Cascade Synthesis of Fenpiprane and Related Pharmaceuticals via Rhodium-Catalyzed Hydroaminomethylation

A novel rhodium catalytic system with Naphos as ligand was developed for an efficient hydroaminomethylation of 1,1-diphenylethene under relatively mild conditions. This will allow for an atom-economic and environmentally benign synthesis of fenpiprane and related pharmaceuticals

Rhodium-Catalyzed Highly Regioselective Hydroaminomethylation of Styrenes with Tetraphosphorus Ligands

The highly linear-selective hydroaminomethylation of styrenes is very challenging. Herein, an efficient, highly chemoselective, and linear-selective hydroaminomethylation (l/b up to >99:1) of styrenes using Rh(nbd)₂SbF₆ with a pyrrole-based 3,3′,5,5′-substituted tetraphosphorus ligand is documented. This is in sharp contrast to other available processes leading to branched amines and provides a novel atom economic approach to 3-arylpropylamines

Cascade Synthesis of Fenpiprane and Related Pharmaceuticals via Rhodium-Catalyzed Hydroaminomethylation

A novel rhodium catalytic system with Naphos as ligand was developed for an efficient hydroaminomethylation of 1,1-diphenylethene under relatively mild conditions. This will allow for an atom-economic and environmentally benign synthesis of fenpiprane and related pharmaceuticals

Exploration of Novel Botanical Insecticide Leads: Synthesis and Insecticidal Activity of β‑Dihydroagarofuran Derivatives

The discovery of novel leads and new mechanisms of action is of vital significance to the development of pesticides. To explore lead compounds for botanical insecticides, 77 β-dihydroagarofuran derivatives were designed and synthesized. Their structures were mainly confirmed by ¹H NMR, ¹³C NMR, DEPT-135°, IR, MS, and HRMS. Their insecticidal activity was evaluated against the third-instar larvae of Mythimna separata Walker, and the results indicated that, of these derivatives, eight exhibited more promising insecticidal activity than the positive control, celangulin-V. Particularly, compounds <b>5.7</b>, <b>6.6</b>, and <b>6.7</b> showed LD₅₀ values of 37.9, 85.1, and 21.1 μg/g, respectively, which were much lower than that of celangulin-V (327.6 μg/g). These results illustrated that β-dihydroagarofuran ketal derivatives can be promising lead compounds for developing novel mechanism-based and highly effective botanical insecticides. Moreover, some newly discovered structure–activity relationships are discussed, which may provide some important guidance for insecticide development

Assessing the Influence of Side-Chain and Main-Chain Aromatic Benzyltrimethyl Ammonium on Anion Exchange Membranes

3,3′-di­(4″-methyl-phenyl)-4,4′-difluorodiphenyl sulfone (DMPDFPS), a new monomer with two pendent benzyl groups, was easily prepared by Suzuki coupling reaction in high yield. A series of side-chain type ionomers (PAES-Qs) containing pendant side-chain benzyltrimethylammonium groups, which linked to the backbone by alkaline resisting conjugated C–C bonds, were synthesized via polycondensation, bromination, followed by quaternization and alkalization. To assess the influence of side-chain and main-chain aromatic benzyltrimethylammonium on anion exchange membranes (AEMs), the main-chain type ionomers (MPAES-Qs) with the same backbone were synthesized following the similar procedure. GPC and ¹H NMR results indicate that the bromination shows no reaction selectivity of polymer configurations and ionizations of the side-chain type polymers display higher conversions than that of the main-chain type ones do. These two kinds of AEMs were evaluated in terms of ion exchange capacity (IEC), water uptake, swelling ratio, λ, volumetric ion exchange capacity (IEC_Vwet), hydroxide conductivity, mechanical and thermal properties, and chemical stability, respectively. The side-chain type structure endows AEMs with lower water uptake, swelling ratio and λ, higher IEC_Vwet, much higher hydroxide conductivity, more robust dimensional stability, mechanical and thermal properties, and higher stability in hot alkaline solution. The side-chain type cationic groups containing molecular configurations have the distinction of being practical AEMs and membrane electrode assemblies of AEMFCs

Porphyrin Cosensitization for a Photovoltaic Efficiency of 11.5%: A Record for Non-Ruthenium Solar Cells Based on Iodine Electrolyte

Dye-sensitized solar cells (DSSCs) are promising for utilizing solar energy. To achieve high efficiencies, it is vital to synergistically improve the photocurrent (<i>J</i>_sc) and the photovoltage (<i>V</i>_oc). In this respect, conjugation framework extension and cosensitization are effective for improving the absorption and the <i>J</i>_sc, which, however, is usually accompanied by undesirably decreased <i>V</i>_oc. Herein, based on a rationally optimized porphyrin dye, we develop a targeted coadsorption/cosensitization approach for systematically improving the <i>V</i>_oc from 645 to 727, 746, and 760 mV, with synergistical <i>J</i>_sc enhancement from 18.83 to 20.33 mA cm^–2. Thus, the efficiency has been dramatically enhanced to 11.5%, which keeps the record for nonruthenium DSSCs using the I₂/I₃^– electrolyte. These results compose an alternative approach for developing highly efficient DSSCs with relatively high <i>V</i>_oc using traditional iodine electrolyte

Comparative Study on Pyrido[3,4‑<i>b</i>]pyrazine-Based Sensitizers by Tuning Bulky Donors for Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) with cobalt electrolytes have gained increasing attention. In this Research Article, two new pyrido­[3,4-<i>b</i>]­pyrazine-based sensitizers with different cores of bulky donors (indoline for <b>DT-1</b> and triphenylamine for <b>DT-2</b>) were designed and synthesized for a comparative study of their photophysical and electrochemical properties and device performance and were also analyzed through density functional theory calculations. The results of density function theory calculations reveal the limited electronic communication between the biphenyl branch at the cis-position of <i>N</i>-phenylindoline and the indoline core, which could act as an insulating blocking group and inhibit the dye aggregation and charge recombination at the interface of TiO₂/dye/electrolyte. As expected, DSSCs based on <b>DT-1</b> with cobalt redox electrolyte gained a higher photoelectric conversion efficiency of 8.57% under standard AM 1.5 G simulated sunlight, with <i>J</i>_sc = 16.08 mA cm^–2, <i>V</i>_oc = 802 mV, and FF = 0.66. Both electrochemical impedance spectroscopy (EIS) and intensity-modulated photovoltage spectroscopy (IMVS) suggest that charge recombination in DSSCs based on <b>DT-1</b> is much less than that in their counterparts of <b>DT-2</b>, owing to the bigger donor size and the insulating blocking branch in the donor of <b>DT-1</b>

Cosensitized Porphyrin System for High-Performance Solar Cells with TOF-SIMS Analysis

To date, development of organic sensitizers has been predominately focused on light harvesting, highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels, and the electron transferring process. In contrast, their adsorption mode as well as the dynamic loading behavior onto nanoporous TiO₂ is rarely considered. Herein, we have employed the time-of-flight secondary ion mass spectrometry (TOF-SIMS) to gain insight into the competitive dye adsorption mode and kinetics in the cosensitized porphyrin system. Using novel porphyrin dye <b>FW-1</b> and D–A−π–A featured dye <b>WS-5</b>, the different bond-breaking mode in TOF-SIMS and dynamic dye-loading amount during the coadsorption process are well-compared with two different anchoring groups, such as benzoic acid and cyanoacrylic acid. With the bombardment mode in TOF-SIMS spectra, we have speculated that the cyano group grafts onto nanoporous TiO₂ as tridentate binding for the common anchoring unit of cyanoacrylic acid and confirmed it through extensive first-principles density functional theory calculation by anchoring either the carboxyl or cyano group, which shows that the cyano group can efficiently participate in the adsorption of the <b>WS-5</b> molecule onto the TiO₂ nanocrystal. The grafting reinforcement interaction between the cyano group and TiO₂ in <b>WS-5</b> can well-explain the rapid adsorption characteristics. A strong coordinate bond between the lone pair of electrons on the nitrogen or oxygen atom and the Lewis acid sites of TiO₂ can increase electron injection efficiencies with respect to those from the bond between the benzoic acid group and the Brønsted acid sites of the TiO₂ surface. Upon optimization of the coadsorption process with dye <b>WS-5</b>, the photoelectric conversion efficiency based on porphyrin dye <b>FW-1</b> is increased from 6.14 to 9.72%. The study on the adsorption dynamics of organic sensitizers with TOF-SIMS analysis might provide a new venue for improvement of cosensitized solar cells

Development of a Series of (1-Benzyl-3-(6-methoxypyrimidin-3-yl)-5-(trifluoromethoxy)‑1<i>H</i>‑indol-2-yl)methanols as Selective Protease Activated Receptor 4 (PAR4) Antagonists with in Vivo Utility and Activity Against γ‑Thrombin

Here, we describe the development of a series of highly selective PAR4 antagonists with nanomolar potency and selectivity versus PAR1, derived from the indole-based <b>3</b>. Of these, <b>9j</b> (PAR4 IC₅₀ = 445 nM, PAR1 response IC₅₀ > 30 μM) and <b>10h</b> (PAR4 IC₅₀ = 179 nM, PAR1 response IC₅₀ > 30 μM) maintained an overall favorable in vitro DMPK profile, encouraging rat/mouse in vivo pharmacokinetics (PK) and activity against γ-thrombin

Development of a Series of (1-Benzyl-3-(6-methoxypyrimidin-3-yl)-5-(trifluoromethoxy)‑1<i>H</i>‑indol-2-yl)methanols as Selective Protease Activated Receptor 4 (PAR4) Antagonists with in Vivo Utility and Activity Against γ‑Thrombin

Here, we describe the development of a series of highly selective PAR4 antagonists with nanomolar potency and selectivity versus PAR1, derived from the indole-based <b>3</b>. Of these, <b>9j</b> (PAR4 IC₅₀ = 445 nM, PAR1 response IC₅₀ > 30 μM) and <b>10h</b> (PAR4 IC₅₀ = 179 nM, PAR1 response IC₅₀ > 30 μM) maintained an overall favorable in vitro DMPK profile, encouraging rat/mouse in vivo pharmacokinetics (PK) and activity against γ-thrombin