Yan,
• Junyan Dou,
• Hai-Bo Yang,
• Xin Zhao and
• Chang-Qi Ma

Beilstein J. Org. Chem. 2016, 12, 1788–1797, doi:10.3762/bjoc.12.169

• variation, and good reproducibility in photovoltaic performance [5][6][7]. To date, PCEs of more than 9% for small molecule OSCs (SMOSCs) have been reported [8][9][10][11][12]. Among various electron-donating moieties, benzo[1,2-b:4,5-b′]dithiophene (BDT) has been widely used as the central building block

• terthiophene-bridged small molecule with a BDT core [8]. Currently, there are three main structure modifications of A–π–D–π–A-type molecules with a BDT core. One is the substitution on the 4,8-positions of the BDT core with aromatic units, including alkyl/alkoxyl/alkylthiol-substituted phenyl groups [15

Dinuclear thiazolylidene copper complex as highly active catalyst for azid–alkyne cycloadditions

• Anne L. Schöffler,
• Ata Makarem,
• Frank Rominger and
• Bernd F. Straub

Beilstein J. Org. Chem. 2016, 12, 1566–1572, doi:10.3762/bjoc.12.151

• bioactive surfaces [8][14], imaging of biochemical processes [15], localization of bioactive compounds inside living cells [16], syntheses of small-molecule screening libraries [17], catenane and rotaxane syntheses [18], in reactions under continuous flow processing [19], polymer and surface science [20][21

Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

• Hideaki Komiyama,
• Chihaya Adachi and
• Takuma Yasuda

Beilstein J. Org. Chem. 2016, 12, 1459–1466, doi:10.3762/bjoc.12.142

• highly different from that of the reported general polymer- and small-molecule-based OSCs. A star-shaped molecular structure containing a two-dimensionally extended π-conjugated system is a promising electronic system for designing photovoltaic organic materials, as a result of its excellent

Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

• Bernardas Morkunas,
• Balint Gal,
• Warren R. J. D. Galloway,
• James T. Hodgkinson,
• Brett M. Ibbeson,
• Yaw Sing Tan,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2016, 12, 1428–1433, doi:10.3762/bjoc.12.137

• , UK Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671 10.3762/bjoc.12.137 Abstract Pyocyanin is a small molecule produced by Pseudomonas aeruginosa that plays a crucial role in the pathogenesis of infections by this notorious opportunistic pathogen. The inhibition

• ]. Pyocyanin is an important redox active small molecule virulence factor which is widely considered to play a crucial role in the pathogenesis of P. aeruginosa infections (Figure 1) [8][9][17][18]. The inhibition of pyocyanin production has been identified as an attractive antivirulence strategy for the

• compounds with the ability to reduce pyocyanin production, there are several well-documented problems associated with the potential use of molecules based on the AHL framework in a therapeutic context [9][12][20]. Thus, there is interest in the identification of new structural classes of small-molecule

3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic–organic hybrid perovskite solar cells

• Wei Li,
• Munechika Otsuka,
• Takehito Kato,
• Yang Wang,
• Takehiko Mori and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2016, 12, 1401–1409, doi:10.3762/bjoc.12.134

• as its complicated multistep synthesis, low hole mobility in its pristine form, and expensive fabrication costs of the PSCs due to the sublimable small molecule. Accordingly, solution-processable hole-transporting polymers with simple structures have also been pursued as HTMs in the PSCs. Common p

The role of alkyl substituents in deazaadenine-based diarylethene photoswitches

• Christopher Sarter,
• Michael Heimes and
• Andres Jäschke

Beilstein J. Org. Chem. 2016, 12, 1103–1110, doi:10.3762/bjoc.12.106

• and function, as it is non-invasive, provides high spatio-temporal resolution, and offers the option of orthogonality [13][14]. One of the common approaches for introducing photoresponsiveness into biomolecules is their covalent functionalization with small-molecule photoswitches [1][2][13][15][16][17

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• has been reported to be able to inhibit the EWS-FLI1/RHA interactions specifically, significantly more potent than its (R)-enantiomer and racemic compound [12]. Additionally, the 3-hydroxyoxindoles as versatile intermediates have also been used to construct small-molecule libraries for drug screening

Opportunities and challenges for direct C–H functionalization of piperazines

• Zhishi Ye,
• Kristen E. Gettys and
• Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

• Zhishi Ye Kristen E. Gettys Mingji Dai Department of Chemistry and Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907, United States 10.3762/bjoc.12.70 Abstract Piperazine ranks within the top three most utilized N-heterocyclic moieties in FDA-approved small-molecule

• : α-lithiation; C–H functionalization; heterocycle; photoredox catalysis; piperazine; Introduction Piperazine is one of the most important saturated N-heterocycles frequently found in life-saving small-molecule pharmaceuticals [1]. In a recent statistical study done by Njardarson and co-workers

• used to treat HIV/AIDS [5]. Gatifloxacin is an important fluoroquinolone antibiotic [6]. Despite the high frequency appearance of piperazines in small-molecule pharmaceuticals, over 80% only contain substituents at the two nitrogen atoms and a very small fraction of them have simple carbon

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

• dimethylbenzil is irradiated, the encapsulated sensitizer is excited and can transfer its energy to an oxygen molecule adventitiously entering the capsule. (Although guest exchange is slow on the NMR timescale, there is a much faster dynamic breathing of the capsule that allows small molecule entry and egress

My maize and blue brick road to physical organic chemistry in materials

• Anne J. McNeil

Beilstein J. Org. Chem. 2016, 12, 229–238, doi:10.3762/bjoc.12.24

• field of supramolecular chemistry, specifically, and organic materials, broadly. My research group’s efforts toward designing new sensors based on small molecule gelators are described. In particular, I highlight how our design strategy has evolved as we learn more about molecular gelators. This

A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

• Steven C. Zimmerman

Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14

• early career efforts in molecular recognition, especially molecular tweezers. Although designed to complex DNA, these hosts proved more applicable to the field of host–guest chemistry. This early experience and interest in intercalation ultimately led to the current efforts to develop small molecule

• understood even today, my idea as a graduate student was to make a bisintercalator that was so rigid it could not form the mono-intercalated complex in Figure 2d. The ultimate goal was to develop a small molecule ligand that might intercalate at sites that lack a conventional neighboring intercalation site

• , students were not so interested in this area of research, perhaps because I had little training in DNA/small molecule recognition. Whatever the reason, we temporarily suspended this research effort. Fortunately, others were more persevering and pushed the concept forward in important new directions

Learning from the unexpected in life and DNA self-assembly

• Jennifer M. Heemstra

Beilstein J. Org. Chem. 2015, 11, 2713–2720, doi:10.3762/bjoc.11.292

• presence of a small-molecule or protein target [5][6]. Thus, they combine my two favorite themes, as they use molecular recognition to drive self-assembly. At the point that we began our research program, all of the reported work on split aptamers had focused on detecting non-covalent assembly for systems

• demonstrated that we could use our split aptamer ligation method to measure the concentration of a small-molecule target, but doing so required analysis via gel electrophoresis. Thus, we sought to create an assay that would be capable of the high throughput needed for clinical diagnostics applications, and we

• binding events to be “remembered” through covalent trapping of the assembled split aptamer. Thus, the ability to generate target-dependent signal is preserved even if target binding is lost in the washing steps. At this point, we were excited by our successes in the development of small-molecule detection

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

• Mino R. Caira,
• Susan A. Bourne,
• Halima Samsodien and
• Vincent J. Smith

Beilstein J. Org. Chem. 2015, 11, 2616–2630, doi:10.3762/bjoc.11.281

• feature, while commonly observed in protein–ligand recognition and selection, is rare for small molecule structures [1]. In addition to the solid-state results detailed below, we report original data on the use of CDs to enhance the aqeous solubility of 2ME. The title steroid, originally identified as an

Smart molecules for imaging, sensing and health (SMITH)

• Bradley D. Smith

Beilstein J. Org. Chem. 2015, 11, 2540–2548, doi:10.3762/bjoc.11.274

• . This vision merges classical supramolecular chemistry with materials self-assembly. The projects will be technically challenging, as they will require nanoscale characterization methods that are not familiar to most small molecule chemists. Thus, collaboration is likely to be a key element for this

Recent developments in copper-catalyzed radical alkylations of electron-rich π-systems

• Kirk W. Shimkin and
• Donald A. Watson

Beilstein J. Org. Chem. 2015, 11, 2278–2288, doi:10.3762/bjoc.11.248

• used extensively in polymer chemistry because of the ability of alkyl radicals to participate in chain reactions [2][3][4]. They have also been used extensively in small molecule synthesis, particularly in an intramolecular cyclization setting [5][6][7][8][9]. However, while the ability of alkyl

Nitro-Grela-type complexes containing iodides – robust and selective catalysts for olefin metathesis under challenging conditions

• Andrzej Tracz,
• Mateusz Matczak,
• Katarzyna Urbaniak and
• Krzysztof Skowerski

Beilstein J. Org. Chem. 2015, 11, 1823–1832, doi:10.3762/bjoc.11.198

• small molecule of ethylene is coordinated to the ruthenium generating highly active methylidene species. Macrocyclization reactions As model substrates for macrocyclization we choose esters 17 and 18 which are metathesized to the 16- and 14- membered lactones. The RCM was run in toluene, at 70 °C and at

Azobenzene-based inhibitors of human carbonic anhydrase II

• Leander Simon Runtsch,
• David Michael Barber,
• Peter Mayer,
• Michael Groll,
• Dirk Trauner and
• Johannes Broichhagen

Beilstein J. Org. Chem. 2015, 11, 1129–1135, doi:10.3762/bjoc.11.127

• as well as Eric P. Trautman and Martin Maier for excellent synthetic assistance. Author Contributions D.T. supervised the research. J.B. and D.T. conceived and designed the study. J.B. and L.S.R. performed chemical, biological and small molecule crystallization experiments. J.B. performed protein

DNA display of glycoconjugates to emulate oligomeric interactions of glycans

• Alexandre Novoa and
• Nicolas Winssinger

Beilstein J. Org. Chem. 2015, 11, 707–719, doi:10.3762/bjoc.11.81

• surface glycans are important actors in cellular recognition and have been implicated in numerous events such as fertilization, embryonic development, lymphocyte trafficking and cancer metastasis [1][2][3][4]. In contrast to many small molecule ligands where a functional output is often the product of a

• used to display glycans with a synergy between the interactions of the individual ligands binding with a target. Progress in this area has paralleled similar developments with small molecule conjugates [48][54][55][56][57][58][59][60][61][62][63]. Technological developments in conjugation chemistry and

Synthesis and biological evaluation of a novel MUC1 glycopeptide conjugate vaccine candidate comprising a 4’-deoxy-4’-fluoro-Thomsen–Friedenreich epitope

• Manuel Johannes,
• Maximilian Reindl,
• Bastian Gerlitzki,
• Edgar Schmitt and
• Anja Hoffmann-Röder

Beilstein J. Org. Chem. 2015, 11, 155–161, doi:10.3762/bjoc.11.15

• , the search for novel anticancer therapies is of high current interest. For instance, promising approaches such as targeted therapy with small molecule tyrosine kinase inhibitors [1][2] and active cancer immune therapy have emerged [3][4] with the latter one being particularly attractive in terms of

Organic chemistry on surfaces: Direct cyclopropanation by dihalocarbene addition to vinyl terminated self-assembled monolayers (SAMs)

• Malgorzata Adamkiewicz,
• David O’Hagan and
• Georg Hähner

Beilstein J. Org. Chem. 2014, 10, 2897–2902, doi:10.3762/bjoc.10.307

• -difluorocyclopropane-terminated SAMs by generating difluorocarbene, following the procedure of Wang et al. [22] for small molecule transformations. This involved stirring a solution of NaI (0.2 equiv) and TMSCF3 in THF (2 mL), and then immersing the silicon wafers (1 cm × 1.5 cm) into the reaction mixture at 65 °C for

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

• have found numerous applications as laser dyes [5][6][7], labels for biological imaging [8][9][10] and low band-gap polymers [11][12][13]. Being efficient emitters in solution, small molecule BODIPY compounds often show signs of aggregation at high concentration and in solid films [14][15], which

Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells

• Diego Cortizo-Lacalle,
• Calvyn T. Howells,
• Upendra K. Pandey,
• Joseph Cameron,
• Neil J. Findlay,
• Anto Regis Inigo,
• Tell Tuttle,
• Peter J. Skabara and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2683–2695, doi:10.3762/bjoc.10.283

• -diaza-s-indacene (BODIPY) units attached by thiophene rings have been synthesised having high molar extinction coefficients. These triads were characterised and used as donor materials in small molecule, solution processable organic solar cells. Both triads were blended with PC71BM as an acceptor in

• processing during device fabrication. The difference in power conversion efficiencies (PCEs) between polymer and small-molecule based OPVs is decreasing and PCEs over 7% have been realised in the case of the latter [18][19]. Small molecules used in OPVs are most commonly based on oligothiophenes and their

• results [26][27][28]. A PCE greater than 4% was achieved in combination with phenyl-C71-butyric acid methyl ester (PC71BM) [29]. Interestingly, a small molecule based on a DPP core substituted with electron-withdrawing units was also used as an acceptor in OPVs as a substitute for fullerene with PCEs of 1

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

• electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously