Benzophenone Research Articles

Tert-Butyl Bromide-Promoted Intramolecular Cyclization of 2-Arylamino Phenyl Ketones and Its Combination with Cu-Catalyzed C-N Coupling: Synthesis of Acridines at Room Temperature.

Herein, a facile intramolecular cyclization of 2-arylamino phenyl ketones is established to supersede the traditional high-temperature, strongly acidic conditions and achieve 9-substituted acridines, by virtue of the combination of 2,2,2-trifluoroethanol and tert-butyl bromide. This protocol can be merged well with the preceding Cu-catalyzed intermolecular Chan-Evans-Lam cross-coupling reactions, therefore enabling pot-economic modular synthesis of 9-substituted acridines from readily available 2-amino phenyl ketones and aryl boronic acids at room temperature.

Electrically Healable and Mechano‐Sensitive Gel Composites of Carbon Nanotubes and Conducting Polymers

AbstractWe performed a one‐pot mechanosynthesis of adaptive conducting gels using carbon nanotubes (CNTs) and a non‐volatile eutectic liquid (EL) of diphenylamine (DP) with benzophenone (BP). Upon further mixing with ammonium persulfate (APS), oxidative polymerization of DPs enabled the generation of electrically healable conductors containing poly(diphenylamine) (PDPA) as an adaptive matrix. The resulting composite gels were created through a synergistic combination of CNTs and PDPAs, which exhibited printable and conductive characteristics. Thus, after printing on an elastic substrate, the conducting ink composite displayed excellent electromechanical sensory properties.

Synthesis and application of new S-benzoheterocycle thiobenzoates photoinitiators

A series of free radical photoinitiators with thioester bonds were synthesized by the nucleophilic substitution reaction of acyl chloride and thiol or thiophenol. These compounds could be efficiently obtained under mild reaction conditions and were fully characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry. This kind of compounds exhibited a strong ultraviolet–visible light absorption spectrum with an extended absorption around 330 nm in DMSO. Moreover, these compounds were utilized as free radical photoinitiators in ultraviolet curing and the resulting films exhibited comparable mechanical properties in comparison with commercially available photoinitiators, such as 1-hydroxycyclohexyl phenyl ketone (Irgacure 184) and benzophenone. We also proposed a probable photoinitiated polymerization mechanism for S-benzoheterocycle thiobenzoates as photoinitiators.

Sulphate radical oxidation of benzophenone: kinetics, mechanisms and influence of water matrix anions

ABSTRACT Benzophenone (BP) is an emerging contaminant that is widely distributed in soil, groundwater, sediment and surface water. In this study, the degradation kinetics, mechanisms, and influence of anions on thermally activated persulphate (TAP) oxidation of BP were systematically investigated. BP degradation was promoted by elevated temperature. The BP degradation data fitted well to the Arrhenius equation with calculated activation energy of 122.8 kJ/mol. BP degradation was also promoted by alkaline pH and high persulphate concentrations. Radical scavenging experiments suggested that both SO4 •− and HO• were involved in BP oxidation. Ultra-high-performance liquid chromatography coupled to Orbitrap mass spectrometry (UHPLC-Orbitrap-MS) identified six degradation intermediates. Based on these results, two possible reaction pathways were proposed. Water matrix anions had complex impacts on BP degradation by TAP. Cl− had dual effects on the reaction: low concentration promoted it while high concentration inhibited it. Br− strongly suppressed the reaction. SO4 2− and NO3 − did not affect the reaction. Overall, this study shows that thermally activated persulphate can effectively remove BP and water matrix anions greatly influence the reaction.

Water Stable Heterometallic Zn-Tb Coordination Polymer for Rapid Detection of the Ultraviolet Filter Benzophenone.

Benzophenone (BP) is an ultraviolet filter (UVF) widely used in personal care products such as sunscreens and cosmetics. Excessive exposure to BP-type UVFs is a potential threat to human's health because of their endocrine-disrupting activity. Water stability of lanthanide compounds is crucial when they serve as luminescent sensors because of the practicality and recyclability. In this study, a water-stable luminescent Zn-Tb heterometallic coordination polymer was rationally designed and synthesized for rapid detection of BP. This material showed a high quenching effect, excellent selectivity, and fast response toward BP.

Photocross-linking Kinetics Study of Benzophenone Containing Zwitterionic Copolymers.

The kinetics of benzophenone (BP) and its derivatives have been widely studied in different solvents by nanosecond laser flash photolysis as well as in the polymer matrix. With the development of functional polymer coating, BP, as well as other photocross-linkers, has been incorporated into the polymer backbone or side chain to form the covalent connection between polymer coatings and substrates, which can improve the mechanical and chemical stability of the coatings. In this work, a series of BP pendent zwitterionic copolymer kinetics were investigated using UV–vis for the first time. Because of the high hydrophilicity of the zwitterionic monomer, the influence of the polymer matrix’s polarity on the cross-linking rate was observed. With a higher zwitterionic percentage in the copolymer, the polarity of the copolymer increases, BP reactivity decreases, and a hypothesis between the BP rate constant and partial coefficient log P was raised. Moreover, the thermal property is also an important factor affecting the BP reactivity. For polymers with high glass-transition temperature, the reactivity was not dominated by the chemical environment such as polarity, and the restricted segment movement reduces the cross-linking rate. Additionally, the ring substituents show similar effects to BP pendent copolymers as with small molecules. Electron-withdrawing groups help to stabilize the BP triplet radical and facilitate cross-linking, while electron-donating groups work conversely. Therefore, polarity, thermal properties, and substituents should be taken into consideration when designing BP-containing functional polymers.

A hybrid block consisting of covalent triazine frameworks and GO aerogel with switchable selectivity between adsorption of UV filters and regeneration under sunlight

UV filters, a kind of personal care product (PCP), are intractably degraded using conventional processes because of their trace concentration in the environment. The exploration of high-performance, stable, and reusable materials for the highly efficient removal of UV filters is of great importance. In this study, a series of three-dimensional graphene oxide-covalent triazine-based frameworks aerogels (3D GO-CTF) prepared with different concentration ratios were designed to remove trace concentrations of benzophenone (BP), 2,4-dihydroxybenzophenone (BP-1) and 2-hydroxy-4-methoxybenzophenone (BP-3) from water, which are regenerated by sunlight. 3D GO-CTF not only adsorbs UV filters with high efficiency (0.0311 ± 0.0009 g/(μmol·s)) and capacity (2963.708 ± 4.637 μmol/g), but can also be regenerated with an extremely high percentage recovery of 90–95% in the 4th cycle. These 3D GO-CTF materials exhibit switchable selectivity between the adsorption of the UV filters and regeneration of the 3D GO-CTF by regulating the content of GO to function as the adsorbent and CTF for photocatalytic regeneration. Moreover, the high reusability and extreme stability of the 3D GO-CTF aerogels were verified over seven cycles of night-day testing in a real water matrix, which demonstrated their potential application in the efficient removal of micropollutants from the environment.

Occurrence and transfer of benzophenone-type ultraviolet filters from the pregnant women to fetuses

Benzophenone (BP)-type ultraviolet (UV) filters are widely used in personal care products. Some of them have been identified as endocrine disrupting chemicals. However, little is known about the occurrence of BP-type UV filters in paired maternal-fetal samples. In this study, we investigated the occurrence of eight BP-type UV filters in paired maternal-fetal samples collected from Southern China. Among target analytes, only benzophenone-3 (BP-3) was frequently (detection rate > 80%) detected in maternal-fetal samples, i.e., maternal serum (MS), cord serum (CS), maternal urine (MU) and amniotic fluid (AF). BP-3 was the dominant compound in MS (median: 0.14 ng/mL), CS (0.16) and AF (0.12); whereas MU was dominated by benzophenone-1 (BP-1, 2.85). The median CS/MS ratios (i.e., placental transfer rates) of 4-hydroxy benzophenone (4-OH-BP, 2.35), BP-1 (1.52), benzophenone-4 (BP-4, 1.06), and BP-3 (1.03) were higher than 1.0, suggesting that exposure levels of these chemicals in fetuses were greater than those in mothers. Significant positive correlations (r = 0.667, p < 0.001) of BP-3 concentrations were found between MS and CS, which suggested that MS could be an indicator of fetal exposure to BP-3. Furthermore, the CS/MS ratios of 4-OH-BP, BP-1, BP-3, and benzophenone-8 (BP-8) increased with decreasing molecular weight or log Kow. Passive diffusion may play an important role in placental transfer of these BP type UV filters. The MU/MSBP-3 ratio (5.86) was relatively higher than that of MU/MSBP-1 (0.89), which indicated that BP-3 excretes rapidly in urine. The present study documents the occurrence of eight BP-type UV filters in matched MS, CS, MU and AF samples for the first time in China.

Post-synthesis modification of polyethersulfone membrane by grafting hyperbranched polyethylene glycol for oily wastewater treatment

The main goal of this study is to modify the polyethersulfone membrane by the grafting hyperbranched polyethylene glycol (HB-PEG) via a two-step grafting method: (1) membrane surface activation with a photo-initiator under UV irradiation and (2) grafting HB-PEG onto the surface-activated membrane. The separation efficiency and fouling tendency of the modified membranes were evaluated for the treatment of a synthetic oily wastewater. A mechanism was proposed for the grafting reaction, and Lambert–Beer law was employed to determine the effect of benzophenone (BP) concentration as a photo-initiator on the grafting reaction. It was found that the rate of the grafting reaction has a maximum at the BP concentration of 0.33 mol/L. The FTIR and SEM analyses confirmed that the HB-PEG was successfully grafted on the surface of activated PES membranes. Moreover, the grafting HB-PEG onto the surface of the PES membranes alerted the surface hydrophilicity and led to the improvement of the anti-fouling property and oil–water permeation flux of all modified membranes without any remarkable changes in the oil rejection, as 48% and 52% enhancement in the pure water flux and oil–water flux were observed, respectively, compared to the neat PES membrane. Finally, the chemical stability of the modified membrane was investigated and the recovery of the fouled membrane after basic and acidic cleaning was 58% and 94%, respectively.

Liquid-Phase Total Synthesis of Plecanatide Aided by Diphenylphosphinyloxyl Diphenyl Ketone (DDK) Derivatives.

Plecanatide is an oral guanylate cyclase-C agonist for the treatment of gastrointestinal disorders. The large-scale supply of plecanatide is restrained primarily by its industrial manufacture. Herein we developed diphenylphosphinyloxyl diphenyl ketone (DDK) derivatives as greener supports with unique precipitation-inducing properties to aid the liquid-phase total synthesis of plecanatide without the use of chromatography. Plecanatide could be obtained in high yield, and the ultimately sheared DDK derivative residue could be directly recycled or regenerated for reuse.

Inactivation of bacteria in plasma by photosensitizers benzophenone and vitamins K3, B1 and B6 with UV A light irradiation.

A photosensitizer is a light-activated molecule that can generate reactive oxygen species or directly interact with nucleic acids. Both consequences can be applied to reduction of pathogens in various media and to selectively attack tumor cells. Numerous natural and synthesized photosensitizers have been identified for pathogen reduction. The photosensitizers of vitamins K3 (VK3), B1 (VB1), B6 (VB6) and benzophenone (BP) were prepared in 100-200 μM of PBS solution, irradiated with UVA at 0-48 J/cm2 for absorption spectrum alterations analysis. Bacteria species of E. coli, B. cereus, S. aureus and K. pneumoniae were mixed with 0-200 mM concentration of compounds and exposed to UVA irradiation of different dose at 6, 12 or 18 J/cm2 to assess the bactericidal effects. Over six logs CFU/ml reduction of E. coli suspended in PBS occurred after treatment with either VB1, VB6, VK3 or BP combined with UVA irradiation. When bacteria were suspended in plasma, two to seven logs reduction occurred depending on the UVA dose, photosensitizer concentration, and bacteria species. Among these photosensitizers, BP had the most potent bactericidal effect and is a promising UVA photosensitizer for pathogen reduction. The level of absorption spectrum alteration after UVA irradiation was profound for VK3 and VB6 but minimal for BP and VB1. The UV-vis absorption spectrum changes did not correlate with the bactericidal effect indicating that molecule modification by UVA light is not required for the bactericidal activity.

Emerging micropollutants determination by NIR spectroscopy using pseudo-univariate calibration and TF-SPME coupled with 96-well plate system

In this study, an innovative approach was developed to determine simultaneously the emerging micropollutants bisphenol A (BPA), 3-(4-methylbenzylidene) camphor (4-MBC), triclocarban (TCC), benzophenone (BZP) and 2-ethyl-hexyl-4-trimethoxycinnamate (EHMC) in water employing near infrared spectroscopy (NIR) coupled with thin film solid-phase microextraction (TF-SPME) using the chemometric tool of multivariate curve resolution with alternating least squares (MCR-ALS). In addition, a 96-well plate system was employed to increase the analysis throughput of the proposed methodology. Samples were submitted to TF-SPME procedure (previously optimized in previous work to exhibit the best performance for extraction and desorption conditions) and its extracts were analyzed by NIR. A pseudo-univariate calibration model for each analyte was developed by associating the relative concentration obtained using MCR-ALS with the reference concentration (i.e. theoretical concentration). The correlation coefficients obtained were 0.9238, 0.8722, 0.7872, 0.8856 and 0.9128 for BPA, 4-MBC, TCC, BZP and EHMC, respectively. With the use of these pseudo-univariate models, the determination of the analytes exhibited absolute errors lowers than those of the chromatographic technique for BZP and TCC. For BPA, 4-MBC and EHMC the absolute error was lower than 10 µg L − 1. This approach can provide a cheap and rapid strategy for the direct quantification of these micropollutants in water samples.

UV filters in matched seminal fluid-, urine-, and serum samples from young men.

Recent in vitro studies have shown that some chemical UV filters mimic the effect of progesterone in the activation of the CatSper Ca2+ channel in human spermatozoa. However, so far, the extent of exposure of human spermatozoa to chemical UV filters via the presence of these chemicals in seminal fluid has been unknown. Here, we present levels of UV filters measured in human seminal fluid and comparisons to levels measured in concurrently collected urine and serum samples. In total nine UV filters were analysed by TurboFlow-LC-MS/MS in paired urine, serum, and seminal fluid samples from 300 young Danish men from the general population; each man collected one of each sample type within 1 h. The samples were collected during February-December 2013 and only six of the men reported having used sunscreen during the 48 h preceding the sample collection. Four of the examined UV filters could be detected in seminal fluid samples at levels above LOD in more than 10% of the samples. Benzophenone (BP), benzophenone-1 (BP-1), and benzophenone-3 (BP-3) were most frequently detected in, respectively, 18%, 19%, and 27% of the seminal fluid samples albeit at levels one to two orders of magnitude lower than the levels observed in urine. 4-methyl-benzophenone (4-MBP) was detectable in 11% of the seminal fluid samples while in <5% of the urine samples. Overall 45% of the men had at least one of the UV filters present in their seminal fluid at detectable levels. For BP-1 and BP-3 individual levels in urine and seminal fluid were significantly correlated, while this was not evident for BP nor 4-MBP. In conclusion, chemical UV filters are present in men's seminal fluid; some of which can activate the human sperm-specific CatSper Ca2+ channel and thereby potentially interfere with the fertilisation process.

Pestalotiones A-D: Four New Secondary Metabolites from the Plant Endophytic Fungus Pestalotiopsis Theae.

Two new xanthone derivatives, pestalotiones A (1) and B (2), one new diphenyl ketone riboside, pestalotione C (7), and one new diphenyl ether, pestalotione D (8), along with five known compounds isosulochrin dehydrate (3), 3,8-dihydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylate (4), isosulochrin (5), chloroisosulochrin (6), and pestalotether D (9), were isolated from the crude extract of the plant endophytic fungus Pestalotiopsis theae (N635). The structures of the new compounds were unambiguously deduced by HRESIMS and 1D/2D-NMR spectroscopic data. Compound 6 showed modest cytotoxicity against the HeLa cell line with an IC50 value of 35.2 μM. Compound 9 also showed cytotoxic to the HeLa and MCF-7 cell lines, with IC50 values of 60.8 and 22.6 μM, respectively. Additionally, compounds 1 and 2 exhibited antioxidant activity in scavenging DPPH radical with IC50 values of 54.2 and 59.2 μg/mL, respectively.

Synthesis and photopolymerization of novel UV-curable macro-photoinitiators

The design and development of macro-photoinitiators applicable to UV system has been attracted increasing attention for their excellent performance of low migration and high compatibility. Herein, four kinds of novel macro-photoinitiators (PI1-PI4) used in UV-curable coatings were synthesized by different isocyanates, 1-hydroxycyclohexyl phenyl ketone (Irgacure 184), 2-hydroxyethyl methacrylate (HEMA) and pentaerythritol triacrylate (PETA). The structures were analyzed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Moreover, the photopolymerization kinetics of the macro-photoinitiators were investigated by real-time FTIR. Results revealed that the macro-photoinitiators display higher curing efficiency, lower migration performance and better compatibility with formulation compositions compared to Irgacure 184. On the other hand, the macro-photoinitiators also served as self-initiating oligomers and had good thermal stability with 10 % weight loss temperatures (T10 %) above 299.7 °C. The UV-cured films consisting of oligomers and tripropylene glycol diacrylate (TPGDA) showed excellent physical properties and high curing efficiency and rapid curing rate.

The preparation of dual-functional hydrogel as the surface coating of plastics in biomedical applications

Poly(2-ethyl-2-oxazoline) (PEOXA) is among polymers that have been reported to show anti-adhesive (bio-passive) behavior in numerous biomaterial applications. This work aimed to develop dual-functional hydrogel coatings, with PEOXA as hydrophilic polymer and benzophenone as cross-linker. PEOXA was partially hydrolyzed in acidic conditions to form PEOXA-m% EI that contains ethyleneimine (EI) groups. The EI groups were used as conjugation sites for incorporation of benzophenone (BP) molecules to PEOXA chains to form PEOXA-m% EIBP. Thin films of surface-attached polymer networks were generated from PEOXA-m% EIBP copolymers composed of PEOXA as platform and benzophenone as crosslinker units. The polymer became crosslinked through benzophenone units and forms a hydrogel as biopassive platform during irradiation with ultraviolet (UV) light. Laminin was incorporated into biopassive polymer network to allow for preparation of dual-functional hydrogel. NMR spectra indicated successful control of PEOXA partial hydrolysis and conjugation of benzophenone molecules to PEOXA chains. Ellipsometry and ATR-FTIR results showed that wavelength of UV light during C, H-insertion reaction influences stability of polymer network (hydrogel) on the substrate surface. XPS spectra verified that a stable film could be generated using suitable UV light during preparation of polymer network. Cell culture study on laminin/PEOXA-coated PMAA plastics showed dual-functional properties.

Simultaneous estimation of dimenhydrinate, cinnarizine and their toxic impurities benzophenone and diphenylmethylpiperazine; in silico toxicity profiling of impurities.

The British Pharmacopeia (BP) reported that the carcinogenic and hepatotoxic, benzophenone (BZP) is a dimenhydrinate (DMH) impurity. On the other hand, cinnarizine (CIN) is reported to have five impurities (A–E). The toxicity profile of CIN impurities was studied and the in silico data revealed that impurity A [1-(diphenylmethyl)piperazine] (DPP) was the most toxic CIN impurity, and hence it was selected during this work. TLC-densitometric method was developed for separation and simultaneous quantitation of DMH, CIN and their toxic impurities. In the proposed method hexane : ethanol : acetone : glacial acetic acid (7 : 3 : 0.7 : 0.5, by volume) with UV scanning at 225 nm were used. Method validation was carried out according to ICH guidelines and linearity was achieved in the range 0.2–4, 0.5–5, 0.1–2.0, and 0.05–2.2 μg per band for DMH, CIN, BZP and DPP, respectively. On the application of the method to pharmaceutical formulation, no interference from additives was observed. The greenness of the method was evaluated using the analytical eco-scale and the results revealed the low negative environmental impact of the developed method.

Regioselectivity in the adiabatic photocleavage of DNA-based oxetanes.

Direct absorption of UVB light by DNA may induce formation of cyclobutane pyrimidine dimers and pyrimidine-pyrimidone (6-4) photoproducts. The latter arise from the rearrangement of unstable oxetane intermediates, which have also been proposed to be the electron acceptor species in the photoenzymatic repair of this type of DNA damage. In the present work, direct photolysis of oxetanes composed of substituted uracil (Ura) or thymine (Thy) derivatives and benzophenone (BP) have been investigated by means of transient absorption spectroscopy from the femtosecond to the microsecond time-scales. The results showed that photoinduced oxetane cleavage takes place through an adiabatic process leading to the triplet excited BP and the ground state nucleobase. This process was markedly affected by the oxetane regiochemistry (head-to-head, HH, vs. head-to-tail, HT) and by the nucleobase substitution; it was nearly quantitative for all investigated HH-oxetanes while it became strongly influenced by the substitution at positions 1 and 5 for the HT-isomers. The obtained results clearly confirm the generality of the adiabatic photoinduced cleavage of BP/Ura or Thy oxetanes, as well as its dependence on the regiochemistry, supporting the involvement of triplet exciplexes. As a matter of fact, when formation of this species was favored by keeping together the Thy and BP units after splitting by means of a linear linker, a transient absorption at ∼400 nm, ascribed to the exciplex, was detected.

Regiochemical memory in the adiabatic photolysis of thymine-derived oxetanes. A combined ultrafast spectroscopic and CASSCF/CASPT2 computational study.

The photoinduced cycloreversion of oxetanes has been thoroughly investigated in connection with the photorepair of the well-known DNA (6-4) photoproducts. In the present work, the direct photolysis of the two regioisomers arising from the irradiation of benzophenone (BP) and 1,3-dimethylthymine (DMT), namely the head-to-head (HH-1) and head-to-tail (HT-1) oxetane adducts, has been investigated by combining ultrafast spectroscopy and theoretical multiconfigurational quantum chemistry analysis. Both the experimental and computational results agree with the involvement of an excited triplet exciplex 3[BPDMT]* for the photoinduced oxetane cleavage to generate 3BP* and DMT through an adiabatic photochemical reaction. The experimental signature of 3[BPDMT]* is the appearance of an absorption band at ca. 400 nm, detected by femtosecond transient absorption spectroscopy. Its formation is markedly regioselective, as it is more efficient and proceeds faster for HH-1 (∼2.8 ps) than for HT-1 (∼6.3 ps). This is in line with the theoretical analysis, which predicts an energy barrier to reach the triplet exciplex for HT-1, in contrast with a less hindered profile for HH-1. Finally, the more favorable adiabatic cycloreversion of HH-1 compared to that of HT-1 is explained by its lower probability to reach the intersystem crossing with the ground state, which would induce a radiationless deactivation process leading either to a starting adduct or to a dissociated BP and DMT.

Photopolymerization of Acrylated Epoxidized Soybean Oil: A Photocalorimetry-Based Kinetic Study.

Photocure kinetics of acrylated epoxidized soybean oil (AESO) was studied via photocalorimetry without adding any diluent/comonomer, in the presence of two different photoinitiators, namely, 2,2-dimethoxy phenylacetophenone and 1-hydroxycyclohexyl phenyl ketone. The effect of varying photoinitiator concentration, light intensity, and temperature on the extent of crosslinking was calculated from the ratio of experimentally measured reaction enthalpy to the theoretical enthalpy of reaction (ΔHtheoretical). Photocuring of AESO was observed to be a second-order reaction exhibiting autocatalytic behavior. Nevertheless, due to the occurrence of vitrification, incomplete crosslinking (α ≠ 1) was observed in most curing conditions. Rate constants and activation energies were determined using both nonlinear model-fitting and model-free isoconversional methods. Activation energy, as determined from the model-free isoconversional method, was observed to increase as the reaction proceeded, indicating the shift in cure mechanism from kinetic-controlled to diffusion-controlled. Finally, the reaction termination mechanism was observed to be a combination of second-order and primary radical termination mechanisms.