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Search for "fluorene" in Full Text gives 43 result(s) in Beilstein Journal of Organic Chemistry.
Switchable molecular tweezers: design and applications
- Pablo Msellem,
- Maksym Dekthiarenko,
- Nihal Hadj Seyd and
- Guillaume Vives
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
Graphical Abstract
Figure 1: Principle of switchable molecular tweezers.
Figure 2: Principle of pH-switchable molecular tweezers 1 [19].
Figure 3: a) pH-Switchable tweezers 2 substituted with alkyl chains as switchable lipids. b) Schematic depict...
Figure 4: Modification of spectral properties of 3 by controlled induction of Pt–Pt interactions.
Figure 5: Conformational switching of di(hydroxyphenyl)pyrimidine-based tweezer 4 upon alkylation or fluoride...
Figure 6: Hydrazone-based pH-responsive tweezers 5 for mesogenic modulation.
Figure 7: pH-Switchable molecular tweezers 6 bearing acridinium moieties.
Figure 8: a) Terpyridine and pyridine-hydrazone-pyridine analogs molecular tweezers and b) extended pyridine ...
Figure 9: Terpyridine-based molecular tweezers with M–salphen arms and their field of application. Figure 9 was adapt...
Figure 10: a) Terpyridine-based molecular tweezers for diphosphate recognition [48]; b) bishelicene chiroptical te...
Figure 11: Terpyridine-based molecular tweezers with allosteric cooperative binding.
Figure 12: Terpyridine-based molecular tweezers presenting closed by default conformation.
Figure 13: Pyridine-pyrimidine-pyridine-based molecular tweezers.
Figure 14: Coordination-responsive molecular tweezers based on nitrogen-containing ligands.
Figure 15: Molecular tweezers exploiting the remote bipyridine or pyridine binding to trigger the conformation...
Figure 16: Bipyridine-based molecular tweezers exploiting the direct s-trans to s-cis-switching for a) anion b...
Figure 17: a) Podand-based molecular tweezers [66,67]. b) Application of tweezers 32 for the catalytic allosteric reg...
Figure 18: Anion-triggered molecular tweezers based on calix[4]pyrrole.
Figure 19: Anion-triggered molecular tweezers.
Figure 20: a) Principle of the weak link approach (WLA) developed by Mirkin and its application to b) symmetri...
Figure 21: Molecular tweezers as allosteric catalyst in asymmetric epoxide opening [80].
Figure 22: Allosteric regulation of catalytic activity in ring-opening polymerization with double tweezers 41.
Figure 23: a) Conformational switching of 42 by intramolecular –S–S– bridge formation. b) Shift of conformatio...
Figure 24: a) Redox-active glycoluril-TTF tweezers 44. b) Mechanism of stepwise oxidation of said tweezers wit...
Figure 25: Mechanism of formation of the mixed-valence dimers of tweezers 45.
Figure 26: Mechanism of carbohydrate liberation upon redox-mediated conformation switching of 46.
Figure 27: a) The encapsulation properties of 47 as well as the DCTNF release process from its host–guest comp...
Figure 28: Redox-active bipyridinium-based tweezers. a) With a ferrocenyl hinge 49, b) with a propyl hinge 50 ...
Figure 29: Redox-active calix[4]arene porphyrin molecular tweezers.
Figure 30: a) Mechanism of the three orthogonal stimuli. b) Cubic scheme showing the eight different states of ...
Figure 31: Redox-controlled molecular gripper based on a diquinone resorcin[4]arene.
Figure 32: a) Shinkai's butterfly tweezers and their different host–guest properties depending on the isomer. ...
Figure 33: Cyclam-tethered tweezers and their different host–guest complexes depending on their configuration.
Figure 34: Azobenzene-based catalytic tweezers.
Figure 35: Photoswitchable PIEZO channel mimic.
Figure 36: Stilbene-based porphyrin tweezers for fullerene recognition.
Figure 37: Stiff-stilbene-based tweezers with urea or thiourea functional units for a) anion binding, b) anion...
Figure 38: Feringa’s photoswitchable organocatalyst (a) and different catalyzed reactions with that system (b)....
Figure 39: a) Irie and Takeshita’s thioindigo-based molecular tweezers. b) Family of hemithioindigo-based mole...
Figure 40: Dithienylethylene crown ether-bearing molecular tweezers reported by Irie and co-workers.
Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units
- Christina Schøttler,
- Kasper Lund-Rasmussen,
- Line Broløs,
- Philip Vinterberg,
- Ema Bazikova,
- Viktor B. R. Pedersen and
- Mogens Brøndsted Nielsen
Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8
- indenofluorene (IF) or fluorene cores and containing various dithiafulvene (DTF) donor units that gain aromaticity upon oxidation and a variety of acceptor units, such as vinylic diesters, enediynes, and cross-conjugated radiaannulenes (RAs) that gain aromaticity upon reduction. In some cases, the DTF units are
- the introduction of an indeno[1,2-b]fluorene (IF) core [13], providing indenofluorene-extended TTFs (IF-TTFs) of the general structure shown in Figure 1. The π-system can be further expanded as well at the dithiole rings. For example, we have recently developed a synthetic protocol for fusing a
- smaller fluorene PAH. These compounds were prepared by a Lawesson’s reagent-promoted coupling between fluorenone 5 and the Ts-protected 1,3-dithiole-2-thione building blocks 2 and 3, respectively, shown in Scheme 3 (albeit in modest yields). Fluorene-based DTF compounds have previously been explored in
Graphical Abstract
Figure 1: Overview of structural motifs relevant for the work described herein.
Figure 2: Dione/ketones 1, 4–6 and 1,3-dithiole-2-thione compounds 2, 3, 7, and 8 are building blocks used in...
Scheme 1: Synthesis of IF-DTF ketones 9–12 and dimer 13.
Scheme 2: Further functionalization of the IF-DTF ketone 11 via Ramirez/Corey–Fuchs dibromo-olefination and K...
Scheme 3: Coupling of 1,3-dithiole-2-thione building blocks 2 and 3 with fluorenone 5 to afford fluorene-exte...
Scheme 4: Synthesis of acetylenic scaffolds based on IF-DTF. Conditions: (a) Pd(PPh3)2Cl2, CuI, THF, Et3N, rt...
Scheme 5: Synthesis of acetylenic scaffolds with IF as central core. *Not fully characterized due to poor sol...
Scheme 6: Reduction of IF dione 1 to dihydro-IF 29.
Figure 3: UV–vis absorption spectra of compounds 4, 9–12, and 15 in PhMe at 25 °C.
Figure 4: UV–vis absorption spectra of compounds 13, 16, 17, and 30 in CH2Cl2 at 25 °C.
Figure 5: UV–vis absorption spectra of compounds 22, 23, 26, and 27 in CH2Cl2 at 25 °C.
Figure 6: Cyclic voltammograms of compounds 11 (in MeCN), 13 (in CH2Cl2), 15 (in MeCN), 16 (in CH2Cl2), and 17...
Figure 7: Comparison of properties of compounds 13 and 17.
Figure 8: Cyclic voltammograms of compounds 22, 23, 26, and 27 in CH2Cl2; supporting electrolyte: 0.1 M Bu4NPF...
Figure 9: Radical anion (left), dianion (middle), and radical cation (right) of compound 23; the radical anio...
Figure 10: ORTEP plots (50% probability) and crystal packing of compounds a) 25, b) 26, and c) 29. The respect...
Figure 11: Labels of bonds within five-membered ring.
Pyridine C(sp2)–H bond functionalization under transition-metal and rare earth metal catalysis
- Haritha Sindhe,
- Malladi Mounika Reddy,
- Karthikeyan Rajkumar,
- Akshay Kamble,
- Amardeep Singh,
- Anand Kumar and
- Satyasheel Sharma
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
- intact under the reaction conditions without any further oxidation. Different oxidants resulted in different products such as the monoarylated product 118 formed in the presence of TBHP as oxidant and the benzylated product 119 was obtained when potassium persulfate was used. Interestingly, aza-fluorene
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons
- Hengjia Liu and
- Guohua Xie
Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83
- optoelectronic properties of a fluorene-based copolymer with an sp2 nitrogen heteroatom via supramolecular coordination [33]. The PL emission in solution showed an obvious red-shifted profile. The polymer LED with different molar equivalents of Lewis acids was investigated. The EL peak wavelength was gradually
- . Regarding the materials developed by Lin et al., supramolecular coordination of PF8-co-DAF8 (13, Figure 5) with Lewis acids played an important role. They selected the more rigid 4,5-diazafluorene (DAF) with nitrogen atoms inserted at the 4 and 5-positons of the fluorene moiety [33]. The heteroatomic
- fluorene showed enhanced planarity of the molecule. The coordination tended to be more efficient if a stronger Lewis acid was employed. The bipolar host material 35DCzPPy (14, Figure 5) was initially synthesized by Kido’s group [39]. It combines two carbazole electron donors with high triplet energy and a
Graphical Abstract
Figure 1: Chemical structures of Lewis acid examples.
Figure 2: Chemical structures of Lewis basic fluorescent polymer poly{2,5-pyridylene-co-1,4-[2,5-bis(2-ethylh...
Figure 3: (a) Normalized PL spectra of films with compound 1 doped with different Lewis acids. (b) PL spectra...
Figure 4: Schematic diagram of a BF3·OEt2 vapor-treated device and the macroscopic gradation emissive pattern...
Figure 5: Chemical structures of Lewis basic fluorescent compounds 3–14.
Figure 6: (a) PL spectra of compound 6 in toluene after addition of 0.0 (black line), 0.1 (red line), 0.3 (gr...
Figure 7: Photos of a solution of compound 12 and B(C6F5)3 at different ratios in toluene under a 365 nm UV l...
Figure 8: Structure of small molecule 15 containing pyridine and thiazole groups reported by Bazan et al. and...
Figure 9: (a) 1H NMR spectra in the aromatic region and (b) 19F NMR spectra of compound 15 (top) and the mixt...
Figure 10: Pyrazine-containing polymers 19 and 20 investigated by Li et al.
Figure 11: (a) HOMO/LUMO orbitals and energy levels (unit: eV) and (b) electrostatic potential surface (EPS) m...
Figure 12: (a) UV–vis absorbance and (b) PL spectra (excited by 330 nm) for 35DCzPPy (compound 14), B(C6F5)3, ...
Figure 13: (a) Schematic diagram of the low-band gap materials 21 and 22. (b) Ground state geometry optimizati...
Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures
- Mengjie Wang,
- Lanping Dang,
- Wan Xu,
- Zhiying Ma,
- Liuliu Shao,
- Guangxia Wang,
- Chunli Li and
- Hua Wang
Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81
- similar method, Takimiya reported the synthesis of six-ring-fused and four-ring-fused heteroacenes containing selenopheno[3,2-b]selenophene in 2007 and 2009, respectively [23][24]. Five years later, Cheng reported the synthesis of two types of five-ring-fused isomers of diselenopheno[2,3-b:7,6-b′]fluorene
- and diselenopheno[3,2-b:6,7-b′]fluorene through the cyclization of terminal acetylene as well as six types of biselenophene-based fused tricyclic derivatives [25][26]. In 2017, we reported the first member of diselenoselenophenes (DSSs), 2,5-di(trimethylsilanyl)diseleno[2,3-b:3′,2′-d]selenophene ((TMS
Graphical Abstract
Figure 1: Molecular structures of bull horn-shaped heteroacene 1, selenophene-based [7]helicene 2 and novel c...
Scheme 1: Synthetic route to S-shaped double helicenes DH-1–3.
Figure 2: Five kinds of isomer structures of 5 and two kinds of possible oxidative photocyclization product s...
Figure 3: Molecular structures and side view for DH-1 and DH-2. A and B are molecular structures for DH-1 and ...
Figure 4: UV–vis absorption spectra of DH-1–3 in CH2Cl2 ([c] = 1 × 10−5 M).
Chemical syntheses and salient features of azulene-containing homo- and copolymers
- Vijayendra S. Shetti
Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139
- sensitivity could be attributed to the resonance stabilization of the positive charge on the five-membered ring of the azulene by the electron-donating groups at the 2-position. These polymers were quite robust as they underwent several cycles of electro-cycling before degradation. Azulene-fluorene copolymers
- In 2009, Xu and co-workers [40] synthesized various examples of azulene-fluorene conjugated polymers by using Suzuki cross-coupling reactions. The first set of polymers, poly[2,7-(9,9-dialkylfluorenyl)-alt-(1’,3’-azulenyl)] 106–109 was prepared by the reaction of 1,3-dibromoazulene (4) with 9,9
- )azulene (114) was required, and its synthesis was achieved from 2-bromofluorene (110) by following the protocol presented in Scheme 19B. The reaction of 114 with fluorene borates 102 and 104 under Suzuki conditions yielded polymers 115 and 116, respectively (Scheme 19C). The solubility of all polymers was
Graphical Abstract
Figure 1: Chemical structure, numbering scheme, and resonance form of azulene.
Scheme 1: Synthesis of polyazulene-iodine (PAz-I2) and polyazulene-bromine (PAz-Br2) complexes.
Scheme 2: Synthesis of ‘true polyazulene’ 3 or 3’ by cationic polymerization.
Scheme 3: Synthesis of 1,3-polyazulene 5 by Yamamoto protocol.
Scheme 4: Synthesis of 4,7-dibromo-6-(n-alkyl)azulenes 12–14.
Scheme 5: Synthesis of (A) 4,7-diethynyl-6-(n-dodecyl)azulene (16) and (B) 4,7-polyazulene 17 containing an e...
Scheme 6: Synthesis of directly connected 4,7-polyazulenes 18–20.
Scheme 7: Synthesis of (A) tert-butyl N-(6-bromoazulen-2-yl)carbamate (27), (B) dimeric aminoazulene 29, and ...
Figure 2: Iminium zwitterionic resonance forms of poly[2(6)-aminoazulene] 31.
Scheme 8: Synthesis of poly{1,3-bis[2-(3-alkylthienyl)]azulene} 33–38.
Scheme 9: Synthesis of polymer ruthenium complexes 40–43.
Scheme 10: Synthesis of 4,7-polyazulenes 45 containing a thienyl linker.
Scheme 11: Synthesis of azulene-bithiophene 48 and azulene-benzothiadiazole 52 copolymers. Conditions: (a): (i...
Scheme 12: Synthesis of azulene-benzodithiophene copolymer 54 and azulene-bithiophene copolymer 56.
Scheme 13: Synthesis of (A) 5,5’-bis(trimethylstannyl)-3,3’-didodecyl-2,2’-bithiophene (60) and (B) azulene-bi...
Scheme 14: Synthesis of 1,3-bisborylated azulene 67.
Scheme 15: Synthesis of D–A-type azulene-DPP copolymers 69, 71, and 72. Conditions: (a) Pd(PPh3)4, K2CO3, Aliq...
Scheme 16: Synthesis of the key precursor TBAzDI 79.
Scheme 17: Synthesis of TBAzDI-based polymers 81 and 83. Conditions: (a) P(o-tol)3, Pd2(dba)3, PivOH, Cs2CO3, ...
Scheme 18: Synthesis of (A) 1,3-dibromo-2-arylazulene 92–98 and (B) 2-arylazulene-thiophene copolymers 99–101.
Scheme 19: Synthesis of (A) poly[2,7-(9,9-dialkylfluorenyl)-alt-(1’,3’-azulenyl)] 106–109, (B) 1,3-bis(7-bromo...
Scheme 20: Synthesis of azulene-fluorene copolymers 117–121 containing varying ratios of 1,3- and 4,7-connecte...
Scheme 21: Synthesis of (A) 2,6-dibromoazulene (125), (B) azulene-fluorene copolymer 126, and (C) azulene-fluo...
Scheme 22: Synthesis of 2-arylazulene-fluorene copolymers 131–134.
Scheme 23: Synthesis of azulene-fluorene-benzothiadiazole terpolymers 136–138.
Scheme 24: Synthesis of azulene-carbazole-benzothiadiazole-conjugated polymers 140–144.
Scheme 25: Synthesis of (A) azulene-2-yl methacrylate (146) and (B) the triazole-containing azulene methacryla...
Scheme 26: Synthesis of (A) azulene methacrylate polymer 151 and (B) triazole-containing azulene methacrylate ...
Scheme 27: Synthesis of azulene methyl methacrylate polymers 154, 155 (A and B) and azulene-sulfobetaine metha...
Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools
- Shakeel Alvi and
- Rashid Ali
Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96
- , superior solubility, improve morphological, optical, electrical and film-forming properties because of the involvement of extra dimensionality. Amongst them, the heptacyclic truxene scaffold possessing three overlapping fluorene units and its congeners are of archetypal interest due to their potential
- 600 to 4000 cm−1. UV–vis spectra were recorded on a UV-1800 Shimadzu spectrophotometer and the fluorescence spectra were recorded on an Agilent Carry Eclipse spectrofluorimeter. Synthesis of 10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene (7): Truxene scaffold 7 was prepared according to a literature
- followed by dichloromethane gave a white powder (4.7 g, 80%). Synthesis of 5,5,10,10,15,15-hexabutyl-10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene (2): Truxene (7, 4 g, 11.68 mmol), DMSO (35 mL), and t-BuOK (11.79 g, 105.12 mmol) were mixed in a two-necked round bottom flask (100 mL) under nitrogen
Graphical Abstract
Scheme 1: Retrosynthetic pathways to the pyrrole-based C3-symmetric truxene derivative 6.
Scheme 2: Synthesis of tripyrrolotruxene 6 via cyclotrimerization and RCM as crucial steps.
Scheme 3: Synthesis of star-shaped molecule 6 utilizing the Clauson–Kaas pyrrole strategy.
Scheme 4: Synthesis of truxene derivative 6 involving Ullmann-type cross-coupling reaction.
Scheme 5: Synthesis of imidazole and benzimidazole containing truxene derivatives 14 and 16.
Scheme 6: Construction of truxene-based di- and trioxazole derivatives 21 and 20.
Scheme 7: Synthesis of benzene-bridged rings containing trioxazolotruxene system 25.
Figure 1: Normalized absorption (left); fluorescence spectra (right) of the synthesized truxene derivatives (...
[2 + 1] Cycloaddition reactions of fullerene C60 based on diazo compounds
- Yuliya N. Biglova
Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55
- Scheme 32 from 9,9-didecyl-9H-fluorene and monomethyl terephthalate chloride [152]. The authors of reference [153] presented a series of 2,2';6',2"-terpyridine (tpy)-substituted methanofullerenes and pyrrolidinofullerene dyads 184–186 linked through para-phenylene or para-phenyleneethynylphenylene units
CF3-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry
- Anthony J. Fernandes,
- Armen Panossian,
- Bastien Michelet,
- Agnès Martin-Mingot,
- Frédéric R. Leroux and
- Sébastien Thibaudeau
Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32
- alcohols was shown by Cohen and Kaluszyner [55][56] and by Streitwieser et al. [57]. The cyclodehydration of 9c occurs in polyphosphoric acid to afford fluorene 37 (Scheme 8) [57]. A mechanistic proposal invoking the initial generation of the α-(trifluoromethyl)carbenium ion 10c↔10c’ was mentioned by the
- authors [55][56]. Related studies on diphenyl derivative 9c in a mixture of H2SO4 and chloroform also showed the formation of fluorene derivative 37 in 25% yield [58]. Exploiting this impact of the trifluoromethyl substituent in the cationic Nazarov electrocyclization, the synthesis of CF3-substituted
Graphical Abstract
Figure 1: Stabilizing interaction in the CF3CH2+ carbenium ion (top) and structure of the first observable fl...
Scheme 1: Isodesmic equations accounting for the destabilizing effect of the CF3 group. ΔE in kcal⋅mol−1, cal...
Scheme 2: Stabilizing effect of fluorine atoms by resonance electron donation in carbenium ions (δ in ppm).
Scheme 3: Direct in situ NMR observation of α-(trifluoromethyl)carbenium ion or protonated alcohols. Δδ = δ19...
Scheme 4: Reported 13C NMR chemical shifts for the α-(trifluoromethyl)carbenium ion 10c (δ in ppm).
Scheme 5: Direct NMR observation of α-(trifluoromethyl)carbenium ions in situ (δ in ppm).
Scheme 6: Illustration of the ion pair solvolysis mechanism for sulfonate 13f. YOH = solvent.
Figure 2: Solvolysis rate for 13a–i and 17.
Figure 3: Structures of allyl triflates 18 and 19 and allyl brosylate 20. Bs = p-BrC6H4SO2.
Figure 4: Structure of tosylate derivatives 21.
Figure 5: a) Structure of triflate derivatives 22. b) Stereochemistry outcomes of the reaction starting from (...
Scheme 7: Solvolysis reaction of naphthalene and anthracenyl derivatives 26 and 29.
Figure 6: Structure of bisarylated derivatives 34.
Figure 7: Structure of bisarylated derivatives 36.
Scheme 8: Reactivity of 9c in the presence of a Brønsted acid.
Scheme 9: Cationic electrocyclization of 38a–c under strongly acidic conditions.
Scheme 10: Brønsted acid-catalyzed synthesis of indenes 42 and indanes 43.
Scheme 11: Reactivity of sulfurane 44 in triflic acid.
Scheme 12: Solvolysis of triflate 45f in alcoholic solvents.
Scheme 13: Synthesis of labeled 18O-52.
Scheme 14: Reactivity of sulfurane 53 in triflic acid.
Figure 8: Structure of tosylates 56 and 21f.
Scheme 15: Resonance forms in benzylic carbenium ions.
Figure 9: Structure of pyrrole derivatives 58 and 59.
Scheme 16: Resonance structure 60↔60’.
Scheme 17: Ga(OTf)3-catalyzed synthesis of 3,3’- and 3,6’-bis(indolyl)methane from trifluoromethylated 3-indol...
Scheme 18: Proposed reaction mechanism.
Scheme 19: Metal-free 1,2-phosphorylation of 3-indolylmethanols.
Scheme 20: Superacid-mediated arylation of thiophene derivatives.
Scheme 21: In situ mechanistic NMR investigations.
Scheme 22: Proposed mechanisms for the prenyltransferase-catalyzed condensation.
Scheme 23: Influence of a CF3 group on the allylic SN1- and SN2-mechanism-based reactions.
Scheme 24: Influence of the CF3 group on the condensation reaction.
Scheme 25: Solvolysis of 90 in TFE.
Scheme 26: Solvolysis of allyl triflates 94 and 97 and isomerization attempt of 96.
Scheme 27: Proposed mechanism for the formation of 95.
Scheme 28: Formation of α-(trifluoromethyl)allylcarbenium ion 100 in a superacid.
Scheme 29: Lewis acid activation of CF3-substituted allylic alcohols.
Scheme 30: Bimetallic-cluster-stabilized α-(trifluoromethyl)carbenium ions.
Scheme 31: Reactivity of cluster-stabilized α-(trifluoromethyl)carbenium ions.
Scheme 32: α-(Trifluoromethyl)propargylium ion 122↔122’ generated from silyl ether 120 in a superacid.
Scheme 33: Formation of α-(trifluoromethyl)propargylium ions from CF3-substituted propargyl alcohols.
Scheme 34: Direct NMR observation of the protonation of some trifluoromethyl ketones in situ and the correspon...
Scheme 35: Selected resonance forms in protonated fluoroketone derivatives.
Scheme 36: Acid-catalyzed Friedel–Crafts reactions of trifluoromethyl ketones 143a,b and 147a–c.
Scheme 37: Enantioselective hydroarylation of CF3-substituted ketones.
Scheme 38: Acid-catalyzed arylation of ketones 152a–c.
Scheme 39: Reactivity of 156 in a superacid.
Scheme 40: Reactivity of α-CF3-substituted heteroaromatic ketones and alcohols as well as 1,3-diketones.
Scheme 41: Reactivity of 168 with benzene in the presence of a Lewis or Brønsted acid.
Scheme 42: Acid-catalyzed three-component asymmetric reaction.
Scheme 43: Anodic oxidation of amines 178a–c and proposed mechanism.
Scheme 44: Reactivity of 179b in the presence of a strong Lewis acid.
Scheme 45: Trifluoromethylated derivatives as precursors of trifluoromethylated iminium ions.
Scheme 46: Mannich reaction with trifluoromethylated hemiaminal 189.
Scheme 47: Suitable nucleophiles reacting with 192 after Lewis acid activation.
Scheme 48: Strecker reaction involving the trifluoromethylated iminium ion 187.
Scheme 49: Reactivity of 199 toward nucleophiles.
Scheme 50: Reactivity of 204a with benzene in the presence of a Lewis acid.
Scheme 51: Reactivity of α-(trifluoromethyl)-α-chloro sulfides in the presence of strong Lewis acids.
Scheme 52: Anodic oxidation of sulfides 213a–h and Pummerer rearrangement.
Scheme 53: Mechanism for the electrochemical oxidation of the sulfide 213a.
Scheme 54: Reactivity of (trifluoromethyl)diazomethane (217a) in HSO3F.
Figure 10: a) Structure of diazoalkanes 217a–c and b) rate-limiting steps of their decomposition.
Scheme 55: Deamination reaction of racemic 221 and enantioenriched (S)-221.
Scheme 56: Deamination reaction of labeled 221-d2. Elimination products were formed in this reaction, the yiel...
Scheme 57: Deamination reaction of 225-d2. Elimination products were also formed in this reaction in undetermi...
Scheme 58: Formation of 229 from 228 via 1,2-H-shift.
Scheme 59: Deamination reaction of 230. Elimination products were formed in this reaction, the yield of which ...
Scheme 60: Deamination of several diazonium ions. Elimination products were formed in these reactions, the yie...
Scheme 61: Solvolysis reaction mechanism of alkyl tosylates.
Scheme 62: Solvolysis outcome for the tosylates 248 and 249 in HSO3FSbF5.
Figure 11: Solvolysis rate of 248, 249, 252, and 253 in 91% H2SO4.
Scheme 63: Illustration of the reaction pathways. TsCl, pyridine, −5 °C (A); 98% H2SO4, 30 °C (B); 98% H2SO4, ...
Scheme 64: Proposed solvolysis mechanism for the aliphatic tosylate 248.
Scheme 65: Solvolysis of the derivatives 259 and 260.
Scheme 66: Solvolysis of triflate 261. SOH = solvent.
Scheme 67: Intramolecular Friedel–Crafts alkylations upon the solvolysis of triflates 264 and 267.
Scheme 68: α-CF3-enhanced γ-silyl elimination of cyclobutyltosylates 270a,b.
Scheme 69: γ-Silyl elimination in the synthesis of a large variety of CF3-substituted cyclopropanes. Pf = pent...
Scheme 70: Synthetic pathways to 281. aNMR yields.
Scheme 71: The cyclopropyl-substituted homoallylcyclobutylcarbenium ion manifold.
Scheme 72: Reactivity of CF3-substituted cyclopropylcarbinyl derivatives 287a–c. LG = leaving group.
Scheme 73: Reactivity of CF3-substituted cyclopropylcarbinyl derivatives 291a–c.
Scheme 74: Superacid-promoted dimerization or TFP.
Scheme 75: Reactivity of TFP in a superacid.
Scheme 76: gem-Difluorination of α-fluoroalkyl styrenes via the formation of a “hidden” α-RF-substituted carbe...
Scheme 77: Solvolysis of CF3-substituted pentyne 307.
Scheme 78: Photochemical rearrangement of 313.
Figure 12: Structure of 2-norbornylcarbenium ion 318 and argued model for the stabilization of this cation.
Figure 13: Structures and solvolysis rate (TFE, 25 °C) of the sulfonates 319–321. Mos = p-MeOC6H4SO2.
Scheme 79: Mechanism for the solvolysis of 323. SOH = solvent.
Scheme 80: Products formed by the hydrolysis of 328.
Scheme 81: Proposed carbenium ion intermediates in an equilibrium during the solvolysis of tosylates 328, 333,...
Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes
- Thomas Schneider,
- Michael Keim,
- Bianca Seitz and
- Gerhard Maas
Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173
- good yield. Dehydrogenation of 7 with chloranil then provided 9-(dimethylamino)-9-(trifluoromethyl)fluorene 8. In an analogous reaction sequence, 11H-benzo[a]fluorene derivative 9 was obtained from 3-(2-naphthyl)propyn-1-iminium salt 1b and 2,3-dimethylbutadiene (Scheme 2) in a one-pot three-step
- -up were identified by their NMR and analytical data as 2-(1-phenylvinyl)indene 12a and a small amount of benzo[a]fluorene 13a (δF = −69.74 and −69.20 ppm, respectively). The results obtained with styrenes bearing a substituent at the olefinic bond provide useful information with respect to the
Graphical Abstract
Scheme 1: Diels–Alder reaction of propyn-1-iminium salt 1a compared with the reported [29] reaction of 4-phenyl-1...
Scheme 2: Sequential Diels–Alder/intramolecular SE(Ar) reaction of propyn-1-iminium triflates 1a,b. Condition...
Scheme 3: Diels–Alder reaction of 1a and anthracene followed by an intramolecular SE(Ar) reaction.
Figure 1: Solid-state molecular structure of 11 (ORTEP plot).
Scheme 4: Reactions of propyn-1-iminium salt 1a with styrenes.
Figure 2: Solid-state molecular structure of 12c (ORTEP plot).
Figure 3: Solid-state molecular structure of 12d (ORTEP plot). Both the R and the S enantiomer are present in...
Scheme 5: A mechanistic proposal for the reaction of alkyne 1a with styrenes.
Scheme 6: Reaction of alkyne 1a with 1,2-dihydronaphthalene.
Scheme 7: Synthesis and solid-state molecular structure (ORTEP plot) of pentafulvene 19; selected bond distan...
Scheme 8: Proposed mechanistic pathway leading to fulvene 19.
Clickable azide-functionalized bromoarylaldehydes – synthesis and photophysical characterization
- Dominik Göbel,
- Marius Friedrich,
- Enno Lork and
- Boris J. Nachtsheim
Beilstein J. Org. Chem. 2020, 16, 1683–1692, doi:10.3762/bjoc.16.139
- cycloadditions with model alkynes. Besides two ortho- and para-bromo-substituted benzaldehydes, the azide functionalization of a fluorene-based structure will be presented. The copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) of the so-synthesized azide-functionalized bromocarbaldehydes with terminal
- -methylbenzaldehyde). Bromofluorenecarbaldehyde 5 The synthetic route to azide-functionalized 7-bromofluorene-2-carbaldehyde 5 started from unfunctionalized fluorene. Double bromination to 14, followed by double methylation of the methylene bridge to 15 and a lithiation/formylation sequence afforded 7-bromofluorene-2
- previous deprotection reactions, fluorene 21 was converted by means of a three-step sequence to the desired azide-functionalized 7-bromofluorene-2-carbaldehyde 5 in 86% yield and an overall yield of 45% (starting from fluorene). The molecular structure of 5 could be verified by X-ray diffraction (XRD, see
Graphical Abstract
Scheme 1: a) Schematic depiction of the Jablonski diagram. b) Schematic representation of El-Sayed’s rule.
Figure 1: Top: literature examples of organic compounds showing RTP in the crystalline state (a) and in solut...
Scheme 2: Reaction conditions for para-bromobenzaldehyde 3: a) 1) 2-amino-2-methylpropan-1-ol, 4 Å MS, CH2Cl2...
Scheme 3: Reaction conditions: a) Br2, Fe powder, CHCl3, 0 °C, 4 h, 99%; b) KOH, KI, MeI, DMSO, 25 °C, 18 h, ...
Scheme 4: Reaction conditions: a) 1) NaH, THF, 0 °C, 30 min; 2) MeI, THF, 0 °C to 25 °C, 2 h, 99%; b) 1) MeOT...
Scheme 5: a) CuAAC reactions of azide-functionalized bromocarbaldehydes 3, 4 and 5 with terminal alkynes to t...
Figure 2: a) Normalized UV–vis absorption spectra of 3 (blue line), 34 (olive line), 4 (green line) and 38 (r...
Figure 3: a) Normalized UV–vis absorption spectra of 5 (blue line), 16 (green line), 42 (olive line) and 45 (...
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
- (Figure 11) [129]. Four conjugated polymers containing dibenzothiophene sulfone (FSO) monomers, linked by either biphenyl (FSO-BP), fluorene (FSO-F), 2,8-dibenzothiophene (FSO-FSz), or 3,7-dibenzothiophene (FSO-FS) monomers were synthesised and applied in the photocatalytic hydrogen evolution reaction
Graphical Abstract
Figure 1: A) Bar chart of the publications per year for the topics “Photocatalysis” (49,662 instances) and “P...
Figure 2: A) Professor Giacomo Ciamician and Dr. Paolo Silber on their roof laboratory at the University of B...
Scheme 1: PRC trifluoromethylation of N-methylpyrrole (1) using hazardous gaseous CF3I safely in a flow react...
Figure 3: A) Unit cells of the three most common crystal structures of TiO2: rutile, brookite, and anatase. R...
Figure 4: Illustration of the key semiconductor photocatalysis events: 1) A photon with a frequency exceeding...
Figure 5: Photocatalytic splitting of water by oxygen vacancies on a TiO2(110) surface. Reprinted with permis...
Figure 6: Proposed adsorption modes of A) benzene, B) chlorobenzene, C) toluene, D) phenol, E) anisole, and F...
Figure 7: Structures of the sulfonate-containing organic dyes RB5 (3) and MX-5B (4) and the adsorption isothe...
Figure 8: Idealised triclinic unit cell of a g-C3N4 type polymer, displaying possible hopping transport scena...
Figure 9: Idealised structure of a perfect g-C3N4 sheet. The central unit highlighted in red represents one t...
Figure 10: Timeline of the key processes of charge transport following the photoexcitation of g-C3N4, leading ...
Scheme 2: Photocatalytic bifunctionalisation of heteroarenes using mpg-C3N4, with the selected examples 5 and ...
Figure 11: A) Structure of four linear conjugated polymer photocatalysts for hydrogen evolution, displaying th...
Figure 12: Graphical representation of the common methods used to immobilise molecular photocatalysts (PC) ont...
Figure 13: Wireless light emitter-supported TiO2 (TiO2@WLE) HPCat spheres powered by resonant inductive coupli...
Figure 14: Graphical representation of zinc–perylene diimide (Zn-PDI) supramolecular assembly photocatalysis v...
Scheme 3: Upconversion of NIR photons to the UV frequency by NaYF4:Yb,Tm nanocrystals sequentially coated wit...
Figure 15: Types of reactors employed in heterogeneous photocatalysis in flow. A) Fixed bed reactors and the s...
Figure 16: Electrochemical potential of common semiconductor, transition metal, and organic dye-based photocat...
Scheme 4: Possible mechanisms of an immobilised molecular photoredox catalyst by oxidative or reductive quenc...
Scheme 5: Scheme of the CMB-C3N4 photocatalytic decarboxylative fluorination of aryloxyacetic acids, with the...
Scheme 6: Scheme of the g-C3N4 photocatalytic desilylative coupling reaction in flow and proposed mechanism [208].
Scheme 7: Proposed mechanism of the radical cyclisation of unsaturated alkyl 2-bromo-1,3-dicarbonyl compounds...
Scheme 8: N-alkylation of benzylamine and schematic of the TiO2-coated microfluidic device [213].
Scheme 9: Proposed mechanism of the Pt@TiO2 photocatalytic deaminitive cyclisation of ʟ-lysine (23) to ʟ-pipe...
Scheme 10: A) Proposed mechanism for the photocatalytic oxidation of phenylboronic acid (24). B) Photos and SE...
Scheme 11: Proposed mechanism for the DA-CMP3 photocatalytic aza-Henry reaction performed in a continuous flow...
Scheme 12: Proposed mechanism for the formation of the cyclic product 32 by TiO2-NC HPCats in a slurry flow re...
Scheme 13: Reaction scheme for the photocatalytic synthesis of homo and hetero disulfides in flow and scope of...
Scheme 14: Reaction scheme for the MoOx/TiO2 HPCat oxidation of cyclohexane (34) to benzene. The graph shows t...
Scheme 15: Proposed mechanism of the TiO2 HPC heteroarene C–H functionalisation via aryl radicals generated fr...
Scheme 16: Scheme of the oxidative coupling of benzylamines with the HOTT-HATN HPCat and selected examples of ...
Scheme 17: Photocatalysis oxidation of benzyl alcohol (40) to benzaldehyde (41) in a microflow reactor coated ...
Figure 17: Mechanisms of Dexter and Forster energy transfer.
Scheme 18: Continuous flow process for the isomerisation of alkenes with an ionic liquid-immobilised photocata...
Scheme 19: Singlet oxygen synthetic step in the total synthesis of canataxpropellane [265].
Scheme 20: Scheme and proposed mechanism of the singlet oxygen photosensitisation by CMP_X HPCats, with the st...
Scheme 21: Structures of CMP HPCat materials applied by Vilela and co-workers for the singlet oxygen photosens...
Scheme 22: Polyvinylchloride resin-supported TDCPP photosensitisers applied for singlet oxygen photosensitisat...
Scheme 23: Structure of the ionically immobilised TPP photosensitiser on amberlyst-15 ion exchange resins (TPP...
Scheme 24: Photosensitised singlet oxygen oxidation of citronellol (46) in scCO2, with automatic phase separat...
Scheme 25: Schematic of PS-Est-BDP-Cl2 being applied for singlet oxygen photosensitisation in flow. A) Pseudo-...
Scheme 26: Reaction scheme of the singlet oxygen oxidation of furoic acid (54) using a 3D-printed microfluidic...
Figure 18: A) Photocatalytic bactericidal mechanism by ROS oxidative cleavage of membrane lipids (R = H, amino...
Figure 19: A) Suggested mechanisms for the aqueous pollutant degradation by TiO2 in a slurry flow reactor [284-287]. B)...
Figure 20: Schematic of the flow system used for the degradation of aqueous oxytetracycline (56) solutions [215]. M...
Scheme 27: Degradation of a salicylic acid (57) solution by a coupled solar photoelectro-Fenton (SPEF) process...
Figure 21: A) Schematic flow diagram using the TiO2-coated NETmix microfluidic device for an efficient mass tr...
Synthesis and properties of quinazoline-based versatile exciplex-forming compounds
- Rasa Keruckiene,
- Simona Vekteryte,
- Ervinas Urbonas,
- Matas Guzauskas,
- Eigirdas Skuodis,
- Dmytro Volyniuk and
- Juozas V. Grazulevicius
Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101
- efficiency (EQE) of 19.2% [7]. Two blue emitters based on fluorene-bridged quinazoline and quinoxaline derivatives were used in the active layers of OLEDs with EQEs of 1.58% and 1.30%, suggesting that the self-aggregation of emitters had a considerable effect on the photoluminescent and electroluminescent
Graphical Abstract
Scheme 1: Synthesis of quinazoline derivatives 1–3. Conditions: i) ammonium acetate, copper(II) chloride, iso...
Figure 1: DSC (a, b, c) and TGA (d) curves of compounds 1–3. Scan rates were 20 °C/min (TGA) and 10 °C/min (D...
Figure 2: Frontier-orbital distributions and optimized geometries at the ground state of quinazoline-based co...
Figure 3: Cyclic voltammograms of quinazoline-based compounds 1–3.
Figure 4: UV–vis absorption spectra of compounds 1–3. a) Theoretical and b) experimental spectra of compounds ...
Figure 5: Fluorescence spectra (a) of dilute solutions and thin films of compounds 1–3 (λexc = 350 nm and PL ...
Figure 6: Electron and hole NTOs of compounds 1–3 in the S1 excited state (vacuum).
Figure 7: Chemical structures of exciplex-forming materials used, and visualization of white electroluminesce...
Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses
- Anne-Marie Caminade,
- Artem Zibarov,
- Eduardo Cueto Diaz,
- Aurélien Hameau,
- Maxime Klausen,
- Kathleen Moineau-Chane Ching,
- Jean-Pierre Majoral,
- Jean-Baptiste Verlhac,
- Olivier Mongin and
- Mireille Blanchard-Desce
Beilstein J. Org. Chem. 2019, 15, 2287–2303, doi:10.3762/bjoc.15.221
- dendrimers functionalized with TPA fluorophores used a blue-emitting quadrupolar fluorophore based on a fluorene core [37][38][39][40][41] and functionalized by a phenol on one side. The synthesis was carried out from generation 1 (12 fluorophores) to generation 4 (96 fluorophores) (Scheme 2). The
Graphical Abstract
Figure 1: Jablonski-type diagram displaying the classical one-photon excited fluorescence (left), and the les...
Figure 2: Two ways to represent schematized structures of dendrimers, showing the different generations (laye...
Scheme 1: Synthesis of phosphorhydrazone dendrimers, from the core to generation 2. Generation 1 dendrimers w...
Scheme 2: Full structure of the generation 1 dendrimer bearing 12 blue-emitting TPA fluorophores on the surfa...
Figure 3: Linear structure of the generation 2 dendrimer bearing 24 green-emitting TPA fluorophores on the su...
Scheme 3: Synthesis of the dioxaborine-functionalized dendrimer of generation 4.
Figure 4: Diverse structures of multistilbazole compounds, and graph of the σ2max/εmax response, depending on...
Figure 5: Nile Red derivatives: monomer (M) and two generations of dendrimers.
Scheme 4: Dumbbell-like dendrimers (third generation) having one TPA fluorophore at the core, and ammonium te...
Scheme 5: Another example of dumbbell-like dendrimers having one TPA fluorophore at the core, and P(S)Cl2 or ...
Scheme 6: The 12 steps needed to synthesize a sophisticated TPA fluorophore, to be used as branches of dendri...
Scheme 7: Synthesis of dendrimers having TPA fluorophores as branches and water-solubilizing functions on the...
Figure 6: Other types of dendrimers having TPA fluorophores as branches and water-solubilizing functions on t...
Figure 7: Generations 0, 1, and 2 of dumbbell-like dendrimers having one fluorophore at the core and either 1...
Figure 8: Double layer fluorescent dendrimer.
Figure 9: Dumbbell-like dendrimer used for two-photon imaging of the blood vessels of a living rat olfactory ...
Figure 10: Fluorescent gold complex having high antiproliferative activities against different tumor cell line...
Figure 11: A fluorescent water-soluble dendrimer, applicable for two-photon photodynamic therapy and imaging.
Figure 12: Schematization of the different types of TPA fluorescent phosphorus dendrimers and dendritic struct...
Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts
- Rodrigo Abonia,
- Luisa F. Gutiérrez,
- Braulio Insuasty,
- Jairo Quiroga,
- Kenneth K. Laali,
- Chunqing Zhao,
- Gabriela L. Borosky,
- Samantha M. Horwitz and
- Scott D. Bunge
Beilstein J. Org. Chem. 2019, 15, 642–654, doi:10.3762/bjoc.15.60
- aldehydes, chromone aldehydes, and fluorene aldehydes (Ar2CHO) and coumarins (Ar3) in 1:1:1 ratio to form the corresponding tris(heteroaryl)methanes (Ar1Ar2Ar3)CH along with (Ar1Ar1Ar2)CH triads. A series of new 2:1 triads were also synthesized by coupling substituted indoles with Ar2CHO. The coupling
- new structure. This concept has recently received attention by the pharmaceutical industry because it provides new options to develop more specific drugs for the treatment of persistent and challenging pathologies [27][28] (Scheme 1). The indole, coumarin, quinoline, chromone and fluorene moieties are
- ternary heteroarylmethane-inspired hybrids by coupling diversely substituted indoles (Ar1) with quinoline aldehydes, quinolone aldehydes, chromone aldehydes, and fluorene aldehydes (Ar2CHO) and coumarins (Ar3) in 1:1:1 ratio by simple reflux in ethanol solvent to form the corresponding highly crowded tris
Graphical Abstract
Scheme 1: Representative examples of tris(hetero/aryl)methanes, molecular hybrids and bis(indolyl)methanes wi...
Scheme 2: Previous synthetic approaches for the synthesis of triarylmethane analogues in comparison to the pr...
Scheme 3: Synthesis of the starting N-alkylindoles 1{4–10}.
Scheme 4: General procedure for the synthesis of the starting quinoline-/quinolone aldehydes 6{1–7}.
Scheme 5: Chemset of coumarins 7{1–4} for elaboration in the MCR experiments.
Scheme 6: Exploratory reaction leading to isolation of products 8{1,1,1} and 9{1,1,1}.
Figure 1: Pseudo-three-component synthesis of bisindole triads 8 employing quinoline-/quinolone-CHO 6{1–6}, c...
Scheme 7: Chemset of further aldehydes 6{8–10} for elaboration in the MCR experiments.
Figure 2: Three-component synthesis of tris(heteroaryl)methane triads 9. aThis product was obtained as an ins...
Figure 3: Thermal ellipsoid plot (40% probability level) of the tris(heteroaryl)methane triad 9{4,7,1}.
Figure 4: DFT-optimized structure of 9{4,7,1} triad.
Scheme 8: Synthesis of crowed (Het12Het2/Ar2)C+PF6− salts 10.
Figure 5: 1D- and 2D-based NMR assignments for methylium-PF6 salt 10{4,4,8}.
Figure 6: 1D- and 2D-based NMR assignments for methylium-PF6 salt 10{4,4,11}.
Figure 7: Optimized geometry of methylium-PF6 salts 10{4,4,8}.
Figure 8: Optimized geometry of methylium-PF6 salt 10{4,4,11}.
Selective benzylic C–H monooxygenation mediated by iodine oxides
- Kelsey B. LaMartina,
- Haley K. Kuck,
- Linda S. Oglesbee,
- Asma Al-Odaini and
- Nicholas C. Boaz
Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55
- , it shows incompatibility with functional groups such as alkenes, phenols, phenyl ethers, and alcohols, which are readily oxidized. The dibenzylic C–H bonds of fluorene and xanthene were also able to be functionalized. Xanthene (4a) was over-oxidized to the ketone (xanthone, 5a) in 57% yield (Figure 3
- ). Similarly, fluorene was oxidized to a mixture of 9-fluorenyl acetate (5b, 31%) and fluorenone (5c, 20%). The same mixture of acetate and ketone is observed at a higher temperature (150 °C), but the overall yield was lower. It is proposed that the stabilizing presence of two benzene rings on the monooxidized
Graphical Abstract
Figure 1: Catalyst optimization for the monooxidation of n-butylbenzene mediated by the iodate anion.
Figure 2: NHPI-catalyzed oxidation of secondary benzylic C–H bonds mediated by iodine(V). a100 °C for 18 h; b...
Figure 3: NHPI-catalyzed oxidation of di-benzylic C–H bonds mediated by iodate.
Figure 4: NHPI-catalyzed oxidation of substrates containing primary and tertiary benzylic C–H bonds. aReactio...
Figure 5: Competitive deuterium KIE for the oxidation of ethyl benzene by the NHPI-iodate system.
Figure 6: Pyrolysis of an acyl perester in the presence of molecular iodine.
Figure 7: Proposed mechanism for the selective monooxygenation of benzylic C–H bonds.
Olefin metathesis in multiblock copolymer synthesis
- Maria L. Gringolts,
- Yulia I. Denisova,
- Eugene Sh. Finkelshtein and
- Yaroslav V. Kudryavtsev
Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21
- ) polymerization. This approach was implemented for the preparation of fluorene-containing multiblock copolymers [62][63]. Poly(9,9-di-n-octylfluorene-2,7-vinylene, PFV) obtained by ADMET polymerization of 2,7-divinyl-9,9-di-n-octylfluorene in the presence of Gr2 under reduced pressure (Scheme 4), possessed
Graphical Abstract
Scheme 1: Multiblock copolymer synthesis by sequential ROMP, replotted from [51].
Figure 1: The most known commercially available catalysts for olefin metathesis.
Scheme 2: Multiblock copolymer synthesis by combining ROMP and NMP, replotted from [56].
Figure 2: A highly fluorescent multiblock copolymer for bioimaging and in vivo tumor targeting [60].
Scheme 3: Multiblock copolymer synthesis by combining ROMP and click reactions replotted from [61].
Scheme 4: Multiblock copolymer synthesis by combining ADMET and other reactions, replotted from [63,64].
Scheme 5: Synthesis of multiblock bottle-brush copolymers by ROMP, replotted from [68].
Scheme 6: Sacrificial synthesis of multiblock copolymers, replotted from [70].
Scheme 7: Synthesis of supramolecular multiblock copolymers, replotted from [74].
Figure 3: The multiblock copolymer capable of post-functionalization [76].
Figure 4: Multiblock copolymers synthesized by macromolecular cross metathesis.
Scheme 8: Macromolecular cross metathesis.
Figure 5: Changes in the DSC thermograms during MCM of PBD and polyesters (left) [84] and PNB–PCOE (right) mediat...
Figure 6: The 13C NMR spectrum recorded after 8 h of the reaction between PCOE, PNB, and Gr1; the homo- and h...
Scheme 9: Elementary reactions of MCM between PNB and PCOE, replotted from [90].
Figure 7: The 1H NMR spectrum recorded after 24 h of the reaction between PCOE, PNB, and Gr1 in CDCl3. The ca...
Scheme 10: Post-modification of multiblock copolymers by hydrogenation (A) [85] and epoxidation (B) [101] of C=C double...
Figure 8: Integral distribution functions for the lamella thickness of crystallites in thermally fractionated...
Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps
- Sambasivarao Kotha,
- Milind Meshram and
- Chandravathi Chakkapalli
Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223
- product 35 was subjected to SM coupling using phenylboronic acid (36) to afford the cross-coupling product 37 (97%, Scheme 5). In another instance, a simple synthetic approach to spiro-fluorene derivative 41 was described involving a serial usage of RCM and SM coupling [37]. To this end, bromofluorene 38
Graphical Abstract
Figure 1: Various catalysts used for metathesis reactions.
Scheme 1: SM coupling and RCM protocol to substituted indene derivative 10.
Scheme 2: Synthesis of polycycles via SM and RCM approach.
Figure 2: Various angucyclines.
Scheme 3: SM coupling and RCM protocol to the benz[a]anthracene skeleton 26.
Scheme 4: Synthesis of substituted spirocycles via RCM and SM sequence.
Scheme 5: Synthesis of highly functionalized bis-spirocyclic derivative 37.
Scheme 6: Synthesis of spirofluorene derivatives via RCM and SM coupling sequence.
Scheme 7: Synthesis of truxene derivatives via RCM and SM coupling.
Scheme 8: Synthesis of substituted isoquinoline derivative via SM and RCM protocol.
Scheme 9: Synthesis to 8-aryl substituted coumarin 64 via RCM and SM sequence.
Scheme 10: Synthesis of cyclic sulfoximine 70 via SM and RCM as key steps.
Scheme 11: Synthesis of 1-benzazepine derivative 75 via SM and RCM as key steps.
Scheme 12: Synthesis of naphthoxepine derivative 79 via RCM followed by SM coupling.
Scheme 13: Sequential CM and SM coupling approach to Z-stilbene derivative 85.
Scheme 14: Synthesis of substituted trans-stilbene derivatives via SM coupling and RCM.
Scheme 15: Synthesis of biaryl derivatives via sequential EM, DA followed by SM coupling.
Scheme 16: Synthesis of the dibenzocyclooctadiene core of schisandrene.
Scheme 17: Synthesis of cyclophane 115 via SM coupling and RCM as key steps.
Scheme 18: Synthesis of cyclophane 120 and 122 via SM coupling and RCM as key steps.
Scheme 19: Synthesis of cyclophanes via SM and RCM.
Scheme 20: Synthesis of MK-6325 (141) via RCM and SM coupling.
An overview of recent advances in duplex DNA recognition by small molecules
- Sayantan Bhaduri,
- Nihar Ranjan and
- Dev P. Arya
Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93
Graphical Abstract
Figure 1: A figure showing the hydrogen bonding patterns observed in (a) duplex (b) triplex and (c) quadruple...
Figure 2: (a) Portions of MATα1–MATα2 are shown contacting the minor groove of the DNA substrate. Key arginin...
Figure 3: Chemical structures of naturally occurring and synthetic hybrid minor groove binders.
Figure 4: Synthetic structural analogs of distamycin A by replacing one or more pyrrole rings with other hete...
Figure 5: Pictorial representation of the binding model of pyrrole–imidazole (Py/Im) polyamides based on the ...
Figure 6: Chemical structures of synthetic “hairpin” pyrrole–imidazole (Py/Im) conjugates.
Figure 7: (a) Minor groove complex formation between DNA duplex and 8-ring cyclic Py/Im polyamide (conjugate ...
Figure 8: Telomere-targeting tandem hairpin Py/Im polyamides 23 and 24 capable of recognizing >10 base pairs; ...
Figure 9: Representative examples of recently developed DNA minor groove binders.
Figure 10: Chemical structures of bisbenzamidazoles Hoechst 33258 and 33342 and their synthetic structural ana...
Figure 11: Chemical structures of bisamidines such as diminazene, DAPI, pentamidine and their synthetic struct...
Figure 12: Representative examples of recently developed bisamidine derivatives.
Figure 13: Chemical structures of chromomycin, mithramycin and their synthetic structural analogs 91 and 92.
Figure 14: Chemical structures of well-known naturally occurring DNA binding intercalators.
Figure 15: Naturally occurring indolocarbazole rebeccamycin and its synthetic analogs.
Figure 16: Representative examples of naturally occurring and synthetic derivatives of DNA intercalating agent...
Figure 17: Several recent synthetic varieties of DNA intercalators.
Figure 18: Aminoglycoside (neomycin)–Hoechst 33258/intercalator conjugates.
Figure 19: Chemical structures of triazole linked neomycin dimers and neomycin–bisbenzimidazole conjugates.
Figure 20: Representative examples of naturally occurring and synthetic analogs of DNA binding alkylating agen...
Figure 21: Chemical structures of naturally occurring and synthetic analogs of pyrrolobenzodiazepines.
Fluorogenic PNA probes
- Tirayut Vilaivan
Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17
- oligonucleotides or analogues. One notable example is the use of a labeled PNA probe in combination with water-soluble cationic conjugated polyelectrolytes (CCP) for the FRET-based detection of DNA [114]. The CCP is typically an extended π-conjugated system, such as oligophenylene/fluorene with appending
- DNA. In addition to TO, other environment-sensitive labels, such as fluorene [168], pyrene [167][169][170], diaminocarbazole [171] and Nile red [172], have been successfully employed in the development of single-labeled fluorogenic aegPNA, γPNA and acpcPNA probes (Figure 18). Up to a 73-fold
Graphical Abstract
Figure 1: The design of classical DNA molecular beacons.
Figure 2: Structures of DNA and selected PNA systems.
Figure 3: Various binding modes of PNA to double stranded DNA including triplex formation, triplex invasion, ...
Figure 4: The design and working principle of the PNA beacons according to (A) Ortiz et al. [41] and (B) Armitage...
Figure 5: The design of "stemless" PNA beacons.
Figure 6: The applications of PNA openers to facilitate the binding of PNA beacons to double stranded DNA [40,47].
Figure 7: The working principle of snap-to-it probes that employed metal chelation to bring the dyes in close...
Figure 8: Examples of pre-formed dye-labeled PNA monomers and functionalizable PNA monomers.
Figure 9: Dual-labeled PNA beacons with end-stacking or intercalating quencher.
Figure 10: The working principle of hybrid PNA-peptide beacons for detection of (A) proteins [80] and (B) protease...
Figure 11: The working principle of binary probes.
Figure 12: The working principle of nucleic acid templated fluorogenic reactions leading to a (A) ligated prod...
Figure 13: Catalytic cycles in fluorogenic nucleic acid templated reactions [90].
Figure 14: The working principle of strand displacement probes.
Figure 15: (A) Examples of CPP successfully used with labeled PNA probes. (B) The use of single-labeled PNA pr...
Figure 16: The concept of PNA–GO platform for DNA/RNA sensing.
Figure 17: Single-labeled fluorogenic PNA probes.
Figure 18: Examples of environment sensitive fluorescent labels that have been incorporated into PNA probes as...
Figure 19: The mechanism of fluorescence change in TO dye.
Figure 20: Fluorescent nucleobases capable of hydrogen bonding that have been incorporated into PNA probes.
Figure 21: Comparison of the designs of the (A) light-up PNA probe and (B) FIT PNA probe.
Figure 22: The structures of TO and its analogues that have successfully been used in FIT PNA probes.
Figure 23: The working principle of dual-labeled FIT PNA probes [222,223].
Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications
- Vinila N. Viswanathan,
- Arun D. Rao,
- Upendra K. Pandey,
- Arul Varman Kesavan and
- Praveen C. Ramamurthy
Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87
- 10.3762/bjoc.13.87 Abstract A series of low band gap, planar conjugated polymers, P1 (PFDTBT), P2 (PFDTDFBT) and P3 (PFDTTBT), based on fluorene and benzothiadiazole, was synthesized. The effect of fluorine substitution and fused aromatic spacers on the optoelectronic and photovoltaic performance was
- studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1, exhibited a highest occupied molecular orbital (HOMO) energy level at −5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine
- endeavored to obtain a series of low band gap polymers, P1, P2, and P3, with matching HOMO–LUMO energy levels with the acceptor moiety, without sacrificing the planarity of the molecule. Benzothiadiazole and fluorene, which are commonly used moieties in D–A–D-type polymers, have been chosen as the acceptor
Graphical Abstract
Scheme 1: Synthetic route towards monomers M1, M2 and M3.
Scheme 2: Synthesis of polymers P1, P2, and P3.
Figure 1: Isodensity surface plots of frontier molecular orbitals and optimized molecular geometries of P1, P2...
Figure 2: Theoretical absorption spectra of the polymers P1–P3 calculated using TDDFT.
Figure 3: Electrochemical spectra of polymers P1–P3.
Figure 4: Normalized absorption spectra of the polymers in solution, film and annealed film (130 °C) forms.
Figure 5: Photoluminescence spectra of polymers P1–P3 and polymer:PC70BM blends.
Figure 6: Bulk heterojunction solar cells device architecture, illustrating favorable conditions for absorpti...
Figure 7: J–V Spectra in chlorobenzene (CB) for which the ratio of polymer:PC70BM was optimized as follows: P1...
Figure 8: External quantum efficiency spectra of optimized devices fabricated with polymers P1, P2 and P3 and...
Synthesis of 1-indanones with a broad range of biological activity
- Marika Turek,
- Dorota Szczęsna,
- Marek Koprowski and
- Piotr Bałczewski
Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48
Graphical Abstract
Figure 1: Biologically active 1-indanones and their structural analogues.
Figure 2: Number of papers about (a) 1-indanones, (b) synthesis of 1-indanones.
Scheme 1: Synthesis of 1-indanone (2) from hydrocinnamic acid (1).
Scheme 2: Synthesis of 1-indanone (2) from 3-(2-bromophenyl)propionic acid (3).
Scheme 3: Synthesis of 1-indanones 5 from 3-arylpropionic acids 4.
Scheme 4: Synthesis of kinamycin (9a) and methylkinamycin C (9b).
Scheme 5: Synthesis of trifluoromethyl-substituted arylpropionic acids 12, 1-indanones 13 and dihydrocoumarin...
Scheme 6: Synthesis of 1-indanones 16 from benzoic acids 15.
Scheme 7: Synthesis of 1-indanones 18 from arylpropionic and 3-arylacrylic acids 17.
Scheme 8: The NbCl5-induced one-step synthesis of 1-indanones 22.
Scheme 9: Synthesis of biologically active 1-indanone derivatives 26.
Scheme 10: Synthesis of enantiomerically pure indatraline ((−)-29).
Scheme 11: Synthesis of 1-indanone (2) from the acyl chloride 30.
Scheme 12: Synthesis of the mechanism-based inhibitors 33 of coelenterazine.
Scheme 13: Synthesis of the indane 2-imidazole derivative 37.
Scheme 14: Synthesis of fluorinated PAHs 41.
Scheme 15: Synthesis of 1-indanones 43 via transition metal complexes-catalyzed carbonylative cyclization of m...
Scheme 16: Synthesis of 6-methyl-1-indanone (46).
Scheme 17: Synthesis of 1-indanone (2) from ester 48.
Scheme 18: Synthesis of benzopyronaphthoquinone 51 from the spiro-1-indanone 50.
Scheme 19: Synthesis of the selective endothelin A receptor antagonist 55.
Scheme 20: Synthesis of 1-indanones 60 from methyl vinyl ketone (57).
Scheme 21: Synthesis of 1-indanones 64 from diethyl phthalate 61.
Scheme 22: Synthesis of 1-indanone derivatives 66 from various Meldrum’s acids 65.
Scheme 23: Synthesis of halo 1-indanones 69.
Scheme 24: Synthesis of substituted 1-indanones 71.
Scheme 25: Synthesis of spiro- and fused 1-indanones 73 and 74.
Scheme 26: Synthesis of spiro-1,3-indanodiones 77.
Scheme 27: Mechanistic pathway for the NHC-catalyzed Stetter–Aldol–Michael reaction.
Scheme 28: Synthesis of 2-benzylidene-1-indanone derivatives 88a–d.
Scheme 29: Synthesis of 1-indanone derivatives 90a–i.
Scheme 30: Synthesis of 1-indanones 96 from o-bromobenzaldehydes 93 and alkynes 94.
Scheme 31: Synthesis of 3-hydroxy-1-indanones 99.
Scheme 32: Photochemical preparation of 1-indanones 103 from ketones 100.
Scheme 33: Synthesis of chiral 3-aryl-1-indanones 107.
Scheme 34: Photochemical isomerization of 2-methylbenzil 108.
Scheme 35: Synthesis of 2-hydroxy-1-indanones 111a–c.
Scheme 36: Synthesis of 1-indanone derivatives 113 and 114 from η6-1,2-dioxobenzocyclobutene complex 112.
Scheme 37: Synthesis of nakiterpiosin (117).
Scheme 38: Synthesis of 2-alkyl-1-indanones 120.
Scheme 39: Synthesis of fluorine-containing 1-indanone derivatives 123.
Scheme 40: Synthesis of 2-benzylidene and 2-benzyl-1-indanones 126, 127 from the chalcone 124.
Scheme 41: Synthesis of 2-bromo-6-methoxy-3-phenyl-1-indanone (130).
Scheme 42: Synthesis of combretastatin A-4-like indanones 132a–s.
Figure 3: Chemical structures of investigated dienones 133 and synthesized cyclic products 134–137.
Figure 4: Chemical structures of 1-indanones and their heteroatom analogues 138–142.
Scheme 43: Synthesis of 2-phosphorylated and 2-non-phosphorylated 1-indanones 147 and 148 from β-ketophosphona...
Scheme 44: Photochemical synthesis of 1-indanone derivatives 150, 153a, 153b.
Scheme 45: Synthesis of polysubstituted-1-indanones 155, 157.
Scheme 46: Synthesis of 1-indanones 159a–g from α-arylpropargyl alcohols 158 using RhCl(PPh3)3 as a catalyst.
Scheme 47: Synthesis of optically active 1-indanones 162 via the asymmetric Rh-catalyzed isomerization of race...
Scheme 48: Mechanism of the Rh-catalyzed isomerization of α-arylpropargyl alcohols 161 to 1-indanones 162.
Figure 5: Chemical structure of abicoviromycin (168) and its new benzo derivative 169.
Scheme 49: Synthesis of racemic benzoabicoviromycin 172.
Scheme 50: Synthesis of [14C]indene 176.
Scheme 51: Synthesis of indanone derivatives 178–180.
Scheme 52: Synthesis of racemic pterosin A 186.
Scheme 53: Synthesis of trans-2,3-disubstituted 1-indanones 189.
Scheme 54: Synthesis of 3-aryl-1-indanone derivatives 192.
Scheme 55: Synthesis of 1-indanone derivatives 194 from 3-(2-iodoaryl)propanonitriles 193.
Scheme 56: Synthesis of 1-indanones 200–204 by cyclization of aromatic nitriles.
Scheme 57: Synthesis of 1,1’-spirobi[indan-3,3’-dione] derivative 208.
Scheme 58: Total synthesis of atipamezole analogues 211.
Scheme 59: Synthesis of 3-[4-(1-piperidinoethoxy)phenyl]spiro[indene-1,1’-indan]-5,5’-diol hydrochloride 216.
Scheme 60: Synthesis of 3-arylindan-1-ones 219.
Scheme 61: Synthesis of 2-hydroxy-1-indanones 222.
Scheme 62: Synthesis of the 1-indanone 224 from the THP/MOM protected chalcone epoxide 223.
Scheme 63: Synthesis of 1-indanones 227 from γ,δ-epoxy ketones 226.
Scheme 64: Synthesis of 2-hydroxy-2-methylindanone (230).
Scheme 65: Synthesis of 1-indanone derivatives 234 from cyclopropanol derivatives 233.
Scheme 66: Synthesis of substituted 1-indanone derivatives 237.
Scheme 67: Synthesis of 7-methyl substituted 1-indanone 241 from 1,3-pentadiene (238) and 2-cyclopentenone (239...
Scheme 68: Synthesis of disubstituted 1-indanone 246 from the siloxydiene 244 and 2-cyclopentenone 239.
Scheme 69: Synthesis of 5-hydroxy-1-indanone (250) via the Diels–Alder reaction of 1,3-diene 248 with sulfoxid...
Scheme 70: Synthesis of halogenated 1-indanones 253a and 253b.
Scheme 71: Synthesis of 1-indanones 257 and 258 from 2-bromocyclopentenones 254.
Scheme 72: Synthesis of 1-indanone 261 from 2-bromo-4-acetoxy-2-cyclopenten-1-one (260) and 1,2-dihydro-4-viny...
Scheme 73: Synthesis of 1-indanone 265 from 1,2-dihydro-7-methoxy-4-vinylnaphthalene (262) and bromo-substitut...
Scheme 74: Synthesis of 1-indanone 268 from dihydro-3-vinylphenanthrene 266 and 4-acetoxy-2-cyclopenten-1-one (...
Scheme 75: Synthesis of 1-indanone 271 from phenylselenyl-substituted cyclopentenone 268.
Scheme 76: Synthesis of 1-indanone 272 from the trienone 270.
Scheme 77: Synthesis of the 1-indanone 276 from the aldehyde 273.
Scheme 78: Synthesis of 1-indanones 278 and 279.
Scheme 79: Synthesis of 1-indanone 285 from octa-1,7-diyne (282) and cyclopentenone 239.
Scheme 80: Synthesis of benz[f]indan-1-one (287) from cyclopentenone 239 and o-bis(dibromomethyl)benzene (286)....
Scheme 81: Synthesis of 3-methyl-substituted benz[f]indan-1-one 291 from o-bis(dibromomethyl)benzene (286) and...
Scheme 82: Synthesis of benz[f]indan-1-one (295) from the anthracene epidioxide 292.
Scheme 83: Synthesis of 1-indanone 299 from homophthalic anhydride 298 and cyclopentynone 297.
Scheme 84: Synthesis of cyano-substituted 1-indanone derivative 301 from 2-cyanomethylbenzaldehyde (300) and c...
Scheme 85: Synthesis of 1-indanone derivatives 303–305 from ketene dithioacetals 302.
Scheme 86: Synthesis of 1-indanones 309–316.
Scheme 87: Mechanism of the hexadehydro-Diels–Alder (HDDA) reaction.
Scheme 88: Synthesis of 1-indenone 318 and 1-indanones 320 and 321 from tetraynes 317 and 319.
Scheme 89: Synthesis of 1-indanone 320 from the triyn 319.
Scheme 90: Synthesis 1-indanone 328 from 2-methylfuran 324.
Scheme 91: Synthesis of 1-indanones 330 and 331 from furans 329.
Scheme 92: Synthesis of 1-indanone 333 from the cycloadduct 332.
Scheme 93: Synthesis of (S)-3-arylindan-1-ones 335.
Scheme 94: Synthesis of (R)-2-acetoxy-1-indanone 338.
Figure 6: Chemical structures of obtained cyclopenta[α]phenanthrenes 339.
Scheme 95: Synthesis of the benzoindanone 343 from arylacetaldehyde 340 with 1-trimethylsilyloxycyclopentene (...
Cross-linked cyclodextrin-based material for treatment of metals and organic substances present in industrial discharge waters
- Élise Euvrard,
- Nadia Morin-Crini,
- Coline Druart,
- Justine Bugnet,
- Bernard Martel,
- Cesare Cosentino,
- Virginie Moutarlier and
- Grégorio Crini
Beilstein J. Org. Chem. 2016, 12, 1826–1838, doi:10.3762/bjoc.12.172
- PAHs: naphthalene (NAP), acenaphthene (ACE), acenaphthylene (ACY), fluorene (FLU), phenanthrene (PHE), anthracene (ANT), fluoranthene (FLT) and pyrene (PYR); eight heavy PAHs: benz[a]anthracene (BaANT), chrysene (CHY), benzo[b]fluoranthene (BbFLT), benzo[k]fluoranthene (BkFLT), benzo[a]pyrene (BaPYR
Graphical Abstract
Figure 1: Chemical structure of the non-activated polyBTCA-CD.
Figure 2: Determination of the PZC for the non-activated and activated polyBTCA-CD polymers (pHi: initial pH ...
Figure 3: XRD pattern of the two polymers: non-activated and activated polyBTCA-CD.
Figure 4: CPMAS and MAS spectra of polyBTCA-CD.
Figure 5: Adsorption capacity (%) of (a) the non-activated and (b) the activated (NaHCO3 treatment) polyBTCA-...
Figure 6: Adsorption kinetics for two solutions containing five metals at two concentrations (solution at 10 ...
Figure 7: Removal efficiency (%) after treatment with activated polyBTCA-CD (concentration = 2 g·L−1) for (a)...
Figure 8: Removal efficiency (%) of inorganic elements after treatment of five DWs by polyBTCA-CD (concentrat...
Amidofluorene-appended lower rim 1,3-diconjugate of calix[4]arene: synthesis, characterization and highly selective sensor for Cu2+
- Rahman Hosseinzadeh,
- Mohammad Nemati,
- Reza Zadmard and
- Maryam Mohadjerani
Beilstein J. Org. Chem. 2016, 12, 1749–1757, doi:10.3762/bjoc.12.163
- of 9.6 × 10−8 M. Keywords: calix[4]arene; chemosensor; copper ions; fluorene; fluorescence; Introduction Owing to the substantial role of fluorescent chemosensors in biological, environmental, and chemical processes, their design and synthesis, especially for detection of metal ions has attracted
- report here the design and synthesis of a new fluorene-appended 1,3-diconjugate of calix[4]arene (L), which possess distal amide groups on the lower rim of the conical framework to recognize Cu2+ with high sensitivity and specificity (Scheme 1). Results and Discussion Synthesis The synthesis of
- 1 afforded the 5,11,17,23-tetra-tert-butyl-25,27-di(hydroxycarbonylmethoxy)-26-28-dihydroxy calix[4]arene (2) in high yield. Coupling of this diacid 2 with 9H-fluoren-2-amine (4, obtained from nitration of fluorene and reduction of the resulting 2-nitrofluorene, (3)) in the presence of N,N
Graphical Abstract
Scheme 1: Fluorene appended 1,3-diconjugate of calix[4]arene.
Scheme 2: Synthesis route of fluorene-appended amido-linked 1,3-diconjugate of calix[4]arene L.
Figure 1: Absorption spectra of L (1.0 × 10−5 M) and its complexes with different metals (10 equiv) in MeCN.
Figure 2: Color changes of receptor L upon addition of 10 equiv of various metal ions as their perchlorate sa...
Figure 3: Influence of the addition of increasing amounts (0–100 equiv) of Cu2+ on the absorption spectra of L...
Figure 4: Fluorescence spectra of L (1.0 × 10−5 M) in MeCN upon addition of different metal ions (10 equiv) w...
Figure 5: (a) Fluorescence spectra (1.0 × 10−5 M) of L recorded upon the addition of copper ion (0–5 equiv) i...
Figure 6: Fluorescence intensity of L (1.0 × 10−5 M) upon the addition of 10 equiv Cu2+ in the presence of 10...
Figure 7: 1 H NMR (400 MHz, CD3CN) spectra of L upon addition of (a) 0.0 equiv, (b) 0.2 equiv, (c) 0.4 equiv,...
Scheme 3: A proposed binding mode between L and Cu2+.
Synthesis of ferrocenyl-substituted 1,3-dithiolanes via [3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl S-methanides
- Grzegorz Mlostoń,
- Róża Hamera-Fałdyga,
- Anthony Linden and
- Heinz Heimgartner
Beilstein J. Org. Chem. 2016, 12, 1421–1427, doi:10.3762/bjoc.12.136
- , [M + H]+), 571 (60, [M+]); anal. calcd for C29H24FeS2Se (571.44): C, 60.95; H, 4.23; S, 11.22; found: C, 61.04; H, 4.33; S, 11.01. 5-Ferrocenyl-5-phenylspiro[1,3-dithiolane-4,9’-[9H]fluorene] (5g): Yield: 206 mg (40%). Orange crystals; mp >185 °C (decomposition); IR (KBr) ν: 3057 (m), 2918 (m), 1636
Graphical Abstract
Scheme 1: Reactions of aromatic thiocarbonyl S-methanides 2a,b with ferrocenyl thioketones 1 (Table 1).
Figure 1: ORTEP Plot [16] of the molecular structures of the ferrocenyl-substituted 1,3-dithiolanes 5b and 5f (wi...
Scheme 2: Reactions of cycloaliphatic thiocarbonyl S-methanides with ferrocenyl hetaryl thioketones 1 (Table 1).
Scheme 3: Reaction of 3c with ferrocenyl methyl thioketone 1e.
Scheme 4: Mesomeric stabilization of the 1,5-diradical intermediate in the reaction of aromatic thiocarbonyl S...
