Regioselective palladium(II)-catalyzed aerobic oxidative Heck-type C3 alkenylation of sulfocoumarins

An efficient method for the direct C-H olefination of sulfocoumarins with a wide range of alkenes is developed. Moreover, O2 was successfully utilized as the sole oxidant for the oxidative Heck reaction. This approach enables the rapid generation of various 3-alkenylated sulfocoumarins. © 2016 the Partner Organisations1111sciescopu

One-pot catalysis of dehydrogenation of cyclohexanones to phenols and oxidative Heck coupling: expedient synthesis of coumarins

One-pot reactions leading to highly functionalized coumarins have been developed via a Pd(II)-catalyzed dehydrogenation-oxidative Heck-cyclization process.133391sciescopu

AgSbF6-controlled diastereodivergence in alkyne hydroarylation: facile access to Z- and E-alkenyl arenes

AgSbF6-controlled diastereodivergent hydroarylation reactions were developed. Unprecedented and remarkable switching of the E/Z-stereoselectivity could be obtained by adjusting the AgSbF6 loading.118201sciescopu

Rhodium-Catalyzed Direct C-H Phosphorylation of (Hetero)arenes Suitable for Late-Stage Functionalization

Efficient rhodium-catalyzed direct C-H phosphorylation of (hetero)arenes was developed. Various directing groups and a wide range of substrates, including heterocycles, can be utilized in this C-H phosphorylation process, allowing for the rapid installation of the phosphonate group into medicinally and biologically important privileged scaffolds. The efficient and straightforward method could serve as a new tool to streamline late-stage C-H functionalization for preparing aryl phosphonates, which are important structural motif in synthetic and medicinal chemistry (c) 2016 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim113141sciescopu

Unraveling innate substrate control in site-selective palladium-catalyzed C-H heterocycle functionalization

Understanding the regioselectivity of C-H activation in the absence of directing groups is an important step towards the design of site-selective C-H functionalizations. The Pd(ii)-catalyzed direct arylation of chromones and enaminones provides an intriguing example where a simple substitution leads to a divergence in substrate-controlled site-selectivity. We describe computational and experimental studies which reveal this results from a switch in mechanism and therefore the selectivity-determining step. We present computational results and experimentally measured kinetic isotope effects and labelling studies consistent with this proposal. The C-H activation of these substrates proceeds via a CMD mechanism, which favors more electron rich positions and therefore displays a pronounced kinetic selectivity for the C3-position. However, C2-selective carbopalladation is also a competitive pathway for chromones so that the overall regiochemical outcome depends on which substrate undergoes activation first. Our studies provide insight into the site-selectivity based on the favorability of two competing CMD and carbopalladation processes of the substrates undergoing coupling. This model can be utilized to predict the regioselectivity of coumarins which are proficient substrates for carbopalladation. Furthermore, our model is able to account for the opposite selectivities observed for enaminone and chromone, and explains how a less reactive coupling partner leads to a switch in selectivity. This journal is © The Royal Society of Chemistry 2016117181sciescopu

Analytical Quality by Design (AQbD) Approach to the Development of Analytical Procedures for Medicinal Plants

Scientific regulatory systems with suitable analytical methods for monitoring quality, safety, and efficacy are essential in medicinal plant drug discovery. There have been only few attempts to adopt the analytical quality by design (AQbD) strategy in medicinal plants analysis over the last few years. AQbD is a holistic method and development approach that understands analytical procedure, from risk assessment to lifecycle management. The enhanced AQbD approach reduces the time and effort necessary to develop reliable analytical methods, leads to flexible change control through the method operable design region (MODR), and lowers the out-of-specification (OOS) results. However, it is difficult to follow all the AQbD workflow steps in the field of medicinal plants analysis, such as defining the analytical target profiles (ATPs), identifying critical analytical procedure parameters (CAPPs), among others, because the complexity of chemical and biological properties in medicinal plants acts as a barrier. In this review, various applications of AQbD to medicinal plant analytical procedures are discussed. Unlike the analysis of a single compound, medicinal plant analysis is characterized by analyzing multiple components contained in biological materials, so it will be summarized by focusing on the following points: Analytical methods showing correlations within analysis parameters for the specific medicinal plant analysis, plant raw material diversity, one or more analysis targets defined for multiple phytochemicals, key analysis attributes, and analysis control strategies. In addition, the opportunities available through the use of design-based quality management techniques and the challenges that coexist are also discussed

Direct Phosphonation of Quinolinones and Coumarins Driven by the Photochemical Activity of Substrates and Products

Light-promoted phosphonation of quinolinones and coumarins was developed without the need for an external photocatalyst. Investigations support a mechanism whereby both starting materials and products act as photosensitizers upon excitation using compact fluorescent light sources to photochemically promote the dissociation of the N–O bond in the pyridinium salt by a single electron transfer pathway. A wide range of quinolinone and coumarin substrates can be utilized in the phosphonation process under mild reaction conditions

Boosting up the electrical performance of low-grade PEDOT:PSS by optimizing non-ionic surfactants

Although PEDOT:PSS has already been applied to various electronic devices, commercialized PEDOT:PSS products having high conductivity are expensive, which is a considerable burden on device manufacturing. In this study, we optimize non-ionic surfactants mixed in a PEDOT:PSS solution to upgrade a low-grade product of low conductivity to the level of a high-grade product of high conductivity. This study systematically investigates the phase diagram, morphology, conductivity, and mechanical stability of the PEDOT:PSS films according to the hydrophilicity of non-ionic surfactants. This study reveals that the conductivity of the PEDOT:PSS film varies greatly depending on the chemical structure of the surfactant and its weight fraction in the thin film. Under the optimum conditions (chemical structure and weight fraction) of the surfactant, the conductivity of the low value product could be improved to the conductivity level of the high value product. The electrical properties of the films were excellently stable even under the extreme cyclic bending tests at a bending radius of 1.5 mm. The low-grade and high grade products showed the same electrical performance when they were used in the Ag nanowires/PEDOT: PSS hybrid transparent electrodes. The results are expected to be applied immediately not only in the laboratory but also in various industrial fields.112sciescopu

Anti-Inflammatory, Barrier-Protective, and Antiwrinkle Properties of Agastache rugosa Kuntze in Human Epidermal Keratinocytes

This work aimed to assess the skin-beneficial properties of Agastache rugosa Kuntze, an herbal medication used to treat different types of disorders in traditional folk medicine. The total phenolic compounds and total antiradical, nitrite scavenging, superoxide scavenging, antielastase, and antihyaluronidase activities of a hot water extract of A. rugosa Kuntze leaves (ARE) were spectrophotometrically determined. Intracellular reactive oxygen species (ROS) was fluorometrically quantitated using 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA). Inducible nitric oxide synthase (iNOS) and filaggrin were evaluated using Western analysis. Real-time quantitative RT-PCR was used to measure filaggrin mRNA. Caspase-14 activity was determined using a fluorogenic substrate. ARE contained the total phenolic content of 38.9 mg gallic acid equivalent/g extract and exhibited 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide radical, and nitrite scavenging activities with the SC50 values of 2.9, 1.4, and 1.7 mg/mL, respectively. ARE exerted suppressive activities on nitric oxide (NO) and ROS levels elevated by lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α) in HaCaT keratinocytes. It attenuated the LPS-stimulated expression of iNOS. ARE augmented the UV-B-reduced filaggrin expression on both protein and mRNA levels and was capable of upregulating the UV-B-reduced caspase-14 activity. ARE inhibited in vitro elastase and hyaluronidase activities associated with the wrinkling process. ARE, at the concentrations used, did not interfere with the viability of HaCaT keratinocytes. These findings preliminarily imply that the leaves of A. rugosa possess desirable cosmetic potentials, such as anti-inflammatory, barrier protective, and antiwrinkle activities, which infers their skin healing potentials