Showing papers on "Benzophenone published in 2019"
TL;DR: A dual catalytic protocol for the direct arylation of non-activated C(sp3 )-H bonds has been developed using the excited triplet state of a diaryl ketone photosensitizer for the generation of benzylic radicals which subsequently enter a nickel catalytic cycle.
Abstract: A dual catalytic protocol for the direct arylation of non-activated C(sp3 )-H bonds has been developed. Upon photochemical excitation, the excited triplet state of a diaryl ketone photosensitizer abstracts a hydrogen atom from an aliphatic C-H bond. This inherent reactivity was exploited for the generation of benzylic radicals which subsequently enter a nickel catalytic cycle, accomplishing the benzylic arylation.
110 citations
TL;DR: The cost-effective treatment toward target compounds removal in different water matrices was further evaluated using EE/O and in most cases, UV/H2O2 process is more economically competitive than UV/PDS process.
69 citations
TL;DR: Lignin nanospheres with broad-spectrum UV adsorption and excellent antioxidant properties were obtained by demethoxylation of alkali lignin and grafting the benzophenone moiety.
Abstract: Lignin nanospheres with broad-spectrum UV adsorption and excellent antioxidant properties were obtained by demethoxylation of alkali lignin (AL) and grafting the benzophenone moiety (UV-0) followed...
52 citations
TL;DR: The results illustrate that the electrochemical technique with Ti/SnO2-Sb/Ce-PbO2 anode is expected to be an effective way for removing BP-3 and its metabolite 4-OH-BP from wastewater.
50 citations
TL;DR: Among the series of novel benzophenones conjugated with oxadiazole sulphur bridge pyrazole moiety 8a-l, compound 8i with electron withdrawing fluoro group at the para position of the benzoyl ring of benzophenone was characterized by highest IC50 values for both COX-1 andCOX-2 inhibition, which is comparable to the standard drug.
41 citations
TL;DR: A novel copper-catalyzed C(sp3)-N coupling of cycloketone oxime esters with nitrogen nucleophiles has been realized and resultant cyano-containing alkyl amines were proven to be versatile synthetic building blocks in a variety of chemical transformations.
32 citations
TL;DR: This catalyst outperforms closely related bi- and tridentate phosphine-based Ni catalysts and suggests a reaction pathway involving a hemilabile interaction of the C=O unit with the nickel center.
Abstract: Adaptive ligands, which can adapt their coordination mode to the electronic structure of various catalytic intermediates, offer the potential to develop improved homogeneous catalysts in terms of activity and selectivity. 2,2′-Diphosphinobenzophenones have previously been shown to act as adaptive ligands, the central ketone moiety preferentially coordinating reduced metal centers. Herein, the utility of this scaffold in nickel-catalyzed alkyne cyclotrimerization is investigated. The complex [(p-tolL1)Ni(BPI)] (p-tolL1 = 2,2′-bis(di(para-tolyl)phosphino)-benzophenone; BPI = benzophenone imine) is an active catalyst in the [2 + 2 + 2] cyclotrimerization of terminal alkynes, selectively affording 1,2,4-substituted benzenes from terminal alkynes. In particular, this catalyst outperforms closely related bi- and tridentate phosphine-based Ni catalysts. This suggests a reaction pathway involving a hemilabile interaction of the C═O unit with the nickel center. This is further borne out by a comparative study of t...
31 citations
TL;DR: It is reported that the polymerization of such olefins is strongly limited or suppressed when combining the photocatalytic activity of benzophenone with a catalytic amount of Cu(OAc) 2 .
Abstract: Photocatalyzed Giese-type alkylations of C(sp3 )-H bonds are very attractive reactions in the context of atom-economy in C-C bond formation. The main limitation of such reactions is that when using highly polymerizable olefin acceptors, such as unsubstituted acrylates, acrylonitrile, or methyl vinyl ketone, radical polymerization often becomes the dominant or exclusive reaction pathway. Herein, we report that the polymerization of such olefins is strongly limited or suppressed when combining the photocatalytic activity of benzophenone (BP) with a catalytic amount of Cu(OAc)2 . Under mild and operationally simple conditions, the Giese adducts resulting from the C(sp3 )-H functionalization of amines, alcohols, ethers, and cycloalkanes could be synthesized. Preliminary mechanistic studies have revealed that the reaction does not proceed through a radical chain, but through a dual BP/Cu photocatalytic process, in which both CuII and low-valent CuI/0 species, generated in situ by reduction by the BP ketyl radical, may react with α-keto or α-cyano intermediate radicals, thus preventing polymerization.
25 citations
TL;DR: The preparation of some hypervalent iodine reagents containing a transferable amino group derived from benzophenone imine derivatives is reported, and were successfully used in the transition-metal-free oxidative amination of silyl ketene acetals to afford the corresponding α-amino esters.
Abstract: The preparation of some hypervalent iodine reagents containing a transferable amino group derived from benzophenone imine derivatives is reported. The reagents can be readily prepared and stored as a bench-stable solid, and were successfully used in the transition-metal-free oxidative amination of silyl ketene acetals to afford the corresponding α-amino esters, the benzophenone imine moieties of which could be easily hydrolyzed, thereby leading to the formation of primary amines.
25 citations
TL;DR: In this article, two new asymetric D-A-D type compounds containing benzophenone and diphenylsulfone as electron accepting core, and acridan and thianthrene as electron donating moieties were designed as multifunctional materials.
23 citations
TL;DR: BPTCA-N had the synergistic antibacterial effect of quaternary ammonium salt and benzophenones and has the potential application in the biomedical field as highly effective antimicrobial agents or antimicrobial biomaterials.
Abstract: Developing an efficient antimicrobial surface has important significance in the field of advanced biomaterials. A novel water-soluble benzophenone tetracarboxylamine derivative containing two quaternary ammonium groups, 3,3'-[4,4'-carbonyl-diphthalimide-]-bis(N-benzyl-N,N-dimethyl-N-propyl-1-aminium)dichloride (BPTCA-N), as a photoactive antibacterial agent was designed and synthesized. The ability of BPTCA-N to generate reactive oxygen species (ROS) in solution was investigated by light-induced activity. Its antibacterial activity in a dark environment or UV exposure was tested on Staphylococcus aureus and Escherichia coli. The influences of different solvents and the pH values on the ability of BPTCA-N to generate ROS were also discussed. BPTCA-N possessed high photoactivity and efficient ROS generation ability. The generation of hydroxyl radicals could be greatly affected by addition of other solvents and H+ or OH-. For the BPTCA-N solution at a concentration of 0.2 mmol/L, the reduction of S. aureus and E. coli could all reach 99.99%. The BPTCA-N compound was assembled onto wool protein fibers. The modified protein fabrics also showed excellent photoactivity and antibacterial property against S. aureus and E. coli. For the wool fabric modified with 30 g/L of BPTCA-N, the reduction of S. aureus could reach 99.91% and that of E. coli was 91.23%. BPTCA-N had the synergistic antibacterial effect of quaternary ammonium salt and benzophenones. It has potential application in the biomedical field as highly effective antimicrobial agent or antimicrobial biomaterial.
TL;DR: Irradiation of a series of p-substituted aryl benzoates under N2 atmosphere in homogeneous and micellar media was investigated by means of steady-state condition and of time-resolved spectroscopy and a notable selectivity in favor of the 2-hydroxybenzophenone derivatives was observed in miceLLar media.
Abstract: Irradiation of a series of p-substituted aryl benzoates under N2 atmosphere in homogeneous and micellar media was investigated by means of steady-state condition and of time-resolved spectroscopy. A notable selectivity in favor of the 2-hydroxybenzophenone derivatives was observed in micellar media. The benzophenone derivatives were the main photoproduct. On the other hand, in homogeneous media (cyclohexane, acetonitrile, and methanol) the observed product distribution was entirely different, viz. substituted 2-hydroxybenzophenones, p-substituted phenols, benzyl and benzoic acid were found. The binding constants in the surfactant were also measured and NOESY experiments showed that the aryl benzoates were located in the hydrophobic core of the micelle. Laser flash photolysis experiments led to the characterization of both p-substituted phenoxy radical and substituted 2-benzoylcyclohexadienone transients in homogeneous and micellar environment.
TL;DR: An aliphatic polyester from ethylene oxide and maleic anhydride is reported, which exhibits reversible transformation between amorphous and crystalline states controlled by cis-trans isomerization of C=C bonds in the polymer backbone without any change in both the molecular weight and dispersity of polymer.
Abstract: An aliphatic polyester has been prepared from ethylene oxide and maleic anhydride that undergoes reversible transformation between amorphous (Tg =18 °C) and crystalline (Tm =124 °C) states through cis-trans isomerization of the C=C bonds in the polymer backbone without any change in either the molecular weight or dispersity of the polymer. A similar transformation was also observed in chiral unsaturated polyesters formed from enantiopure terminal epoxides, such as epichlorohydrin, phenyl glycidyl ether, and (2,3-epoxypropyl)benzene. These unsaturated polyesters with 100 % E-configuration in the crystalline state were prepared by quantitative isomerization of their Z-configuration analogues in the presence of a catalytic amount of diethylamine, while in the presence of benzophenone, irradiation with 365 nm UV light resulted in the transformation of about 30 % trans-alkene to cis-maleate form, thereby affording amorphous polyesters.
TL;DR: A rapid, effective and simple one-step strategy for PVC surface functionalization by combining the "sulfur(vi)-fluoride exchange" (SuFEx) reaction with benzophenone photochemistry is presented.
08 Nov 2019
TL;DR: A promising spirolactam-functionalized chemosensor, rhodamine-appended benzophenone (HBR), is designed and characterized by spectroscopic data along with the single-crystal X-ray diffraction technique, and this “turn-on” probe has successfully applied to image the Pd2+ ion in cultured MDA-MB-231 cells.
Abstract: Designing a fluorogenic probe for the determination of Pd2+ is a challenging analytical task. Pd2+ is a potentially toxic and harmful substance even at a very low level of contamination in the end product. Herein, a promising spirolactam-functionalized chemosensor, rhodamine-appended benzophenone (HBR), is designed and characterized by spectroscopic (1H NMR, 13C NMR, ESI-MS, and FT-IR) data along with the single-crystal X-ray diffraction technique. It acts as a highly sensitive and selective fluorogenic chemosensor for Pd2+ ions over other environmentally relevant cations in aqueous ethanol (1:1, v/v) at pH 7.4. The limit of detection (LOD) is 34 nM that is far below the WHO recommended Pd uptake (47 μM). The plausible mechanism involves the specific binding of HBR with Pd2+ and the formation of 1:1 stoichiometry of the complex, which has been supported by ESI-MS, FT-IR data, Job plot, and association constant data (Benesi-Hildebrand plot). The computation study has been attempted to explain the ring cleavage fluorescence enhancement scheme of HBR upon binding with Pd2+. Furthermore, this "turn-on" probe has successfully applied to image the Pd2+ ion in cultured MDA-MB-231 cells.
TL;DR: Identifications of three bioactive compounds from P. guajava L. leaves and their anti-cancer effects against human colon cancer cells are provided, which could facilitate the utilization of these compounds and P. Guajava leaves as potential chemoprevention agents against colon carcinogenesis.
Abstract: Psidium guajava L. leaves have a long history of being consumed as herbal teas in many countries. The aim of this study was to identify compounds with anticancer potentials from Psidium guajava L. leaves. Utilizing various extraction and chromatographical techniques, we have isolated one new (2) and two known compounds (1, 3). Structural analyses by the spectroscopic methods of TOF-MS, 1H NMR, 13C NMR, HSQC, and HMBC identified these three compounds as guavinoside E (1), 3,5-dihydroxy-2,4-dimethyl-1-O-(6'-O-galloyl-β-d-glucopyranosyl)-benzophenone (2), and guavinoside B (3). Cell viability assays showed that compounds 2 and 3 inhibited the growth of HCT116 human colon cancer cells in a dose-dependent manner, where compound 2 was more potent than compound 3. Based on flow cytometry analysis, compound 2 showed stronger activity in inducing cellular apoptosis in cancer cells than compound 3. Furthermore, compounds 2 and 3 modulated expression levels of key proteins involved in cell proliferation and apoptotic signaling. Specifically, compound 2 increased the levels of p53, p-ERK1/2, p-JNK, and cleaved caspases 8 and 9, and compound 3 increased the levels of p53 and cleaved caspase 8. Overall, this study provided identities of three bioactive compounds from P. guajava L. leaves and their anti-cancer effects against human colon cancer cells, which could facilitate the utilization of these compounds and P. guajava L. leaves as potential chemoprevention agents against colon carcinogenesis.
TL;DR: In this article, a series of donor-acceptor (D-A) compounds consisting of a thianthrene donor and either a benzophenone or a diphenylsulfone acceptor units were designed and synthesized via Suzuki cross-coupling.
TL;DR: Asymmetric insertion of α-diazoesters into the N–H bond of N-sp2-hybridized benzophenone imine was realized by using Rh2(esp)2 and chiral guanidine cooperative catalysis.
Abstract: Efficient enantioselective insertion of α-diazoesters into the N–H bond of N-sp2-hybridized benzophenone imine was realized by using Rh2(esp)2 and chiral guanidine cooperative catalysis. Both aliphatic and aromatic substituted α-amino esters were obtained in high yields (up to 99%) and good enantioselectivities (up to 95.5 : 4.5 er) under mild reaction conditions.
TL;DR: Four novel benzophenone derivatives, cytosporins A-D (1-4), hemiterpene-conjugated phenolics with an unprecedented benzo[b][1,5]dioxocane skeleton, were isolated from Cytospora rhizophorae A761.
Abstract: Four novel benzophenone derivatives, cytosporins A–D (1–4), hemiterpene-conjugated phenolics with an unprecedented benzo[b][1,5]dioxocane skeleton, were isolated from Cytospora rhizophorae A761. The structures of the new compounds were fully characterized on the basis of extensive spectroscopic analysis. The deduced structure represents the first example of natural meroterpenoids which bear a benzo[b][1,5]dioxocane framework embodying hemiterpene and benzophenone moieties. Moreover, compounds 1–4 were evaluated for in vitro antimicrobial activity.
TL;DR: The red-edge excitation effect is exploited to demonstrate that by sub-ensemble selective excitation of Bzp molecules, either coordinated or non-coordinated to phenol through hydrogen bonding in a dichloromethane solution, the rate of an H-atom abstraction reaction can be accelerated by a factor of ~40.
Abstract: A long-standing ambition of photochemists is to excite species selectively in a complex liquid solution and in turn instigate a controlled chemical reaction. Benzophenone (Bzp) has been studied ove...
TL;DR: In this article, a poly(N,N-dimethylacrylamide) (PDMAA) chains that contains 5% of benzophenone molecules was synthesized and coated on bare organic substrates.
Abstract: In this study poly(N,N-dimethylacrylamide) (PDMAA) chains that contains 5 mol% of benzophenone molecules was synthesized and coated on bare organic substrates. Upon irradiation under UV light, the photo-active benzophenone molecules enabled the formation of polymer network as well as attachment of the polymer network onto the organic substrates. From the film thickness (AFM) and photoreaction kinetics of benzophenone (UV-Vis spectroscopy), the surface density of unreacted (active) benzophenone could be controlled. Five model surfaces carrying different densities of active benzophenone were prepared by pre-irradiating approximately 1000-nm spin-coated polymer films at various irradiation energy doses. Addition of protein (laminin) as the bioactive ligands to the partially cross-linked polymeric layer followed by additional irradiation of the mixture under UV light enabled the C,H-insertion crosslinking (CHiC) process between the polymer and the bioactive ligands. This resulted in the so-called dual-functional surface that contains bioactive spots on a biopassive background. Results from immunostaining and cell adhesion experiments showed that the surface density of active benzophenone (0–2.28 × 109 molecules/nm2) played role to the bioactive properties of laminin-decorated spots, while FTIR results indicated that laminin was stable upon irradiation under UV light (365 nm) up to 18 J/cm2.
TL;DR: Preliminary studies on catalytic hydrosilylation using PhSiH3 indicate that the hydridozinc cation in the presence of BPh3 can selectively reduce CO2 to PhSi(OCHO)3.
TL;DR: In this article, a silica-supported ultrafine Ni catalyst for the selective hydrogenation of benzophenone was reported, achieving a 97.7% selectivity for benzhydrol.
Abstract: In this work, we report a silica-supported ultrafine Ni catalyst for the selective hydrogenation of benzophenone. This material was developed by a facile one-pot co-assembly syntheses strategy, using Ni(II) chelated alginate hydrogel as metal precursor and sacrificial template. Due to the highly active and uniformly dispersed Ni nanoparticles (NPs), 99.8% of benzophenone conversion was achieved. Remarkably, it also reached a 97.7% of selectivity for benzhydrol during benzophenone hydrogenation. Temperature-programmed desorption of ammonia (NH3-TPD) and Density Functional Theory (DFT) results reveal that the in-situ generated sodium carbonate (Na2CO3) derived from sodium alginate is essential in tuning the selectivity of benzhydrol: the existence of Na2CO3 reduces the surface acidity of catalyst and promotes the desorption of intermediate benzhydrol, preventing its further hydrogenolysis on the surface acidic sites of catalyst. Moreover, the supported Ni catalyst shows no significant loss of its activity during 20 times of recycling.
TL;DR: In this article, a straightforward method for preparing well-defined polymeric nanoparticles using radical coupling process of ketyl moieties resulted from triplet excitation of pendant benzophenone groups.
TL;DR: In this article, the photocatalytic reduction of benzophenone was studied focusing on improving the yield to benzhydrol, using a commercial TiO2-P25 as a reference.
Abstract: The photocatalytic reduction of benzophenone was studied focusing on improving the yield to benzhydrol. TiO2 was synthesized by means of a hydrothermal technique. TiO2 (Degussa TiO2-P25) was used as a reference. Catalysts were characterized by XRD and nitrogen physisorption. The photocatalytic reduction was carried out in a batch reactor at 25 °C under nitrogen atmosphere, acetonitrile as solvent and isopropanol as electron donor. A 200 W Xe-Hg lamp (λ = 360 nm) was employed as irradiation source. The chemical com- position of the reaction system was determined by HPLC. Structural and textural properties of the synthesized TiO2 depended on the type of acid used during sol formation step. Using HCl, a higher specific surface area and narrower pore size distribution of TiO2 was obtained in comparison with acetic acid. As expected, the photochemical reduction of benzophenone yielded benzopinacol as main product, whereas, benzhydrol is only produced in presence of TiO2 (i.e. photo- catalytic route). In general, the hydrothermally synthesized catalysts were less active and with a lower yield to benzhydrol. The optimal reaction conditions to highest values of benzhydrol yield (70-80%) were found at 2 g/L (catalyst loading) and 0.5 mM of initial concen- tration of benzophenone, using commercial TiO2-P25.
TL;DR: Despite the lack of substantial radical character on the ligands, alkyne and ketone fragments can couple to form a high-spin iron(III) complex with a cyclized metalladihydrofuran core.
TL;DR: In this article, the authors proposed a N-protected primary amine intermediate for the Buchwald-Hartwig amination, which is a useful ammonia equivalent to benzophenone imine.
14 Feb 2019
TL;DR: An analytical workflow for the interpretation of MS spectra is proposed, giving access to information on the CPP/lipid interaction at a molecular level such as depth of insertion or membrane fluidity in the C PP vicinity.
Abstract: Affinity photo-cross-linking coupled to mass spectrometry, using benzophenone (Bzp)-functionalized peptides, was used to study the noncovalent interactions of cell-penetrating peptides and lipid me...
TL;DR: A photo-assisted three-step procedure to fix carbon dioxide (CO2) onto aryl bromides is reported in this article, where CO2 is temporarily fixed onto benzophenone to furnish benzilic acid.
Abstract: A photo-assisted three-step procedure to fix carbon dioxide (CO2) onto aryl bromides is reported. In the first photoinduced step, CO2 is temporarily fixed onto benzophenone to furnish benzilic acid...