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Search for "aqueous medium" in Full Text gives 113 result(s) in Beilstein Journal of Organic Chemistry.
Amino acid-based surfactants: sustainable synthesis and antimicrobial mechanisms
- Rafaela Gomes Bezerra,
- Lourdes Pérez and
- Francisco Fábio Oliveira de Sousa
Beilstein J. Org. Chem. 2026, 22, 1067–1085, doi:10.3762/bjoc.22.85
Graphical Abstract
Figure 1: General structure of a surfactant monomer. The monomer consists of a hydrophilic (polar) head and a...
Figure 2: Micellization process. Surfactant monomers progressively reduce surface tension until reaching the ...
Figure 3: Study selection flowchart based on PRISMA guidelines. The process includes identification, screenin...
Figure 4: Representative synthetic routes illustrating the main structural classes of amino acid-based surfac...
Synthesis of novel 1,2,4-oxadiazole-isoxazoline hybrids and their in silico potential with adenosine receptors
- Pshtiwan S. Mohammed,
- Mohammed K. S. Dalo,
- Onur C. Yazıcı,
- Muhammet Yildirim and
- Akın Sağırlı
Beilstein J. Org. Chem. 2026, 22, 1033–1047, doi:10.3762/bjoc.22.82
- cycloaddition products in reactions involving N,N-dimethylaminobenzaldoxime (2e) and p-hydroxybenzaldoxime (2d) can be ascribed to side reactions induced by excess sodium hypochlorite in the aqueous medium, leading to the formation of chlorinated amine salts or chlorophenol byproducts, respectively. These
Graphical Abstract
Figure 1: General structure of isoxazoline, 1,2,4-oxadiazole and biologically active 1,2,4-oxadizole, isoxazo...
Scheme 1: Recent studies for the synthesis of 1,2,4-oxadiazole-isoxazoline hybrids.
Figure 2: Various adenosine receptor (AR) antagonists, catechol-O-methyltransferase (COMT) and 1,2,4-oxadiazo...
Scheme 2: Synthesis of novel 1,2,4-oxadiazole-isoxazoline lead compounds by 1,3-DC.
Scheme 3: Synthetic methods for accessing the starting compounds (2a–k, 6a–j). Reagents and conditions: a) NH2...
Scheme 4: Mechanism for the formation of novel 3,5-disubstituted 1,2,4-oxadiazolyl diarylisoxazolines 7a–ay (...
Figure 3: 3D and 2D binding interactions of best scoring compounds (7x-(S), 7x-(R), 7j-(S), 7aw-(S), 7aw-(R),...
The role of spacer length and flexibility in peptide self-assembly
- Julian Link,
- Albin Lahu,
- Manfred Wagner,
- Tanja Weil and
- David Y. W. Ng
Beilstein J. Org. Chem. 2026, 22, 986–996, doi:10.3762/bjoc.22.77
- effects are noticeable. This observation is consistent with a largely monomeric state in aqueous medium with a small population of aggregates contributing to slower molecular tumbling and thus line broadening. In contrast, the peptide conjugates with longer spacer lengths show no observable NMR signals at
Graphical Abstract
Scheme 1: Synthetic scheme for the naphthalene–peptide conjugates C6-Nap-ICA 6, C3-Nap-ICA 7, and C0-Nap-ICA 8...
Figure 1: A) Bar plot representing the assembly conversion of C6-Nap-ICA 6, C3-Nap-ICA 7, and C0-Nap-ICA 8 (a...
Figure 2: A) Scheme depicting the self-assembly propensities of C6-Nap-ICA 6, C3-Nap-ICA 7, and C0-Nap-ICA 8 ...
Figure 3: A) Fluorescence emission and B) absorbance of C6-Nap-ICA 6, C3-Nap-ICA 7, and C0-Nap-ICA 8 (all 100...
Figure 4: 1H NMR spectroscopy data (700 MHz, 298 K, mixtures of TFE-d3 and D2O) of C0-Nap-ICA 8 (left), C3-Na...
Symmetrical D–π–A–π–D indanone dyes: a new design for nonlinear optics and cyanide detection
- Ergin Keleş,
- Alberto Barsella,
- Nurgül Seferoğlu,
- Zeynel Seferoğlu and
- Burcu Aydıner
Beilstein J. Org. Chem. 2026, 22, 131–142, doi:10.3762/bjoc.22.6
- proposed mechanism was investigated in more detail by DFT studies. It is given in the next section. In order to examine the sensitivity of the dyes to anions in aqueous media, firstly, the best ratio with DMSO as a co-solvent for aqueous medium was determined. For this purpose, absorption spectra were
Graphical Abstract
Figure 1: Design of the functional dyes.
Scheme 1: Synthetic pathway of compounds.
Figure 2: Normalized absorption spectra of dyes 2a (a), 2b (b), and 2c (c); Photographs of dyes in the given ...
Figure 3: Absorption spectra of dyes 2a (a), 2b (b), and 2c (c) upon addition of 20 equiv of anions in DMSO; ...
Figure 4: Absorption spectra of titrated dyes (2a–c) with up to 50 equiv of CN− (a) 6:4, (b) 7:3, and (c) 4:6...
Figure 5: Partial 1H NMR spectral change of 2b (c = 10 mM) after up to 2 equiv of TBACN (c = 1 M) in DMSO-d6.
Scheme 2: Proposed interaction mechanism with CN−.
Figure 6: Optimized geometries of 2a–c and 2a–c+CN− obtained at the B3LYP/6-31+G(d,p) level.
Figure 7: Frontier molecular orbitals of a) 2a, b) 2a+CN−.
Figure 8: TGA curves of dyes.
Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids
- Luan A. Martinho,
- Victor H. J. G. Praciano,
- Guilherme D. R. Matos,
- Claudia C. Gatto and
- Carlos Kleber Z. Andrade
Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203
- observed, however, with an increase in fluorescence emission. Interestingly, in DMSO, a bathochromic effect was observed alongside a significant increase in fluorescence intensity. In aqueous medium, a pronounced red shift was verified, likely due to stabilization of the excited state by water molecules
Graphical Abstract
Figure 1: Structure of thiazolidinone derivatives.
Figure 2: Selected examples of commercial drugs containing the thiazolidinone core.
Scheme 1: Multicomponent reaction of benzaldehyde, rhodanine, and piperidine in ethanol leading directly to a...
Scheme 2: Substrate scope of the EDA-catalyzed Knoevenagel condensation reactions using a range of aromatic/h...
Scheme 3: Limitations of the EDA-catalyzed Knoevenagel reactions for the synthesis of rhodanine or thiazolidi...
Scheme 4: Plausible reaction mechanism for the EDA-catalyzed Knoevenagel condensation reactions.
Scheme 5: Substrate scope of the HPW-catalyzed GBB reactions.
Scheme 6: Synthesis of imidazo[1,2-a]pyridine-thiazolidinone hybrids by EDA-catalyzed Knoevenagel condensatio...
Figure 3: Overlay of predicted (red) and experimental (black) NMR spectra for compound 3n: a) 1H NMR spectra ...
Figure 4: a) Molecular structure of 3n with crystallographic labeling (50% probability displacement). b) Pers...
Scheme 7: a) Tautomeric forms of thiazolidinones and b) resonance structures for compounds 3n and 4n.
Figure 5: Molecular energy as a function of the torsion angle obtained from a relaxed dihedral scan at the M0...
Figure 6: Identification of the carbon atoms used in the theoretical study of chemical shifts. In red, easily...
Figure 7: a) Visual impressions of the solvatochromic study in various solvents (10−5 M) after excitation wit...
Scheme 8: Proposed ICT-type mechanism for the fluorescence process, adapted from ref. [89].
Figure 8: Photophysical study in aqueous solution under different pH values for compound 3n (10−5 M) at room ...
Scheme 9: Two equilibria of compound 3n in aqueous solutions, adapted from ref. [92,93].
Figure 9: Molecular fragments associated with intramolecular charge transfer states.
Figure 10: Frontier molecular orbitals of compounds 3n and 4n in three different states: protonated, deprotona...
Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity
- Giuseppe Granata,
- Loredana Ferreri,
- Claudia Giovanna Leotta,
- Giovanni Mario Pitari and
- Grazia Maria Letizia Consoli
Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195
- chains at the lower rim. The resulting amphiphilic calix[4]arene derivative 3 spontaneously self-assembled into nanoscale aggregates in aqueous medium, as demonstrated by dynamic light scattering analysis. The cytotoxicity of compound 3 towards cancer cells was assessed using human renal carcinoma cells
- anticancer activity. The synthesis and structural characterization of compound 3 were carried out, and its self-assembly behavior in aqueous medium was investigated using dynamic light scattering (DLS) and electrophoretic light scattering (ELS). The anticancer potential of compound 3 was assessed in human
- functionalization of the calix[4]arene skeleton blocked in cone conformation, as evidenced by the AX system (3.13 and 4.26 ppm) for the bridged CH2 protons. Spontaneous self-assembly Due to the amphiphilic nature, compound 3 could spontaneously self-assemble in aqueous medium. This was confirmed by dynamic light
Graphical Abstract
Scheme 1: Procedure for the synthesis of compound 3.
Figure 1: 1H NMR (left) and 13C NMR (right) spectra of compound 3 in DMSO-d6 (400.13 MHz, 297 K).
Figure 2: Intensity-weighted mean hydrodynamic diameter (left), and zeta potential distribution (right) of co...
Figure 3: Antiproliferative effects by compound 3 and its chemical precursor 1. A) Results on proliferative k...
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
- . In the biobased reaction from furfural to CPN, the key points influencing the selectivity and yield are the choice of metal catalyst, hydrogen pressure and supporting acidic materials [168][198]..When carried out in aqueous medium, the reaction was found to provide better selectivity by limiting 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®.
Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs
- Almaz A. Zagidullin,
- Emil R. Bulatov,
- Mikhail N. Khrizanforov,
- Damir R. Davletshin,
- Elvina M. Gilyazova,
- Ivan A. Strelkov and
- Vasily A. Miluykov
Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148
- HSA in aqueous medium shows a characteristic oxidation wave that begins to rise around +0.5 V and significantly increases up to +1.2 V vs Ag/AgCl (Figure 3). This wave is attributed to oxidation processes at peptide bonds or specific side chains (such as cysteine, methionine, tyrosine, serine
Graphical Abstract
Figure 1: Structures of some pharmacological important phosphorus-containing molecules with oxirane or azirid...
Scheme 1: Synthesis of glycidyl esters of phosphorus acids 1–3.
Figure 2: Dose–response curves for the cytotoxic effects of glycidyl esters of phosphorus acids 1–3 on human ...
Figure 3: Linear sweep voltammograms of 1 × 10−4 М HSA (black) and HSA mixed with each of the three alkylatin...
Figure 4: Chemical structure of alkylating fragment of 1–3 and the associated chemical pathway of its covalen...
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
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...
Deciphering the mechanism of γ-cyclodextrin’s hydrophobic cavity hydration: an integrated experimental and theoretical study
- Stiliyana Pereva,
- Stefan Dobrev,
- Tsveta Sarafska,
- Valya Nikolova,
- Silvia Angelova,
- Tony Spassov and
- Todor Dudev
Beilstein J. Org. Chem. 2024, 20, 2635–2643, doi:10.3762/bjoc.20.221
- 3. The enthalpies estimated for the subsequent binding process of water molecules to γ-CD in both the gas phase (ΔH1) and aqueous medium (ΔH78) at both levels of theory are presented in Table 1. The two sets of calculations using different basis sets (M062X/6-31G(d,p) and M062X/6-311++G(d,p)//M062X
Graphical Abstract
Figure 1: Chemical structure of γ-CD (A); M062X/6-31G(d,p) optimized conformers of nonhydrated γ-CD in two pr...
Figure 2: Schematic representation of γ-CD–nH2O complexes (where n = 1–7) with water molecules/clusters locat...
Figure 3: M062X/6-31G(d,p) optimized structures of the most stable (a/b structures from Figure 2) γ-CD–nH2O (n = 1–7)...
Figure 4: DSC curve (A) and TG analysis for γ-CD (B). Compared to our previous studies, the hydrated γ-cyclod...
Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds
- Ka-Lung Hung,
- Leong-Hung Cheung,
- Yikun Ren,
- Ming-Hin Chau,
- Yan-Yi Lam,
- Takashi Kajitani and
- Franco King-Chi Leung
Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142
- Abstract In the design of photoharvesting and photoresponsive supramolecular systems in aqueous medium, the fabrication of amphiphilic photoswitches enables a noninvasive functional response through photoirradiation. Although most aqueous supramolecular assemblies are driven by high-energy and biodamaging
- moiety. The excellent photoswitchability in organic medium and the photoresponsiveness in aqueous medium, driven by visible light, were investigated by UV–vis absorption spectroscopy. The assembled supramolecular nanostructures were confirmed by electron microscopy, while the supramolecular packing was
- found in nature in order to enable different biological functions in a precise manner, e.g., actin in biological molecular motors, the cytoskeleton, and cell membrane [5][6][7][8]. Mimicking natural supramolecular assemblies in aqueous medium, the intrinsic supramolecular dynamicity, stimuli
Graphical Abstract
Scheme 1: Illustration of the reversible visible-light-controlled ring closure and thermal-driven ring-openin...
Scheme 2: Synthetic pathway to DAn.
Figure 1: UV–vis-absorption-spectral changes of DAn in THF solution (20 μM). (a) DA11, (c) DA7, (e) DA6 solut...
Figure 2: UV–vis absorption spectra of DAn in aqueous solution (43 μM). (a) DA11 (inset: enlarged 400–480 nm ...
Figure 3: TEM images of freshly prepared aqueous solutions before irradiation of (a) DA11 (0.25 wt %, 4.1 mM)...
Figure 4: Photograph of a freshly prepared aqueous DA11 solution (82.0 mM) ejected into a shallow pool of CaCl...
Figure 5: Photographs of macroscopic soft scaffolds prepared from aqueous solutions of (a) DA11 (32.9 mM), (c...
Figure 6: Macroscopic soft DAn scaffolds fabricated by the shear-flow method. Images taken during fluorescenc...
Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide
- Vishnu Selladurai and
- Selvakumar Karuthapandi
Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105
- selenious acid containing polyaniline via chemical oxidation of aniline with SeO2 as oxidant [45]. Further, Tanini et al. described that selenium dioxide has potential to oxidize aniline to form nitrobenzene in aqueous medium [46]. These findings irrevocably confirmed that aniline undergoes significant
Graphical Abstract
Scheme 1: Reported synthetic methods for the selenation of aromatic compounds.
Scheme 2: Reaction of selenium dioxide with aniline.
Scheme 3: Reaction of selenium dioxide with o-anisidine.
Scheme 4: Reaction of methyl anthranilate with SeO2.
Scheme 5: Reaction mechanism for the formation of diaryl monoselenides.
Scheme 6: Reaction mechanism for the formation of oxamides.
Scheme 7: Reaction mechanism for the formation of quinone 10.
Figure 1: Molecular structure of 3. Thermal ellipsoids drawn at 50% probability. Selected bond lengths (Å): O...
Figure 2: Molecular structure of 9. Thermal ellipsoids drawn at 50% probability. Selected bond lengths (Å): O...
Figure 3: Molecular structure of 13. Thermal ellipsoids drawn at 50% probability. Selected bond lengths (Å): ...
Figure 4: Molecular structure of 10. Thermal ellipsoids drawn at 50% probability. Selected bond lengths (Å) a...
Figure 5: Molecular structure of 11. Thermal ellipsoids drawn at 50% probability. Selected bond angles (°): C...
Figure 6: Molecular structure of 12. Thermal ellipsoids drawn at 50% probability. Selected bond angles (°): C...
Figure 7: Relative energy levels of arylamines and SeO2.
Figure 8: Computationally optimized structure of aniline (a), o-anisidine (b), and methyl anthranilate (c), w...
Scheme 8: Resonance structures for the delocalization of the nitrogen lone pair into the π-system.
Synthesis and characterization of water-soluble C60–peptide conjugates
- Yue Ma,
- Lorenzo Persi and
- Yoko Yamakoshi
Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71
- very small hydrodynamic diameter in a neutral aqueous medium, as shown by DLS analysis. Visible-light-induced 1O2 generation by C60–oligo-Lys (5a) was confirmed by ESR spin trapping. This suggests the high potential of 5a as a basis for a fullerene-derived PS in biological applications. Experimental
Graphical Abstract
Figure 1: a) Synthesis of C60–oligopeptide conjugates 5a–c and b) synthesis of compound 3. Fulleropyrrolidine...
Figure 2: Structure of C60–oligo-Lys (5a), C60–oligo-Glu (5b), and C60–oligo-Arg (5c) and images of dissolved...
Figure 3: DLS diagrams of C60–peptide conjugates 5a (1 mM, in Milli-Q® water), 5b (1 mM, in Milli-Q® water or...
Figure 4: UV–vis spectra of C60–peptide conjugates 5a and 5b (20 μM in Milli-Q® water for 5a and in pH 9.0 TR...
Figure 5: 1H NMR spectrum of C60–peptide conjugate 5a in D2O (above) and of the precursor monoadduct in CDCl3...
Figure 6: 13C NMR spectrum of C60–peptide conjugate 5a in D2O and of the precursor monoadduct in CDCl3 at 150...
Figure 7: a) X-band ESR spectra of the 4-oxo-TEMP adduct with 1O2 generated by C60–oligo-Lys (5a) and rose be...
Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles
- Periklis X. Kolagkis,
- Eirini M. Galathri and
- Christoforos G. Kokotos
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
- of just 0.5 mol %, while providing satisfying yields (60–96%) in just 1 hour. The employment of a green aqueous medium, the mild reaction conditions and the relatively broad substrate scope are some of the benefits that render this protocol more efficient than previous halogen-bonding methodologies
Graphical Abstract
Scheme 1: Examples of BIMs used for their medicinal properties.
Scheme 2: Mechanisms for the synthesis of BIMs using protic or Lewis acids as catalysts.
Scheme 3: Synthesis of bis(indolyl)methanes using DBDMH.
Scheme 4: Competition experiments and synthesis of bis(indolyl)methanes using DBDMH.
Scheme 5: Proposed mechanism for formation of BIM of using DBDMH.
Scheme 6: Synthesis of bis(indolyl)methanes using I2.
Scheme 7: General reaction mechanism upon halogen bonding.
Scheme 8: Synthesis of bis(indolyl)methanes using I2, introduced by Ji.
Scheme 9: Synthesis of bis(indolyl)methanes using Br2 in CH3CN.
Scheme 10: Βidentate halogen-bond donors.
Scheme 11: Synthesis of bis(indolyl)methanes using bidentate halogen-bond donor 26.
Scheme 12: Proposed reaction mechanism.
Scheme 13: Synthesis of bis(indolyl)methanes using iodoalkyne as catalyst.
Scheme 14: Proposed reaction mechanism.
Scheme 15: Optimized reaction conditions used by Ramshini.
Scheme 16: Activation of the carbonyl group by HPA/TPI-Fe3O4.
Scheme 17: Synthesis of BIMs in the presence of nanoAg-Pt/SiO2-doped silicate.
Scheme 18: Mechanism of action proposed by Khalafi-Nezhad et al.
Scheme 19: Activation of the carbonyl group by the Cu–isatin Schiff base complex.
Scheme 20: Optimum reaction conditions published by Jain.
Scheme 21: Organocatalytic protocol utilizing nanoparticles introduced by Bankar.
Scheme 22: Activation of the carbonyl group by the AlCl3·6H2O-SDS-SiO2 complex.
Scheme 23: Optimal reaction conditions for the aforementioned nano-Fe3O4 based catalysts.
Scheme 24: Nanocatalytic protocol proposed by Kaur et al.
Scheme 25: Microwave approach introduced by Yuan.
Scheme 26: Microwave approach introduced by Zahran et al.
Scheme 27: Microwave irradiation protocol introduced by Bindu.
Scheme 28: Silica-supported microwave irradiation protocol.
Scheme 29: Proposed mechanism for formation of BIM by Nongkhlaw.
Scheme 30: Microwave-assisted synthesis of BIMs catalyzed by succinic acid.
Scheme 31: Proposed mechanism of action of MMO-4.
Scheme 32: Catalytic approach introduced by Muhammadpoor-Baltork et al.
Scheme 33: Reaction conditions used by Xiao-Ming.
Scheme 34: Ultrasonic irradiation-based protocol published by Saeednia.
Scheme 35: Pyruvic acid-mediated synthesis of BIMs proposed by Thopate.
Scheme 36: Synthesis of BIMs using [bmim]BF4 or [bmim]PF6 ionic liquids.
Scheme 37: Synthesis of BIMs utilizing In(OTf)3 in octylmethylimidazolium hexafluorophosphate as ionic liquid.
Scheme 38: FeCl3·6H2O-catalyzed synthesis of BIMs with use of ionic liquid.
Scheme 39: Synthesis of BIMs utilizing the [hmim]HSO4/EtOH catalytic system.
Scheme 40: Synthesis of BIMs utilizing acidic ionic liquid immobilized on silica gel (ILIS-SO2Cl).
Scheme 41: The [bmim][MeSO4]-catalyzed reaction of indole with various aldehydes.
Scheme 42: The role of [bmim][MeSO4] in catalyzing the reaction of indole with aldehydes.
Scheme 43: Synthesis of BIMs utilizing FeCl3-based ionic liquid ([BTBAC]Cl-FeCl3) as catalyst.
Scheme 44: Synthesis of BIMs using [Msim]Cl at room temperature.
Scheme 45: [Et3NH][H2PO4]-catalyzed synthesis of bis(indolyl)methanes.
Scheme 46: PILs-catalyzed synthesis of bis(indolyl)methanes.
Scheme 47: FSILs-mediated synthesis of bis(indolyl)methanes.
Scheme 48: Possible “release and catch” catalytic process.
Scheme 49: Synthesis of bis(indolyl)methanes by [DABCO-H][HSO4].
Scheme 50: Synthesis of bis(indolyl)methanes by [(THA)(SO4)].
Scheme 51: Synthesis of BBSI-Cl and BBSI-HSO4.
Scheme 52: Synthesis of BIMs in the presence of BBSI-Cl and BBSI-HSO4.
Scheme 53: Chemoselectivity of the present method.
Scheme 54: Synthesis of BIMs catalyzed by chitosan-supported ionic liquid.
Scheme 55: Proposed mechanism of action of CSIL.
Scheme 56: Optimization of the reaction in DESs.
Scheme 57: Synthesis of BIMs using ChCl/SnCl2 as DES.
Scheme 58: Synthesis of BIMs derivatives in presence of DES.
Scheme 59: BIMs synthesis in choline chloride/urea (CC/U).
Scheme 60: Flow chemistry-based synthesis of BIMs by Ley.
Scheme 61: Flow chemistry-based synthesis of BIMs proposed by Nam et al.
Scheme 62: Amino-catalyzed reaction of indole with propionaldehyde.
Scheme 63: Aminocatalytic synthesis of BIMs.
Scheme 64: Proposed mechanism for the aminocatalytic synthesis of BIMs.
Scheme 65: Enzymatic reaction of indole with aldehydes.
Scheme 66: Proposed mechanism for the synthesis of BIMs catalyzed by TLIM.
Scheme 67: Proposed reaction mechanism by Badsara.
Scheme 68: Mechanism proposed by D’Auria.
Scheme 69: Photoinduced thiourea catalysis.
Scheme 70: Proposed mechanism of photoacid activation.
Scheme 71: Proposed mechanism of action for CF3SO2Na.
Scheme 72: Proposed mechanism for the synthesis of BIMs by Mandawad.
Scheme 73: Proposed mechanism for the (a) acid generation and (b) synthesis of BIMs.
Scheme 74: a) Reaction conditions employed by Khaksar and b) activation of the carbonyl group by HFIP.
Scheme 75: Activation of the carbonyl group by the PPy@CH2Br through the formation of a halogen bond.
Scheme 76: Reaction conditions utilized by Mhaldar et al.
Scheme 77: a) Reaction conditions employed by López and b) activation of the carbonyl group by thiourea.
Scheme 78: Infrared irradiation approach introduced by Luna-Mora and his research group.
Scheme 79: Synthesis of BIMs with the use of the Fe–Zn BMOF.
Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes
- Michio Yamada
Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13
- pyrrolidine at 0 °C, the pentafulvene derivative 36 was obtained with 63% yield via an additional ring-opening process. Similar skeletal transformation reactions were observed for azulene derivatives bearing similar substructures. The reaction of 1 with TCNE in an aqueous medium containing a surfactant
Graphical Abstract
Scheme 1: Pathway of the [2 + 2] CA–RE reaction of an electron-rich alkyne with TCNE or TCNQ. EDG = electron-...
Scheme 2: Reaction pathway for DMA-appended acetylene and TCNEO.
Scheme 3: Pathway of the [2 + 2] CA–RE reaction between 1 and DCFs.
Scheme 4: Sequential double [2 + 2] CA–RE reactions between 1 and TCNE.
Scheme 5: Divergent chemical transformation pathways of TCBD 6.
Scheme 6: Synthesis of 12.
Scheme 7: [2 + 2] CA–RE reaction of 1 with 14. TCE = 1,1,2,2-tetrachloroethane.
Scheme 8: Autocatalytic model proposed by Nielsen et al.
Scheme 9: Synthesis of anthracene-embedded TCBD compound 19.
Scheme 10: Sequence of the [2 + 2] CA–RE reaction between dibenzo-fused cyclooctyne or cyclooctadiyne and TCNE...
Scheme 11: [2 + 2] CA–RE reaction between the CPP derivatives and TCNE. THF = tetrahydrofuran.
Scheme 12: [2 + 2] CA–RE reaction between ethynylfullerenes 31 and TCNE and subsequent thermal rearrangement.
Scheme 13: Pathway of the [2 + 2] CA–RE reaction between TCNE and 34, followed by additional skeletal transfor...
Scheme 14: Synthesis scheme for heterocycle 38 from the reaction between TCNE and 1 in water and a surfactant.
Scheme 15: Synthesis scheme of the CDA product 41.
Scheme 16: Synthesis of rotaxanes 44 and 46 via the [2 + 2] CA–RE reaction.
Scheme 17: Synthesis of a CuI bisphenanthroline-based rotaxane 50.
Figure 1: Structures of the chiral push–pull chromophores 51–56.
Figure 2: Structures of the axially chiral TCBD 57 and DCNQ 58 bearing a C60 core.
Figure 3: Structures of the axially chiral SubPc–TCBD–aniline conjugates 59 and 60 and the subporphyrin–TCBD–...
Figure 4: Structures of 63 and the TCBD 64.
Figure 5: Structures of the fluorophore-containing TCBDs 65–67.
Figure 6: Structures of the fluorophore-containing TCBDs 68–72.
Figure 7: Structures of the urea-containing TCBDs 73–75.
Figure 8: Structures of the fullerene–TCBD and DCNQ conjugates 76–79 and their reference compounds 80–83.
Figure 9: Structures of the ZnPc–TCBD–aniline conjugates 84 and 85.
Figure 10: Structures of the ZnP–PCBD and TCBD conjugates 86–88.
Figure 11: Structures of the porphyrin-based donor–acceptor conjugates (89–104).
Figure 12: Structures of the porphyrin–PTZ or DMA conjugates 105–112.
Figure 13: Structures of the BODIPY–Acceptor–TPA or PTZ conjugates 113–116.
Figure 14: Structures of the corrole–TCBD conjugates 117 and 118.
Figure 15: Structure of the dendritic TCBD 119.
Figure 16: Structures of the TCBDs 120–126.
Figure 17: Structures of the precursor 127 and TCBDs 128–130.
Figure 18: Structures of 131–134 utilized for BHJ OSCs.
Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups
- Dayanne Martins,
- Roberta Lamosa,
- Talis Uelisson da Silva,
- Carolina B. P. Ligiero,
- Sérgio de Paula Machado,
- Daphne S. Cukierman and
- Nicolás A. Rey
Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125
- stability in aqueous medium. Thus, the electronic absorption spectra of hdz-CH3 and hdz-NO2 were recorded in a 10% DMSO/buffer solution (pH 7.4) immediately after preparation and at regular time intervals. The UV–vis spectrum of hdz-CH3 between 250 and 450 nm (Figure 6A) shows two multicomponent absorptions
Graphical Abstract
Scheme 1: Structure of (A) 3-methylsalicylaldehyde 3,4,5-trimethoxybenzoyl hydrazone (hdz-CH3) and (B) 3-nitr...
Figure 1: ORTEP representation of the new N-acylhydrazones synthesized in the present work, drawn with therma...
Figure 2: (A) Superposition of molecular structures and stacked motifs of (B) hdz-CH3 and (C) hdz-NO2.
Figure 3: Overlap of the experimental (carbon atoms colored in gray) and theoretical structures (calculated w...
Figure 4: Mid-infrared spectra of the compounds. Experimental conditions: KBr pellets, room temperature. Calc...
Figure 5: 1H NMR (400 MHz) spectra of (A) hdz-CH3 and (B) hdz-NO2 in DMSO-d6 at 25 °C.
Figure 6: Electronic absorption spectra in a selected wavelength region for a solution of hdz-CH3 in 10% DMSO...
Figure 7: Electronic absorption spectra of hdz-NO2 in selected wavelength regions. Experimental conditions: l...
Scheme 2: General scheme for the synthesis of the studied hydrazones.
Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach
- Dileep Kumar Singh and
- Rajesh Kumar
Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71
- -free conditions, and under microwave irradiation. (1) Reactions in water In recent years, organic reactions in aqueous medium have grown in popularity due to their low cost and environmental friendliness. The use of water as a solvent medium for the synthesis of pyrrole derivatives using various
Graphical Abstract
Figure 1: Various pyrrole containing molecules.
Scheme 1: Various synthestic protocols for the synthesis of pyrroles.
Figure 2: A tree-diagram showing various conventional and green protocols for Clauson-Kaas pyrrole synthesis.
Scheme 2: A general reaction of Clauson–Kaas pyrrole synthesis and proposed mechanism.
Scheme 3: AcOH-catalyzed synthesis of pyrroles 5 and 7.
Scheme 4: Synthesis of N-substituted pyrroles 9.
Scheme 5: P2O5-catalyzed synthesis of N-substituted pyrroles 11.
Scheme 6: p-Chloropyridine hydrochloride-catalyzed synthesis of pyrroles 13.
Scheme 7: TfOH-catalyzed synthesis of N-sulfonylpyrroles 15, N-sulfonylindole 16, N-sulfonylcarbazole 17.
Scheme 8: Scandium triflate-catalyzed synthesis of N-substituted pyrroles 19.
Scheme 9: MgI2 etherate-catalyzed synthesis and proposed mechanism of N-arylpyrrole derivatives 21.
Scheme 10: Nicotinamide catalyzed synthesis of pyrroles 23.
Scheme 11: ZrOCl2∙8H2O catalyzed synthesis and proposed mechanism of pyrrole derivatives 25.
Scheme 12: AcONa catalyzed synthesis of N-substituted pyrroles 27.
Scheme 13: Squaric acid-catalyzed synthesis and proposed mechanism of N-substituted pyrroles 29.
Figure 3: Reusability of catalyst γ-Fe2O3@SiO2-Sb-IL in six cycles.
Scheme 14: Magnetic nanoparticle-supported antimony catalyst used in the synthesis of N-substituted pyrroles 31...
Scheme 15: Iron(III) chloride-catalyzed synthesis of N-substituted pyrroles 33.
Scheme 16: Copper-catalyzed Clauson–Kaas synthesis and mechanism of pyrroles 35.
Scheme 17: β-CD-SO3H-catalyzed synthesis and proposed mechanism of pyrroles 37.
Figure 4: Recyclability of β-cyclodextrin-SO3H.
Scheme 18: Solvent-free and catalyst-free synthesis and plausible mechanism of N-substituted pyrroles 39.
Scheme 19: Nano-sulfated TiO2-catalyzed synthesis of N-substituted pyrroles 41.
Figure 5: Plausible mechanism for the formation of N-substituted pyrroles catalyzed by nano-sulfated TiO2 cat...
Scheme 20: Copper nitrate-catalyzed Clauson–Kaas synthesis and mechanism of N-substituted pyrroles 43.
Scheme 21: Synthesis of N-substituted pyrroles 45 by using Co catalyst Co/NGr-C@SiO2-L.
Scheme 22: Zinc-catalyzed synthesis of N-arylpyrroles 47.
Scheme 23: Silica sulfuric acid-catalyzed synthesis of pyrrole derivatives 49.
Scheme 24: Bismuth nitrate-catalyzed synthesis of pyrroles 51.
Scheme 25: L-(+)-tartaric acid-choline chloride-catalyzed Clauson–Kaas synthesis and plausible mechanism of py...
Scheme 26: Microwave-assisted synthesis of N-substituted pyrroles 55 in AcOH or water.
Scheme 27: Synthesis of pyrrole derivatives 57 using a nano-organocatalyst.
Figure 6: Nano-ferric supported glutathione organocatalyst.
Scheme 28: Microwave-assisted synthesis of N-substituted pyrroles 59 in water.
Scheme 29: Iodine-catalyzed synthesis and proposed mechanism of pyrroles 61.
Scheme 30: H3PW12O40/SiO2-catalyzed synthesis of N-substituted pyrroles 63.
Scheme 31: Fe3O4@-γ-Fe2O3-SO3H-catalyzed synthesis of pyrroles 65.
Scheme 32: Mn(NO3)2·4H2O-catalyzed synthesis and proposed mechanism of pyrroles 67.
Scheme 33: p-TsOH∙H2O-catalyzed (method 1) and MW-assisted (method 2) synthesis of N-sulfonylpyrroles 69.
Scheme 34: ([hmim][HSO4]-catalyzed Clauson–Kaas synthesis of pyrroles 71.
Scheme 35: Synthesis of N-substituted pyrroles 73 using K-10 montmorillonite catalyst.
Scheme 36: CeCl3∙7H2O-catalyzed Clauson–Kaas synthesis of pyrroles 75.
Scheme 37: Synthesis of N-substituted pyrroles 77 using Bi(NO3)3∙5H2O.
Scheme 38: Oxone-catalyzed synthesis and proposed mechanism of N-substituted pyrroles 79.
pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene
- Nan Yang,
- Yi-Yan Zhu,
- Wei-Xiu Lin,
- Yi-Long Lu and
- Wen-Rong Xu
Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45
- water. The anionic bowl-shaped tribenzotriquinacene derivative TBTQ-C6 was incorporated into the polycationic CS-TPE to form electrostatically induced host–guest supra-amphiphiles, which further self-assembled into supramolecular nanoparticles in aqueous medium driven by the hydrophobic effect. As
- . The fluorescence properties of CS-TPE and TBTQ-C6/CS-TPE with three different Rf in aqueous medium were investigated by fluorescence spectrophotometry. The fluorescence emission of CS-TPE was significantly enhanced with the increase of its Rf/DL (Figure 7a). This may be caused by the increased
- labelling of hydrophobic TPE fluorogens, reducing the affinity of the CS chains to the aqueous medium and resulting in the entanglement or wrapping of the TPE fluorogens by polymer chains. As a result, the RIR process was enhanced, greatly increasing the fluorescence. In addition, the fluorescence intensity
Graphical Abstract
Scheme 1: (a) Synthesis route to CS-TPE. (b) Structure of TBTQ-C6. (c) Construction of TBTQ-C6/CS-TPE supramo...
Figure 1: Partial 1H NMR spectra (400 MHz, CD3COOD/D2O, 25 °C) of (a) CS, (b) CS-TPE-2%, (c) CS-TPE-10%, and ...
Figure 2: (a) Optical images of CS-TPE under daylight (top) and 365 nm UV light (bottom) in the solid state; ...
Figure 3: TEM images of (a) CS-TPE-2%, (b) CS-TPE-10%, and (c) CS-TPE-20% assemblies at pH 5.3; TEM images of...
Figure 4: (a, c, e) Optical transmittance and (b, d, f) transmittance as a function of [TBTQ-C6] at 293 nm of...
Figure 5: (a, c, e) Optical transmittance and (b, d, f) CS-TPE concentration-dependent optical transmittance ...
Figure 6: TEM images of (a) TBTQ-C6/CS-TPE-10% in aqueous solution at pH 5.3, (b) after adjustment of the sol...
Figure 7: (a) Fluorescence spectra of CS-TPE with different Rf in aqueous solutions at pH 5.3 and 10.4; (b) f...
Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme
- Josipa Matić,
- Tana Tandarić,
- Marijana Radić Stojković,
- Filip Šupljika,
- Zrinka Karačić,
- Ana Tomašić Paić,
- Lucija Horvat,
- Robert Vianello and
- Lidija-Marija Tumir
Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40
- membrane (Figure S26, Supporting Information File 1). The compound showed not to be toxic to the HeLa cells as no visible damage was detected. Interactions of Phen-Py-1 and Phen-Py-2 with ds-polynucleotides and enzyme dipeptidyl peptidase III in an aqueous medium Interactions of Phen-Py-1 and Phen-Py-2
- by a distortion of polynucleotide helicity upon addition of Phen-Py-1, or this change was a result of uniform orientation of the dye with respect to DNA chiral axis. Binding of Phen-Py-1 to enzyme dipeptidyl peptidase III in an aqueous medium Binding of Phen-Py-1 to dipeptidyl peptidase (DPPIII
Graphical Abstract
Scheme 1: Novel pyrene–phenanthridine conjugates Phen-Py-1 (longer, flexible linker) and Phen-Py-2 (shorter, ...
Scheme 2: Synthesis of Phen-Py-1 and Phen-Py-2 by amide formation; Reagents and conditions: 1. TFA–H2O mixtur...
Figure 1: 2D (left) and 3D (right) representation of fluorescence emission spectra of Phen-Py-1 (c = 2 × 10−6...
Figure 2: Most representative structures of the conjugates Phen-Py-1 and Phen-Py-2 at different pH conditions...
Figure 3: UV–vis titration of Phen-Py-1 with ct-DNA,; changes in the UV–vis spectra of Phen-Py-1 at λ = 350 n...
Figure 4: . Experimental (■) and calculated (–) (by Scatchard equation Table 2) fluorescence intensities of compound ...
Figure 5: Comparison of spectra of DNA-dye complex (r = 0.5, black) and sum of DNA and dye spectra (red) of a...
Figure 6: Fluorimetric titration of Phen-Py-1, λexc = 352 nm, c = 1 × 10−6 mol dm−3 with dipeptidyl peptidase...
Figure 7: A: ITC titration: raw titration data from the experimental injections of human DPP III enzyme mutan...
CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview
- Dileep Kumar Singh
Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29
- -base analogues 41a,b were also obtained by the treatment with HCl in dioxane. The conjugation of carbohydrate with porphyrin improves the solubility of porphyrin in aqueous medium and also improves the optical and medicinal properties of porphyrins [30]. Considering these properties of glycoporphyrins
Graphical Abstract
Figure 1: Alkyne–azide "click reaction".
Figure 2: β- and meso-triazole-linked porphyrin.
Scheme 1: Synthesis of β-triazole-linked porphyrins 3a–c.
Scheme 2: Synthesis of β-triazole-bridged porphyrin-coumarin conjugates 11–20.
Scheme 3: Synthesis of β-triazole-bridged porphyrin-xanthone conjugates 23–27 and xanthone-bridged β-triazolo...
Scheme 4: Synthesis of meso-triazoloporphyrins 32a–c and triazole-bridged diporphyrins 34.
Scheme 5: Synthesis of meso-triazole-linked porphyrin-ferrocene conjugates 37a–d.
Scheme 6: Synthesis of meso-triazole-linked porphyrin conjugates 40a,b and 41a,b.
Scheme 7: Synthesis of meso-triazole-linked glycoporphyrins 43a–c.
Scheme 8: Synthesis of meso-triazole-linked porphyrin-coumarin conjugates 44–48.
Scheme 9: Synthesis of meso-triazole-bridged porphyrin-DNA conjugate 50.
Scheme 10: Synthesis of meso-linked porphyrin-triazole conjugates 53 and 57.
Scheme 11: Synthesis of meso-triazole-linked porphyrin-corrole conjugate 60.
Scheme 12: Synthesis of porphyrin conjugates 64a,b and 67a,b. Reaction conditions: (i) CuSO4, sodium ascorbate...
Scheme 13: Synthesis of meso-triazole-bridged porphyrin-quinolone conjugates 70a–e.
Scheme 14: Synthesis of meso-triazole-linked porphyrin-fluorescein dyad 73.
Scheme 15: Synthesis of meso-triazole-linked porphyrin-carborane conjugates 76a,b.
Scheme 16: Synthesis of meso-triazole-bridged porphyrin-BODIPY conjugates 78 and 80.
Scheme 17: Synthesis of meso-triazole-linked cationic porphyrin conjugates 85 and 87. Reaction conditions: (i)...
Scheme 18: Synthesis of meso-triazole-cobalt-porphyrin diimine-dioxime conjugate 91. Reactions conditions: (i)...
Scheme 19: Synthesis of triazole-linked porphyrin-bearing N-doped graphene hybrid 96.
Scheme 20: Synthesis of meso-triazole-linked porphyrin-fullerene dyads 100a–d and 104a,b.
Scheme 21: Synthesis of meso-triazole-bridged diporphyrin conjugates 107 and 108.
Scheme 22: Synthesis of porphyrin-ruthenium (II) conjugates 112a,b and 116a,b. Reaction conditions: (i) Zn(OAc)...
Scheme 23: Synthesis of meso-triazole-linked porphyrin dyad 119 and triad 121.
Scheme 24: Synthesis of di-triazole-bridged porphyrin-β-CD conjugate 126.
Scheme 25: Synthesis of meso-triazole-bridged porphyrin star trimer 129.
Scheme 26: Synthesis of 1,2,3-triazole-linked porphyrin-β-CD conjugates 131a,b.
Scheme 27: Synthesis of tritriazole-bridged porphyrin-lantern-DNA sequence 134.
Scheme 28: Synthesis of meso-triazole-linked porphyrin-polymer conjugates 137 and 139.
Scheme 29: Synthesis of triazole-linked capped porphyrin 142; Reaction conditions: method A: 10% H2O in THF, C...
Scheme 30: Synthesis of meso-tetratriazole-linked porphyrin-maleimine conjugates 145a–c.
Scheme 31: Synthesis of meso-tetratriazole-linked porphyrin-cholic acid complex 148a,b.
Scheme 32: Synthesis of meso-tetratriazole-linked porphyrin conjugates 151–153.
Scheme 33: Synthesis of meso-tetratrizole-porphyrin-carborane conjugates 155, 156 and 158a–c.
Scheme 34: Synthesis of meso-tetratriazole-porphyrin-cardanol conjugates 160 and 162.
Scheme 35: Synthesis of meso-tetratriazole-linked porphyrin-BODIPY conjugate 164.
Scheme 36: Synthesis of meso-tetratriazole-linked porphyrin-β-CD conjugates 166a,b.
Scheme 37: Synthesis of tetratriazole-bridged meso-arylporphyrins 171a–c and 172a–c.
Scheme 38: Synthesis of octatriazole-bridged porphyrin-β-CD conjugate 174 and porphyrin-adamantane conjugates ...
Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene
- Konstantin Lebedinskiy,
- Volodymyr Lobaz and
- Jindřich Jindřich
Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170
- parameters is impossible. ITC (isothermal titration calorimetry) is a popular technique for evaluating supramolecular interaction with CDs [38], mainly in the aqueous medium. We performed the titrations of tetracene DMSO solution by the series of CDs used in the solubility experiments (Figure 7, Figure 8
Graphical Abstract
Scheme 1: The synthesis of 6A-azido-6A-deoxy-per-6-O-tert-butyldimethylsilyl-β-cyclodextrin.
Scheme 2: The synthesis of β-cyclodextrin dimers with permethylated secondary rims.
Scheme 3: The synthesis of β-cyclodextrin dimers with permethylated primary rims.
Figure 1: The fragments of 1H NOESY NMR spectra of 4 (a), 10 (b), and 9 (c) indicating the interaction betwee...
Figure 2: The fragment of the 1H NMR spectrum of compounds 9 (green); 10 (red); 12 (blue) representing the si...
Figure 3: Other cyclodextrins that were used in the solubilization experiments with tetracene.
Figure 4: The tetracene UV absorbance dependence on concentration at 476 nm.
Figure 5: The relative concentrations of tetracene in DMSO solutions with hosts 4, 5, 10, 12, 13–18 referred ...
Figure 6: "Tail-to-tail" (a) and "head-to-head" (b) orientation of two cyclodextrin moieties and primary-rim ...
Figure 7: Isotherms of the titration of tetracene with "dimeric" CD solutions in DMSO at 298 K (circles – 10;...
Figure 8: Isotherms of the titration of tetracene with "monomeric" CD solutions in DMSO at 298 K (circles – 16...
Supramolecular approaches to mediate chemical reactivity
- Pablo Ballester,
- Qi-Qiang Wang and
- Carmine Gaeta
Beilstein J. Org. Chem. 2022, 18, 1463–1465, doi:10.3762/bjoc.18.152
- -workers [19] reported an efficient photocatalytic supramolecular system based on a self-assembled nanosystem. The self-assembled system was obtained in an aqueous medium by inclusion of ammonium benzoyl-ʟ-alaninate (G) in a tetraphenylethylene-embedded pillar[5]arene (m-TPEWP5). The resulting worm-like
Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis
- Prodip Howlader and
- Michael Schmittel
Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62
- aromatic walls that offer van-der-Waals and π–π stacking interactions in order to compensate for the absence of a strong electrostatic interaction. These non-covalent/ionic interactions play an important role in encapsulating aromatic organic molecules, especially in aqueous medium. Along this rationale
- tetraphenylethene (TPE) units which act as an aggregation-induced emissive (AIE) fluorophore [65]. The newly designed TPE-based tetraimidazole donor 19 has been treated with 180°/120° trans-Pt(II) acceptors which led to the coordination-driven self-assembly of 3D discrete molecular cages in aqueous medium (Figure 5
Graphical Abstract
Figure 1: Butterfly 1 (Figure was reprinted with permission from [45]. Copyright 2012 American Chemical Society. ...
Figure 2: Synthesis of the three-component heteroleptic molecular boat 8 and its use as a catalyst for the Kn...
Figure 3: Synthesis of the two-component triangle 14 and three-component heteroleptic prism 15 [59]. Figure was a...
Figure 4: Catalytic Michael addition reaction using the urea-decorated molecular prism 15 [59].
Figure 5: Self-assembly of two-component tetragonal prismatic architectures with different cavity size. Figur...
Figure 6: Construction of artificial LHS using rhodamine B as an acceptor and 24b as donor generating a photo...
Figure 7: Synthesis of supramolecular spheres with varying [AuCl] concentration inside the cavity. Figure was...
Figure 8: Hydroalkoxylation reaction of γ-allenol 34 in the presence of [AuCl]-encapsulated molecular spheres ...
Figure 9: Two-component heteroleptic triangles of different size containing a BINOL functionality. Figure was...
Figure 10: Asymmetric conjugate addition of chalcone 42 with trans-styrylboronic acid (43) catalyzed by BINOL-...
Figure 11: Encapsulation of monophosphoramidite-Rh(I) catalyst into a heteroleptic tetragonal prismatic cage 47...
Figure 12: (a) Representations of the basic HETPYP, HETPHEN, and HETTAP complex motifs. (b) The three-componen...
Figure 13: Two representative four-component rotors, with a (top) two-arm stator and (bottom) a four-arm stato...
Figure 14: Four-component rotors with a monohead rotator. Figure was adapted with permission from [94]. Copyright ...
Figure 15: (left) Click reaction catalyzed by rotors [Cu2(55)(60)(X)]2+. (right) Yield as a function of the ro...
Figure 16: A supramolecular AND gate. a) In truth table state (0,0) two nanoswitches serve as the receptor ens...
Figure 17: Two supramolecular double rotors (each has two rotational axes) and reference complex [Cu(78)]+ for...
Figure 18: The slider-on-deck system (82•X) (X = 83, 84, or 85). Figure is from [98] and was reprinted from the jo...
Figure 19: Catalysis of a conjugated addition reaction in the presence of the slider-on-deck system (82•X) (X ...
Figure 20: A rotating catalyst builds a catalytic machinery. For catalysis of the catalytic machinery, see Figure 21. F...
Figure 21: Catalytic machinery. Figure was adapted from [100] (“Evolution of catalytic machinery: three-component n...
Figure 22: An information system based on (re)shuffling components between supramolecular structures [99]. Figure ...
Figure 23: Switching between dimeric heteroleptic and homoleptic complex for OFF/ON catalytic formation of rot...
Figure 24: A chemically fueled catalytic system [112]. Figure was adapted from [112]. Copyright 2021 American Chemical S...
Figure 25: (Top) Operation of a fuel acid. (Bottom) Knoevenagel addition [112].
Figure 26: Development of the yield of Knoevenagel product 118 in a fueled system [112]. Figure was reprinted with ...
Figure 27: Weak-link strategy to increased catalytic activity in epoxide opening [119]. Figure was adapted from [24]. C...
Figure 28: A ON/OFF polymerization switch based on the weak-link approach [118]. Figure was reprinted with permissi...
Figure 29: A weak-link switch turning ON/OFF a Diels–Alder reaction [132]. Figure was reprinted with permission fro...
Figure 30: A catalyst duo allowing selective activation of one of two catalytic acylation reactions [133] upon subs...
Figure 31: A four-state switchable nanoswitch (redrawn from [134]).
Figure 32: Sequential catalysis as regulated by nanoswitch 138 and catalyst 139 in the presence of metal ions ...
Figure 33: Remote control of ON/OFF catalysis administrated by two nanoswitches through ion signaling (redrawn...
A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments
- Constantine V. Milyutin,
- Andrey N. Komogortsev,
- Boris V. Lichitsky and
- Valeriya G. Melekhina
Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61
- solvents excluding acetic acid, DMSO and DMF. Initially, UV irradiation of compound 12a was carried out at a wavelength of 365 nm in a solution of DMSO in common glassware for 24 h. However, subsequent water treatment did not allow the isolation of the target product 14a. Due to the fact that aqueous
- medium accelerates the decomposition of target α-hydroxy-1,2-diketone 14a. Subsequently, we used DMF as a solvent for carrying out the studied photoreaction. Unexpectedly, the starting pyrazole 12a was isolated unchanged after 24 hours of UV irradiation, indicating that DMF also is not suitable for the
Graphical Abstract
Scheme 1: Photochemical transformations of 3-hydroxypyran-4-one derivatives.
Scheme 2: Synthesis and study of the photochemical behavior of compound 16.
Scheme 3: Photoreaction of compound 12a.
Figure 1: 1H NMR monitoring of the photoreaction of compound 12a under UV irradiation (365 nm) in DMSO-d6 sol...
Scheme 4: Proposed mechanism for the photoreaction of compound 11a.
Scheme 5: Synthesis of compounds 15a–l. Reaction conditions: 1) 12a–l (0.5 mmol), AcOH (25 mL), UV irradiatio...
Figure 2: The X-ray crystal structure of compound 15a.
Scheme 6: Synthesis of compounds 15m–o. Reaction conditions: 1) 12m–o (0.5 mmol), AcOH (25 mL), UV irradiatio...
Figure 3: The X-ray crystal structure of compound 15m.
Scheme 7: Synthesis of compound 18.
Figure 4: The X-ray crystal structure of compound 18.
Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides
- Md Imran Hossain,
- Md Imdadul H. Khan,
- Seong Jong Kim and
- Hoang V. Le
Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47
- % water, 95% methanol mixture in the presence of DIPEA overnight, no degradation was observed. Conclusion We have developed a method for the synthesis of 3,4,5-trisubstituted isoxazoles in aqueous medium under mild basic conditions at room temperature. The reaction proceeds via a [3 + 2]-cycloaddition of
Graphical Abstract
Figure 1: Routes to isoxazoles.
Figure 2: Possible products of the reaction between nitrile oxides and 1,3-diketones. Path D (C-trapping) pro...
Figure 3: Reactions between various arylhydroximoyl chlorides and 1,3-diketones. The reactions were performed...
Figure 4: Reactions between various phenyl hydroximoyl chlorides and β-ketoesters or β-ketoamides. The reacti...
Figure 5: Reactions between 4-fluorophenyl hydroximoyl chloride (1a) and diethyl malonate (2j) or dibenzyl ma...
Figure 6: Reactions between phenyl hydroximoyl chlorides 1a,c and 4,4,4-trifluoro-1-phenyl- (2l) and 4,4,4-tr...
Figure 7: 1H NMR spectra of 1-phenyl-1,3-butanedione (2a) in methanol-d4 (top) and in CDCl3 (bottom).
Figure 8: A plausible mechanism for the formation of the 3,4,5-trisubstituted isoxazoles 3 in the presence of...
Figure 9: Structures of β-lactamase-resistant antibiotics oxacillin, cloxacillin, dicloxacillin, and flucloxa...
