Automated high-content imaging for cellular uptake, from the Schmuck cation to the latest cyclic oligochalcogenides

• Rémi Martinent,
• Javier López-Andarias,
• Dimitri Moreau,
• Yangyang Cheng,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2020, 16, 2007–2016, doi:10.3762/bjoc.16.167

• associated to the master object (the cell), a set of meaningful data can be extracted from each object in the different fluorescent channels. The data set generated for each cell can later be used for a deep phenotypic analysis, using an advanced unsupervised statistical analysis method (e.g., principal

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• temperature (rt, 25 °C) (Scheme 2) [16]. By warming the mixture up to 50 °C, the yield of 2a dropped to 89% after 1 h, and we noticed in the crude the appearance of an additional product, which was detected as a fluorescent spot on TLC, whose amount increased by increasing the temperature. After 4 h warming

• fluorescent spot was detected on TLC plate in the presence of an excess of Et3N (3 equiv). After column chromatography on silica gel, we were able to isolate a new product that was characterized as 2,4-dibenzoyl-6-phenylpyrimidine (7a, 55% yield) in addition to 3a/3a' (26% yield), the remaining being starting

Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Valerii V. Tkachev,
• Andrey N. Utenyshev,
• Olga Yu. Karlutova,
• Alexander D. Dubonosov,
• Vladimir A. Bren,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149

• ; X-ray diffraction; Introduction Photochromic compounds are of considerable interest as molecular switches, elements of optical memory and molecular logic devices [1][2][3][4]. Fulgides and fulgimides possessing excellent thermal and photochemical stability, structurally modulated fluorescent

Et₃N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

• Dharmender Singh,
• Vipin Kumar and
• Virender Singh

Beilstein J. Org. Chem. 2020, 16, 1740–1753, doi:10.3762/bjoc.16.146

• abecarnil, tadalafil, cipargamin, yohimbine, etc. which are used in the treatment of various ailments [14][15]. Apart from their pharmaceutical properties, β-carboline derivatives also found various applications in fields such as organocatalysts, as ligands, and fluorescent probes [16][17][18]. Importantly

• , β-carbolines are also used as fluorescence standards. Recently, a novel β-carboline-based fluorescent chemosensor was developed by Batra and co-workers for the quantitative analysis of fluoride ions (F−) at ppb level [19]. Sulfur-containing organic compounds are broadly associated with numerous

• aldehydes 1a-b, 1d and 1h in 76–91% yields (Scheme 1). The methodology was found to be general in nature and produced the fluorescent β-carboline-linked benzothiophenone derivatives 2aA-bA, 2dA and 2hA within 15–45 min in DMSO at 70 °C as depicted in Scheme 2. The analytically pure products were obtained in

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• -mannose (the α-anomer also shows biological activity, but to a lesser extent) [13][14][15], a short-chain (citronellol) mimic of dolichol [1][2][13], and a functional tag. The latter may either be a chemically reactive group (in MPC-1) or a fluorescent reporter group (in MPC-2). MPC-1 bears a benzophenone

• ][28][29]. The phosphoramidite approach was also applied to the synthesis of a second molecular probe, MPC-2, an anomerically pure, β-linked ᴅ-mannosephosphate derivative, which serves as a fluorescent MPD analog for scramblase activity screening assays. Although similar experiments have been described

• candidates (identification by mass spectrometry), and the other probe, MPC-2, consists of a fluorescent label to test candidates for scramblase activity in reconstitution-based assays. The molecular probes were prepared via phosphoramidite chemistry, which allowed the incorporation of the carbohydrate

Photocatalyzed syntheses of phenanthrenes and their aza-analogues. A review

• Alessandra Del Tito,
• Havall Othman Abdulla,
• Davide Ravelli,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 1476–1488, doi:10.3762/bjoc.16.123

• topoisomerase 1 inhibitor [14] and DNA intercalator), bicolorine (5-methyl-[1,3]dioxolo[4,5-j]phenanthridin-5-ium ion, a trypanocidal) [15], and the antimalarian nitidine, as well as ethidium bromide (EB), that has been employed as a DNA- and RNA-fluorescent marker for a long time (some examples are collected

Synthesis of new fluorescent molecules having an aggregation-induced emission property derived from 4-fluoroisoxazoles

• Kazuyuki Sato,
• Akira Kawasaki,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2020, 16, 1411–1417, doi:10.3762/bjoc.16.117

• Kazuyuki Sato Akira Kawasaki Yukiko Karuo Atsushi Tarui Kentaro Kawai Masaaki Omote Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan 10.3762/bjoc.16.117 Abstract Fluorescent molecules based on a fluorinated isoxazole scaffold were

• -opening reaction of 4-fluoroisoxazoles and exhibited highly fluorescent luminescence and aggregation-induced emission (AIE), showing promise as a new fluorophore. Keywords: aggregation-induced emission; boron ketoiminates; fluorescent probe; α-fluorinated boron ketoiminates; 4-fluoroisoxazoles

• be visualized using fluorescent probes, the use of AIE fluorescent probes is being investigated as a tool for analyzing the causal relationship between prion diseases and prion proteins. The importance of fluorinated heterocyclic derivatives in the pharmaceutical and agrochemical industries continues

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• complexes to produce fluorescent species [16]; (5) sodium borohydride to reduce carbonyls [17]; (6) red phosphorous to produce polyphosphides [18]. Our initial foray into this area was born out of necessity. We wanted to conduct flow reactions that required solids, and packed beds facilitated the use of

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• protocol for fluorescent bistolane derivatives. Nonfluorinated bistolane derivatives exclusively gave the corresponding products with a bisbenzil scaffold, whereas the fluorinated bistolane derivatives generated not only mono-oxidized benzil derivatives bearing a fluorinated tolane scaffold, but also the

• assist the development of environmentally benign, pure organic phosphorescent materials. (A) Transition-metal-containing and (B) pure organic phosphorescent materials reported thus far (bpy: 2,2'-bipyridine, ppy: 2-phenylpyridine, OEP: octaethylporphyrin). (A) Chemical structures of fluorescent bistolane

A smart deoxyribozyme-based fluorescent sensor for in vitro detection of androgen receptor mRNA

• Ekaterina A. Bryushkova,
• Erik R. Gandalipov and
• Julia V. Nuzhina

Beilstein J. Org. Chem. 2020, 16, 1135–1141, doi:10.3762/bjoc.16.100

• types of compounds. It is most promising to develop simple and effective biosensors for the use in situations where traditional methods are not available due to their complexity and laboriousness. In this project, a novel smart deoxyribozyme-based fluorescent sensor for the detection of androgen

• -based fluorescent sensor (SDFS), designed for the quick and efficient verification of human androgen receptor (AR) mRNA. The AR (alternative name NR3C4) belongs to the steroid nuclear receptor superfamily, capable of being activated after a direct interaction with nuclear DNA and works as a

• (Figure 2A). At 25 °C, SDFS gave more unassuming results after 24 h of incubation and 1 h of cooling at 4 °C, demonstrating only 10 times increased fluorescent signal in comparison with individual MGA strands (Figure 2B). Finally, there was no significant fluorescence increase observed after incubation at

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• chromatography (TLC) was performed on Macherey-Nagel Polygram® SIL G/UV254 silica gel on polyester sheets, with manganese-activated zinc silicate with green fluorescence for short-wave UV (254 nm) and special inorganic fluorescent pigment with blue fluorescence for long-wave UV (366 nm) as indicators. Fluka

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• properties such as high hole-transporting mobility [12][25][26][27], pronounced thermal stability [2] and high fluorescent quantum yields [28][29] our attention was focused on carbazole derivatives. In addition to that, carbazole is a rigid aromatic molecule [30] with many different modification sites for

• . This indicates that the excited state dipole moment is much greater than the ground state dipole moment. Quantum yields The relative fluorescent quantum yields (ϕFL) of compounds 7a and 7b were determined in dichloromethane by using rhodamine B (ϕFL = 49% at λexc=355 nm) in ethanol as reference [45

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• been shown that derivatives thereof have a great potential to serve as functional units in DNA-binding ligands [54], fluorescent dyes and chemosensors [55][56][57][58][59]. Furthermore, we have already demonstrated that styryl-substituted quinolizinium derivatives exhibit ideal photophysical and DNA

• -binding properties to be used as DNA-sensitive fluorescent probes in cell imaging [60][61][62] or as photoswitchable DNA ligands [63]. Therefore, we were interested in a combination of the photochromic properties of the spirooxazine moiety with the advantageous photophysical and biological properties of

• fluorescence at ca. 1 h after the addition. All the other tested metal ions (see above) did not cause a change of the absorption and emission. The coralyne–spirooxazine conjugate 3b was weakly fluorescent upon the excitation at λex = 400 nm, with a broad emission band at λfl = 481 nm (Φfl = 0.007 relative to

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• ) as the polymerization initiator and benzaldehyde derivatives as organic photocatalysts [49]. 23 W compact fluorescent lamps were employed as the light source and N,N-dimethylaniline (51) was used as a potential reductant. The benzaldehyde derivatives tested are presented in Scheme 13 and included 4

• household 23 W compact fluorescent light (CFL) bulb at ambient temperature [55]. A base, 2,6-lutidine, was used to neutralize traces of HX (X = halogen), which formed by the homolytic cleavage of the C–X bond of the haloalkanes 93 (Scheme 24). Among the aldehydes tested, benzaldehyde (8) and 4

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• essentially half a porphyrin molecule. These highly fluorescent organic compounds are a part of the difluoroboraindacene family. Owing to their versatility, they have become increasingly popular for their use as fluorophores [17][18][19]. BODIPY-based dyes have found application in many areas including

• material was purified via column chromatography using silica gel. The BODIPY dimer 7 was prepared using 6 [38] and was obtained as a fluorescent orange solution or as pink-orange crystals in a 30% yield. Similarly, the Pd-catalyzed Sonogashira cross-coupling reaction [39] was successful for the reaction

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• fluorescent dye that is tethered to an acetyllysine-containing peptide. If the acetyl moiety of the fluorophore is enzymatically hydrolyzed by HDAC8, it will produce a strongly fluorescent signal at 360 nm. Table 1 shows the percentage of HDAC8 inhibition at 100, 10, and 1 µM concentration of the designed

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• -EBX reagents. This atom-economical method for the late-stage alkynylation of BODIPY dyes could be an alternate approach for functionalized fluorescent dyes without the need of preparing unstable halogenated pyrrole precursors. The resulting α- and β-ethynyl-substituted BODIPYs displayed distinct

• novel functional fluorescent materials. (a) Chemical structures of BODIPY (1) and dipyrromethane (2). (b) C–C bond forming alkynylations of pyrrole and its derivatives by Sonogashira coupling and electrophilic alkynylation. (c) Peripheral alkynylated BODIPY derivatives (3–6) prepared in this work. TIPS

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• less as aforementioned molecular ovens. Recently development of light sources in the NIR based on LEDs brought new hope in this field [65]. Furthermore, the fact that still some fluorescence occurs makes them interesting as fluorescent probes for imaging applications. NIR radiation possesses a

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• catalysts, such as low toxicity, their functioning at room temperature, and smooth irradiation requirements with low-energy lights (e.g., LEDs, fluorescent bulbs, etc.) made this area of research very interesting. Within a very short time, photoredox catalysis has emerged as an important future direction

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• heterostilbenes that deliver green fluorescent protein (GFP)-orthogonal MT photocontrol [17]. However, in both azobenzene and heterostilbene scaffolds, the steric properties of the E- and Z-isomer are so different that the protein binding site shape determines that the Z-isomer (the lit-form) is the more

Photocontrolled DNA minor groove interactions of imidazole/pyrrole polyamides

• Sabrina Müller,
• Jannik Paulus,
• Jochen Mattay,
• Heiko Ihmels,
• Veronica I. Dodero and
• Norbert Sewald

Beilstein J. Org. Chem. 2020, 16, 60–70, doi:10.3762/bjoc.16.8

• the ligands E-P1–E-P3 did not bind significantly to the oligonucleotide sequences D1–D3. However, considering their polyamide structure, they should at least exhibt a weak affinity toward double-stranded DNA. The fluorescent indicator displacement (FID) assay was performed with E-P1 as representative

• ligand to examine the propensity of these derivatives to bind to DNA. The known intercalator thiazole orange (TO) was chosen as indicator because it exhibits an intense fluorescence band at 526 nm when bound to DNA, whereas it is only weakly fluorescent in solution. The displacement of TO from its DNA

Preparation of anthracene-based tetraperimidine hexafluorophosphate and selective recognition of chromium(III) ions

• Qing-Xiang Liu,
• Feng Yang,
• Zhi-Xiang Zhao,
• Shao-Cong Yu and
• Yue Ding

Beilstein J. Org. Chem. 2019, 15, 2847–2855, doi:10.3762/bjoc.15.278

• ; chromium(III) ion; tetraperimidine; Introduction Fluorescent chemosensors are an attractive and efficient tool for the detection of metal ions in environmental and biological science because of their high sensitivity, selectivity, and simple usage [1][2][3][4][5][6][7][8]. Among metal ions, the detection

• monitoring. In recent years, some fluorescent chemosensors for the detection of chromium(III) have been developed [15][16][17][18][19][20][21][22][23]. Generally, chemosensors with fluorescence enhancement are more efficient than fluorescence turn-off chemosensors [24][25][26][27][28][29] because the

• ethylenediaminetetraacetic acid (EDTA) were added to a solution of Cr3+ (c = 1.5⋅10−4 M) and 3 (c = 5.0⋅10−6 M), which led to a reduction of the fluorescence intensity at 388–500 nm. This reduced fluorescent intensity was analogous to that of free 3, displaying that 3 was regenerated in its uncomplexed form. When Cr3+ was

Design, synthesis and investigation of water-soluble hemi-indigo photoswitches for bioapplications

• Daria V. Berdnikova

Beilstein J. Org. Chem. 2019, 15, 2822–2829, doi:10.3762/bjoc.15.275

• that allowed to obtain an RNA-binding hemi-indigo derivative with photoswitchable fluorescent properties. Keywords: hemi-indigo; molecular switches; photochromism; photoswitching; visible light; water solubility; Introduction The application of organic photochromes in biological systems is fraught

• methoxy group to the 3-position of the phenyl ring in Z-1c did not shift the absorption maximum and just slightly affected the extinction (Table 1). Hemi-indigo derivatives Z-1a–c are not fluorescent in aqueous solution. To assess the potential applicability of hemi-indigo derivatives Z-1a–c in biological

• -1b and E-1c are not fluorescent in aqueous medium. The analysis of the isomeric compositions of the photostationary states was performed by the Fischer method [21] because NMR-spectroscopic analysis was precluded by insufficient solubility or/and possible aggregation at higher concentrations. Thus

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• an internal solution containing (in mM): 135 potassium gluconate, 4 MgCl2, 10 HEPES, 4 Na2-ATP, 0.4 Na2-GTP, 10 Na2-phosphocreatine, pH 7.35. The red fluorescent dye Alexa 594 (0.05 mM, ThermoFisher Scientific, Waltham, MA, USA) was added to visualize the morphology of the neurons. Normal ACSF was

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• μM, respectively). Reversible photoliberation/uptake leading to a variation of free calcium concentration in solution was detected using a fluorescent Ca2+ chemosensor. Keywords: azobenzene; BAPTA; calcium binding; photorelease; photoswitch; Introduction In terms of synthetic calcium binding

• , as elucidated by the crystallographic structure of a 1:1 host–guest BAPTA system [2]. This moiety has been exploited in the development of various fluorescent supramolecular chemosensor systems and even molecular logic systems [3][4][5][6][7][8][9][10][11]. Equally, the incorporation of

• liberation of Ca2+ upon photexcitation in solution, azobenzene macrocyle 1 was used as a reversible Ca2+ photoejector in the presence of a Ca2+-selective “turn-on” fluorescent probe (3, Figure 7) [41]. The fluorescence of BODIPY dye 3 in the absence of calcium, is quenched by an intramolecular photoinduced