Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• catalyst at room temperature. In addition, the free-base porphyrin-carborane conjugate 76b was successfully obtained after the treatment of 76a with trifluoroacetic acid in СН2Сl2. The research group of Ravikanth [42] prepared the triazole-bridged porphyrin-BODIPY conjugates 78 and 80 via CuAAC reaction in

• 45–50% yields. This click reaction was performed between 3-azido-BODIPY 77 and zinc porphyrin 35a or 21,23-dithiaporphyrin 79 in the presence of CuI/DIPEA in THF/CH3CN (Scheme 16). UV–vis absorption and electrochemical studies revealed the presence and interaction of both the moieties in the

• conjugates. In addition to this, the fluorescence studies suggested that the energy transfer was not efficient in Zn(II) porphyrin-BODIPY and 21,23-dithiaporphyrin-BODIPY conjugates. Dalip Kumar and his co-workers reported a CuAAC click reaction to prepare novel water soluble triazole-linked cationic

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• ][29] and specialized on the specific types of organophotoredox catalysts, such as quinone derivatives [30][31], carbon nitrides [32][33], eosin [34][35][36], 4CzIPN [37][38], Bodipy derivatives [39], methylene blue [40], pyrylium salts [41], and perylene diimides [42]. Photochemical processes

Sustainable manganese catalysis for late-stage C–H functionalization of bioactive structural motifs

• Jongwoo Son

Beilstein J. Org. Chem. 2021, 17, 1733–1751, doi:10.3762/bjoc.17.122

• adjacent directing group (see 31h). This manganese(I)-catalyzed late-stage glycosylation provides hexaglycopeptide conjugate 31m without epimerization. Moreover, the late-stage C–H diversification process enabled bioorthogonal access to glycosylated peptides, such as a fluorescent BODIPY-labeled tryptophan

• , fluorinations, allylations, alkynylations, alkenylations, and fluorescent labeling with BODIPY. Moreover, manganese catalysis exhibits excellent functional group tolerance in late-stage C–H functionalization, indicating a robust and versatile catalytic system. Several challenges still remain since there are

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• + and crown ether, leading to the formation of cyclobutane in a high yield. D’Souza et al. constructed a photosynthetic triad 4 to mimic the photosynthetic reaction center [19]. A BODIPY, an ammonium-functionalized fullerene, and a zinc porphyrin functioned as the energy donor, electron acceptor, and

• BODIPY and the zinc porphyrin. The excited zinc porphyrin further transferred the electron to the fullerene, yielding a charge-separated state, with a long lifetime of 23 µs, indicating the charge stabilization of the supramolecular assembly. Thus, an artificial photocatalytic system that can mimic the

• photochemical synthesis of an unsymmetrical cyclobutane” by O. Fedorova et al., Photochem. Photobiol. Sci. vol. 6, issue 10, © 2007); permission conveyed through Copyright Clearing Center, Inc. Energy transfer system constructed of a BODIPY–zinc porphyrin–crown ether triad assembly bound to a fulleropyrrolidine

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• phenylboronic acid (PBA)-functionalized boron dipyrromethene (BODIPY) applying the ball milling approach. The ball milling formation of boron esters between PBA BODIPY and dextran proved to be more efficient in terms of reaction time, amount of reactants, and labelling degree compared to the corresponding

• solution-based synthetic route. PBA-BODIPY dextran assembles into nanoparticles of around 200 nm by hydrophobic interactions. The resulting PBA-BODIPY dextran nanoparticles retain an apolar interior as proved by pyrene fluorescence, suitable for the encapsulation of hydrophobic drugs with high

• biocompatibility while remaining fluorescent. Keywords: ball milling; boronic ester; dextran; bodipy; nanoparticles; Introduction In the last few decades, mechanochemistry has gathered a great deal of attention and a lot of efforts have been focused on its use in organic synthesis, catalysis, biotransformation

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• from our own group include the synthesis of a polystyrene gel with a photocatalytic cross-linking monomer, 4,7-bis(4-vinylphenyl)benzo[c][1,2,5]thiadiazole (St-BTZ) [47]. Additionally, we showed the direct synthesis of a BODIPY photocatalyst as a postsynthetic modification to an aldehyde-functionalised

• the efficiency of synthesising and purifying immobilised photosensitisers [63]. A BODIPY photosensitiser was immobilised to an aldehyde-functionalised Merrifield resin (poly(styrene-co-divinylbenzene-co-4-formylstyrene)) in continuous flow and concurrently in an analogous batch procedure. The coupling

• efficiency was initially found to be almost double in flow versus batch [63]. The materials were also purified in flow and Soxhlet extractions, respectively, with the same solvent mixtures and time periods. The Soxhlet-extracted batch HPCats were found to have significant quantities of the homogeneous BODIPY

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

• evident linearity in these systems. Moreover, initial UV–vis and fluorescence studies show the promise of triptycene as a linker for electron transfer studies, showcasing its isolating nature. Keywords: BODIPY; Pd-catalyzed cross-coupling; porphyrins; Sonogashira cross-coupling; triptycene; Introduction

• 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

• bridgehead positions of triptycenes in 5 (Scheme 1) and 12 (Scheme 2), efforts were made to attach various chromophores in order to investigate the effects of triptycene as a linker for electron transfer properties. With the goal of synthesizing various new triptycene-linked porphyrin and BODIPY dimers

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

• , Japan 10.3762/bjoc.16.53 Abstract A series of α- and β-ethynyl-substituted BODIPY derivatives (3a, 4a, 5a, 5b, 6a, 6b) were synthesized by gold(I)-catalyzed direct C–H alkynylation reactions of dipyrromethane and BODIPY, respectively, with ethynylbenziodoxolone (EBX) in a regioselective manner

• . Depending on the position of the ethynyl substituent in the BODIPY skeleton, the photophysical properties of the resulting α- and β-substituted BODIPYs are notably altered. The lowest S0–S1 transition absorbance and fluorescence bands are both bathochromically shifted as the number of substituents increases

• , while the emission quantum yields of the β-ethynylated derivatives are significantly lower than those of α-ethynylated ones. The current method should be useful for fine-tuning of the photophysical properties of BODIPY dyes as well as for constructing BODIPY-based building cores for functional π

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

• 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

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• advantageous photophysical properties that include spectrally tunable and highly intense fluorescence [1][2]. On the one hand, those compounds that contain the boron atom in a valence-saturated situation corresponding to sp3 hybridization (such as Bodipy dyes [3][4], N,C-chelate organoboron dyes [5][6][7][8][9

Synthesis of a dihalogenated pyridinyl silicon rhodamine for mitochondrial imaging by a halogen dance rearrangement

• Jessica Matthias,
• Thines Kanagasundaram,
• Klaus Kopka and
• Carsten S. Kramer

Beilstein J. Org. Chem. 2019, 15, 2333–2343, doi:10.3762/bjoc.15.226

• trends for both radiative and nonradiative decays still remain difficult to predict despite theoretical and experimental efforts of the past years [29]. Here we initially assume that, in analogy to BODIPY fluorophores [30], restricted rotation around the xanthene aryl bond should lead to an improved

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• Polymères Université de Mons - UMONS / Materia Nova Place du Parc, 20, B-7000 Mons, Belgium ICPEES – UMR7515, CNRS-Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg CEDEX 02, France 10.3762/bjoc.15.169 Abstract We report two novel functional dyes based on a boron-dipyrromethene (BODIPY) core

• displaying a panchromatic absorption with an extension to the near-infrared (NIR) range. An innovative synthetic approach for preparing the 2,3,5,6-tetramethyl-BODIPY unit is disclosed, and a versatile way to further functionalize this unit has been developed. The optoelectronic properties of the two dyes

• -dipyrromethene; BODIPY; dye-sensitized solar cells; near-infrared absorbers; organic dyes; Introduction The past two decades have witnessed tremendous efforts to develop alternative photovoltaic (PV) technologies. Among them, dye-sensitized solar cells (DSSCs) display numerous advantages compared to its fully

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• the detection of ethylene in live cells [91]. BODIPY fluorophores bearing the isopropyloxybenzylidene moiety (101 and 103) reacted with the G-II catalyst to form the HG-II derivatives 102 and 104, respectively (Scheme 21). The resulting compounds are Ru-based profluorescent probes that become

• -metathesis reaction of allyl sulfide 99. Preparation of BODIPY-containing profluorescent probes 102 and 104. Metathesis-based ethylene detection in live cells. First example of stapled peptides via olefin metathesis. RCM of challenging substrate 17 in air and in the presence of water. RCM of N,N

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril

• Mohammad A. Alnajjar,
• Jürgen Bartelmeß,
• Robert Hein,
• Pichandi Ashokkumar,
• Mohamed Nilam,
• Werner M. Nau,
• Knut Rurack and
• Andreas Hennig

Beilstein J. Org. Chem. 2018, 14, 1961–1971, doi:10.3762/bjoc.14.171

• -dipyrromethene (BODIPY) dyes as a new class of fluorophores for the design of reporter dyes for supramolecular host–guest complex formation with cucurbit[7]uril (CB7). The BODIPYs contain a protonatable aniline nitrogen in the meso-position of the BODIPY chromophore, which was functionalized with known binding

• . This includes indicator displacement assays with favourable absorption and emission wavelengths in the visible spectral region, fluorescence correlation spectroscopy, and noncovalent surface functionalization with fluorophores. Keywords: BODIPY; cucurbituril; fluorescence; pH; photoinduced electron

• stability under various conditions, particularly under physiological conditions. Although most BODIPYs are insensitive to pH changes, pH-activatable optical probes for cancer imaging have been reported, in which an aniline substituent in the meso-position of the BODIPY core led to efficient fluorescence

Synthesis and spectroscopic properties of β-meso directly linked porphyrin–corrole hybrid compounds

• Baris Temelli and
• Hilal Kalkan

Beilstein J. Org. Chem. 2018, 14, 187–193, doi:10.3762/bjoc.14.13

• obtaining multiporphyrin arrays [7][8][9] that could stabilize only metal ions in a bivalent state. To overcome this limitation, porphyrin conjugates with different chromophore groups such as fullerene [10][11][12], BODIPY [13][14][15], corrole [16][17][18][19][20][21][22][23], phthalocyanine [24][25][26

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

• ·TLR4 complex, such that the full TLR4-mediated activity would be preserved. Accordingly, the 6’-O-glycine-linked BODIPY (4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene)-labeled lipid A was previously synthesized [79]. However, this compound revealed only a weak fluorescence in aqueous solution

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• against competing microorganisms was not the evolutionary driver for the emergence of the toxin. It is generally assumed in the literature that mycolactones reach their cellular targets by passive diffusion [91]. Based on competition experiments with the fluorescent, boron-dipyrromethene (BODIPY)-labeled

• significant binding to the nucleus, mitochondria or actin being detectable. Similar results were obtained by Blanchard and co-workers with the fully synthetic 8-desmethylmycolactone analog 13, which bears a BODIPY tag as a partial replacement for the core extension [92]. According to unpublished data from the

BODIPY-based fluorescent liposomes with sesquiterpene lactone trilobolide

• Ludmila Škorpilová,
• Silvie Rimpelová,
• Michal Jurášek,
• Miloš Buděšínský,
• Jana Lokajová,
• Roman Effenberg,
• Petr Slepička,
• Tomáš Ruml,
• Eva Kmoníčková,
• Pavel B. Drašar and
• Zdeněk Wimmer

Beilstein J. Org. Chem. 2017, 13, 1316–1324, doi:10.3762/bjoc.13.128

• reduces its potential medicinal applications. The targeted delivery of hydrophobic drugs can be achieved using liposome-based carriers. Therefore, we designed a traceable liposomal drug delivery system for trilobolide. The fluorescent green-emitting dye BODIPY, cholesterol and trilobolide were used to

• theranostic applications. Keywords: BODIPY conjugates; cancer targeting; drug delivery; liposomes; natural compounds; sesquiterpene lactone trilobolide; Introduction Targeted (smart) drug delivery is a method for specific delivering of an active compound preferentially to some cells or tissues in the human

• , sensitivity and good spatio-temporal resolution altogether [5]. From the plethora of known fluorescent compounds, there are widely used small organic fluorophores, such as BODIPY dyes. BODIPYs are fluorescent dyes based on the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene scaffold, which have recently

Benzothiadiazole oligoene fatty acids: fluorescent dyes with large Stokes shifts

• Lukas J. Patalag and
• Daniel B. Werz

Beilstein J. Org. Chem. 2016, 12, 2739–2747, doi:10.3762/bjoc.12.270

• as the carbohydrate part of glycolipids [7][8]. A further alternative is to render the lipid and especially the fatty acid part fluorescently active by the introduction of fluorescent moieties (Figure 1). Prominent examples in this area are NBD- (nitrobenzoxadiazole) [9][10], BODIPY- (boron

• membrane core with high bulkiness. BODIPY and BOIMPY scaffolds on the other hand expose fluoride residues which might be able to interact with polarized H–X bonds. Therefore, we synthesized pentaene and hexaene fatty acids which bear five or six double bonds at the terminus or in the middle of the acyl

A self-assembled cyclodextrin nanocarrier for photoreactive squaraine

• Ulrike Kauscher and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2016, 12, 2535–2542, doi:10.3762/bjoc.12.248

• scattering and absorption by tissue is minimized and a more in-depth therapy becomes possible. The search for more effective compounds with absorption in the near infrared includes amongst others cyanine [10], bodipy [11], and phthalocyanine [12] photosensitizers and has lately led to the consideration of a

Synthesis of a deuterated probe for the confocal Raman microscopy imaging of squalenoyl nanomedicines

• Eric Buchy,
• Branko Vukosavljevic,
• Maike Windbergs,
• Dunja Sobot,
• Camille Dejean,
• Simona Mura,
• Patrick Couvreur and
• Didier Desmaële

Beilstein J. Org. Chem. 2016, 12, 1127–1135, doi:10.3762/bjoc.12.109

• , the use of fluorescent probes requires the covalent binding of large dye molecules (bodipy, cyanine, rhodamine etc, ...) to the drug conjugate, thus potentially modifying its physicochemical profile as well as the in vivo fate and the pharmacological activity. A simple encapsulation of an amphiphilic

Synthesis, antimicrobial and cytotoxicity evaluation of new cholesterol congeners

• Mohamed Ramadan El Sayed Aly,
• Hosam Ali Saad and
• Shams Hashim Abdel-Hafez

Beilstein J. Org. Chem. 2015, 11, 1922–1932, doi:10.3762/bjoc.11.208

• regulator of cellular cholesterol [8]. Synthetic BODIPY–cholesterol conjugates were reported as probes for visualization of intracellular cholesterol pools and for monitoring cholesterol efflux from cells to extracellular receptors [9]. ABCA1 plays an inevitable role in the resistance against tumorgenesis

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

• Alexander L. Kanibolotsky,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

• units into a conjugated network is a standard way to narrow the HOMO/LUMO band gap and examples of such units include dioxopyrrolopyrrole (DPP) [17][18][19], benzodifuranone [20] and boron-dipyrromethene (BODIPY) [21][22]. As a different class of electroactive materials, TTF derivatives are well-known