Search results
Search for "visible" in Full Text gives 652 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Molecular tweezer–peptide conjugates disrupt the protein–protein interaction between survivin and histone H3 essential in mitosis
- Catherine Gsell,
- Philipp Rebmann,
- Karina Opara,
- Christine Beuck,
- Peter Bayer,
- David Bier,
- Ingrid R. Vetter and
- Thomas Schrader
Beilstein J. Org. Chem. 2026, 22, 557–567, doi:10.3762/bjoc.22.41
- Ca2+ cation from the crystallization buffer, is visible next to the cavity (Figure S12 in Supporting Information File 1). From recent complexation experiments with lipids, it is known that even uncharged alkyl groups may occupy the tweezer cavity and gain binding energy through dispersive interactions
- . Importantly, the peptide moiety itself cannot be modified substantially without losing affinity as described in the literature [8][21]. In most survivin–H3 peptide crystal structures, residues 1–4 have visible electron density, and only in few cases the following glutamine/threonine could be located as well
Graphical Abstract
Figure 1: Mechanism of CPC recruitment to centromeres and kinetochores. A) Initially phosphomarks are placed ...
Figure 2: Ribbon model of crystal structure PDB ID 4A0J (https://doi.org/10.2210/pdb4A0J/pdb) [8] of survivin (o...
Scheme 1: A) Peptide tweezer conjugates 1 and 2a with triazoles linking the tweezer and H3 peptide at its C-t...
Figure 3: Survivin complexes with peptide tweezers: Fluorescence polarization measurements of wild type and m...
Figure 4: Crystal structure of the survivin dimer with complexed tweezer H3 conjugate 2a. To distinguish both...
Figure 5: Survivin–borealin–INCENP complex structures (PDB ID 2QFA) [5] with tweezer model, side and top views. ...
Figure 6: A) Lewis structure of the truncated tweezer peptide monophosphate 2b. B) Close-up of the binding mo...
Scheme 2: A) Lewis structures of the new slightly extended binding peptide 3b and the respective click conjug...
Get a better glimpse on sequential photoreactions of trisnorbornadienes with 19F NMR spectroscopy
- Julian Felix Maria Hebborn,
- Ben Eric Merten,
- Thomas Paululat and
- Heiko Ihmels
Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38
- /quadricyclane system 1f/2f0,3 has some favorable MOST properties, namely a high energy density and a long half-life of the trisquadricyclane. In addition, the cycloaddition reaction can be initiated under mild conditions with visible light (λex = 405 or 420 nm) in the presence of Ir(ppy)3 or flavine 4 as
Graphical Abstract
Scheme 1: Photochromic reaction of norbornadiene (1a) and quadricyclane (2a) and selected physicochemical pro...
Figure 1: Structures and MOST parameters of representative bis- and trisnorbornadienes 1b–d; t1/2 = half-life...
Scheme 2: Synthesis and photochromic reaction of trisnorbornadiene 1f to the trisquadricyclane 2f0,3 (numberi...
Figure 2: Photometric monitoring of the photoreaction of 1f in MeCN (c = 20 µM) at λex = 315 nm. Inset: plot ...
Figure 3: Left: 19F NMR-spectroscopic monitoring of the photocycloaddition reaction of 1f in the presence of ...
Scheme 3: Stepwise photoreaction of 1f to 2f0,3 (numbering of quadricyclanes 2fm,n: m = number of norbornadie...
Synthesis of a HDAC inhibitor–nanogold probe for cryo-EM visualization in class I HDAC co-repressor complexes
- Wiktoria A. Pytel,
- John W. R. Schwabe and
- James T. Hodgkinson
Beilstein J. Org. Chem. 2026, 22, 480–485, doi:10.3762/bjoc.22.35
- CoREST ternary complex structure [10]. The Au–(CI-994) probe was visible in some classes due to its distinct, brighter contrast. While various orientations of the complex were captured, the probe was absent in side-view classes. These views are especially important for visualizing the active sites of
Graphical Abstract
Figure 1: HDAC1–3 inhibitor CI-994; HDAC inhibitor–nanogold probe Au–(CI-994); structure of amine-functionali...
Scheme 1: Synthesis of CI-994 and the Au–(CI-994) conjugate. Conditions: a) Boc2O, NEt3, THF, 0 °C to rt, 19 ...
Figure 2: Left: Single point concentration HDAC assay. Concentration of Au–NH2 and Au–(CI-994) = 0.54 µM. Con...
Figure 3: Final round of 2D classification of the cross-linked CoREST complex in the presence of Au–(CI-994) ...
Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates
- Rajkumar Ravi and
- Selvakumar Karuthapandi
Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29
- and 8 have similar electronic structure and stability. The computed HOMO–LUMO gaps for the compounds are in good agreement with the experimentally measured HOMO–LUMO gaps measured using UV–visible spectroscopy. The UV–visible absorption spectra of compounds 7 and 8 were recorded in chloroform at a
Graphical Abstract
Figure 1: Representative structures of organoselenium compounds and naphthalimide derivatives are reported as...
Scheme 1: Reagents and conditions for the step-wise synthesis of diorganyl monoselenides 7 and 8: (a) N-(3-br...
Figure 2: a) ORTEP diagram of compound 7 with thermal ellipsoids drawn at the 50% probability, b) and c) show...
Figure 3: DFT optimised structure of compounds a) 7 and b) 8.
Figure 4: HOMO, LUMO, and the energy gap of the compounds: a) 7 and b) 8.
Figure 5: Mulliken atomic charge of the compounds: a) 7 and b) 8.
Figure 6: MEP analysis of the compounds: a) 7 and b) 8.
Figure 7: log concentration (µM) vs cell viability (%) of compounds of a) 7 and b) 8.
Figure 8: Significant difference of control vs concentration: a) compound 7, b) compound 8.
Figure 9: 2D and 3D binding interaction of active (1M17) EGFR tyrosine kinase and synthesised compounds: a) 7...
Figure 10: 2D and 3D binding interaction of inactive (4HJO) EGFR tyrosine kinase and synthesised compounds: a) ...
Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF
- Ruiyan Wang and
- Yunan Wu
Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16
- fluorescence band with its maximum emission at 530 nm, which corresponds to typical fluorescence behavior in this material under the given excitation conditions. Upon turning off the UV light source, the sample continues to emit light, displaying a persistent afterglow that remains visible (Figure 4e). The
- enhanced, and both intra- and intermolecular non-radiative pathways are suppressed. This enables the forbidden T1→S0 transition to manifest at room temperature, resulting in stable, visible phosphorescence. In contrast, in a disordered/amorphous environment without π–π stacking, the lack of rigid
Graphical Abstract
Figure 1: a) Single-crystal structure of 1, b) HOMO distribution calculated on the crystallographic geometry,...
Figure 2: Photophysical properties of 1 in solvents of varying polarity: a) UV–vis absorption spectra and b) ...
Figure 3: Fluorescence and phosphorescence spectra of 1 in THF (excitation wavelength: 365 nm).
Figure 4: a) Steady-state and delayed emission spectra of 1, b) room-temperature emission lifetimes monitored...
Figure 5: a) Phosphorescence spectra of 1 in the powder state at room temperature and at 77 K, and in dilute ...
Figure 6: a) The bimolecular packing arrangement in the crystal of 1 and intersystem crossing pathways of 1 i...
Figure 7: Photoluminescence lifetime of vacuum-deposited 1 films at different temperatures (excitation wavele...
Figure 8: a) TG curve of 1 and b) DSC curve of 1.
Figure 9: a) Electroluminescence spectrum of the device with 1 as the emissive layer, b) relationship between...
Scheme 1: Synthetic pathway to 1 via imide formation and Suzuki–Miyaura cross-coupling.
A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts
- Holly Helmers,
- Mark Horton,
- Julie Concepcion,
- Jeffrey Bjorklund and
- Nicholas C. Boaz
Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10
- . Plotting absorbance versus pH yields a pKa value of 11.9 ± 0.05 (Supporting Information File 1, Figure S17). Above a pH of 12.18, a peak at 448 nm grows while the peak at 749 nm decreases (Supporting Information File 1, Figure S18). The changes in the visible spectra of 9 above a pH of 12.18 no longer
Graphical Abstract
Scheme 1: A) Generalized synthetic scheme for several previous syntheses of 6,6’-dibromoindigo. B) The synthe...
Scheme 2: Synthetic scheme for the preparation of 6,6’-dibromoindigo from p-bromotoluene (5).
Scheme 3: Nitration of p-bromotoluene (5) yields a mixture of regioisomers 3 and 7.
Scheme 4: Benzylic bromination of 4-bromo-2-nitrotoluene (3).
Scheme 5: A) Treatment of 4-bromo-2-nitrobenzyl bromide (6) with DMSO did not yield the alkoxysulfonium ion i...
Scheme 6: Condensation of 4-bromo-2-nitrobenzaldehyde (4) to yield 6,6’-dibromoindigo (1).
Scheme 7: A) Disulfonation of 6,6’-dibromoindigo (1), to yield 6,6’-dibromo-5,5’-indigodisulfonic acid disodi...
Figure 1: A) UV–vis spectra of 6,6’-dibromo-5,5’,7-indigotrisulfonic acid trisodium salt (10) (10 μM) in aque...
Advances in Zr-mediated radical transformations and applications to total synthesis
- Hiroshige Ogawa and
- Hugh Nakamura
Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3
- a halogen‑atom transfer (XAT) mechanism, they initiated the development of monofluoroalkyl group functionalization. Upon visible-light irradiation in the presence of an Ir photocatalyst and dibutylzirconocene, α-fluorocarbonyl compounds 45 underwent XAT with low-valent zirconium species to generate
Graphical Abstract
Figure 1: Historical background of zirconium and its physical properties. Image depicted in the background of ...
Scheme 1: Zr-mediated radical cyclization.
Scheme 2: Ni/Zr-mediated one-pot ketone synthesis.
Scheme 3: Zirconocene-catalyzed alkylative dimerization of 2-methylene-1,3-dithiane.
Scheme 4: Zirconium complexes as a photoredox catalyst.
Scheme 5: Zr-catalyzed reductive ring opening of epoxides.
Scheme 6: Zr-catalyzed reductive ring opening of oxetanes. a10 mol % of Cp2Zr(OTf)2·THF was used. bPhCF3 was ...
Scheme 7: Zr-catalyzed halogen atom transfer of alkyl chlorides.
Scheme 8: Zr-catalyzed radical homo coupling of alkyl chlorides.
Scheme 9: Zr-catalyzed fluorine atom transfer.
Scheme 10: Zr-catalyzed C–O bond cleavage. aYield without the use of P(OEt)3.
Scheme 11: Application to the total synthesis of halichondrins.
Scheme 12: Zr-catalyzed C3 dimerization of 3-bromotryptophan derivatives. aCp2ZrCl2 was used.
Scheme 13: Mechanistic studies.
Scheme 14: Application to the total synthesis of cyctetryptomycins. A photo of compound 61b was taken by the a...
Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review
- Daniel S. Müller
Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1
Graphical Abstract
Figure 1: Representative alkenyl chloride motifs in natural products. References: Pinnaic acid [8], haterumalide ...
Figure 2: Representative alkenyl chloride motifs in pharmaceuticals and pesticides. References: clomifene [25], e...
Figure 3: Graphical overview of previously published reviews addressing the synthesis of alkenyl chlorides.
Figure 4: Classification of synthetic approaches to alkenyl chlorides.
Scheme 1: Early works by Friedel, Henry, and Favorsky.
Scheme 2: Product distribution obtained by H NMR integration of crude compound as observed by Kagan and co-wo...
Scheme 3: Side reactions observed for the reaction of 14 with PCl5.
Scheme 4: Only compounds 15 and 18 were observed in the presence of Hünig’s base.
Scheme 5: Efficient synthesis of dichloride 15 at low temperatures.
Scheme 6: Various syntheses of alkenyl chlorides on larger scale.
Scheme 7: Scope of the reaction of ketones with PCl5 in boiling cyclohexane.
Scheme 8: Side reactions occur when using excess amounts of PCl5.
Scheme 9: Formation of versatile β-chlorovinyl ketones.
Scheme 10: Mixture of PCl5 and PCl3 used for the synthesis of 49.
Scheme 11: Catechol–PCl3 reagents for the synthesis of alkenyl chlorides.
Scheme 12: (PhO)3P–halogen-based reagents for the synthesis of alkenyl halides.
Scheme 13: Preparation of alkenyl chlorides from alkenyl phosphates.
Scheme 14: Preparation of alkenyl chlorides by treatment of ketones with the Vilsmeier reagent.
Scheme 15: Preparation of electron-rich alkenyl chlorides by treatment of ketones with the Vilsmeier reagent.
Scheme 16: Cu-promoted synthesis of alkenyl chlorides from ketones and POCl3.
Figure 5: GC yield of 9 depending on time and reaction temperature.
Figure 6: Broken reaction flask after attempts to clean the polymerized residue.
Figure 7: GC yield of 9 depending on the amount of CuCl and time.
Scheme 17: Treatment of 4-chromanones with PCl3.
Scheme 18: Synthesis of alkenyl chlorides from the reaction of ketones with acyl chlorides.
Scheme 19: ZnCl2-promoted alkenyl chloride synthesis.
Scheme 20: Regeneration of acid chlorides by triphosgene.
Scheme 21: Alkenyl chlorides from ketones and triphosgene.
Scheme 22: Various substitution reactions.
Scheme 23: Vinylic Finkelstein reactions reported by Evano and co-workers.
Scheme 24: Challenge of selective monohydrochlorination of alkynes.
Scheme 25: Sterically encumbered internal alkynes furnish the hydrochlorination products in high yield.
Scheme 26: Recent work by Kropp with HCl absorbed on alumina.
Scheme 27: High selectivities for monhydrochlorination with nitromethane/acetic acid as solvent.
Figure 8: Functionalized alkynes which typically afford the monhydrochlorinated products.
Scheme 28: Related chorosulfonylation and chloroamination reactions.
Scheme 29: Reaction of organometallic reagents with chlorine electrophiles.
Scheme 30: Elimination reactions of dichlorides to furnish alkenyl chlorides.
Scheme 31: Elimination reactions of allyl chloride 182 to furnish alkenyl chloride 183.
Scheme 32: Detailed studies by Schlosser on the elimination of dichloro compounds.
Scheme 33: Stereoselective variation caused by change of solvent.
Scheme 34: Elimination of gem-dichloride 189 to afford alkene 190.
Scheme 35: Oxidation of enones to dichlorides and in situ elimination thereof.
Scheme 36: Oxidation of allylic alcohols to dichlorides and in situ elimination thereof.
Scheme 37: Chlorination of styrenes with SOCl2 and elimination thereof.
Scheme 38: Chlorination of styrenes with SOCl2 and elimination thereof.
Scheme 39: Fluorine–chlorine exchange followed by elimination.
Scheme 40: Intercepting cations with alkynes and trapping of the alkenyl cation intermediate with chloride.
Scheme 41: Investigations by Mayr and co-workers.
Scheme 42: In situ activation of benzyl alcohol 230 with BCl3.
Scheme 43: In situ activation of benzylic alcohols with TiCl4.
Scheme 44: In situ activation of benzylic alcohols with FeCl3.
Scheme 45: In situ activation of benzylic alcohols with FeCl3.
Scheme 46: In situ activation of aliphatic chlorides and alcohols with ZnCl2, InCl3, and FeCl3.
Scheme 47: In situ generation of benzylic cations and trapping thereof with alkynes.
Scheme 48: Intramolecular trapping reactions affording alkenyl halides.
Scheme 49: Intramolecular trapping reactions affording alkenyl chlorides.
Scheme 50: Intramolecular trapping reactions of oxonium and iminium ions affording alkenyl chlorides.
Scheme 51: Palladium and nickel-catalyzed coupling reactions to afford alkenyl chlorides.
Scheme 52: Rhodium-catalyzed couplings of 1,2-trans-dichloroethene with arylboronic esters.
Scheme 53: First report on monoselective coupling reactions for 1,1-dichloroalkenes.
Scheme 54: Negishi’s and Barluenga’s contributions.
Scheme 55: First mechanistic investigation by Johnson and co-workers.
Scheme 56: First successful cross-metathesis with choroalkene 260.
Scheme 57: Subsequent studies by Johnson.
Scheme 58: Hoveyda and Schrock’s work on stereoretentive cross-metathesis with molybdenum-based catalysts.
Scheme 59: Related work with (Z)-dichloroethene.
Scheme 60: Further ligand refinement and traceless protection of functional groups with HBpin.
Scheme 61: Alkenyl chloride synthesis by Wittig reaction.
Scheme 62: Alkenyl chloride synthesis by Julia olefination.
Scheme 63: Alkenyl chloride synthesis by reaction of ketones with Mg/TiCl4 mixture.
Scheme 64: Frequently used allylic substitution reactions which lead to alkenyl chlorides.
Scheme 65: Enantioselective allylic substitutions.
Scheme 66: Synthesis of alkenyl chlorides bearing an electron-withdrawing group.
Scheme 67: Synthesis of α-nitroalkenyl chlorides from aldehydes.
Scheme 68: Synthesis of alkenyl chlorides via elimination of an in situ generated geminal dihalide.
Scheme 69: Carbenoid approach reported by Pace.
Scheme 70: Carbenoid approach reported by Pace.
Scheme 71: Ring opening of cyclopropenes in the presence of MgCl2.
Scheme 72: Electrophilic chlorination of alkenyl MIDA boronates to Z- or E-alkenyl chlorides.
Scheme 73: Hydroalumination and hydroboration of alkynyl chlorides.
Scheme 74: Carbolithiation of chloroalkynes.
Scheme 75: Chlorination of enamine 420.
Scheme 76: Alkyne synthesis by elimination of alkenyl chlorides.
Scheme 77: Reductive lithiation of akenyl chlorides.
Scheme 78: Reactions of alkenyl chlorides with organolithium reagents.
Scheme 79: Reactions of alkenyl chlorides with organolithium reagents.
Scheme 80: Addition–elimination reaction of alkenyl chloride 9 with organolithium reagents.
Scheme 81: C–H insertions of lithiumcarbenoids.
Scheme 82: Pd-catalyzed coupling reactions with alkenyl chlorides as coupling partner.
Scheme 83: Ni-catalyzed coupling of alkenylcopper reagent with alkenyl chloride 183.
Scheme 84: Ni-catalyzed coupling of heterocycle 472 with alkenyl chloride 473.
Scheme 85: Synthesis of α-chloroketones by oxidation of alkenyl chlorides.
Scheme 86: Tetrahalogenoferrate(III)-promoted oxidation of alkenyl chlorides.
Scheme 87: Chlorine–deuterium exchange promoted by a palladium catalyst.
Scheme 88: Reaction of alkenyl chlorides with thiols in the presence of AIBN (azobisisobutyronitrile).
Scheme 89: Chloroalkene annulation.
Recent advancements in the synthesis of Veratrum alkaloids
- Morwenna Mögel,
- David Berger and
- Philipp Heretsch
Beilstein J. Org. Chem. 2025, 21, 2657–2693, doi:10.3762/bjoc.21.206
Graphical Abstract
Scheme 1: Representatives of steroid alkaloid classes. Marked in blue is the steroidal cholestane framework, ...
Scheme 2: Subclasses of Veratrum alkaloids: jervanine, veratramine and cevanine-type [8].
Scheme 3: Flow chart presentation of the synthesis of (−)-englerin A developed by the Christmann group [10].
Scheme 4: Structures and year of synthesis of the three types of Veratrum alkaloids reported in the literatur...
Scheme 5: Key step in the synthesis of cyclopamine (6) by the Giannis group [21].
Scheme 6: Overview of the semisynthesis of cyclopamine (6) reported by the Giannis group in 2009 [21].
Scheme 7: Key steps in the synthesis of cyclopamine (6) by the Baran group [23].
Scheme 8: Overview of the total synthesis of cyclopamine (6) by the Baran group in 2023 [23].
Scheme 9: Key steps in the synthesis of cyclopamine (6) by the Zhu/Gao group [25].
Scheme 10: Overview of the total synthesis of cyclopamine (6) by the group of Zhao/Gao in 2023 [25].
Scheme 11: Key steps in the synthesis of cyclopamine (6) by the Liu/Qin group [26].
Scheme 12: Overview of the semisynthesis of cyclopamine (6) by the Liu/Qin group in 2024 [26].
Scheme 13: Key steps in the synthesis of jervine (12) by the Masamune group [14].
Scheme 14: Overview of the total synthesis of jervine (12) by the Masamune group in 1968 [14].
Scheme 15: Color-coded schemes of the presented cyclopamine (6) syntheses by Giannis, Baran, Zhu/Gao, and Liu/...
Scheme 16: Key steps in the total synthesis of veratramine (13) by the Johnson group [15].
Scheme 17: Overview of the total synthesis of veratramine (13) by the Johnson group in 1967 [15].
Scheme 18: Key steps in the synthesis of veratramine (13) by the Zhu/Gao group [25].
Scheme 19: Shortened overview of the total synthesis of veratramine (13) by the Zhu/Gao group in 2023 [25].
Scheme 20: Key steps in the synthesis of veratramine by the Liu/Qin group [26].
Scheme 21: Overview of the semisynthesis of veratramine (13) by the Liu/Qin group in 2024 [26].
Scheme 22: Key steps in the synthesis of veratramine (13) by the Trauner group [27].
Scheme 23: Overview of the total synthesis of veratramine (13) by the Trauner group in 2025 [27].
Scheme 24: Key steps in the synthesis of verarine (14) by the Kutney group [16-19].
Scheme 25: Overview of the total synthesis of verarine (14) by the Kutney group reported 1962–1968 [16-19].
Scheme 26: Color-coded schemes of the presented veratramine-type alkaloid synthesis of Zhu/Gao, Liu/Qin and Tr...
Scheme 27: Structures of veracevine (86), veratridine (87), and cevadine (88).
Scheme 28: Key step in the semisynthesis of verticine (15) by the Kutney group (1977) [20,46].
Scheme 29: Overview of the semisynthesis of verticine (15) by the Kutney group (1977) [20,46].
Scheme 30: Key step of the total synthesis of (±)-4-methylenegermine (17) by the Stork group (2017) [22].
Scheme 31: Overview of the total synthesis of (±)-4-methylenegermine (17) by the Stork group (2017) [22].
Scheme 32: Key step of the total synthesis of heilonine (16) by Cassaidy and Rawal (2021) [24].
Scheme 33: Overview of the total synthesis of heilonine (16) by Cassaidy and Rawal (2021) [24]. FGI: functional gr...
Scheme 34: Key steps of the synthesis of heilonine (16) by Dai and co-workers (2024) [28].
Scheme 35: Overview of the total synthesis of heilonine (16) by Dai and co-workers (2024) [28].
Scheme 36: Key steps of the total synthesis of zygadenine (18) reported by Luo and co-workers [29].
Scheme 37: Overview of the total synthesis of zygadenine (18) by Luo and co-workers (2023) [29].
Scheme 38: Key step of the divergent total syntheses of highly oxidized cevanine-type alkaloids by Luo and co-...
Scheme 39: Divergent syntheses of highly oxidized cevanine-type alkaloids by Luo and co-workers (2024) [30].
Scheme 40: Color-coded overview of the presented cevanine-type alkaloid syntheses [10,20,22,24,28-30,46]. LLS: longest linear sequen...
Silica gel with covalently attached bambusuril macrocycle for dicyanoaurate sorption from water
- Michaela Šusterová and
- Vladimír Šindelář
Beilstein J. Org. Chem. 2025, 21, 2604–2611, doi:10.3762/bjoc.21.201
- . Other bands corresponding to BU1 were also visible in the spectrum, confirming the presence of the macrocycle in both materials. The attachment of APTES and subsequently BU1 on SG was further confirmed by thermogravimetric analysis (TGA) (Figure 1A). Pure SG is highly thermally stable, undergoing only
Graphical Abstract
Scheme 1: Synthesis of SG-NHCO-BU1 and SG-BU1 materials based on covalently and non-covalently attached BU1 o...
Figure 1: A) Thermogravimetric analyses of BU1, SG, a-SG, and SG-NHCO-BU1. B) UV–vis titration of K[Au(CN)2] ...
Figure 2: The efficiency of materials (blue SG-BU1, grey SG-NHCO-BU1) in sorbing dicyanoaurate from its water...
Visible-light-driven NHC and organophotoredox dual catalysis for the synthesis of carbonyl compounds
- Vasudevan Dhayalan
Beilstein J. Org. Chem. 2025, 21, 2584–2603, doi:10.3762/bjoc.21.200
- Vasudevan Dhayalan Department of Chemistry, National Institute of Technology Puducherry, Karaikal-609609, Puducherry, India 10.3762/bjoc.21.200 Abstract Over the past two decades, organocatalyzed visible-light-mediated radical chemistry has significantly influenced modern synthetic organic
- ; NHC; organic photocatalyst; radicals; visible-light; Introduction Over the last ten years, NHC-catalyzed visible-light-promoted radical chemistry has been extensively developed for the cost-effective and practical synthesis of bioactive intermediates, pharmaceuticals, drugs, and natural products [1
- ]. The use of visible light as an energy source has significantly expanded the scope of organic molecule activation and its application in organic synthesis or medicinal chemistry [12], thereby driving the fast development of various photocatalytic transformations. Among these advances, dual catalysis
Graphical Abstract
Scheme 1: NHC-catalyzed umpolung strategy for the metal-free synthesis of amide via dual catalysis.
Scheme 2: Visible-light promoted cooperative NHC/photoredox catalyzed ring-opening of aryl cyclopropanes.
Scheme 3: NHC-catalyzed benzylic C–H acylation by dual catalysis.
Scheme 4: NHC/photoredox-catalyzed three-component coupling reaction for the preparation of γ-aryloxy ketones....
Scheme 5: NHC-catalyzed silyl radical generation from silylboronate via dual catalysis.
Scheme 6: NHC-catalyzed C–H acylation of arenes and heteroarenes through photocatalysis.
Scheme 7: NHC-catalyzed iminoacylation of alkenes via photoredox dual organocatalysis.
Scheme 8: NHC/photoredox catalyzed direct synthesis of β-arylketoesters.
Scheme 9: Visible-light-driven NHC/photoredox catalyzed borylacylation of alkenes.
Scheme 10: NHC-catalyzed oxidative functionalization of cinnamaldehyde.
Scheme 11: NHC/photocatalyzed oxidative Smiles rearrangement.
Scheme 12: NHC-catalyzed synthesis of cyclohexanones through photocatalyzed annulation.
Scheme 13: Dual organocatalyzed meta-selective acylation of electron-rich arenes and heteroarenes using blue L...
Scheme 14: Asymmetric synthesis of fused pyrrolidinones via organophotoredox/N‑heterocyclic carbene dual catal...
Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B
- Si-Chen Yao,
- Jing-Si Cao,
- Jian Xiao,
- Ya-Wen Wang and
- Yu Peng
Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197
- (2) and C (3), featuring a visible light-catalyzed radical cation cascade for the formation of the C8–C8′ and C2–C7′ bonds [6]. Subsequently, they improved the reaction conditions to achieve the racemic synthesis of aglacins A (1) and E (4) as well [7]. In 2021, the Gao group described the total
Graphical Abstract
Figure 1: The structures of aglacins A, B, C, and E.
Scheme 1: Retrosynthetic analysis of (+)-aglacin B (2).
Scheme 2: Synthesis of cyclization precursor 5.
Scheme 3: Synthesis of (+)-aglacin B (2).
Pentacyclic aromatic heterocycles from Pd-catalyzed annulation of 1,5-diaryl-1,2,3-triazoles
- Kaylen D. Lathrum,
- Emily M. Hanneken,
- Katelyn R. Grzelak and
- James T. Fletcher
Beilstein J. Org. Chem. 2025, 21, 2524–2534, doi:10.3762/bjoc.21.194
- -shifting of UV–visible absorbance signals relative to their non-annulated counterparts. Structural rigidity of annulated systems compared to non-annulated counterparts was reflected by emission signals with increased intensity and decreased Stokes shifts. Five benzotriazolophenanthroline regioisomers
- the NMR timescale. These trends were observed similarly for the other analogs of this study (see Supporting Information File 1). Optoelectronic properties of each annulated product and its respective control compound were examined via UV–visible absorption and emission spectroscopy. Figure 6 shows the
- –42) or standard base-catalyzed [53] click conditions (43–48) with isolated yields shown. Exemplary comparison of 1H NMR aromatic signal shifts for annulated and non-annulated compounds (CDCl3 solvent). UV–visible absorbance spectra of annulated 13–18 (black lines) compared with their non-annulated
Graphical Abstract
Figure 1: Examples of polycyclic aromatic heterocycle structures: phenanthridine (left), 1,5-naphthyridine (c...
Figure 2: Overview of the synthetic scheme employed by this study.
Figure 3: Base-catalyzed [53] tandem deprotection/cycloaddition reaction conditions used to prepare 1,5-diaryl-1,...
Figure 4: Identity of 1,5-diaryl-1,2,3-triazole control compounds prepared from tandem deprotection/click con...
Figure 5: Exemplary comparison of 1H NMR aromatic signal shifts for annulated and non-annulated compounds (CD...
Figure 6: UV–visible absorbance spectra of annulated 13–18 (black lines) compared with their non-annulated co...
Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions
- Udyogi N. K. Conthagamage,
- Lilia Lopez,
- Zuliah A. Abdulsalam and
- Víctor García-López
Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192
- extend into the longer UV and near-visible range when conjugated to chromophores or electron-rich groups [22][23][24], which is not the case here. Despite the lack of significant absorption at 370–467 nm, dye release was clearly observed, but only in vesicles containing EYPC. Possible explanations
Graphical Abstract
Figure 1: a) Structural components of the rotaxanes (PEG, polyethylene glycol chain; BAA (benzylalkylammonium...
Figure 2: Photoisomerization of rotaxane 1.
Figure 3: Reversible photoswitching of rotaxane 1 in LUVs with varying lipid compositions. Left column: UV–vi...
Figure 4: Summary of sulforhodamine B release from LUVs of varying lipid compositions. a) Dye release after 7...
Figure 5: Percentage of sulforhodamine B released from EYPC/Chol 8:2 LUVs upon five irradiation cycles after ...
Figure 6: Percentage of sulforhodamine B released from LUVs containing rotaxane 1 upon five alternating light...
Figure 7: Evaluation of effect of axle 3 upon light exposure. a) Percentage of sulforhodamine B released from...
Figure 8: a) Illustration of rotaxane 4 in its preferred orientation within a lipid bilayer; percentage of su...
Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate
- Roman A. Irgashev
Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191
- visible region, and improved morphological stability [4][5][6]. Recent reports have shown that the development of alkyl-supported TT-based semiconductors has led to high-performance, air-stable OFETs [7], while integration of TT frameworks into donor–acceptor architectures has enabled the development of
Graphical Abstract
Scheme 1: The synthetic routes to 3-hydroxy-substituted TT derivatives.
Scheme 2: The present retrosynthetic plan for constructing TT molecules.
Scheme 3: An attempt to nucleophilically substitute the NO2 group in ester 1.
Scheme 4: The reaction of ester 1 with potassium thioacetate.
Scheme 5: A probable mechanism for the formation of compounds 2 and 3.
Scheme 6: The synthesis of 3-(alkylthio)thiophene-2,5-dicarboxylates 4–6, yields, and scope of products. *Fro...
Scheme 7: The synthesis of TT derivatives, yields, and scope of products. Conditions: i) LiH (5 equiv), DMF, ...
Conformational effects on iodide binding: a comparative study of flexible and rigid carbazole macrocyclic analogs
- Guang-Wei Zhang,
- Yong Zhang,
- Le Shi,
- Chuang Gao,
- Hong-Yu Li and
- Lei Xue
Beilstein J. Org. Chem. 2025, 21, 2369–2375, doi:10.3762/bjoc.21.181
- rotationally restricted, all its accessible conformations constitute a subset of PBG's conformations. The binding constants and conformational change mechanisms of the two analogs were quantitatively evaluated by proton nuclear magnetic resonance spectroscopy (1H NMR), ultraviolet–visible absorption
- . This experiment supports a 1:1 stoichiometric binding between the guest TBAI and the host PBG in CDCl3. Then, the binding affinity of the two receptors to iodine ions was further studied, and the changes of UV–visible absorption and fluorescence spectra of the two receptors to anions in CHCl3 were
Graphical Abstract
Scheme 1: Synthesis routes of PBG and WDG.
Figure 1: (a) partial 1H NMR spectrum of PBG in CDCl3 (400 MHz, CDCl3, 25 °C), (b) Partial 1H NMR spectrum of ...
Figure 2: (a) Partial 1H NMR spectra of PBG and TBAI at different equivalent concentrations in CDCl3 (400 MHz...
Figure 3: (a) UV–vis spectra of PBG (10 μM) in CHCl3 with TBAI concentration, (b) UV–vis spectra of WDG (10 μ...
Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications
- Jullyane Emi Matsushima,
- Khushbu,
- Zuliah Abdulsalam,
- Udyogi Navodya Kulathilaka Conthagamage and
- Víctor García-López
Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179
- reversible deformation upon irradiation with UV or visible light, which triggers the isomerization of the azobenzene moiety, leading to structural changes in the rotaxane linkers. Notably, the dry state of the material, when uniaxially stretched, shows an enhanced response compared to its hydrogel form
- content, compared to pure acetonitrile. Photocyclization of the dithienylethene with UV light quenches the fluorescence of the TPE due to Förster resonance energy transfer (FRET) between the TPE (donor) and the closed dithienylethene (acceptor). Irradiation with visible light triggers the cycloreversion
- of the C–O bond “opens” the molecule, generating the corresponding merocyanine (Figure 2). The reverse photocyclization can occur upon exposure to visible light. Remarkably, the two isomers differ in their chemical and physical properties such as polarity, molecular volume, dipole moment
Graphical Abstract
Figure 1: Schematic of common rotaxanes (left) and depiction of the macrocycle shuttling (right).
Figure 2: Structure of some common photoswitches integrated into rotaxanes.
Figure 3: Rotaxane with an acridane photoswitch on the axle modulates the translation of a CBQT4+ macrocycle ...
Figure 4: Hydrogel composed of [2]rotaxanes featuring a central azobenzene in the axle and a cyclodextrin mac...
Figure 5: Dendrimer composed of [2]rotaxane with an azobenzene photoswitch functioning as a macroscopic actua...
Figure 6: (a) Structure of the [2]rotaxane and (b) mechanism for K+ cations transport across lipid bilayers. Figure 6...
Figure 7: Dithienylethene-based [2]rotaxane used in writing patterning applications: (a) rotaxane with open d...
Figure 8: Dithienylethene-based [1]rotaxane shuttling motion triggered by pH changes (top). Dithienylethene p...
Figure 9: Depiction of a fumaramide-based [2]rotaxane photoswitching cycle and deposition on glass and mica s...
Figure 10: Hydrazone-based rotaxane controls helical pitch in a liquid crystal. Figure 10 was adapted from [73] (© 2024 S. ...
Figure 11: (a) Light- and pH-responsive Förster resonance energy transfer observed on a spiropyran-based [2]ro...
Figure 12: Photoresponsive bending of artificial muscle with [c2]daisy chain reported by Harada and collaborat...
Figure 13: Light-responsive shuttling motion of [2]rotaxane based on a stiff-stilbene photoswitch. Figure 13 was reprod...
Figure 14: Azobenzene-based rotaxane modulating lipid bilayers upon photoisomerization. Figure 14 was adapted from [23] (© ...
Figure 15: Depiction of fluorescence quenching processes upon external stimuli of a dithienylethene-based [2]r...
Figure 16: Diagrammatic illustration of rotaxane 1-H-SP depicting interconversions between the four isomeric s...
Figure 17: Representation of [2]rotaxane chloride binding modulated by photoisomerization of a stiff-stilbene. ...
Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes
- Suvenika Perera,
- Peter Y. Zavalij and
- Lyle Isaacs
Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176
- are reported in cm−1. Mass spectrometry was performed using a JEOL AccuTOF electrospray instrument (ESI). The dye uptake was quantified by UV–vis spectroscopy (Cary 100 Bio UV–visible spectrophotometer) at 25 °C. Incubation of hosts with dyes was performed using an Eppendorf ThermoMixer™ C in 1.5 mL
Graphical Abstract
Figure 1: Chemical structures of selected hosts used as the basis for sequestrants.
Scheme 1: a) Synthesis of triphenylene-derived aromatic walls W1 and W2, and b) structure of commercially ava...
Scheme 2: Synthesis of methylene-bridged glycoluril dimers G2W1–G2W4. Conditions: a) TFA: Ac2O, 95 °C, 3.5 h (...
Figure 2: Chemical structures of dyes used in this study.
Figure 3: 1H NMR spectra recorded (400 MHz, DMSO-d6, rt) for: a) G2W1, b) G2W2, c) G2W3, d) G2W4.
Figure 4: Plot of removal efficiency of dyes from water after incubating with equimolar amounts (7.2 μmol) of ...
Figure 5: Cross-eyed stereoview of: a) one molecule of G2W3 in the crystal, and b) the packing of G2W3 in the...
Figure 6: Cross-eyed stereoview of: a) a molecule of G2W1 in the crystal, b) the packing of G2W1 along the xz...
Figure 7: a) Plot of removal efficiency of methylene blue (240 μM, 1 mL) from water after incubating with dif...
Figure 8: Plot of the removal efficiency versus methylene blue concentration (70, 90, 120, 180, 240, 300, 100...
Figure 9: a) Plot of removal efficiency of methylene blue (240 μM, 1 mL) from water as a function of time aft...
C2 to C6 biobased carbonyl platforms for fine chemistry
- Jingjing Jiang,
- Muhammad Noman Haider Tariq,
- Florence Popowycz,
- Yanlong Gu and
- Yves Queneau
Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165
- 15) [74][75][76]. Tang et al. recently reported the environmentally friendly production of glyceraldehyde and dihydroxyacetone from using glycerol through photocatalytic oxidation under visible light using a Cuδ+-decorated WO3 photocatalyst in the presence of hydrogen peroxide (H2O2) [77]. The
Graphical Abstract
Figure 1: C2–C6 biobased carbonyl building blocks.
Scheme 1: Proposed (2 + 2) route to glycolaldehyde and glycolic acid from erythritol by Cu/AC catalyst (AC = ...
Scheme 2: Reductive amination of GCA.
Scheme 3: N-Formylation of secondary amines by reaction with GCA.
Scheme 4: Synthesis and conversion of hydroxy acetals to cyclic acetals.
Scheme 5: Synthesis of 3-(indol-3-yl)-2,3-dihydrofurans via three-component reaction of glycolaldehyde, indol...
Scheme 6: BiCl3-catalyzed synthesis of benzo[a]carbazoles from 2-arylindoles and α-bromoacetaldehyde ethylene...
Scheme 7: Cu/NCNSs-based conversion of glycerol to glycolic acid and other short biobased acids.
Scheme 8: E. coli-based biotransformation of C1 source molecules (CH4, CO2 and CO) towards C2 glycolic acid.
Scheme 9: N-Formylation of amines with C2 (a) or C3 (b) biomass-based feedstocks.
Scheme 10: Methods for the formation of propanoic acid (PA) from lactic acid (LA).
Scheme 11: Co-polymerization of biobased lactic acid and glycolic acid via a bicatalytic process.
Scheme 12: Oxidation of α-hydroxy acids by tetrachloroaurate(III) in acetic acid–sodium acetate buffer medium.
Figure 2: Selective catalytic pathways for the conversion of lactic acid (LA).
Scheme 13: Synthesis of 1,3-PDO via cross-aldol reaction between formaldehyde and acetaldehyde to 3-hydroxypro...
Scheme 14: Hydrothermal conversion of 1,3-dihydroxy-2-propane and 2,3-dihydroxypropanal to methylglyoxal.
Scheme 15: FLS-catalyzed formose reaction to synthesize GA and DHA.
Scheme 16: GCA and DHA oxidation products of glycerol and isomerization of GCA to DHA under flow conditions us...
Scheme 17: Acid-catalyzed reactions of DHA with alcohols.
Scheme 18: Synthesis of dihydroxyacetone phosphate from dihydroxyacetone.
Scheme 19: Bifunctional acid–base catalyst DHA conversion into lactic acid via pyruvaldehyde or fructose forma...
Scheme 20: Catalytic one-pot synthesis of GA and co-synthesis of formamides and formates from DHA.
Scheme 21: (a) Synthesis of furan derivatives and (b) synthesis of thiophene derivative by cascade [3 + 2] ann...
Scheme 22: Brønsted acidic ionic liquid catalyzed synthesis of benzo[a]carbazole from renewable acetol and 2-p...
Scheme 23: Asymmetric hydrogenation of α-hydroxy ketones to 1,2-diols.
Scheme 24: Synthesis of novel 6-(substituted benzylidene)-2-methylthiazolo [2,3-b]oxazol-5(6H)-one from 1-hydr...
Scheme 25: ʟ-Proline-catalyzed synthesis of anti-diols from hydroxyacetone and aldehydes.
Scheme 26: C–C-bond-formation reactions of a biomass-based feedstock aromatic aldehyde (C5) and hydroxyacetone...
Scheme 27: Ethanol upgrading to C4 bulk chemicals via the thiamine (VB1)-catalyzed acetoin condensation.
Scheme 28: One-pot sequential chemoenzymatic synthesis of 2-aminobutane-1,4-diol and 1,2,4-butanetriol via 1,4...
Scheme 29: Synthesis of 1,4-dihydroxybutan-2-one by microbial transformation.
Scheme 30: Conversion of polyols by [neocuproine)Pd(OAc)]2(OTf)2] to α-hydroxy ketones.
Scheme 31: Chemoselective oxidation of alcohols with chiral palladium-based catalyst 2.
Scheme 32: Electrochemical transformation of furfural to 5-hydroxy-2(5H)-furanone (HFO).
Scheme 33: Selective hydrodeoxygenation of HFO and oxidation to γ-butyrolactone (GBL).
Scheme 34: Photosensitized oxygenation of furan towards HFO via ozonide intermediates.
Scheme 35: Conversion of furfural to HFO and MAN by using mesoporous carbon nitride (SGCN) as photocatalyst.
Scheme 36: Synthesis of HFO from furan derivatives.
Scheme 37: Photooxidation of furfural to 5-hydroxy-2(5H)-furanone (HFO).
Scheme 38: Synthesis of Friedel–Crafts indole adduct from HFO.
Scheme 39: Conversion of HFO to α,γ-substituted chiral γ-lactones.
Scheme 40: Tautomeric transformation of HFO to formylacrylic acid.
Scheme 41: Hydrolysis of HFO to succinic acid in aqueous solution.
Scheme 42: Substitution and condensation reactions of 5-hydroxy-2(5H)-furanone (HFO).
Scheme 43: (a) Conversion of HFO towards valuable C4 chemicals and (b) anodic oxidation of 5-hydroxy-2(5H)-fur...
Figure 3: Conversion of HFO towards other natural and synthetic substances.
Scheme 44: Conversion of furfural to maleic anhydride (reaction a: VOx/Al2O3; reaction b: VPO).
Scheme 45: Conversion of furfural into succinic acid.
Scheme 46: Electro‑, photo‑, and biocatalysis for one-pot selective conversions of furfural into C4 chemicals.
Scheme 47: Production route of furfural from hemicellulose.
Scheme 48: Mechanism for xylose dehydration to furfural through a choline xyloside intermediate.
Scheme 49: Conversion of furfural to furfuryl alcohol and its derivatives.
Scheme 50: Conversion of furfural to furfuryl alcohol and 3-(2-furyl)acrolein.
Scheme 51: The aerobic oxidative condensation of biomass-derived furfural and linear alcohols.
Scheme 52: The single-step synthesis of 2-pentanone from furfural.
Scheme 53: Electrocatalytic coupling reaction of furfural and levulinic acid.
Scheme 54: Conversion of furfural to m-xylylenediamine.
Scheme 55: Conversion of furfural to tetrahydrofuran-derived amines.
Scheme 56: Formation of trans-4,5-diamino-cyclopent-2-enones from furfural.
Scheme 57: Production of pyrrole and proline from furfural.
Scheme 58: Synthesis of 1‑(trifluoromethyl)-8-oxabicyclo[3.2.1]oct-3-en-2-ones from furfural.
Scheme 59: Conversion of furfural to furfural-derived diacids.
Scheme 60: A telescope protocol derived from furfural and glycerol.
Scheme 61: A tandem cyclization of furfural and 5,5-dimethyl-1,3-cyclohexanedione.
Scheme 62: A Ugi four-component reaction to construct furfural-based polyamides.
Scheme 63: One-pot synthesis of γ-acyloxy-Cy7 from furfural.
Scheme 64: Dimerization–Piancatelli sequence toward humins precursors from furfural.
Scheme 65: Conversion of furfural to CPN.
Scheme 66: Synthesis of jet fuels range cycloalkanes from CPN and lignin-derived vanillin.
Scheme 67: Solar-energy-driven synthesis of high-density biofuels from CPN.
Scheme 68: Reductive amination of CPN to cyclopentylamine.
Scheme 69: Asymmetric hydrogenation of C=O bonds of exocyclic α,β-unsaturated cyclopentanones.
Scheme 70: Preparation of levulinic acid via the C5 route (route a) or C6 route (routes b1 and b2).
Scheme 71: Mechanism of the rehydration of HMF to levulinic acid and formic acid.
Scheme 72: Important levulinic acid-derived chemicals.
Scheme 73: Direct conversion of levulinic acid to pentanoic acid.
Scheme 74: Catalytic aerobic oxidation of levulinic acid to citramalic acid.
Scheme 75: Conversion of levulinic acid to 1,4-pentanediol (a) see ref. [236]; b) see ref. [237]; c) see ref. [238]; d) see r...
Scheme 76: Selective production of 2-butanol through hydrogenolysis of levulinic acid.
Scheme 77: General reaction pathways proposed for the formation of 5MPs from levulinic acid.
Scheme 78: Selective reductive amination of levulinic acid to N-substituted pyrroles.
Scheme 79: Reductive amination of levulinic acid to chiral pyrrolidinone.
Scheme 80: Reductive amination of levulinic acid to non-natural chiral γ-amino acid.
Scheme 81: Nitrogen-containing chemicals derived from levulinic acid.
Scheme 82: Preparation of GVL from levulinic acid by dehydration and hydrogenation.
Scheme 83: Ruthenium-catalyzed levulinic acid to chiral γ-valerolactone.
Scheme 84: Catalytic asymmetric hydrogenation of levulinic acid to chiral GVL.
Scheme 85: Three steps synthesis of ε-caprolactam from GVL.
Scheme 86: Multistep synthesis of nylon 6,6 from GVL.
Scheme 87: Preparation of MeGVL by α-alkylation of GVL.
Scheme 88: Ring-opening polymerization of five-membered lactones.
Scheme 89: Synthesis of GVL-based ionic liquids.
Scheme 90: Preparation of butene isomers from GVL under Lewis acid conditions.
Scheme 91: Construction of C5–C12 fuels from GVL over nano-HZSM-5 catalysts.
Scheme 92: Preparation of alkyl valerate from GVL via ring opening/reduction/esterification sequence.
Scheme 93: Construction of 4-acyloxypentanoic acids from GVL.
Scheme 94: Synthesis of 1,4-pentanediol (PDO) from GVL.
Scheme 95: Construction of novel cyclic hemiketal platforms via self-Claisen condensation of GVL.
Scheme 96: Copper-catalyzed lactamization of GVL.
Figure 4: Main scaffolds obtained from HMF.
Scheme 97: Biginelli reactions towards HMF-containing dihydropyrimidinones.
Scheme 98: Hantzsch dihydropyridine synthesis involving HMF.
Scheme 99: The Kabachnik–Fields reaction involving HMF.
Scheme 100: Construction of oxazolidinone from HMF.
Scheme 101: Construction of rhodamine-furan hybrids from HMF.
Scheme 102: A Groebke–Blackburn–Bienaymé reaction involving HMF.
Scheme 103: HMF-containing benzodiazepines by [4 + 2 + 1] cycloadditions.
Scheme 104: Synthesis of fluorinated analogues of α-aryl ketones.
Scheme 105: Synthesis of HMF derived disubstituted γ-butyrolactone.
Scheme 106: Functionalized aromatics from furfural and HMF.
Scheme 107: Diels–Alder adducts from HMF or furfural with N-methylmaleimide.
Scheme 108: Pathway of the one-pot conversion of HMF into phthalic anhydride.
Scheme 109: Photocatalyzed preparation of humins (L-H) from HMF mixed with spoiled HMF residues (LMW-H) and fur...
Scheme 110: Asymmetric dipolar cycloadditions on HMF.
Scheme 111: Dipolar cycloadditions of HMF based nitrones to 3,4- and 3,5-substituted isoxazolidines.
Scheme 112: Production of δ-lactone-fused cyclopenten-2-ones from HMF.
Scheme 113: Aza-Piancatelli access to aza-spirocycles from HMF-derived intermediates.
Scheme 114: Cross-condensation of furfural, acetone and HMF into C13, C14 and C15 products.
Scheme 115: Base-catalyzed aldol condensation/dehydration sequences from HMF.
Scheme 116: Condensation of HMF and active methylene nitrile.
Scheme 117: MBH reactions involving HMF.
Scheme 118: Synthesis of HMF-derived ionic liquids.
Scheme 119: Reductive amination/enzymatic acylation sequence towards HMF-based surfactants.
Scheme 120: The formation of 5-chloromethylfurfural (CMF).
Scheme 121: Conversion of CMF to HMF, levulinic acid, and alkyl levulinates.
Scheme 122: Conversion of CMF to CMFCC and FDCC.
Scheme 123: Conversion of CMF to BHMF.
Scheme 124: Conversion of CMF to DMF.
Scheme 125: CMF chlorine atom substitutions toward HMF ethers and esters.
Scheme 126: Introduction of carbon nucleophiles in CMF.
Scheme 127: NHC-catalyzed remote enantioselective Mannich-type reactions of CMF.
Scheme 128: Conversion of CMF to promising biomass-derived dyes.
Scheme 129: Radical transformation of CMF with styrenes.
Scheme 130: Synthesis of natural herbicide δ-aminolevulinic acid from CMF.
Scheme 131: Four step synthesis of the drug ranitidine from CMF.
Scheme 132: Pd/CO2 cooperative catalysis for the production of HHD and HXD.
Scheme 133: Different ruthenium (Ru) catalysts for the ring-opening of 5-HMF to HHD.
Scheme 134: Proposed pathways for preparing HXD from HMF.
Scheme 135: MCP formation and uses.
Scheme 136: Cu(I)-catalyzed highly selective oxidation of HHD to 2,5-dioxohexanal.
Scheme 137: Synthesis of N‑substituted 3‑hydroxypyridinium salts from 2,5-dioxohexanal.
Scheme 138: Ru catalyzed hydrogenations of HHD to 1,2,5-hexanetriol (a) see ref. [396]; b) see ref. [397]).
Scheme 139: Aviation fuel range quadricyclanes produced by HXD.
Scheme 140: Synthesis of HDGK from HXD and glycerol as a chain extender.
Scheme 141: Synthesis of serinol pyrrole from HXD and serinol.
Scheme 142: Synthesis of pyrroles from HXD and nitroarenes.
Scheme 143: Two-step production of PX from cellulose via HXD.
Scheme 144: Preparation of HCPN from HMF via hydrogenation and ring rearrangement.
Scheme 145: Suggested pathways from HMF to HCPN.
Scheme 146: α-Alkylation of HCPN with ethylene gas.
Scheme 147: Synthesis of 3-(hydroxymethyl)cyclopentylamine from HMF via reductive amination of HCPN.
Scheme 148: Production of LGO and Cyrene® from biomass.
Scheme 149: Synthesis of HBO from LGO and other applications.
Scheme 150: Construction of m-Cyrene® homopolymer.
Scheme 151: Conversion of Cyrene® to THFDM and 1,6-hexanediol.
Scheme 152: RAFT co-polymerization of LGO and butadienes.
Scheme 153: Polycondensation of HO-LGOL and diols with dimethyl adipate.
Scheme 154: Self-condensation of Cyrene® and Claisen–Schmidt reactions.
Scheme 155: Synthesis of 5-amino-2-(hydroxymethyl)tetrahydropyran from Cyrene®.
Bioinspired total syntheses of natural products: a personal adventure
- Zhengyi Qin,
- Yuting Yang,
- Nuran Yan,
- Xinyu Liang,
- Zhiyu Zhang,
- Yaxuan Duan,
- Huilin Li and
- Xuegong She
Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160
- visible light. How to design a bioinspired approach may be most attractive to synthetic chemists. Recently, Tang [16] and Jia [17] independently reviewed their remarkable bioinspired total syntheses as accounts. Tang documented their longtime carrier of learning from nature aiming to achieve better
- invented. Moreover, bioinspired total synthesis involving visible light and enzymes are new significant trends in this field, and these techniques have demonstrated great power in achieving unprecedented selectivity and reactivity. Since nature still prevails in rapid generating molecular complexity and
Graphical Abstract
Figure 1: Representative natural products with biomimetic total synthesis.
Scheme 1: Bioinspired total synthesis of chabranol (2010).
Scheme 2: Proposed biosynthetic pathway of monocerin-family natural products.
Scheme 3: Bioinspired total synthesis of monocerin-family molecules (2013).
Scheme 4: Bioinspired skeletal diversification of (12-MeO-)tabertinggine (2016).
Scheme 5: Structures and our proposed biosynthetic pathway of gymnothelignans.
Scheme 6: Bioinspired total synthesis of gymnothelignans (2014–2025).
Scheme 7: Bioinspired total synthesis of sarglamides (2025).
Solar thermal fuels: azobenzene as a cyclic photon–heat transduction platform
- Jie Yan,
- Shaodong Sun,
- Minghao Wang and
- Si Wu
Beilstein J. Org. Chem. 2025, 21, 2036–2047, doi:10.3762/bjoc.21.159
- visible light under sunlight irradiation [59], achieving a solar efficiency of 0.4% and a solid-state isomerization efficiency of 72.7% (Figure 5b). Feng and co-workers reported the synthesis of three azopyridine polymers (ortho-, meta-, and para-) [60], with the m-azopyridine polymer exhibiting a
- azobenzene small molecules into polymer fibers [65], enabling solvent-free charging and discharging under visible light (Figure 6a). This material exhibited good capacity for releasing high-temperature heat (80–95 °C) at room temperature and in cold environments, along with an energy storage lifetime
- persist. First, a major limitation is that most azobenzene-based solar thermal fuels can only store UV or visible light, which represent a minor portion of the solar spectrum. In contrast, approximately 50% of the solar irradiance is in the form of near-infrared (NIR) radiation, highlighting the urgent
Graphical Abstract
Figure 1: Schematic diagram of molecular solar thermal energy storage system.
Figure 2: Photoisomerization of different types of molecular optical switches. Figure 2 was redrawn from [8].
Figure 3: Nanocarbon-based azobenzene polymer solar thermal fuels: (a) SWCNT templating. Figure 3a is from [43] (T. J. Kuc...
Figure 4: Conjugated azobenzene polymer solar thermal fuels: (a) Photoisomerization and thermally induced rev...
Figure 5: Linear azobenzene polymer solar thermal fuels: (a) Schematic illustration of the trans-to-cis isome...
Figure 6: Representative examples of azobenzene small-molecule derivative solar thermal fuels. (a) Polarized ...
Figure 7: (a) Deicing test of charged solar thermal fuels under green light irradiation (550 nm). Figure 7a was reprin...
Asymmetric total synthesis of tricyclic prostaglandin D2 metabolite methyl ester via oxidative radical cyclization
- Miao Xiao,
- Liuyang Pu,
- Qiaoli Shang,
- Lei Zhu and
- Jun Huang
Beilstein J. Org. Chem. 2025, 21, 1964–1972, doi:10.3762/bjoc.21.152
- , C11, and C12 contiguous stereogenic centers, provided important insights that influenced the design of our second-generation total synthesis. Compared with the Snider-type radical cyclization using stoichiometric amounts of metal oxidants, visible-light-induced photoredox-catalyzed radical cyclization
Graphical Abstract
Scheme 1: Representative prostaglandins and general synthetic strategy toward PGDM methyl ester 4.
Scheme 2: Retrosynthetic analysis for the first generation synthesis of PGDM methyl ester 4.
Scheme 3: Synthesis of bicyclic ketal 25.
Scheme 4: Retrosynthetic analysis for the second-generation synthesis of tricyclic PGDM methyl ester 4.
Scheme 5: Asymmetric total synthesis of tricyclic-PGDM methyl ester 4.
Photoswitches beyond azobenzene: a beginner’s guide
- Michela Marcon,
- Christoph Haag and
- Burkhard König
Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143
- Azoheteroarenes are azoswitches of which at least one aromatic ring is a heteroarene (Figure 3). The variety of heterocycles and substitution patterns that can be used gives rise to a considerable number of variants covering all the UV and visible spectrum and with thermal Z-isomer lifetimes that span from
- pocket in its (metastable) trans-isomer, inhibiting RNA translation (Scheme 16). In contrast, the azo-puromicin did not show significant change in activity between the two isomers [60]. Indigoids Indigoid photoswitches are characterised by switching in both directions with visible light (Figure 11). The
- already known as dye [89] have only been studied very recently. Exchanging the C=C bond for a C=N bond gives a new subclass of extremely short-lived T-type photoswitches with visible light activation, thermal half-lives in the µs range, and very large spectral separation. The study of iminothioindoxyl
Graphical Abstract
Figure 1: Energy diagram of a two-state photoswitch. Figure 1 was redrawn from [2].
Figure 2: Example of the absorption spectra of the isomers of a photoswitch with most efficient irradiation w...
Scheme 1: Photoswitch classes described in this review.
Figure 3: Azoheteroarenes.
Scheme 2: E–Z Isomerisation (top) and mechanisms of thermal Z–E isomerisation (bottom).
Scheme 3: Rotation mechanism favoured by the electron displacement in push–pull systems. Selected examples of...
Figure 4: A) T-shaped and twisted Z-isomers determine the thermal stability and the Z–E-PSS (selected example...
Figure 5: Effect of di-ortho-substitution on thermal half-life and PSS.
Figure 6: Selected thermal lifetimes of azoindoles in different solvents and concentrations. aConcentration o...
Figure 7: Aryliminopyrazoles: N-pyrazoles (top) and N-phenyl (bottom).
Scheme 4: Synthesis of symmetrical heteroarenes through oxidation (A), reduction (B), and the Bayer–Mills rea...
Scheme 5: Synthesis of diazonium salt (A); different strategies of azo-coupling: with a nucleophilic ring (B)...
Scheme 6: Synthesis of arylazothiazoles 25 (A) and heteroaryltriazoles 28 (B).
Scheme 7: Synthesis of heteroarylimines 31a,b [36-38].
Figure 8: Push–pull non-ionic azo dye developed by Velasco and co-workers [45].
Scheme 8: Azopyridine reported by Herges and co-workers [46].
Scheme 9: Photoinduced phase transitioning azobispyrazoles [47].
Figure 9: Diazocines.
Scheme 10: Isomers, conformers and enantiomers of diazocine.
Scheme 11: Partial overlap of the ππ* band with electron-donating substituents and effect on the PSS. Scheme 11 was ada...
Figure 10: Main properties of diazocines with different bridges. aMeasured in n-hexane [56]. bMeasured in THF. cMe...
Scheme 12: Synthesis of symmetric diazocines.
Scheme 13: Synthesis of asymmetric diazocines.
Scheme 14: Synthesis of O- and S-heterodiazocines.
Scheme 15: Synthesis of N-heterodiazocines.
Scheme 16: Puromycin diazocine photoswitch [60].
Figure 11: Indigoids.
Figure 12: The main representatives of the indigoid photoswitch class.
Scheme 17: Deactivation process that prevents Z-isomerisation of indigo.
Figure 13: Stable Z-indigo derivative synthesised by Wyman and Zenhäusern [67].
Figure 14: Selected examples of indigos with aliphatic and aromatic substituents [68]. Dashed box: proposed π–π in...
Scheme 18: Resonance structures of indigo and thioindigo involving the phenyl ring.
Scheme 19: Possible deactivation mechanism for 4,4'-dihydroxythioindigo [76].
Scheme 20: Effect of different heteroaryl rings on the stability and the photophysical properties of hemiindig...
Figure 15: Thermal half-lives of red-shifted hemithioindigos in toluene [79]. aMeasured in toluene-d8.
Scheme 21: Structures of pyrrole [81] and imidazole hemithioindigo [64].
Figure 16: Examples of fully substituted double bond hemithioindigo (left), oxidised hemithioindigos (centre),...
Scheme 22: Structure of iminothioindoxyl 72 (top) and acylated phenyliminoindolinone photoswitch 73 (bottom). ...
Scheme 23: (top) Transition states of iminothioindoxyl 72. The planar transition state is associated with a lo...
Scheme 24: Baeyer–Drewsen synthesis of indigo (top) and N-functionalisation strategies (bottom).
Scheme 25: Synthesis of hemiindigo.
Scheme 26: Synthesis of hemithioindigo and iminothioindoxyl.
Scheme 27: Synthesis of double-bond-substituted hemithioindigos.
Scheme 28: Synthesis of phenyliminoindolinone.
Scheme 29: Hemithioindigo molecular motor [85].
Figure 17: Arylhydrazones.
Scheme 30: Switching of arylhydrazones. Note: The definitions of stator and rotor are arbitrary.
Scheme 31: Photo- and acidochromism of pyridine-based phenylhydrazones.
Scheme 32: A) E–Z thermal inversion of a thermally stable push–pull hydrazone [109]. B) Rotation mechanism favoured...
Scheme 33: Effect of planarisation on the half-life.
Scheme 34: The longest thermally stable hydrazone switches reported so far (left). Modulation of thermal half-...
Figure 18: Dependency of t1/2 on concentration and hypothesised aggregation-induced isomerisation.
Figure 19: Structure–property relationship of acylhydrazones.
Scheme 35: Synthesis of arylhydrazones.
Scheme 36: Synthesis of acylhydrazones.
Scheme 37: Photoswitchable fluorophore by Aprahamian et al. [115].
Scheme 38: The four-state photoswitch synthesised by the Cigáň group [116].
Figure 20: Diarylethenes.
Scheme 39: Isomerisation and oxidation pathway of E-stilbene to phenanthrene.
Scheme 40: Strategies adapted to avoid E–Z isomerisation and oxidation.
Scheme 41: Molecular orbitals and mechanism of electrocyclisation for a 6π system.
Figure 21: Aromatic stabilisation energy correlated with the thermal stability of the diarylethenes [127,129].
Figure 22: Half-lives of diarylethenes with increasing electron-withdrawing groups [128,129].
Scheme 42: Photochemical degradation pathway promoted by electron-donating groups [130].
Figure 23: The diarylethenes studied by Hanazawa et al. [134]. Increased rigidity leads to bathochromic shift.
Scheme 43: The dithienylethene synthesised by Nakatani's group [135].
Scheme 44: Synthesis of perfluoroalkylated diarylethenes.
Scheme 45: Synthesis of 139 and 142 via McMurry coupling.
Scheme 46: Synthesis of symmetrical derivatives 145 via Suzuki–Miyaura coupling.
Scheme 47: Synthesis of acyclic 148, malonic anhydride 149, and maleimide derivatives 154.
Figure 24: Gramicidin S (top left) and two of the modified diarylethene derivatives: first generation (bottom ...
Scheme 48: Pyridoxal 5'-phosphate and its reaction with an amino acid (top). The analogous dithienylethene der...
Figure 25: Fulgides.
Scheme 49: The three isomers of fulgides.
Scheme 50: Thermal and photochemical side products of unsubstituted fulgide [150].
Figure 26: Maximum absorption λc of the closed isomer compared with the nature of the aromatic ring and the su...
Scheme 51: Possible rearrangement of the excited state of 5-dimethylaminoindolylfulgide [153].
Figure 27: Quantum yields of ring closure (ΦE→C) and E–Z isomerisation (ΦE→Z) correlated with the increasing s...
Scheme 52: Active (Eα) and inactive (Eβ) conformers (left) and the bicyclic sterically blocked fulgide 169 (ri...
Scheme 53: Quantum yield of ring-opening (ΦC→E) and E–Z isomerisation (ΦE→Z) for different substitution patter...
Scheme 54: Stobbe condensation pathway for the synthesis of fulgides 179, fulgimides 181 and fulgenates 178.
Scheme 55: Alternative synthesis of fulgides through Pd-catalysed carbonylation.
Scheme 56: Optimised synthesis of fulgimides [166].
Scheme 57: Photoswitchable FRET with a fulgimide photoswitch [167].
Scheme 58: Three-state fulgimide strategy by Slanina's group.
Figure 28: Spiropyrans.
Scheme 59: Photochemical (left) and thermal (right) ring-opening mechanisms for an exemplary spiropyran with a...
Figure 29: Eight possible isomers of the open merocyanine according to the E/Z configurations of the bonds hig...
Scheme 60: pH-Controlled photoisomerisation between the closed spiropyran 191-SP and the open E-merocyanine 19...
Scheme 61: Behaviour of spiropyran in water buffer according to Andréasson and co-workers [180]. 192-SP in an aqueo...
Scheme 62: (left box) Proposed mechanism of basic hydrolysis of MC [184]. (right box) Introduction of electron-dona...
Scheme 63: Photochemical interconversion of naphthopyran 194 (top) and spirooxazine 195 (bottom) photoswitches...
Scheme 64: Synthesis of spiropyrans and spirooxazines 198 and the dicondensation by-product 199.
Scheme 65: Alternative synthesis of spiropyrans and spirooxazines with indolenylium salt 200.
Scheme 66: Synthesis of 4’-substituted spiropyrans 203 by condensation of an acylated methylene indoline 201 w...
Scheme 67: Synthesis of spironaphthopyrans 210 by acid-catalysed condensation of naphthols and diarylpropargyl...
Scheme 68: Photoswitchable surface wettability [194].
Figure 30: Some guiding principles for the choice of the most suitable photoswitch. Note that this guide is ve...
Research progress on calixarene/pillararene-based controlled drug release systems
- Liu-Huan Yi,
- Jian Qin,
- Si-Ran Lu,
- Liu-Pan Yang,
- Li-Li Wang and
- Huan Yao
Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139
- employed as an external trigger for supramolecular systems. Azobenzene can regulate geometry, shape, and interfacial curvature under ultraviolet or visible light irradiation. It undergoes cis–trans isomerization, which can trigger alterations in bioactivity or assembly configurations. Methods for creating
Graphical Abstract
Figure 1: Schematic diagram of drug-controlled release mechanisms based on aromatic macrocycles.
Figure 2: Chemical structure of a) calix[n]arene (m = 1,3,5), and b) pillar[n]arene (m = 1,2,3).
Figure 3: Changes in pH conditions cause the release of drugs from CA8 host–guest complexes [101]. Figure 3 was adapted wi...
Figure 4: The illustration of the pH-mediated 1:1 complex formation between the host and guest molecules in a...
Figure 5: Illustration of the pH-responsive self-assembly of mannose-modified CA4 into micelles and the subse...
Figure 6: Illustration of the assembly of supramolecular prodrug nanoparticles from WP6 and DOX-derived prodr...
Figure 7: Illustration of the formation of supramolecular vesicles and their pH-dependent drug release [93]. Figure 7 was...
Figure 8: Schematic illustration of the application of the multifunctional nanoplatform CyCA@POPD in combined...
Figure 9: Illustration of the photolysis of an amphiphilic assembly via CA-induced aggregation [114]. Figure 9 was reprint...
Figure 10: Schematic illustration of drug release controlled by the photo-responsive macroscopic switch based ...
Figure 11: Schematic illustration of the formation process of Azo-SMX and its photoisomerization reaction unde...
Figure 12: Schematic illustration of the enzyme-responsive behavior of supramolecular polymers [95]. Figure 12 was used wit...
Figure 13: Schematic illustration of the amphiphilic assembly of SC4A and its enzyme-responsive applications [119]. ...
Figure 14: Stimuli-responsive nanovalves based on MSNs and choline-SC4A[2]pseudorotaxanes, MSN-C1 with ester-l...
Figure 15: A schematic diagram showing the construction of a supramolecular system by host–guest interaction b...
Figure 16: A schematic diagram showing the formation of the host–guest complex DOX@Biotin-SAC4A by biotin modi...
Figure 17: A schematic diagram showing the self-assembly of CA4 into a hypoxia-responsive peptide hydrogel, wh...
Figure 18: Schematic illustration of the formation process of Lip@GluAC4A and the release of Lip under hypoxic...
Figure 19: Schematic illustration of the construction of a supramolecular vesicle based on the host–guest comp...
Figure 20: Schematic illustration of WP6 self-assembly at pH > 7, and the stimulus-responsive drug release beh...
Figure 21: Schematic illustration of the formation of supramolecular vesicles based on the WP5⊃G super-amphiph...
Figure 22: Schematic illustrations of the host–guest recognition of QAP5⊃SXD, the formation of the nanoparticl...
Figure 23: Schematic illustration of the activation of T-SRNs by acid, alkali, or Zn2+ stimuli to regulate the...
Figure 24: Illustration of the triggered release of BH from CP[5]A@MSNs-Q NPs in response to a drop in pH or a...
Figure 25: Illustration of the supramolecular amphiphiles TPENCn@1 (n = 6 and 12) self-assembling with disulfi...
Photocatalysis and photochemistry in organic synthesis
- Timothy Noël and
- Bartholomäus Pieber
Beilstein J. Org. Chem. 2025, 21, 1645–1647, doi:10.3762/bjoc.21.128
- ; photochemistry; Soon after its first reported synthesis in 1936 [1], [Ru(bpy)3]Cl2 (bpy = 2,2'-bipyridine) and its derivatives attracted significant attention due to their photophysical properties [2][3][4]. These complexes can efficiently absorb visible light through a metal-to-ligand charge transfer (MLCT
- in the presence of electron donors and acceptors. Furthermore, [Ru(bpy)3]Cl2 can engage in Förster and Dexter energy transfer processes, enabling the transfer of excited-state energy to molecules that do not themselves absorb visible light. This versatility is arguably the reason for the tremendous
- impact of [Ru(bpy)3]Cl2 on several research areas, including solar energy conversion [5], optosensing [6], photodynamic therapy [7][8] and bioimaging [9]. Scattered examples of [Ru(bpy)3]Cl2 being used as a photocatalyst for visible-light-driven organic synthesis appeared in the scientific literature as
