A catalyst-free multicomponent domino sequence for the diastereoselective synthesis of (E)-3-[2-arylcarbonyl-3-(arylamino)allyl]chromen-4-ones

• Pitchaimani Prasanna,
• Pethaiah Gunasekaran,
• Subbu Perumal and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2014, 10, 459–465, doi:10.3762/bjoc.10.43

• ], antiviral [7], antihypertensive [8], anti-oxidant [9][10][11][12], HIV-inhibitory [13], anti-inflammatory [14][15], immunomodulatory [16], antithrombotic [17], and anticancer [18][19][20] activities. Furthermore, some chromone derivatives have been identified as suitable fluorophores for live cell imaging

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

• yellow 139 (12), which is sold by BASF as Paliotol® Yellow K 1841 belongs to the class of highly resistant and effective 1,3-disubstituted isoindoline dyes. Recently, the use of isoindoles as red to near-infrared fluorophores was reported [12]. Another interesting isoindole-based dye, 25, arises from the

Flow synthesis of a versatile fructosamine mimic and quenching studies of a fructose transport probe

• Matthew B. Plutschack,
• D. Tyler McQuade,
• Giulio Valenti and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 2022–2027, doi:10.3762/bjoc.9.238

• of material. More NBDM is required to examine uptake across many cell lines and with access to amine 3, we can prepare analogues with different fluorophores or other types of tags. Finally, access to more NBDM will enable assessment of probe photophysical properties as a function of concentration and

• -throughput process to 3 could be realized with improvements in continuous extraction techniques. That being said, the semi-continuous approach we have defined here results in significant improvements compared to the original batch conditions. Many fluorophores and biologically relevant tags have been

• . Without easy access to NBDM, the use of this compound in biological experiments would supersede the investigation of its fluorescent properties. Fluorescence: Fluorescence in biological systems is often complicated by fluorophore quenching. Alexa fluorophores can be quenched by certain amino acids and NBD

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

• mitochondrial stains rhodamine 123, rhodamine 6G, and rhodamine B, as well as the structurally related fluorophores rhodamine 101, and basic violet 11, revealed that HRB and HR101 are the most potent mitochondrial probes, enabling imaging of mitochondrial motility, fusion, and fission in the germline and other

• expression of mitochondria-targeted fluorescent proteins. The high bioavailabilty of these novel fluorescent probes may facilitate the identification of agents and factors that affect diverse aspects of mitochondrial biology in vivo. Keywords: Caenorhabditis elegans; chemical biology; fission; fluorophores

• variety of analytes, and specific markers of cellular organelles and other components. Although many structurally diverse fluorophores have been reported, many common fluorophores such as dianionic fluorescein (1, Figure 1) are defined by highly polar conjugated π systems. This high polarity confers

Synthesis of chiral sulfoximine-based thioureas and their application in asymmetric organocatalysis

• Marcus Frings,
• Isabelle Thomé and
• Carsten Bolm

Beilstein J. Org. Chem. 2012, 8, 1443–1451, doi:10.3762/bjoc.8.164

• findings include their use as fluoromethylation reagents, as fluorophores or as directing groups [16][17][18][19]. Two quality characteristics make them particularly attractive for asymmetric synthesis: 1) The stereogenic sulfur atom which is stable towards many reaction conditions, and 2) the ease of

Design of a novel tryptophan-rich membrane-active antimicrobial peptide from the membrane-proximal region of the HIV glycoprotein, gp41

• Evan F. Haney,
• Leonard T. Nguyen,
• David J. Schibli and
• Hans J. Vogel

Beilstein J. Org. Chem. 2012, 8, 1172–1184, doi:10.3762/bjoc.8.130

• Trp fluorophores in the various membrane environments. If a Trp side chain inserts into the hydrophobic core of the bilayer, it becomes less accessible to the effects of the soluble acrylamide quencher. The quenching of Trp fluorescence is directly related to the concentration of quencher, so a

• derivatives have large Ksv values in buffer, which is expected if the Trp fluorophores are exposed to the aqueous buffer. In the presence of detergent micelles and LUVs, all of the calculated Ksv values for gp41w-4R decreased dramatically, consistent with this peptide binding to the bilayer and the Trp side

Partial thioamide scan on the lipopeptaibiotic trichogin GA IV. Effects on folding and bioactivity

• Marta De Zotti,
• Barbara Biondi,
• Cristina Peggion,
• Matteo De Poli,
• Haleh Fathi,
• Simona Oancea,
• Claudio Toniolo and
• Fernando Formaggio

Beilstein J. Org. Chem. 2012, 8, 1161–1171, doi:10.3762/bjoc.8.129

• /trans isomerization can be phototriggered by irradiation at about 260 nm [absorption maximum of the -C(=S)NH- π→π* electronic transition]. (iii) It may act as a minimalist, effective quencher for any type of protein and nonprotein fluorophores. Recently, based on the aforementioned characteristics of

The effect of the formyl group position upon asymmetric isomeric diarylethenes bearing a naphthalene moiety

• Renjie Wang,
• Shouzhi Pu,
• Gang Liu and
• Shiqiang Cui

Beilstein J. Org. Chem. 2012, 8, 1018–1026, doi:10.3762/bjoc.8.114

• fluorophores via a Schiff base structure. In a previous work, we developed a new class of diarylethenes with a naphthalene group and a thiophene group. The results revealed that these molecules have excellent photochromism with good fatigue resistance and thermal stability [37]. In this study, in order to

Diarylethene-modified nucleotides for switching optical properties in DNA

• Sebastian Barrois and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103

• representative oligonucleotides by using automated phosphoramidite chemistry, and characterized with respect to its photochromism in DNA. Results and Discussion Design and synthesis of diarylethene-modified 2’-deoxyuridines 4–6 The typical way to tether fluorophores to oligonucleotides is to use an alkyl chain

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• systems 35–43 [25][62][63][64][65][66]. Structure of benzimidazoles (44–47), imidazophenanthrolines (48–57), imidazophenanthrenes (58–60), fluorophores 61, 62, and TCAQ-imidazo-TTF (63) chromophores [23][24][67][68][69][70][71]. General structures of bis(benzimidazole) chromophores 67–71 and pyridinium

Synthesis of dye/fluorescent functionalized dendrons based on cyclotriphosphazene

• Aurélien Hameau,
• Sabine Fuchs,
• Régis Laurent,
• Jean-Pierre Majoral and
• Anne-Marie Caminade

Beilstein J. Org. Chem. 2011, 7, 1577–1583, doi:10.3762/bjoc.7.186

• publications have reported the synthesis, the study of photophysical properties and several uses of fluorescent dendrimers, emphasizing in particular their role as light-harvesters [4] for organic light-emitting diodes (OLEDs) [5] and as tools in biology [6]. Many different types of fluorophores have been

• grafted as terminal groups on to dendrimers. In particular the dansyl group has been frequently used to functionalize poly(propyleneimine) [7][8], poly(lysine) [9], poly(amidoamine) [10], and poly(melamine) [11] dendrimers. It has been shown that no interaction occurs between these terminal fluorophores

Effects of anion complexation on the photoreactivity of bisureido- and bisthioureido-substituted dibenzobarrelene derivatives

• Heiko Ihmels and
• Jia Luo

Beilstein J. Org. Chem. 2011, 7, 278–289, doi:10.3762/bjoc.7.37

• -substituted fluorophores have been used elegantly for the fluorimetric detection of the anion [46], and the photophysical background has been evaluated in detail [47], but the influence of the binding event on the photochemical properties has not been assessed. In this regard, the studies of the

Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission

• Ritesh Nandy and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112

• into the visible region. The most commonly employed strategy for the bathochromic shifting of the emission wavelength is to extend the conjugation of the fluorophores with aryl, ethenyl and ethynyl groups. The addition of electron donating and withdrawing substituents to these conjugation enhancing

• groups also helps in shifting the emission wavelengths further into red region. For example, boron-dipyrrolomethenes (BODIPYs) are a class of molecules whose absorption and fluorescence emission have been fine tuned by suitable substituents [5][6][7]. Fluorophores emitting in the visible region are

• electron transfer [12][13][14][15] and metal ion induced enhancement or quenching of fluorescence [16][17][18][19]. Among these, fluorophores that exhibit excited state ICT are very popular. In this context fluorescent donor-π spacer-acceptor (d-π-a) type molecules are of considerable interest and

Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)

• Katja Hofmann,
• Ingolf Kahle,
• Frank Simon and
• Stefan Spange

Beilstein J. Org. Chem. 2010, 6, No. 79, doi:10.3762/bjoc.6.79

• of the two contacting phases). This approach was developed to carry out functionalization reactions between the water-soluble PVAm and suitable chromophores [30] or fluorophores. In these reactions, silica can be considered as ‘solubilizer’ because PVAm, as well as the reactants, are consecutively

• , 14.63; found C, 74.85; H, 4.37; N, 14.49. Fluorophoric, carbonitrile-functionalized PVAm/silica particles (1-Si) For functionalization of silica with fluorophores and PVAm in aqueous media, 1 (0.1 g, 0.4 mmol) was dissolved in 50 mL of CH2Cl2, then suspended with silica (2.5 g, 41 mmol) and kept

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Synthetic incorporation of Nile Blue into DNA using 2′-deoxyriboside substitutes: Representative comparison of (R)- and (S)-aminopropanediol as an acyclic linker

• Daniel Lachmann,
• Sina Berndl,
• Otto S. Wolfbeis and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2010, 6, No. 13, doi:10.3762/bjoc.6.13

• ][3][4][5][6][7][8][9]. A large variety of organic fluorophores can be incorporated routinely at specific positions within the oligonucleotide using standard phosphoramidite DNA chemistry and commercially available DNA building blocks. However, problems can arise if labels or probes are chemically

• present in biopolymers and react selectively with each other in aqueous solutions. The “click” ligation can avoid the time-consuming synthesis of phosphoramidites as DNA building blocks which is especially important for brightly emitting fluorophores that are not compatible with the acidic, oxidative or

• basic conditions of automated DNA phosphoramidite chemistry and/or DNA workup. We recently presented the postsynthetic incorporation of Nile Blue and a coumarin dye as representatives of base-labile fluorophores by the “click” ligation strategy [17]. Several other fluorophores (spanning the whole