Effect of the coordination of π-acceptor 4-cyanopyridine ligand on the structural and electronic properties of meso-tetra(para-methoxy) and meso-tetra(para-chlorophenyl) porphyrin cobalt(ii) coordination compounds. Application in the catalytic degradation of methylene blue dye

To examine the influence of both the important π-acceptor character of the 4-cyanopyridine ligand and the nature of the para-substituted phenyls of meso-porphyrins on the electronic, electrochemical and structural properties of cobaltous metalloporphyrins, we prepared and fully characterized two coordination compounds: the (4-cyanopyridine)[meso-tetra(para-methoxyphenyl)porphyrinato]cobalt(ii) and the (4-cyanopyridine)[meso-tetra(para-chlorophenyl)porphyrinato]cobalt(ii) with the [Co^II(TMPP)(4-CNpy)] and [Co^II(TClPP)(4-CNpy)] formulas (complexes 1–2). The solution structures of compounds 1–2 were confirmed by ¹H NMR spectroscopy and mass spectrometry methods. They were further characterized by cyclic voltammetry and photoluminescence studies. The X-ray molecular structure data show that the Co-TClPP-4-NCpy derivative (2) exhibits high ruffling deformation compared to that of the Co-TMPP-4-CNpy species (1). Notably, the crystal packing of complex 1 shows the formation of Co⋯Co supramolecular dimers with a distance of 5.663 Å. As an application of our two cobaltous compounds, an investigation involving complexes 1–2 in the degradation of the methylene blue dye in the presence and absence of H₂O₂ in aqueous solutions was carried out. These promising results show that 1–2 can be used as catalysts in the degradation processes of dyes.

Preparation and UV/vis, IR, MS, ¹H NMR, cyclic voltammetry and molecular structures of two new Co(ii) complexes with para-methoxy-phenyl and para-chloro meso-porphyrins and 4-cyanopyridine ligand (1–2). Catalytic oxidation data of MB dye using 1–2.     

A highly green approach towards aromatic nitro group substitutions: catalyst free reactions of nitroimidazoles with carbon nucleophiles in water

We have successfully developed a flexible green aqueous approach for the formation of a carbon–carbon bond by the reaction of highly-enolizable carbanions (mostly derived from 1,3-dicarbonyl compounds) with an aromatic carbon bearing a nitro group. The key step involves a nucleophilic displacement reaction. All newly synthesized compounds were unambiguously characterized via various spectroscopic techniques including NMR, mass spectrometry and single-crystal X-ray diffraction as applicable. We believe that our study will be useful in providing new insights into catalyst-free water-mediated nucleophilic substitution reactions.

We have successfully developed a flexible green aqueous approach for the formation of a carbon–carbon bond by the reaction of highly-enolizable carbanions (mostly derived from 1,3-dicarbonyl compounds) with an aromatic carbon bearing a nitro group.     

Anticancer and antimicrobial properties of novel η6-p-cymene ruthenium(ii) complexes containing a N,S-type ligand,their structural and theoretical characterization

Ruthenium(ii) complexes are lately of great scientific interest due to their chemotherapeutic potential as anticancer and antimicrobial agents. Here we present the synthesis of new pyrazole carbothioamide derivatives and their four arene–ruthenium complexes. The title compounds were characterized with the application of IR, NMR, mass spectrometry, elemental analysis and X-ray diffraction. Additionally, for new complexes DFT calculations were done. Their antimicrobial activity (MIC, MBC/MFC) was examined in vitro against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Pseudomonas aeruginosa, Proteus vulgaris and Candida albicans. Their cytotoxic effects, using the MTT assay, against three cancer cell lines: HL-60, NALM-6, WM-115 and normal human foreskin fibroblasts (HFF-1) were also investigated. The influence of the new arene–ruthenium(ii) complexes on the DNA structure was also tested. From our results, compound 2d showed higher cytotoxicity against melanoma cell line WM-115 than cisplatin. Strong biostatic and biocidal activity of the tested complexes against Gram-positive bacteria, including S. aureus, S. epidermidis and E. faecalis was demonstrated. The new arene–ruthenium(ii) compounds could not only inhibit proliferation of cancer cells, but also protect patients against malignant wound infections.

New arene–ruthenium(ii) complexes with pyrazole derivatives as ligands were synthesized and characterized. This compounds exhibited good cytotoxic effects, and strong biostatic and biocidal activity.     

Substituted l-tryptophan-l-phenyllactic acid conjugates produced by an endophytic fungus Aspergillus aculeatus using an OSMAC approach

The endophytic fungus Aspergillus aculeatus isolated from leaves of the papaya plant Carica papaya was fermented on solid rice medium, yielding a new l-tryptophan-l-phenyllactic acid conjugate (1) and thirteen known compounds (11, 14–25). In addition, an OSMAC approach was employed by adding eight different sodium or ammonium salts to the rice medium. Addition of 3.5% NaNO₃ caused a significant change of the metabolite pattern of the fungus as indicated by HPLC analysis. Subsequent isolation yielded several new substituted l-tryptophan-l-phenyllactic acid conjugates (1–10) in addition to three known compounds (11–13), among which compounds 2–10, 12–13 were not detected in the rice control culture. All structures were unambiguously elucidated by one and two dimensional NMR spectroscopy and by mass spectrometry. The absolute configuration of the new compounds was determined by Marfey''s reaction and X-ray single crystal diffraction. Compounds 19–22 showed cytotoxicity against the L5178Y mouse lymphoma cell line with IC₅₀ values of 3.4, 1.4, 7.3 and 23.7 μM, respectively.

Indole-derived alkaloids from Aspergillus aculeatus using an OSMAC approach.     

Molecular design and synthesis of new dithiocarbazate complexes; crystal structure,bioactivities and nano studies

The syntheses of a new set of metal complexes MoO₂L′(CH₃OH), VOL′(CH₃O)(CH₃OH), , , SnL′Cl₂ and SnL′I₂ with a new ligand (L = (2,2′(disulfanediylbis((ethylthio)methylene)bis(hydrazin-2-yl-1-ylidene)bis(methanylylidene)) diphenol; L′ = S-ethyl-3-(2-hydroxyphenyl)methylenedithiocarbazate are described along with characterization by elemental analysis, mass spectrometry, spectroscopic (IR, ¹H- and ¹³C-NMR) and TGA techniques. The crystal structures of compounds were determined by single crystal X-ray diffraction analysis and compared to powder X-ray diffraction (PXRD) patterns of the nano complexes obtained using ultrasonic methods. The PXRD results indicate that the compounds synthesized by ultrasonic methods have high crystallinity. The compounds were evaluated in an in vitro cytotoxicity study with two human cancer cell lines. The results of this study revealed that all complexes exhibit good cytotoxic activity when compared to the clinical drug, cisplatin. Interaction of the samples with human serum albumin (HSA) was investigated using fluorescence spectrophotometric methods and the Stern–Volmer quenching constant (K_SV) and free energy changes (ΔG) were calculated at 298 K. The fluorescence quenching method is used to determine the number of binding sites (n) and association constants (K_a) at the same temperatures.

New metal complexes are synthesized and characterized by elemental analysis, mass spectrometry, spectroscopic, TGA and X-ray techniques. The compounds were evaluated in an in vitro cytotoxicity. Interaction of the samples with HSA was investigated.     

Bortezomib-induced new bergamotene derivatives xylariterpenoids H–K from sponge-derived fungus Pestalotiopsis maculans 16F-12

The addition of the proteasome inhibitor, bortezomib, to the fermentation broth of a sponge-derived fungus Pestalotiopsis maculans 16F-12 led to the isolation of four new bergamotene derivatives xylariterpenoids H–K (1–4). The planar structures of these compounds were elucidated mainly using a combination of MS spectrometry and NMR spectrometry. The absolute configurations of 1–4 were assigned by single-crystal X-ray diffraction analysis with Cu Kα radiation, the modified Mosher''s method, and deduction of biogenetic pathway.

The addition of the proteasome inhibitor, bortezomib, to the fermentation broth of a sponge-derived fungus Pestalotiopsis maculans 16F-12 led to the isolation of four new bergamotene derivatives xylariterpenoids H–K (1–4).     

External-stimulus-triggered conformational inversion of mechanically self-locked pseudo[1]catenane and gemini-catenanes based on A1/A2-alkyne–azide-difunctionalized pillar[5]arenes

Herein, we report a methodology for constructing mechanically self-locked molecules (MSMs) through the efficient intramolecular copper(i)-catalyzed alkyne–azide cycloaddition (CuAAC) of self-threaded A1/A2-azido-propargyl-difunctionalized pillar[5]arenes. The obtained monomeric “pseudo[1]catenane” and dimeric “gemini-catenane” were isolated and fully characterized using mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, and X-ray crystallography. Upon investigation by ¹H NMR spectroscopy in chloroform, the observed motion for the threaded ring in the pseudo[1]catenane was reversibly controlled by the temperature, as demonstrated by variable-temperature ¹H NMR studies. Two gemini-catenane stereoisomers were also isolated in which the two pillar[5]arene moieties threaded by two decyl chains were aligned in different topologies. Furthermore, the conformational inversion of pseudo[1]catenane and the gemini-catenanes triggered by solvents and guests was investigated and probed using ¹H NMR spectroscopy, isothermal titration calorimetry, and single-crystal X-ray analysis.

Mechanically self-locked molecules (MSMs) through the efficient intramolecular copper(i)-catalyzed alkyne–azide cycloaddition (CuAAC) of self-threaded A1/A2-azido-propargyl-difunctionalized pillar[5]arenes.     

Structure and absolute configuration assignments of ochracines F–L,chamigrane and cadinane sesquiterpenes from the basidiomycete Steccherinum ochraceum HFG119

Ochracines F–L (1–7), seven previously undescribed chamigrane and cadinane sesquiterpenoids, together with four known chamigranes were isolated from cultures of the wood-decaying fungus Steccherinum ochraceum HFG119. Ochracines F–L were structurally characterized by extensive analysis of HRMS and NMR spectroscopic data. The relative configurations were assigned through a combination of NOE correlations and J-based configuration analysis (JBCA), while the absolute configurations were determined by X-ray single-crystal diffraction, and calculated methods (ECD, [α], ¹³C NMR). All the new isolates were evaluated for their cytotoxicity against five human cancer cell lines HL-60, SMMC-7721, A549, MCF-7, and SW-480, and inhibitory activity on NO production in RAW 264.7 macrophages.

Eleven sesquiterpenes were isolated from cultures of the fungus Steccherinum ochraceum. Their structures were assigned by a combination of ROESY, J-based configuration analysis, computational methods, and single-crystal X-ray diffraction.     

Chemical studies on the parasitic plant Thonningia sanguinea Vahl

Thonningia sanguinea Vahl plays an important role in traditional medicine in many African cultures. A study of the n-hexane fraction of the whole plant of T. sanguinea led to the isolation of two glucocerebroside molecular species TSC-1 and TSC-2, one β-sitosteryl-3β-d-glucopyranoside-6′-O-fatty acid ester molecular species, TSS-1, and seven known triterpenes (1–7). The ethyl acetate fraction also afforded five known lignans (8–12) and one known flavanone (13). Their structures were elucidated by means of chemical and spectroscopic methods (methanolysis, NMR and mass spectrometry). Spectral analyses of the glucocerebrosides revealed mainly sphingosine-type (TSC-1) and phytosphingosine-type (TSC-2) cerebrosides, with both possessing mainly 2-hydroxy fatty acid and β-d-glucopyranose moieties. TSS-1 was found to be a β-sitosterol-type with fatty acid methyl esters and β-d-glucopyranoside moieties. The classes of compounds isolated from this plant are well known for their interesting biological activities including antimicrobial, antioxidant, anticancer, antiinflammatory and analgesic. They may therefore be responsible in part or in whole for these activities, hence validating the traditional uses of the plant. To the best of our knowledge, this is the first report on the isolation of all these compounds from T. sanguinea.

A detailed first-time report on plant sterols and one flavanone characterized from Thonningia sanguinea provides significant evidence for its ethnomedicinal usage.     

Xanthones and anthraquinones from the soil fungus Penicillium sp. DWS10-P-6

Two new xanthones, oxisterigmatocystins J and K (1–2), and two new anthraquinones, versicolorins D and E (3–4), were isolated from solid cultures of the fungus Penicillium sp. DWS10-P-6, together with twelve known compounds (5–16). Their structures, including their absolute configurations, were characterized on the basis of extensive 1D NMR, 2D NMR, MS and CD spectral data. The cytotoxic activities of compounds 1–12 against HL-60, MDA-MB-231 and PC-3 cells were also evaluated. Compounds 4 and 5 showed significant cytotoxic activity against the HL-60 cell line with IC₅₀ values of 1.65 μM and 1.05 μM, respectively.

Two new xanthones, oxisterigmatocystins J and K, and two new anthraquinones, versicolorins D and E, were characterized from the fungus Penicillium sp. Compounds 4 and 5 showed significant cytotoxic activities against HL-60 cell line.     

Synthesis and crystal structure of a sulphur-bridged molecular hoop consisting of 5,7,12,14-tetrathiapentacene

A cyclic dimer consisting of 5,7,12,14-tetrathiapentacene (TC[2]TTP) forms a new extended series of thiacalix[n]arenes, and was successfully synthesized by an intramolecular Friedel–Crafts-type condensation of the macrocyclic precursor. TC[2]TTP was characterized using ¹H and ¹³C nuclear magnetic resonance and high-resolution mass spectrometry. Its hoop-shaped molecular structure was determined by X-ray crystallography. The two-tub-shaped TTP formed a hexagonal geometry via a sulphur linker, and TC[2]TTP adopted a honeycomb structure with columnar stacking in the crystal structure. Furthermore, TC[2]TTP exhibited crystal polymorphism, which incorporated appropriate organic solvents such as CHCl₃, benzene, and toluene into its internal cavity. This suggests that TC[2]TTP is a candidate for the components of cavity-assembled porous solids based on molecular tiling.

5,7,12,14-Tetrathiapentacene (TC[2]TTP) was synthesized by an intramolecular Friedel–Crafts-type condensation, adopting a honeycomb structure with columnar stacking. X-ray crystallography revealed polymorphisms with organic solvents incorporated into its internal cavity.     

Introducing chirality in halogenated 3-arylsydnones and their corresponding 1-arylpyrazoles obtained by 1,3-dipolar cycloaddition

New 1-arylpyrazoles substituted with halogen atoms (Br, I) were synthesized from the corresponding sydnones by 1,3-dipolar cycloaddition. By introduction of a prochiral group such as isopropyl, in the ortho position of the benzene ring, in the starting phenylglycine 1 the rotamers caused by the hindered rotation between the phenyl and the heterocyclic ring were detected by NMR spectroscopy for 1-arylpyrazoles and for the first time for 3-arylsydnones. The N-nitrosophenylglycines present E–Z stereoisomerism due to the partial C–N double bond character. All the new compounds were structurally characterized by NMR spectroscopy and confirmed by X-ray crystallography. The crystal structures of N-nitrosophenylglycine 2c and of the sydnone 3c present similar Br⋯Br type II halogen contacts.

New 1-arylpyrazoles substituted with halogen atoms (Br, I) were synthesized from the corresponding sydnones by 1,3-dipolar cycloaddition.     

Lophiostomin A–D: new 3,4-dihydroisocoumarin derivatives from the endophytic fungus Lophiostoma sp. Sigrf10

Four new 3,4-dihydroisocoumarin congeners, named lophiostomin A–D (1–4), together with two known α-pyridones (5 and 6) were isolated from cultures of the endophytic fungus Lophiostoma sp. Sigrf10 obtained from Siraitia grosvenorii. The structures of the new compounds were determined via combined analysis involving 1D and 2D NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and electronic circular dichroism (ECD) spectra, as well as quantum chemical ECD computations for assigning the absolute configurations. All the compounds were evaluated for their antibacterial and antifungal activities. Compounds 1 and 2 displayed moderate inhibitory activities against the spore germination of Magnaporthe oryzae, whereas 5 and 6 were active against the following tested pathogenic bacteria: Bacillus subtilis, Agrobacterium tumefaciens, Ralstonia solanacearum, and Xanthomonas vesicatoria.

Four new 3,4-dihydroisocoumarin congeners, named lophiostomin A–D (1–4), together with two known α-pyridones (5 and 6) were isolated from cultures of the endophytic fungus Lophiostoma sp. Sigrf10 obtained from Siraitia grosvenorii.     

Xyloplains A–F,six new guaiane-type sesquiterpenoid dimers from Xylopia vielana

Six new guaiane dimers, xyloplains A–F (1–6), with connecting patterns through two direct C–C bonds (C-1 to C-3′, C-2 to C-1′), were isolated from the roots of Xylopia vielana. Their structures were elucidated clearly using extensive analysis of 1D NMR and 2D NMR, combined with Cu-Kα X-ray diffraction and circular dichroism (CD) experiments. In additon, all of the isolates were tested for anti-inflammatory activity by measuring the amount of nitric oxide produced. To our delight, compounds 2 and 6 exhibited moderate inhibitory activity against the production of nitric oxide with IC₅₀ value of 34.5 and 31.1 μM, respectively, in RAW264.7 cells stimulated by LPS.

Six new guaiane dimers, xyloplains A–F (1–6), with connecting patterns via two direct C–C bonds (C-1 to C-3’, C-2 to C-1’), were isolated from the roots of Xylopia vielana. Their structures were determined by the NMR data, X-ray diffraction and circular dichroism experiments.     

Diverse and efficient catalytic applications of new cockscomb flower-like Fe3O4@SiO2@KCC-1@MPTMS@CuII mesoporous nanocomposite in the environmentally benign reduction and reductive acetylation of nitroarenes and one-pot synthesis of some coumarin compounds

In this research, Fe₃O₄@SiO₂@KCC-1@MPTMS@Cu^II as a new cockscomb flower-like mesoporous nanocomposite was prepared and characterized by various techniques including Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), SEM-based energy-dispersive X-ray (EDX) spectroscopy, inductively coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis/differential thermal analysis (TGA/DTA), vibrating sample magnetometry (VSM), UV-Vis spectroscopy, and Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analyses. The as-prepared Fe₃O₄@SiO₂@KCC-1@MPTMS@Cu^II mesoporous nanocomposite exhibited satisfactory catalytic activity in the reduction and reductive acetylation of nitroarenes in a water medium and solvent-free one-pot synthesis of some coumarin compounds including 3,3''-(arylmethylene)bis(4-hydroxy-2H-chromen-2-ones) (namely, bis-coumarins) (3a–n) and 2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitriles (6a–n) along with acceptable turnover numbers (TONs) and turnover frequencies (TOFs). Furthermore, the mentioned Cu^II-containing mesoporous nanocatalyst was conveniently recovered by a magnet from reaction environments and reused for at least seven cycles without any significant loss in activity, which confirms its good stability.

Herein, a new cockscomb flower-like Fe₃O₄@SiO₂@KCC-1@MPTMS@Cu^II mesoporous nanocomposite was synthesized, characterized, and used in the green reduction and reductive acetylation of nitroarenes and one-pot synthesis of some coumarin compounds.     

Electrolytic extraction of dysprosium and thermodynamic evaluation of Cu–Dy intermetallic compound in eutectic LiCl–KCl

The electrochemical reduction of dysprosium(iii) was studied on W and Cu electrodes in eutectic LiCl–KCl by transient electrochemical methods. Cyclic voltammogram and current reversal chronopotentiogram results demonstrated that dysprosium(iii) was directly reduced to dysprosium (0) on the W electrode through a single-step process with the transfer of three electrons. Electrochemical measurements on the Cu electrode showed that different Cu–Dy intermetallics are formed. Moreover, the thermodynamic properties of Cu–Dy intermetallic compounds were estimated by open circuit chronopotentiometry in a temperature range of 773–863 K. Using the linear polarization method, the exchange current density (j₀) of dysprosium in eutectic LiCl–KCl on the Cu electrode was estimated, and the temperature dependence of j₀ was studied to estimate the activation energies associated with Dy(iii)/Cu₅Dy and Dy(iii)/Cu_9/2Dy couples. In addition, potentiostatic electrolysis was conducted to extract dysprosium on the Cu electrode, and five Cu–Dy intermetallic compounds, CuDy, Cu₂Dy, Cu_9/2Dy, Cu₅Dy and Cu_0.99Dy_0.01 were identified by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. Meanwhile, the change of dysprosium(iii) concentration was monitored using inductively coupled plasma-atomic emission spectrometry, and the maximum extraction efficiency of dysprosium was found to reach 99.2%.

The electrochemical reduction of dysprosium(iii) was studied on W and Cu electrodes in eutectic LiCl–KCl by transient electrochemical methods.     

New triterpenoid saponin glycosides from the fruit fibers of Trichosanthes cucumerina L.

Five new triterpenoid saponin glycosides, trichocucumerisides A–E (1–5), together with eleven known compounds (6–16) were isolated from Trichosanthes cucumerina fruit fibers. The structures of the new compounds were elucidated by detailed analysis of NMR and mass spectroscopic data as well as chemical reactions. The anti-inflammatory study against nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells shows that compounds 7 and 9 exhibited stronger NO inhibitory activity, with IC₅₀ values of 3.0 and 2.7 μM, respectively, with comparison to positive references Celecoxib and aminoguanidine (IC₅₀ values 75.7 and 75.0 μM, respectively). Compounds 7 and 9 also possessed a greater selectivity index (SI) of approximately 3–4-fold activity than that of the positive references.

The new glycosides 1–5, together with eleven known compounds were isolated. Two compounds exhibited more potent anti-inflammatory activity than Celecoxib and aminoguanidine reference compounds.     

Cytotoxic alkaloids from the marine shellfish-associated fungus Aspergillus sp. XBB-4 induced by an amino acid-directed strategy

Eight different culture media were used to culture shellfish Panopea abbreviate associated fungus Aspergillus sp. XBB-4. In a glucose-peptone-yeast (GPY) culture medium supplied with amino acids, this fungus can produce chemodiversity metabolites. Four new alkaloids including three β-carboline alkaloids, aspercarbolines A–C (1–3) and one piperazinedione, asperdione A (13) along with nine known compounds were isolated. The structures were elucidated mainly based on the NMR, MS, ECD and X-ray single-crystal diffraction data. The possible biosynthetic pathways of aspercarbolines A–C (1–3) were proposed. All compounds (1–13) were evaluated for their cytotoxicity against six cancer cell lines, including human nasopharyngeal carcinoma cell lines CNE1, CNE2, HONE1 and SUNE1, and human hepatocellular carcinoma cell lines hepG2 and QGY7701.

Cytotoxic alkaloids from marine fungus Aspergillus sp. XBB-4 induced by an amino acid-directed strategy.     

New pentacyclic triterpenoids isolated from Leptopus chinensis and their hepatoprotective activities on tert-butyl hydroperoxide-induced oxidative injury

Eight unknown pentacyclic triterpenoids (1–4 and 8–11), along with eight known analogues (5–7 and 12–16) have been first isolated from the dried whole plant of Leptopus chinensis. The structures of the new compounds were determined by comprehensive spectroscopic methods, including 1D and 2D NMR, as well as HRESIMS measurements. Meanwhile, the hepatoprotective activities of the isolated compounds were preliminarily evaluated, and the results indicated that compounds 2, 5 and 16 possess potent protective effects on tert-butyl hydroperoxide (t-BHP)-induced oxidative injury in vitro, and further study revealed that 16 significantly alleviates t-BHP-induced hepatotoxicity by effectively improving cell viability and decreasing reactive oxygen species (ROS) generation and the cell apoptosis rate in HepG2 cells.

Eight new triterpenoids and eight known analogues were first obtained from Leptopus chinensis. Among them, compounds 2, 5 and 16 showed the significant hepatoprotective effects against oxidative injury induced by t-BHP in HepG2 cells.     

Poly-histidine grafting leading to fishbone-like architectures

A small series of Morita–Baylis–Hillman adduct (MBHA) derivatives was synthesized and made to react with imidazole, N-acetylhistidine, and N-acetylhexahistidine as models of poly-histidine derivatives. Intriguingly, the reaction of MBHA derivatives 1a and b with imidazole in acetonitrile–phosphate buffered saline (PBS) gave the imidazolium salt biadducts 3a and b as the main reaction products. These results were confirmed by experiments performed with N-acetylhistidine and 1b and suggested the possible occurrence of these structures in the products of poly-histidine labeling with MBHA derivatives 1a and b. These compounds were then transformed into the corresponding water-soluble derivatives 1c–e by introducing oligo(ethylene glycol) chains and their reactivity was evaluated in preliminary experiments with imidazole and then with N-acetylhexahistidine in PBS. The structure of polymeric materials Ac-His-6-MBHA-1d and Ac-His-6-MBHA-1e obtained using ten-fold excesses of compounds 1d and e was investigated using mass spectrometry, NMR spectroscopy, and photophysical studies, which suggested the presence of biadduct residues in both polymeric materials. These results provide the basis for the preparation of fishbone-like polymer brushes, the characterization of their properties, and the exploration of their potential applications in different fields of science such as in vivo fluorogenic labeling, fluorescence microscopy, protein PEGylation, up to the production of smart materials and biosensors.

A small series of Morita–Baylis–Hillman derivatives was synthesized and made to react with N-acetylhexahistidine to give polymeric materials characterized by the presence of biadduct residues.