From dipivaloylketene to tetraoxaadamantanes
- Gert Kollenz and
- Curt Wentrup
Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1
Graphical Abstract
Scheme 1: Synthetic routes to 2,4,6,8-tetraoxaadamantanes.
Scheme 2: Conversion of dipivaloylketene (2) to bisdioxines (2,6,9-trioxabicyclo[3.3.1]nona-3,7-dienes) 4 and...
Scheme 3: 2,6,9-Trioxabicyclo[3.3.1]nonadienes (bisdioxines, 9–13) derived from dipivaloylketene (2).
Scheme 4: Mechanisms of formation of bisdioxine acid derivatives from dimer 3.
Scheme 5: Recently reported synthesis of chromenobisdioxines.
Scheme 6: Formation of tetraoxaadamantanes.
Scheme 7: Decarboxylative hydrolysis and oxa-Michael-type ring closure.
Scheme 8: Oxime and hydrazine derivatives of bisdioxines and tetraoxaadamantanes.
Figure 1: Bistetraoxaadamantane derivatives.
Scheme 9: Inward-pointing isocyanate, urethane and carbamate groups in bisdioxines. The diisocyanate is obtai...
Scheme 10: Microwave-assisted tetraoxaadamantane formation.
Scheme 11: Cyclic bisdioxine ester derivative 34 forming a single mono-tetraoxaadamantane.
Figure 2: Cyclic bisdioxine derivative not forming a tetraoxaadamantane due to reduced cavity size.
Figure 3: The bisdioxine-calix[6]arene derivative 37 complexes Cs+ but does not form a tetraoxaadamantane der...
Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles
- Vivek Poonthiyil,
- Thisbe K. Lindhorst,
- Vladimir B. Golovko and
- Antony J. Fairbanks
Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2
Graphical Abstract
Figure 1: The three major methods for the synthesis of GAuNPs. (a) Direct reduction of an Au3+ salt in the pr...
Scheme 1: The non-catalysed azide–alkyne Huisgen cycloaddition (NCAAC) between an organic azide (1,3-dipole) ...
Scheme 2: Ligand exchange and NCAAC on an AuNP surface. Reagents and conditions: (a) Br(CH2)11SH in DCM, 60 h...
Scheme 3: Azide functionalization and NCAAC on an AuNP surface using electron deficient alkynes. Reagents and...
Scheme 4: NCAAC performed under hyperbaric conditions. Reagents and conditions: (a) Br(CH2)11SH in C6H6, 48 h...
Scheme 5: The synthesis of AuNPs functionalized with strained alkyne derivatives. HBTU = O-benzotriazole-N,N,N...
Scheme 6: A schematic representation of the SPAAC between azide-functionalized polymersomes and strained alky...
Scheme 7: Functionalization of AuNPs with an azide containing thiol ligand, and subsequent attachment to an a...
Scheme 8: Surface modification of AuNPs using microwave-assisted CuAAC. Reagents and conditions: (a) HS(CH2)11...
Scheme 9: AuNP functionalization and efficient CuAAC with a range of alkynes reported by Boisselier et al. [62]. ...
Scheme 10: Schematic illustration of: (a) AuNP deposition on a carbon electrode; (b) formation of alkyne-termi...
Scheme 11: (a) Synthesis of the alkyne-terminated thiol (ATT) ligand 33; (b) synthesis of 12 nm sized ATT-AuNP...
Scheme 12: Synthesis of (a) cyclooctyne-functionalized AuNPs and (b) GAuNPs using SPAAC [82].
Aminosugar-based immunomodulator lipid A: synthetic approaches
- Alla Zamyatina
Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3
Graphical Abstract
Figure 1: (A) Gram-negative bacterial membrane with LPS as major component of the outer membrane; (B) structu...
Figure 2: Structures of representative TLR4 ligands: TLR4 agonists (E. coli lipid A, N. meningitidis lipid A ...
Figure 3: (A) Co-crystal structure of the homodimeric E. coli Ra-LPS·hMD-2∙TLR4 complex (PDB code: 3FXI); (B)...
Figure 4: Co-crystal structures of (A) hybrid TLR4·hMD-2 with the bound antagonist eritoran (PDB: 2Z65, TLR4 ...
Scheme 1: Synthesis of E. coli and S. typhimurium lipid A and analogues with shorter acyl chains.
Scheme 2: Synthesis of N. meningitidis Kdo-lipid A.
Scheme 3: Synthesis of fluorescently labeled E. coli lipid A.
Scheme 4: Synthesis of H. pylori lipid A and Kdo-lipid A.
Scheme 5: Synthesis of tetraacylated lipid A corresponding to P. gingivalis LPS.
Scheme 6: Synthesis of pentaacylated P. gingivalis lipid A.
Scheme 7: Synthesis of monophosphoryl lipid A (MPLA) and analogues.
Scheme 8: Synthesis of tetraacylated Rhizobium lipid A containing aminogluconate moiety.
Scheme 9: Synthesis of pentaacylated Rhizobium lipid A and its analogue containing ether chain.
Scheme 10: Synthesis of pentaacylated Rhizobium lipid A containing 27-hydroxyoctacosanoate lipid chain.
Scheme 11: Synthesis of zwitterionic 1,1′-glycosyl phosphodiester: a partial structure of GalN-modified Franci...
Scheme 12: Synthesis of a binary 1,1′-glycosyl phosphodiester: a partial structure of β-L-Ara4N-modified Burkh...
Scheme 13: Synthesis of Burkholderia lipid A containing binary glycosyl phosphodiester linked β-L-Ara4N.
Photocatalytic formation of carbon–sulfur bonds
- Alexander Wimmer and
- Burkhard König
Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4
Graphical Abstract
Scheme 1: General overview over the sulfur-based substrates and reactive intermediates that are discussed in ...
Scheme 2: Photoredox-catalyzed radical thiol–ene reaction, applying [Ru(bpz)3](PF6)2 as photocatalyst.
Scheme 3: Photoredox-catalyzed thiol–ene reaction of aliphatic thiols with alkenes enabled by aniline derivat...
Scheme 4: Photoredox-catalyzed radical thiol–ene reaction for the postfunctionalization of polymers (a) and n...
Scheme 5: Photoredox-catalyzed thiol–ene reaction enabled by bromotrichloromethane as redox additive.
Scheme 6: Photoredox-catalyzed preparation of β-ketosulfoxides with Eosin Y as organic dye as photoredox cata...
Scheme 7: Greaney’s photocatalytic radical thiol–ene reaction, applying TiO2 nanoparticles as photocatalyst.
Scheme 8: Fadeyi’s photocatalytic radical thiol–ene reaction, applying Bi2O3 as photocatalyst.
Scheme 9: Ananikov’s photocatalytic radical thiol-yne reaction, applying Eosin Y as photocatalyst.
Scheme 10: Organocatalytic visible-light photoinitiated thiol–ene coupling, applying phenylglyoxylic acid as o...
Scheme 11: Xia’s photoredox-catalyzed synthesis of 2,3-disubstituted benzothiophenes, applying 9-mesityl-10-me...
Scheme 12: Wang’s metal-free photoredox-catalyzed radical thiol–ene reaction, applying 9-mesityl-10-methylacri...
Scheme 13: Visible-light benzophenone-catalyzed metal- and oxidant-free radical thiol–ene reaction.
Scheme 14: Visible-light catalyzed C-3 sulfenylation of indole derivatives using Rose Bengal as organic dye.
Scheme 15: Photocatalyzed radical thiol–ene reaction and subsequent aerobic sulfide-oxidation with Rose Bengal...
Scheme 16: Photoredox-catalyzed synthesis of diaryl sulfides.
Scheme 17: Photocatalytic cross-coupling of aryl thiols with aryl diazonium salts, using Eosin Y as photoredox...
Scheme 18: Photocatalyzed cross-coupling of aryl diazonium salts with cysteines in batch and in a microphotore...
Scheme 19: Fu’s [Ir]-catalyzed photoredox arylation of aryl thiols with aryl halides.
Scheme 20: Fu’s photoredox-catalyzed difluoromethylation of aryl thiols.
Scheme 21: C–S cross-coupling of thiols with aryl iodides via [Ir]-photoredox and [Ni]-dual-catalysis.
Scheme 22: C–S cross-coupling of thiols with aryl bromides, applying 3,7-bis-(biphenyl-4-yl)-10-(1-naphthyl)ph...
Scheme 23: Collin’s photochemical dual-catalytic cross-coupling of thiols with bromoalkynes.
Scheme 24: Visible-light-promoted C–S cross-coupling via intermolecular electron donor–acceptor complex format...
Scheme 25: Li’s visible-light photoredox-catalyzed thiocyanation of indole derivatives with Rose Bengal as pho...
Scheme 26: Hajra’s visible-light photoredox-catalyzed thiocyanation of imidazoheterocycles with Eosin Y as pho...
Scheme 27: Wang’s photoredox-catalyzed thiocyanation reaction of indoles, applying heterogeneous TiO2/MoS2 nan...
Scheme 28: Yadav’s photoredox-catalyzed α-C(sp3)–H thiocyanation reaction for tertiary amines, applying Eosin ...
Scheme 29: Yadav’s photoredox-catalyzed synthesis of 5-aryl-2-imino-1,3-oxathiolanes.
Scheme 30: Yadav’s photoredox-catalyzed synthesis of 1,3-oxathiolane-2-thiones.
Scheme 31: Li’s photoredox catalysis for the preparation of 2-substituted benzothiazoles, applying [Ru(bpy)3](...
Scheme 32: Lei’s external oxidant-free synthesis of 2-substituted benzothiazoles by merging photoredox and tra...
Scheme 33: Metal-free photocatalyzed synthesis of 2-aminobenzothiazoles, applying Eosin Y as photocatalyst.
Scheme 34: Metal-free photocatalyzed synthesis of 1,3,4-thiadiazoles, using Eosin Y as photocatalyst.
Scheme 35: Visible-light photoredox-catalyzed preparation of benzothiophenes with Eosin Y.
Scheme 36: Visible-light-induced KOH/DMSO superbase-promoted preparation of benzothiophenes.
Scheme 37: Jacobi von Wangelin’s photocatalytic approach for the synthesis of aryl sulfides, applying Eosin Y ...
Scheme 38: Visible-light photosensitized α-C(sp3)–H thiolation of aliphatic ethers.
Scheme 39: Visible-light photocatalyzed cross-coupling of alkyl and aryl thiosulfates with aryl diazonium salt...
Scheme 40: Visible-light photocatalyzed, controllable sulfenylation and sulfoxidation with organic thiosulfate...
Scheme 41: Rastogi’s photoredox-catalyzed methylsulfoxidation of aryl diazonium salts, using [Ru(bpy)3]Cl2 as ...
Scheme 42: a) Visible-light metal-free Eosin Y-catalyzed procedure for the preparation of vinyl sulfones from ...
Scheme 43: Visible-light photocatalyzed cross-coupling of sodium sulfinates with secondary enamides.
Scheme 44: Wang’s photocatalyzed oxidative cyclization of phenyl propiolates with sulfinic acids, applying Eos...
Scheme 45: Lei’s sacrificial oxidant-free synthesis of allyl sulfones by merging photoredox and transition met...
Scheme 46: Photocatalyzed Markovnikov-selective radical/radical cross-coupling of aryl sulfinic acids and term...
Scheme 47: Visible-light Eosin Y induced cross-coupling of aryl sulfinic acids and styrene derivatives, afford...
Scheme 48: Photoredox-catalyzed bicyclization of 1,7-enynes with sulfinic acids, applying Eosin Y as photocata...
Scheme 49: Visible-light-accelerated C–H-sulfinylation of arenes and heteroarenes.
Scheme 50: Visible-light photoredox-catalyzed β-selenosulfonylation of electron-rich olefins, applying [Ru(bpy)...
Scheme 51: Photocatalyzed preparation of β-chlorosulfones from the respective olefins and p-toluenesulfonyl ch...
Scheme 52: a) Photocatalyzed preparation of β-amidovinyl sulfones from sulfonyl chlorides. b) Preparation of β...
Scheme 53: Visible-light photocatalyzed sulfonylation of aliphatic tertiary amines, applying [Ru(bpy)3](PF6)2 ...
Scheme 54: Reiser’s visible-light photoredox-catalyzed preparation of β-hydroxysulfones from sulfonyl chloride...
Scheme 55: a) Sun’s visible-light-catalyzed approach for the preparation of isoquinolinonediones, applying [fac...
Scheme 56: Visible-light photocatalyzed sulfonylation/cyclization of vinyl azides, applying [Ru(bpy)3]Cl2 as p...
Scheme 57: Visible-light photocatalyzed procedure for the formation of β-ketosulfones from aryl sulfonyl chlor...
Scheme 58: Zheng’s method for the sulfenylation of indole derivatives, applying sulfonyl chlorides via visible...
Scheme 59: Cai’s visible-light induced synthesis of β-ketosulfones from sulfonyl hydrazines and alkynes.
Scheme 60: Photoredox-catalyzed approach for the preparation of vinyl sulfones from sulfonyl hydrazines and ci...
Scheme 61: Jacobi von Wangelin’s visible-light photocatalyzed chlorosulfonylation of anilines.
Scheme 62: Three-component photoredox-catalyzed synthesis of N-amino sulfonamides, applying PDI as organic dye....
Scheme 63: Visible-light induced preparation of complex sulfones from oximes, silyl enol ethers and SO2.
Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial
- Tamara Šmidlehner,
- Ivo Piantanida and
- Gennaro Pescitelli
Beilstein J. Org. Chem. 2018, 14, 84–105, doi:10.3762/bjoc.14.5
Graphical Abstract
Figure 1: Plane polarized light (PP, cyan) as the sum of the left and right circularly polarized light (L-CP,...
Figure 2: Schematic representation of ligand binding modes to DNA or RNA (left to right: DNA minor groove bin...
Scheme 1: Principal electronic transitions of nucleobases (uracil is similar to thymine, Thy). The arrows dep...
Figure 3: Exciton coupling mechanism in its degenerate (top) and non-degenerate version (bottom). a) Chiralit...
Figure 4: ECD and UV (inset) spectra of poly(dG-dC)–poly(dG-dC) in the B and Z-form, obtained in 59% and 67% ...
Figure 5: Schematic illustration of an ECD instrument. Legend: S, source; M, monochromator (wavelength select...
Figure 6: Exciton coupling in the G-quadruplex [d(TG4T)]4. For this sequence, the quadruplex is formed by fou...
Figure 7: Empirical analysis of ECD and flow LD spectra to establish the preferred orientation of a ligand bo...
Figure 8: CD titration of poly rA-poly rU (left) and poly rU (right) (c(polynucleotide) = 2.0 × 10−5 mol dm−3...
Figure 9: a) Schematic diagram of a flow LD instrument. b) Definition of the optical factor relating the dire...
Figure 10: LD spectrum of calf thymus (ct) DNA (c = 2 × 10−4 M), pH 7, sodium cacodylate buffer, I = 0.05 M.
Figure 11: Schematic illustration of an FDCD a) and a CPL b) instrument. Legend: S, source; M, monochromator (...
Figure 12: Minimal model to be considered to simulate the ICD spectrum of an intercalated ligand. ICD will be ...
Figure 13: Schematic representation of the main steps for calculating the ICD spectrum of a ligand bound to a ...
Stereochemical outcomes of C–F activation reactions of benzyl fluoride
- Neil S. Keddie,
- Pier Alexandre Champagne,
- Justine Desroches,
- Jean-François Paquin and
- David O'Hagan
Beilstein J. Org. Chem. 2018, 14, 106–113, doi:10.3762/bjoc.14.6
Graphical Abstract
Figure 1: C–F activation of benzylic fluorides to generate benzylamine or diarylmethane products.
Figure 2: 7-[2H1]-(R)-Benzyl fluoride ((R)-1).
Scheme 1: Synthesis of enantioenriched 7-[2H1]-(R)-benzyl fluoride ((R)-1) from benzaldehyde (2).
Figure 3: Partial 2H{1H} NMR (107.5 MHz) with PBLG in CHCl3 (13% w/w). (A) racemic sample of 6 (from Table 1, entry ...
Scheme 2: Synthesis of enantioenriched (S)-diarylmethane 10 from diaryl ketone 11 and confirmation of configu...
Figure 4: Possible reactive intermediates for C–F activation of benzyl fluoride 1 with strong hydrogen bond d...
Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications
- Mattias Bood,
- Sangamesh Sarangamath,
- Moa S. Wranne,
- Morten Grøtli and
- L. Marcus Wilhelmsson
Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7
Graphical Abstract
Figure 1: a) Angles and unit vectors used to define the relative orientations of the donor and acceptor trans...
Figure 2: Notable recent examples of fluorescent base analogues. For cnA and dnA the attachment point to the ...
Scheme 1: Synthesis of the tricyclic cytosine aromatic core [39]. (a) Ethylene glycol, K2CO3, 120 °C, 1 h, 40%; (...
Scheme 2: Synthesis of protected tC and tCO deoxyribose phosphonates [41]. (a) Ac2O, pyridine, rt; (b) 2-mesityle...
Scheme 3: Synthesis of protected tCnitro deoxyribose phosphoramidite [14]. a) aq NaOH, 24 h, reflux; b) EtOH, HCl...
Scheme 4: Improved synthesis of tC and tC derivatives, where R = H, 7-MeO or 8-MeO [47]. a) H2NNH2 followed by H2O...
Scheme 5: Improved synthesis of tCO derivatives [47]. a) Ac2O, pyridine, 16 h, rt, 85%; b) PPh3, CCl4, DCM, 5 h, ...
Scheme 6: Synthesis of protected tCO ribose phosphoramidite [50]. a) MesSO2Cl, DIPEA, MeCN, 4 h, rt; b) 2-aminoph...
Scheme 7: Synthesis of protected deoxyribose qA [51]. a) N-(tert-Butoxycarbonyl)-2-(trimethylstannyl)aniline, (Ph3...
Scheme 8: Synthesis of protected deoxyribose qA for DNA SPS [53]. a) AcCl, MeOH, rt, 40 min; b) p-toluoyl chlorid...
Scheme 9: Synthesis of qA derivatives. a) EtI, Cs2CO3, DMF, 4 h, rt, 90%; b) HBPin, Pd(PPh3)4, Et3N, 1,4-diox...
Scheme 10: Synthesis of quadracyclic adenine base–base FRET pair. a) HCHO, NaOH, MeCN, H2O, 50 °C, 1 h; b) TBD...
Figure 3: Absorption and emission of tC (dashed line) and tCO (solid line) in dsDNA. The absorption below 300...
Figure 4: Spectral overlap between the emission of qAN1 (cyan) and the absorption of qAnitro (black) in dsDNA...
Figure 5: Example of typical FRET efficiency as a function of number of base pairs separating the donor and a...
Figure 6: FRET efficiency as a function of number of base pairs separating the donor (qAN1) and acceptor (qAn...
Aminomethylation/hydrogenolysis as an alternative to direct methylation of metalated isoquinolines – a novel total synthesis of the alkaloid 7-hydroxy-6-methoxy-1-methylisoquinoline
- Benedikt C. Melzer,
- Jan G. Felber and
- Franz Bracher
Beilstein J. Org. Chem. 2018, 14, 130–134, doi:10.3762/bjoc.14.8
Graphical Abstract
Figure 1: Previously published total syntheses of alkaloid 1 [11,12].
Scheme 1: Total synthesis of alkaloid 1 via direct ring metalation and methylation.
Scheme 2: Total synthesis of alkaloid 1 via the aminomethyl intermediate 5 and selectivity’s found in debenzy...
Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)
- Tao Wang,
- Kathrin I. Mohr,
- Marc Stadler and
- Jeroen S. Dickschat
Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9
Graphical Abstract
Scheme 1: A selection of widespread fungal volatiles.
Figure 1: Total ion chromatogram of a representative headspace extract from Daldinia clavata MUCL 47436. Peak...
Scheme 2: Identified volatiles from Daldinia clavata MUCL 47436.
Figure 2: Mass spectra of volatiles from D. clavata that were identified by synthesis.
Scheme 3: Synthesis of manicone (10).
Scheme 4: Synthesis of a racemic mixture of all four diastereomers of 11.
Figure 3: Gas chromatographic analysis of 11 on a homochiral stationary phase. a) Synthetic mixture of all ei...
Scheme 5: Enantioselective synthesis of (4R,5S,6S)-11c and (4S,5R,6S)-11d.
Scheme 6: Epimerisations of (4R,5S,6S)-11c and (4S,5R,6S)-11d under basic conditions.
Figure 4: Gas chromatographic analysis of 11 on a homochiral stationary phase. a) Synthetic mixture of all ei...
Scheme 7: Proposed biosynthesis for (4R,5R,6S)-11a.
Figure 5: Mass spectra of a) 6-methyl-5,6-dihydro-2H-pyran-2-one (9), b) 6-propyl-5,6-dihydro-2H-pyran-2-one,...
Scheme 8: Synthesis of 6-methyl-5,6-dihydro-2H-pyran-2-one (9) and 6-nonyl-2H-pyran-2-one (17).
Gram-scale preparation of negative-type liquid crystals with a CF2CF2-carbocycle unit via an improved short-step synthetic protocol
- Tatsuya Kumon,
- Shohei Hashishita,
- Takumi Kida,
- Shigeyuki Yamada,
- Takashi Ishihara and
- Tsutomu Konno
Beilstein J. Org. Chem. 2018, 14, 148–154, doi:10.3762/bjoc.14.10
Graphical Abstract
Figure 1: Typical examples of previously reported negative-type liquid crystals containing a CF2CF2-carbocycl...
Scheme 1: Improved short-step synthetic protocol for multicyclic mesogens 1 and 2.
Scheme 2: Short-step approach to CF2CF2-containing carbocycles.
Figure 2: (a) Expected products of over-reaction in the Grignard reaction of dimethyl tetrafluorosuccinate (7...
Scheme 3: Mechanism for the reaction of γ-keto ester 6 with vinyl Grignard reagents.
Scheme 4: First multigram-scale preparation of CF2CF2-containing multicyclic mesogens.
Scheme 5: Stereochemical assignment of the ring-closing metathesis products.
Progress in copper-catalyzed trifluoromethylation
- Guan-bao Li,
- Chao Zhang,
- Chun Song and
- Yu-dao Ma
Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11
Graphical Abstract
Figure 1: Selected examples of pharmaceutical and agrochemical compounds containing the trifluoromethyl group....
Scheme 1: Introduction of a diamine into copper-catalyzed trifluoromethylation of aryl iodides.
Scheme 2: Addition of a Lewis acid into copper-catalyzed trifluoromethylation of aryl iodides and the propose...
Scheme 3: Trifluoromethylation of heteroaromatic compounds using S-(trifluoromethyl)diphenylsulfonium salts a...
Scheme 4: The preparation of a new trifluoromethylation reagent and its application in trifluoromethylation o...
Scheme 5: Trifluoromethylation of aryl iodides using CF3CO2Na as a trifluoromethyl source.
Scheme 6: Trifluoromethylation of aryl iodides using MTFA as a trifluoromethyl source.
Scheme 7: Trifluoromethylation of aryl iodides using CF3CO2K as a trifluoromethyl source.
Scheme 8: Trifluoromethylation of aryl iodides and heteroaryl bromides using [Cu(phen)(O2CCF3)] as a trifluor...
Scheme 9: Trifluoromethylation of aryl iodides with DFPB and the proposed mechanism.
Scheme 10: Trifluoromethylation of aryl iodides using TCDA as a trifluoromethyl source. Reaction conditions: [...
Scheme 11: The mechanism of trifluoromethylation using Cu(II)(O2CCF2SO2F)2 as a trifluoromethyl source.
Scheme 12: Trifluoromethylation of benzyl bromide reported by Shibata’s group.
Scheme 13: Trifluoromethylation of allylic halides and propargylic halides reported by the group of Nishibayas...
Scheme 14: Trifluoromethylation of propargylic halides reported by the group of Nishibayashi.
Scheme 15: Trifluoromethylation of alkyl halides reported by Nishibayashi’s group.
Scheme 16: Trifluoromethylation of pinacol esters reported by the group of Gooßen.
Scheme 17: Trifluoromethylation of primary and secondary alkylboronic acids reported by the group of Fu.
Scheme 18: Trifluoromethylation of boronic acid derivatives reported by the group of Liu.
Scheme 19: Trifluoromethylation of organotrifluoroborates reported by the group of Huang.
Scheme 20: Trifluoromethylation of aryl- and vinylboronic acids reported by the group of Shibata.
Scheme 21: Trifluoromethylation of arylboronic acids via the merger of photoredox and Cu catalysis.
Scheme 22: Trifluoromethylation of arylboronic acids reported by Sanford’s group. Isolated yield. aYields dete...
Scheme 23: Trifluoromethylation of arylboronic acids and vinylboronic acids reported by the group of Beller. Y...
Scheme 24: Copper-mediated Sandmeyer type trifluoromethylation using Umemoto’s reagent as a trifluoromethylati...
Scheme 25: Copper-mediated Sandmeyer type trifluoromethylation using TMSCF3 as a trifluoromethylation reagent ...
Scheme 26: One-pot Sandmeyer trifluoromethylation reported by the group of Gooßen.
Scheme 27: Copper-catalyzed trifluoromethylation of arenediazonium salts in aqueous media.
Scheme 28: Copper-mediated Sandmeyer trifluoromethylation using Langlois’ reagent as a trifluoromethyl source ...
Scheme 29: Trifluoromethylation of terminal alkenes reported by the group of Liu.
Scheme 30: Trifluoromethylation of terminal alkenes reported by the group of Wang.
Scheme 31: Trifluoromethylation of tetrahydroisoquinoline derivatives reported by Li and the proposed mechanis...
Scheme 32: Trifluoromethylation of phenol derivatives reported by the group of Hamashima.
Scheme 33: Trifluoromethylation of hydrazones reported by the group of Baudoin and the proposed mechanism.
Scheme 34: Trifluoromethylation of benzamides reported by the group of Tan.
Scheme 35: Trifluoromethylation of heteroarenes and electron-deficient arenes reported by the group of Qing an...
Scheme 36: Trifluoromethylation of N-aryl acrylamides using CF3SO2Na as a trifluoromethyl source.
Scheme 37: Trifluoromethylation of aryl(heteroaryl)enol acetates using CF3SO2Na as the source of CF3 and the p...
Scheme 38: Trifluoromethylation of imidazoheterocycles using CF3SO2Na as a trifluoromethyl source and the prop...
Scheme 39: Copper-mediated trifluoromethylation of terminal alkynes using TMSCF3 as a trifluoromethyl source a...
Scheme 40: Improved copper-mediated trifluoromethylation of terminal alkynes reported by the group of Qing.
Scheme 41: Copper-catalyzed trifluoromethylation of terminal alkynes reported by the group of Qing.
Scheme 42: Copper-catalyzed trifluoromethylation of terminal alkynes using Togni’s reagent and the proposed me...
Scheme 43: Copper-catalyzed trifluoromethylation of terminal alkynes using Umemoto’s reagent reported by the g...
Scheme 44: Copper-catalyzed trifluoromethylation of 3-arylprop-1-ynes reported by Xiao and Lin and the propose...
Nucleophilic fluoroalkylation/cyclization route to fluorinated phthalides
- Masanori Inaba,
- Tatsuya Sakai,
- Shun Shinada,
- Tsuyuka Sugiishi,
- Yuta Nishina,
- Norio Shibata and
- Hideki Amii
Beilstein J. Org. Chem. 2018, 14, 182–186, doi:10.3762/bjoc.14.12
Graphical Abstract
Scheme 1: Phthalide and fluorinated phthalides (1).
Scheme 2: Plausible reaction mechanism for the formation of phthalide 1a.
Scheme 3: Synthesis of fluorinated phthalides 1.
Scheme 4: Asymmetric synthesis of 1a using a chiral auxiliary.
Scheme 5: Catalytic asymmetric synthesis of 1a.
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
Graphical Abstract
Scheme 1: Overview of the synthesis of directly linked porphyrin–corrole hybrid compounds.
Scheme 2: Synthesis of β-meso directly linked porphyrin–corrole hybrid compounds.
Scheme 3: Synthesis of porphyrin–corrole hybrid derivatives. *100 mol % of AlCl3 was used as a catalyst.
Figure 1: 1H NMR spectrum of 4a in CDCl3.
Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)
- Michał Nowacki and
- Krzysztof Wojciechowski
Beilstein J. Org. Chem. 2018, 14, 194–202, doi:10.3762/bjoc.14.14
Graphical Abstract
Figure 1: Selected indolo[3,2-b]quinolines (quindolines) with biological activity.
Scheme 1: Selected starting materials for the construction of the quindoline system.
Scheme 2: Synthesis of condensed pyridines mediated by a σH-adduct.
Scheme 3: Formation of condensed isoxazole derivatives.
Scheme 4: Reaction of unprotected indole ester 1c with 4-chloronitrobenzene.
Scheme 5: A plausible mechanism for the formation of 11-(phenylsulfonyl)indolo[3,2-b]quinolines.
5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines
- Ranjana Aggarwal and
- Suresh Kumar
Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15
Graphical Abstract
Figure 1: Selected examples of drugs with fused pyrazole rings.
Figure 2: Typical structures of some fused pyrazoloazines from 5-aminopyrazoles.
Scheme 1: Regiospecific synthesis of 4 and 6-trifluoromethyl-1H-pyrazolo[3,4-b]pyridines.
Scheme 2: Synthesis of pyrazolo[3,4-b]pyridine-6-carboxylates.
Scheme 3: Synthesis of 1,4,6-triaryl-1H-pyrazolo[3,4-b]pyridines with ionic liquid .
Scheme 4: Synthesis of coumarin-based isomeric tetracyclic pyrazolo[3,4-b]pyridines.
Scheme 5: Synthesis of 6-substituted pyrazolo[3,4-b]pyridines under Heck conditions.
Scheme 6: Microwave-assisted palladium-catalyzed synthesis of pyrazolo[3,4-b]pyridines.
Scheme 7: Acid-catalyzed synthesis of pyrazolo[3,4-b]pyridines via enaminones.
Scheme 8: Synthesis of pyrazolo[3,4-b]pyridines via aza-Diels–Alder reaction.
Scheme 9: Synthesis of macrocyclane fused pyrazolo[3,4-b]pyridine derivatives.
Scheme 10: Three-component synthesis of 4,7-dihydro-1H-pyrazolo[3,4-b]pyridine derivatives.
Scheme 11: Ultrasonicated synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,6'(1'H)-diones.
Scheme 12: Synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine] derivatives under conventional heating co...
Scheme 13: Nanoparticle-catalyzed synthesis of pyrazolo[3,4-b]pyridine-spiroindolinones.
Scheme 14: Microwave-assisted multicomponent synthesis of spiropyrazolo[3,4-b]pyridines.
Scheme 15: Unexpected synthesis of naphthoic acid-substituted pyrazolo[3,4-b]pyridines.
Scheme 16: Multicomponent synthesis of variously substituted pyrazolo[3,4-b]pyridine derivatives.
Scheme 17: Three-component synthesis of 4,7-dihydropyrazolo[3,4-b]pyridines and pyrazolo[3,4-b]pyridines.
Scheme 18: Synthesis of pyrazolo[3,4-b]pyridine-5-spirocycloalkanediones.
Scheme 19: Ultrasound-mediated three-component synthesis of pyrazolo[3,4-b]pyridines.
Scheme 20: Multicomponent synthesis of 4-aryl-3-methyl-1-phenyl-4,6,8,9-tetrahydropyrazolo [3,4-b]thiopyrano[4...
Scheme 21: Synthesis of 2,3-dihydrochromeno[4,3-d]pyrazolo[3,4-b]pyridine-1,6-diones.
Scheme 22: FeCl3-catalyzed synthesis of o-hydroxyphenylpyrazolo[3,4-b]pyridine derivatives.
Scheme 23: Ionic liquid-mediated synthesis of pyrazolo[3,4-b]pyridines.
Scheme 24: Microwave-assisted synthesis of pyrazolo[3,4-b]pyridines.
Scheme 25: Multicomponent synthesis of pyrazolo[3,4-b]pyridine-5-carbonitriles.
Scheme 26: Unusual domino synthesis of 4,7-dihydropyrazolo[3,4-b]pyridine-5-nitriles.
Scheme 27: Synthesis of 4,5,6,7-tetrahydro-4H-pyrazolo[3,4-b]pyridines under conventional heating and ultrasou...
Scheme 28: L-Proline-catalyzed synthesis of of pyrazolo[3,4-b]pyridine.
Scheme 29: Microwave-assisted synthesis of 5-aminoarylpyrazolo[3,4-b]pyridines.
Scheme 30: Microwave-assisted multi-component synthesis of pyrazolo[3,4-e]indolizines.
Scheme 31: Synthesis of fluoropropynyl and fluoroalkyl substituted pyrazolo[1,5-a]pyrimidine.
Scheme 32: Acid-catalyzed synthesis of pyrazolo[1,5-a]pyrimidine derivatives.
Scheme 33: Chemoselective and regiospecific synthesis of 2-(3-methylpyrazol-1’-yl)-5-methylpyrazolo[1,5-a]pyri...
Scheme 34: Regioselective synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 35: Microwave-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidine carboxylates.
Scheme 36: Microwave and ultrasound-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 37: Base-catalyzed unprecedented synthesis of pyrazolo[1,5-a]pyrimidines via C–C bond cleavage.
Scheme 38: Synthesis of aminobenzothiazole/piperazine linked pyrazolo[1,5-a]pyrimidines.
Scheme 39: Synthesis of aminoalkylpyrazolo[1,5-a]pyrimidine-7-amines.
Scheme 40: Synthesis of pyrazolo[1,5-a]pyrimidines from condensation of 5-aminopyrazole 126 and ethyl acetoace...
Scheme 41: Synthesis of 7-aminopyrazolo[1,5-a]pyrimidines.
Scheme 42: Unexpected synthesis of 7-aminopyrazolo[1,5-a]pyrimidines under solvent free and solvent-mediated c...
Scheme 43: Synthesis of N-(4-aminophenyl)-7-aryloxypyrazolo[1,5-a]pyrimidin-5-amines.
Scheme 44: Base-catalyzed synthesis of 5,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 45: Synthesis of 6,7-dihydropyrazolo[1,5-a]pyrimidines in PEG-400.
Scheme 46: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine-3-carboxamides.
Scheme 47: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine derivatives under conventional heating and micro...
Scheme 48: Synthesis of N-aroylpyrazolo[1,5-a]pyrimidine-5-amines.
Scheme 49: Regioselective synthesis of ethyl pyrazolo[1,5-a]pyrimidine-7-carboxylate.
Scheme 50: Sodium methoxide-catalyzed synthesis of 3-cyano-6,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 51: Synthesis of various pyrazolo[3,4-d]pyrimidine derivatives.
Scheme 52: Synthesis of hydrazinopyrazolo[3,4-d]pyrimidine derivatives.
Scheme 53: Synthesis of N-arylidinepyrazolo[3,4-d]pyrimidin-5-amines.
Scheme 54: Synthesis of pyrazolo[3,4-d]pyrimidinyl-4-amines.
Scheme 55: Iodine-catalyzed synthesis of pyrazolo[3,4-d]pyrimidinones.
Scheme 56: Synthesis of ethyl 6-amino-2H-pyrazolo[3,4-d]pyrimidine-4-carboxylate.
Scheme 57: Synthesis of 4-substituted-(3,6-dihydropyran-4-yl)-1H-pyrazolo[3,4-d]pyrimidines.
Scheme 58: Synthesis of 1-(2,4-dichlorophenyl)pyrazolo[3,4-d]pyrimidin-4-yl carboxamides.
Scheme 59: Synthesis of 5-(1,3,4-thidiazol-2-yl)pyrazolo[3,4-d]pyrimidine.
Scheme 60: One pot POCl3-catalyzed synthesis of 1-arylpyrazolo[3,4-d]pyrimidin-4-ones.
Scheme 61: Synthesis of 4-amino-N1,C3-dialkylpyrazolo[3,4-d]pyrimidines under Suzuki conditions.
Scheme 62: Microwave-assisted synthesis of pyrazolo[3,4-b]pyrazines.
Scheme 63: Synthesis and derivatization of pyrazolo[3,4-b]pyrazine-5-carbonitriles.
Scheme 64: Synthesis of 2-thioxo-pyrazolo[1,5-a][1,3,5]triazin-4-ones.
Scheme 65: Synthesis of 2,3-dihydropyrazolo[1,5-a][1,3,5]triazin-4(1H)-one.
Scheme 66: Synthesis of pyrazolo[1,5-a][1,3,5]triazine-8-carboxylic acid ethyl ester.
Scheme 67: Microwave-assisted synthesis of 4,7-dihetarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 68: Alternative synthetic route to 4,7-diheteroarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 69: Synthesis of 4-aryl-2-ethylthio-7-methylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 70: Microwave-assisted synthesis of 4-aminopyrazolo[1,5-a][1,3,5]triazine.
Scheme 71: Synthesis of pyrazolo[3,4-d][1,2,3]triazines from pyrazol-5-yl diazonium salts.
Scheme 72: Synthesis of 2,5-dihydropyrazolo[3,4-e][1,2,4]triazines.
Scheme 73: Synthesis of pyrazolo[5,1-c][1,2,4]triazines via diazopyrazolylenaminones.
Scheme 74: Synthesis of pyrazolo[5,1-c][1,2,4]triazines in presence of sodium acetate.
Scheme 75: Synthesis of various 7-diazopyrazolo[5,1-c][1,2,4]triazine derivatives.
Scheme 76: One pot synthesis of pyrazolo[5,1-c][1,2,4]triazines.
Scheme 77: Synthesis of 4-amino-3,7,8-trinitropyrazolo-[5,1-c][1,2,4]triazines.
Scheme 78: Synthesis of tricyclic pyrazolo[5,1-c][1,2,4]triazines by azocoupling reaction.
One-pot sequential synthesis of tetrasubstituted thiophenes via sulfur ylide-like intermediates
- Jun Ki Kim,
- Hwan Jung Lim,
- Kyung Chae Jeong and
- Seong Jun Park
Beilstein J. Org. Chem. 2018, 14, 243–252, doi:10.3762/bjoc.14.16
Graphical Abstract
Figure 1: The selected examples of sulfur(IV) and sulfur(VI) ylides 1 [1], 2 [5-7], 3 [6,7,9], 4 [11,12], 5 [33,34], 6 [35-38].
Figure 2: Metal-free synthesis of thiophene-based heterocycles (A) [54,55], (B) [56].
Scheme 1: One-pot sequential synthesis of the trisubstituted 5-(pyridine-2-yl)thiophenes 8a. Substrate: amalo...
Figure 3: X-ray crystal structures of 8ad and 8an [68].
Figure 4: The proposed structure of sulfur ylide-like intermediates; resonance contributors (mesomeric struct...
Scheme 2: The substitution reaction with MeOH.
Fluorogenic PNA probes
- Tirayut Vilaivan
Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17
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].
Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)
- Thanh-Tuân Bui,
- Fabrice Goubard,
- Malika Ibrahim-Ouali,
- Didier Gigmes and
- Frédéric Dumur
Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18
Graphical Abstract
Figure 1: Radiative deactivation pathways existing in fluorescent, phosphorescent and TADF materials.
Figure 2: Boron-containing TADF emitters B1–B10.
Figure 3: Diphenylsulfone-based TADF emitters D1–D7.
Figure 4: Triazine-based TADF emitters T1–T3, T5–T7 and azasiline derivatives T3 and T4.
Figure 5: Triazine-based TADF emitters T8, T9, T11–T14 and carbazole derivative T10.
Figure 6: Triazine-based TADF emitters T15–T19.
Figure 7: Triazine- and pyrimidine-based TADF emitters T20–T26.
Figure 8: Pyrimidine-based TADF emitters T27–T30.
Figure 9: Triazine-based TADF polymers T31–T32.
Figure 10: Phenoxaphosphine oxide and phenoxathiin dioxide-based TADF emitters P1 and P2.
Figure 11: CN-Substituted pyridine and pyrimidine derivatives CN-P1–CN-P8.
Figure 12: CN-Substituted pyridine derivatives CN-P9 and CN-P10.
Figure 13: Phosphine oxide-based TADF blue emitters PO-1–PO-3.
Figure 14: Phosphine oxide-based TADF blue emitters PO-4–PO-9.
Figure 15: Benzonitrile-based emitters BN-1–BN-5.
Figure 16: Benzonitrile-based emitters BN-6–BN-11.
Figure 17: Benzoylpyridine-carbazole hybrid emitters BP-1–BP-6.
Figure 18: Benzoylpyridine-carbazole hybrid emitters BP-7–BP-10.
Figure 19: Triazole-based emitters Trz-1 and Trz-2.
Figure 20: Triarylamine-based emitters TPA-1–TPA-3.
Figure 21: Distribution of the CIE coordinates of ca. 90 blue TADF emitters listed in this review.
