Ethyl Phenylpropiolate Research Articles

Regioselective Synthesis of Imidazo[4,5‐e][1,3]Thiazino[3,2‐b][1,2,4]Triazines as New Heterocyclic System Derivatives

ABSTRACTA series of new 4a,7a‐diarylperhydroimidazo[4,5‐e][1,2,4]triazine‐3‐thiones were synthesized from 4,5‐diaryl‐4,5‐dihydroxyimidazolidin‐2‐ones and thiosemicarbazide in high yields, and their interaction with ethyl phenylpropiolate was studied. An effective method for the regioselective synthesis of imidazo[4,5‐e][1,3]thiazino[3,2‐b][1,2,4]triazines as new heterocycic system derivatives was proposed based on the reaction of aforementioned imidazotriazinethiones with ethyl phenylpropiolate in the presence of MeONa in methanol. The reaction is initiated by a Michael‐type addition of the imidazotriazinethiones to the triple bond of ethyl phenylpropiolate followed by intramolecular cyclization.

Green synthesis of selenium nanoparticles capped by Tithonia diversifolia pectin for anti‐inflammation activity

AbstractThis work reports a green method to synthesize pectin‐capped selenium nanoparticles (PT‐SeNPs) using ascorbic acid as a reductant under mild conditions. Pectin was extracted from Tithonia diversifolia (Hemsley) A. Gray plant. Pectin played the role of a capping agent preventing the agglomeration of selenium nanoparticles. The synthesized PT‐SeNPs were characterized by UV–Vis spectrophotometry, EDX spectroscopy, TEM, DLS, FT‐IR, XRD, and TG‐DTA. The TEM and DLS techniques revealed monodispersed spherical selenium nanoparticles with sizes range of 100–200 nm. The amorphous PT‐SeNPs showed a phase transformation of nanostructure at 132 °C and a sublimation at 486 °C. The anti‐inflammatory of the obtained PT‐SeNPs was investigated in ethyl phenylpropiolate (EPP)‐induced rats. Rats treated with PT‐SeNPs exhibited ear edema inhibitions of 34.8%, 43.3%, and 46.7%, respectively at 30, 60 and 90 min after EPP injection.

PRELIMINARY INVESTIGATION OF THE LEWIS ACID-MEDIATED REACTIONS OF PHENOLS AND ETHYL PHENYLPROPIOLATE AS A SYNTHETIC ROUTE TO FLAVONOIDS AND ANTIMICROBIAL PROFILE OF THE RESULTANT 7-HYDROXY-4-PHENYL-2H-CHROMEN-2-ONE AND ANALOGS

Synthetic chemists are increasingly exploring alternative routes to target products, considering factors like environmental threats, side product formation, cost, and efficiency. This is coupled with the health challenges that require urgent responses from new chemical entities. In this context, antimicrobial resistance has exacerbated global diseases, making them difficult to treat with prescribed drugs and causing a persistent public health crisis. These triggered our interest in the search for alternative antimicrobial agents, exploring different synthetic strategies for known bioactive natural compounds for further investigations. In this study, Lewis acid catalyst (FeCl3) and tetrahydrofuran as solvents in the one-pot synthesis of (neo)flavonoid derivatives from readily available phenols and ethyl phenylpropiolate were discovered to afford the coumarins in yields of 43–95%. The synthetic derivatives of 7-hydroxy-4-phenyl-2H-chromen-2-one and analogs obtained were biologically investigated for antimicrobial activity. The compounds showed moderate to poor antimicrobial activity. The effects of different substituents (-R) on the yield of the reaction are also discussed. Future studies should enhance the yield of derivative products and use different assay models for biological activity studies to fully explore the compounds` biorelevance.

Antioxidant and Biological Activities of Mahajanaka Mango Pulp Extract in Murine Models

Mahajanaka mango, a hybrid cultivar of Mangifera indica Linn., is a highly nutritional fruit that is popularly consumed in Thailand. It has been used in traditional medicine due to its abundance of phytonutrients. The present study aimed to investigate the chemical compositions and antioxidant activity of Mahajanaka mango pulp extract (MPE) in vitro. Additionally, we examined its biological activities, including the analgesic, anti-inflammatory, gastroprotective, and hepatoprotective effects of MPE, in murine models. MPE exhibited high levels of phenolic compounds, mangiferin, β-carotene, and vitamin C, and it potentially showed antioxidant properties in an ABTS scavenging assay. The animal results have revealed that oral administration of MPE (1000 mg/kg body weight (BW)) significantly decreased acetic acid-induced writhing responses in mice. Interestingly, local applications of MPE at 1 mg/ear ameliorated ethyl phenylpropiolate (EPP)-induced ear edema, while gavage of MPE at 1000 mg/kg BW significantly decreased carrageenan-induced hind paw edema in rats. MPE can also protect against gastric ulcers induced by stress, hydrochloric acid/ethanol, and indomethacin in rats. Indeed, MPE (250 mg/kg BW) markedly lowered the level of serum alanine aminotransferase activity and hepatic lipid accumulation in rats with CCl4- and paracetamol-induced hepatotoxicity. Taken together, the findings suggested that MPE exerts potent antioxidant, analgesic, anti-inflammatory, gastroprotective, and hepatoprotective effects.

Regioselective synthesis of new imidazo[4,5‐e][1,3]thiazino[2,3‐c][1,2,4]triazines via reaction of imidazo[4,5‐e][1,2,4]triazinethiones with ethyl phenylpropiolate

AbstractA method for the regioselective synthesis of imidazo[4,5‐e][1,3]thiazino[2,3‐c][1,2,4]triazine derivatives has been developed by the reaction of imidazotriazinethiones with ethyl phenylpropiolate upon treatment with potassium carbonate or sodium methoxide in methanol. The synthesis was accomplished by Michael‐type addition of the imidazotriazinethiones to the triple bond of ethyl phenylpropiolate followed by subsequent intramolecular cyclization.

Exploring in vitro and in vivo anti-inflammatory activities of the Thai traditional remedy Kheaw-Hom and its bioactive compound, ethyl p-methoxycinnamate, and ethnopharmacological analysis

Ethnopharmacological relevanceKheaw-Hom (KH) remedy, a Thai traditional medicine (TTM) on the National List of Essential Medicines, has long been clinically used to treat fever and inflammation in children. However, no in vitro or in vivo anti-inflammatory or bioactive compound studies are published in the literature. Aims of the studyTo explore the in vitro and in vivo anti-inflammatory activities of KH remedy and its bioactive compound and analyze relationships between flavor and ethnopharmacological activities of plant components in KH remedy according to TTM theory. Materials and methodsEthyl p-methoxycinnamate (EPMC), a bioactive compound of KH remedy was analyzed using high performance liquid chromatography (HPLC). In vitro anti-inflammatory activities of ethanolic extract (KHE), aqueous extract (KHA), acid-hydrolysis of KHA (KHA-h), acid-hydrolysis of KH powder (KHP-h), and EPMC were investigated using lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor-alpha (TNF-α) production in murine macrophage RAW 264.7 cells. In vivo anti-inflammatory activities of KH powder (KHP) and KHE were determined using carrageenan-induced paw edema and ethyl phenylpropiolate (EPP)-induced ear edema in rats and PGE2 production in tissue samples was examined. ResultsKHP-h showed the highest EPMC content (21.33 ± 1.08 mg/g of extract) and inhibited PGE2, NO, and TNF-α production with IC50 values of 11.92 ± 0.21, 30.61 ± 3.12, and 56.71 ± 2.91 μg/mL, respectively, followed by KHE and KHA-h while KHA did not. EPMC, a bioactive compound of KH remedy showed high anti-inflammatory activities through three pathways. KHP oral administration (100 mg/kg) significantly minimized rat paw inflammation at 1, 2, and 3 h while KHE (100 mg/kg) noticeably reduced at 2 and 3 h. KHP (100, 200, and 400 mg/kg) and KHE (100 mg/kg) significantly inhibited PGE2 production. KHP (1% w/v) notably reduced rat ear edema at 30, 60, and 120 min whereas KHE at all concentrations decreased swelling at 120 min. KHP and KHE at all doses significantly inhibited PGE2 production. Cool flavor was the main KH remedy flavor. Spicy plant components and some fragrant components showed high anti-inflammatory activity. ConclusionsResults from the in vivo study strongly paralleled the in vitro study. These findings support the rational use of KH remedy according to TTM theory for fever treatment and inflammation in children.

Anti-inflammatory effects of Pikad Tri-phol-sa-mut-than remedy, consisting of dried fruits of Aegle marmelos (L.) Corrêa, Coriandrum sativum L., and Morinda citrifolia L.

Ethnopharmacological relevanceInflammation has been known to possess some essential roles in many diseases, especially those with chronic or severe conditions. Pikad Tri-phol-sa-mut-than, a Thai traditional herbal remedy, has long been used to treat gastrointestinal sicknesses, fever, and severe illness caused by the deformities of Tridosha. In particular, this recipe has also been applied for inflammation-related conditions including gout and rheumatoid arthritis. The Pikad Tri-phol-sa-mut-than recipe consists of dried fruits of three herbs including Aegle marmelos (L.) Corrêa, Morinda citrifolia L., and Coriandrum sativum L. Each of these plant components of Pikad Tri-phol-sa-mut-than exhibited anti-inflammatory activities. However, anti-inflammatory effect of Pikad Tri-phol-sa-mut-than remedy has not been reported. Aim of the studyThe objective of this study was to elucidate the anti-inflammatory activities of Pikad Tri-phol-sa-mut-than extract (TS) against acute and chronic inflammation in rats. Materials and methodsTo study the effects of TS on acute inflammation, ethyl phenylpropiolate (EPP)-induced ear edema, carrageenan- and arachidonic acid (AA)-induced hind paw edema models were carried out. In addition, cotton pellet-induced granuloma formation was performed to specify the inhibitory effects of TS on chronic inflammation. ResultsThe topical application of TS significantly inhibited EPP-induced ear edema in rats. In the carrageenan- and AA-induced paw edema models, the oral administration of TS significantly reduced paw volumes, compared to those of the control groups. In addition, the 7-day oral treatment of TS demonstrated a significant suppressive effect on cotton pellet-induced granuloma formation. ConclusionsThe current study revealed that TS possesses anti-inflammatory activities against acute and chronic inflammation. Our studies support the use of TS in traditional medicine, and the development of TS as a novel natural product for treating diseases associated with inflammation.

Anti-Inflammatory Activity of Essential Oil from Zingiber ottensii Valeton in Animal Models.

Zingiber ottensii (ZO) Valeton, a local plant in Northern Thailand, has been widely used in traditional medicine. Many studies using in vitro models reveal its pharmacological activities, including the anti-inflammatory activity of ZO essential oil, extracted from ZO rhizomes. However, the scientific report to confirm its anti-inflammatory activity using animal models is still lacking. The present study aimed to evaluate the anti-inflammatory activity and explore the possible mechanisms of action of ZO essential oil in rats. The results revealed that ZO essential oil significantly reduced the ear edema formation induced by ethyl phenylpropiolate. Pre-treatment with ZO essential oil significantly reduced the carrageenan-induced hind paw edema and the severity of inflammation in paw tissue. In addition, pre-treatment with ZO essential oil exhibited decreased COX-2 and pro-inflammatory cytokine TNF-α expression in paw tissue, as well as PGE2 levels in serum. On this basis, our study suggests that ZO essential oil possesses anti-inflammatory activity in animal models. Its possible mechanisms of action may involve the inhibition of TNF-α expression as well as the inhibition of COX-2 and PGE2 production. These findings provide more crucial data of ZO essential oil that may lead to new natural anti-inflammatory product development in the future.

BF3OEt2 and MeSO3H-Promoted reactions of phenols and ethyl phenylpropiolate as a synthetic routes to neoflavones and a potential route to flavones

BF3OEt2 and MeSO3H-Promoted reactions of phenols and ethyl phenylpropiolate as a synthetic routes to neoflavones and a potential route to flavones

Anti-inflammatory, Antinociceptive, and Antitumorigenesis Activities of Terminalia Bellerica (Gaertn.) Roxb. in Animal Models

Previous pharmacological research has demonstrated that Terminalia bellerica (Gaertn.) Roxb. (TB) extract possesses several pharmacological activities. However, there is scant evidence documenting the therapeutic activities of TB extract on inflammation, pain, and cancers. Our study examined the in vivo anti-inflammation, antinociception, and antitumorigenesis effects of TB extract and investigated possible mechanisms for those effects. Anti-inflammation activities of TB extract were evaluated using ethyl phenylpropiolate (EPP)- and arachidonic acid (AA)-induced ear edema models, a cotton pellet-induced granulation formation model, and a carrageenan-induced hind paw edema model. An antinociceptive property of TB extract was assessed using a formalin-induced nociception test. An anticarcinogenesis effect was investigated using a 7,12-dimethylbenz( a) anthracene (DMBA) and 12- O-tetradecanoylphorbol-13-acetate (TPA)-induced tumorigenesis model. In the study, TB extract exhibited significant anti-inflammatory effects against EPP-induced ear edema and carrageenan-induced hind paw edema in rats. However, the TB extract showed insignificant inhibitory activity against AA-induced ear edema and cotton pellet-induced granuloma. A dose-dependent decrease in analgesic activity was observed with TB extract evidenced by decreased licking time in formalin-induced pain in mice in both the early and late phases. TB extract also significantly inhibited DMBA/TPA-induced mouse skin tumorigenesis. In conclusion, TB extract possesses anti-inflammatory, analgesic, and anticarcinogenesis properties which act, at least in part, through inhibitory effects of inflammatory mediator production.

Regioselective synthesis of spirocyclic pyrrolines via a palladium-catalyzed Narasaka-Heck/C-H activation/[4 + 2] annulation cascade reaction.

A novel palladium-catalyzed spirocyclization through sequential Narasaka–Heck cyclization, C–H activation and [4 + 2] annulation has been developed. In this reaction, cheap and readily available 2-chlorobenzoic acid or ethyl phenylpropiolate was employed as the C2 insertion unit to react with γ,δ-unsaturated oxime ester. The key step in this transformation is the regioselective insertion of the C2 synthon into the spiro-palladacycle intermediate that is formed by the δ-C–H activation process, thereby efficiently assembling a series of spirocyclic pyrrolines with high regiocontrol. Furthermore, density functional theory (DFT) calculations and control experiments were performed to gain some insights into the reaction mechanism.

Microwave-assisted synthesis of benzo[b]phosphole oxide derivatives by oxidative addition of acetylenes and secondary phosphine oxides or alkyl phenyl-H-phosphinates

A new and practical microwave (MW)-assisted method was developed for the fast and efficient oxidative addition of secondary phosphine oxides or alkyl phenyl-H-phosphinates and acetylenes. The reaction was optimized in respect of the oxidative agent, the reaction time, the temperature and the molar ratio of the starting materials. The protocol developed enabled the synthesis of novel benzo[b]phosphole oxide derivatives under mild conditions for a short reaction time. By the use of special reagents, such as alkyl phenyl-H-phosphinates or ethyl phenylpropiolate, reactive groups (phosphinic acid ester and carboxylic ester) could be integrated into the benzophosphole skeleton, which may be further functionalized towards various synthetic directions, therefore, fine-tuning the optical properties of the target molecules. The crystal structure of a benzo[b]phosphole oxide derivative was investigated by X-Ray diffraction, which gave structural information about the compound and its molecular interactions in the crystal.

ASPP 092, a phenolic diarylheptanoid from Curcuma comosa suppresses experimentally-induced inflammatory ear edema in mice.

Curcuma comosa Roxb., family Zingiberaceae, exhibits diverse biological activities. This study was aimed to investigate the anti-inflammatory potential of a major phenolic diarylheptanoid isolated from C. comosa, ASPP 092 [(3S)-1-(3,4-dihydroxy-phenyl)-7-phenyl-(6E)-6-hepten-3-ol] in an experimentally-induced inflammatory ear edema model in mice. Ear edema in the mice was induced by the topical application of irritant, ethyl phenylpropiolate (EPP). The topical application of ASPP 092 at the edema site was directed immediately after the EPP application. The edematous responses were assessed at different time points by measuring the thickness of each ear before and after the EPP application followed by histopathology analysis. The expressions of major inflammatory cytokines were analyzed by real-time RT-PCR followed by the immunohistochemistry analysis of cyclooxygenase (COX-2). The topical application of ASPP 092 effectively suppressed the EPP-induced edematous formation in the ear of mice. Histopathological analysis showed substantial improvements in epidermal hyperplasia and inflammatory cell infiltration. ASPP 092 treatment also modulated the expressions of inflammatory cytokines including Tumor Necrosis Factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-1β (IL-1β), and Matrix metalloproteinase-13 (MMP-13). The expressions of cyclooxygenases (COX) including COX-1 and COX-2 were significantly reduced by ASPP 092 treatment. For the first time, our results suggest the efficacy of ASPP 092 to suppress experimentally-induced inflammation in a preclinical model in mice; however, a more detailed evaluation of its mechanism of action is necessary before evaluating its efficacy and safety in randomized trials.

Analgesic, anti-inflammatory and anti-ulcer properties of Thai Perilla frutescence fruit oil in animals.

Perilla frutescens fruit oil (PFO) is rich in α-linolenic acid (ALA) and exhibits biological activities. We aimed to investigate analgesic, anti-inflammatory and anti-ulcer activities of PFO and PFO-supplemented soybean milk (PFO-SM) in animal models. Analgesic activity was assessed in acetic acid-induced writhing in mice, while anti-inflammatory activity was performed in ethyl phenylpropiolate (EPP)-induced ear edema and carrageenan-induced hind paw edema in rats. Anti-ulcer effects were conducted in water immersion stress, HCl/ethanol and indomethacin-induced gastric ulcer in rats. Distinctly, PFO, containing 6.96 mg ALA and 2.61 mg LA equivalence/g, did not induce acute toxicity (LD50 > 10 mL/kg) in mice. PFO (2.5 and 5 mL/kg) and PFO-SM (0.05 mL PFO equivalence/kg) inhibited incidences of writhing (16.8, 18.0 and 32.3%, respectively) in acetic acid-induced mice. In addition, topical applications of PFO (0.1 and 1 mL/ear) significantly inhibited EPP-induced ear edema (59.3 and 65.7%, respectively) in rats, while PFO-SM slightly inhibited ear edema (25.9%). However, PFO and PFO-SM did not inhibit carrageenan-induced hind paw edema in rats. Indeed, PFO (2.5 and 5 mL/kg) significantly inhibited gastric ulcers in rats that induced by water immersion stress (92.4 and 96.6%, respectively), HCl/ethanol (74.8 and 73.3%, respectively) and indomethacin (68.8 and 88.9%, respectively), while PFO-SM did not. PFO displayed potent analgesic, anti-inflammatory and anti-ulcer properties, while PFO-SM exerted only analgesic properties. Thus, Thai PFO and its functional drink offer potential benefits in treatment of analgesic, inflammatory diseases and gastric ulcer.

In Vitro and In Vivo Anti-Inflammatory Activities of Benjakul: A Potential Medicinal Product from Thai Traditional Medicine.

Benjakul (BJK) is a Thai traditional remedy consisting of five plants: Piper chaba Hunt., Piper sarmentosum Roxb., Piper interruptum Opiz., Plumbago indica Linn., and Zingiber officinale Roscoe. It is used as a first-line drug to balance patient's symptoms before other treatments. BJK ethanolic extract has been reported to show anti-inflammatory activity through various mediators, e.g., nitric oxide, TNF-α, IL-1β, and IL-6. Therefore, BJK could serve as a potential novel anti-inflammatory herbal medicine. However, studies on prostaglandin E2 (PGE2), one of the key mediators in acute inflammation, and anti-inflammation in animal models (in vivo) have not been done. This study investigated the anti-inflammatory activity of BJK extract and some of its chemical compounds against PGE2 production in murine macrophage (RAW 264.7) cell line and two in vivo models of anti-inflammatory studies. Ethanolic extract of BJK (BJK[E]) showed high inhibitory activity against PGE2 production with an IC50 value of 5.82 ± 0.10 μg/mL but its water extract (BJK[W]) was inactive. Two chemicals from BJK[E], i.e., plumbagin and myristicin, which served as biological markers, showed strong activity with IC50 values of 0.08 ± 0.01 and 1.80 ± 0.06 μg/mL, respectively. BJK[E] was administered both topically and orally to rats inhibited with inflammation induced by ethyl phenylpropiolate (rat ear edema model) and carrageenan (hind paw edema model). Moreover, the biological activity of BJK extract did not reduce after six-month storage under accelerated condition (40°C, 75% RH). This indicated its stability and a 24-month shelf-life under normal condition. These results supported not only the use of BJK in Thai traditional medicine but also the possibility of further development of phytopharmaceutical products from BJK.

Monitoring Hydrogenation Reactions using Benchtop 2D NMR with Extraordinary Sensitivity and Spectral Resolution.

Low‐field benchtop nuclear magnetic resonance (BT‐NMR) spectrometers with Halbach magnets are being increasingly used in science and industry as cost‐efficient tools for the monitoring of chemical reactions, including hydrogenation. However, their use of low‐field magnets limits both resolution and sensitivity. In this paper, we show that it is possible to alleviate these two problems through the combination of parahydrogen‐induced polarization (PHIP) and fast correlation spectroscopy with time‐resolved non‐uniform sampling (TR‐NUS). PHIP can enhance NMR signals so that substrates are easily detectable on BT‐NMR spectrometers. The interleaved acquisition of one‐ and two‐dimensional spectra with TR‐NUS provides unique insight into the consecutive moments of hydrogenation reactions, with a spectral resolution unachievable in a standard approach. We illustrate the potential of the technique with two examples: the hydrogenation of ethylphenyl propiolate and the hydrogenation of a mixture of two substrates – ethylphenyl propiolate and ethyl 2‐butynoate.

Bioactive components, antioxidant, and anti-inflammatory activities of the wood of Albizia myriophylla

The scientific basis corresponding with the folkloric use of Albizia myriophylla Benth., Fabaceae, for the treatment of inflammation-related diseases was established by measuring antioxidant potential using 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) free radicals, and ferric reducing antioxidant power assays as well as anti-inflammatory effect using nitrite assay and ethyl phenylpropiolate (EPP)-induced rat ear edema model. Both ethanol extract (DPPH, IC50 46.23μg/ml; ABTS, IC50 57.14μg/ml; FRAP, 950.14mM Fe (II)/g) and dichloromethane fraction (DPPH, IC50 29.54μg/ml; ABTS, IC50 40.36μg/ml; FRAP, 946.69mM Fe (II)/g) from A. myriophylla demonstrated a promising antioxidant activity. Furthermore, it was found that the ethanol extract of A. myriophylla showed significant inhibitory activity against lipopolysaccharide (LPS)-induced nitric oxide production in murine macrophage cells (IC50 13.8μg/ml). The ethanol extract (15% w/v) also exhibited the maximum percentage inhibition (81–95%) of inflammation in the ear edema model at all assessment times comparable to indomethacin (0.5mg/ear). Among all isolates 1–5 from the active extract of A. myriophylla, indenoic acid (1) (DPPH, IC50 8.96μg/ml; ABTS, IC50 10.12μg/ml) and 8-methoxy-7,3′,4′-trihydroxyflavone (2) (DPPH, IC50 5.05μg/ml; ABTS, IC50 7.89μg/ml) had potent free radical scavenging effects comparable to those of ascorbic acid (DPPH, IC50 2.12μg/ml; ABTS, IC50 3.26μg/ml). Compound 2 also displayed remarkable reducing power in FRAP test (261.81mg QE/g) and showed a marked inhibition of the cellular nitric oxide production (IC50 27.7μg/ml). Our results suggest that the anti-inflammatory mechanism of A. myriophylla is most probably based on its capacity to suppress nitric oxide production as well as to be free radical scavenger.

Layered double hydroxide-derived Ni-Cu nanoalloy catalysts for semi-hydrogenation of alkynes: Improvement of selectivity and anti-coking ability via alloying of Ni and Cu

Environmental benign non-noble NiCu catalysts with well-distributed homogeneous nanoalloy structure was fabricated from layered double hydroxide for semi-hydrogenation of acetylene. Compared with monometallic Ni catalyst, the introduction of Cu enhanced ethene selectivity and decreased the deactivation rate in long-term reaction. Furthermore, to give a thorough understanding on structure dependent performance, conventional impregnation was also used to obtain bimetallic NiCu catalyst for comparison. Interestingly, imp-NiCu/MMO presented the mixture of monometallic Ni, Cu and bimetallic NiCu. Catalytic results indicated that 100% conversion was achieved at 160 °C with improved selectivity (>70%) over NiCu nanoalloy catalyst, while bimetallic NiCu catalyst with mixed structure showed both poor conversion (50%) and selectivity (65%). Enhanced activity was attributed to small particle size (3.2 nm) and high metal dispersion (31.4%). Improved selectivity and anti-coking ability were related to the alloying of Ni with Cu, which was conducive to isolate Ni atoms from one another confirmed by STEM-EDX and transfer electron from Cu to Ni certified by XPS. Additionally, superior performance was also found in semi-hydrogenations of hexyne, phenylacetylene, 1,2-diphenylethyne and ethyl phenylpropiolate over NiCu nanoalloy.

Nanoparticles, nanosponges, methods of synthesis, and methods of use

Environmental benign non-noble NiCu catalysts with well-distributed homogeneous nanoalloy structure was fabricated from layered double hydroxide for semi-hydrogenation of acetylene. Compared with monometallic Ni catalyst, the introduction of Cu enhanced ethene selectivity and decreased the deactivation rate in long-term reaction. Furthermore, to give a thorough understanding on structure dependent performance, conventional impregnation was also used to obtain bimetallic NiCu catalyst for comparison. Interestingly, imp-NiCu/MMO presented the mixture of monometallic Ni, Cu and bimetallic NiCu. Catalytic results indicated that 100% conversion was achieved at 160 °C with improved selectivity (>70%) over NiCu nanoalloy catalyst, while bimetallic NiCu catalyst with mixed structure showed both poor conversion (50%) and selectivity (65%). Enhanced activity was attributed to small particle size (3.2 nm) and high metal dispersion (31.4%). Improved selectivity and anti-coking ability were related to the alloying of Ni with Cu, which was conducive to isolate Ni atoms from one another confirmed by STEM-EDX and transfer electron from Cu to Ni certified by XPS. Additionally, superior performance was also found in semi-hydrogenations of hexyne, phenylacetylene, 1,2-diphenylethyne and ethyl phenylpropiolate over NiCu nanoalloy.

Revisiting the Intermolecular Fujiwara Hydroarylation of Alkynes

The Fujiwara hydroarylation of alkynes was reinvestigated using the addition of indole to methyl or ethyl phenylpropiolate catalyzed by Pd(OAc)2 as a model reaction. Reactions were monitored by both 1H NMR spectroscopy and electrospray ionization mass spectrometry (ESI/MS), and also through reactions carried out in the gas phase using MS/MS experiments. Contrary to the original suggestion for exclusive heteroarene activation, the data supports the coexistence of both heteroarene activation (C–H activation) and alkyne activation (Friedel–Crafts‐type pathway). Under the reaction conditions used in this work, intermediates for both mechanisms were detected by NMR spectroscopy and MS, but alkyne activation seems to be predominant according to 1H NMR spectroscopic studies and theoretical predictions. Alkyne activation is promoted by the coordination of an electrophilic palladium species to the C–C triple bond, followed by nucleophilic attack of the heteroaryl counterpart. Two previously undetected equilibria in this reaction involving the vinylpalladium intermediates and the final products were also found to be critical to the stereoselectivity of the reaction.