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Furanoid 8-epidiosbulbin E acetate (EEA) is a major constituent of herbal medicine Dioscorea bulbifera L. (DB), a traditional Chinese medicine herb. Our preliminary studies demonstrated that administration of EEA caused acute hepatotoxicity in mice, and the observed toxicity required cytochromes P450-mediated metabolism. Metabolic activation studies of EEA were performed in vitro and in vivo. Microsomal incubations of EEA supplemented with N-acetyl lysine (NAL) and glutathione (GSH) generated six metabolites (M1-M6). M1-M4 were characterized as pyrrole derivatives, and M5 and M6 were pyrrolinones. M2-M6 were detected in bile and/or urine of rats given EEA. Dimethyldioxirane-mediated oxidation of EEA in the presence of NAL and GSH produced M1-M6, all of which were generated in microsomal incubations. The structures of M3 and M6 were confirmed by (1)H and (13)C NMR. These findings provide evidence for the metabolic activation of EEA to the corresponding cis-enedial intermediate both in vitro and in vivo. Ketoconazole inhibited the microsomal production of the cis-enedial, and P450 3A4 was found to be the primary enzyme involved in the bioactivation of EEA.

A deeper understanding of the relationships among composition–structure–transport properties in inorganic solid ionic conductors is of paramount importance to develop highly conductive phases for future employment in solid-state Li-ion battery applications. To shed light on the mechanisms that regulate these relationships, in this work, we perform a “two-dimensional” substitution series in the thio-LISICON family Li4Ge1–x Sn x S4–y Se y . The structural modifications brought up by the elemental substitutions were investigated via Rietveld refinements against high-resolution neutron diffraction data that allowed a precise characterization of the anionic framework and lithium substructure. The analyses show that the anionic and cationic substitutions influence the polyhedral and unit cell volumes in different fashions and that the size of the polyanionic groups alone is not enough to describe lattice expansion in these materials. Moreover, we show that the lithium disorder that is crucial to achieve fast ionic mobility may be correlated to the lithium polyhedral volumes. The correlation of these structural modifications with the transport properties, investigated via electrochemical impedance spectroscopy and 7Li nuclear magnetic resonance spin-lattice relaxation measurements, shows a nonmonotonic behavior of the ionic conductivity and activation energy against the lithium polyhedral volumes, hinting to an optimal size of the conduction pathways for the ionic diffusion. Ultimately, the results obtained in this work will help to establish new guidelines for the optimization of solid electrolytes and gain a more profound understanding of the influence of the substituents on the structure and transport properties of Li-ion conductors.

A new synthetic method toward ethylene-annulated di(perylene diimides) from easily available ethylene-annulated di(perylene esters), which is conducted by ICl-induced cyclization and Mizoroki-Heck coupling of ethynylene-linked di(perylene esters), is reported.

A facile and efficient route for the synthesis of tetrasubstituted imidazoles from amidines and chalcones via FeCl3/I2-catalyzed aerobic oxidative coupling has been developed. This new strategy is featured by high regioselectivity and yields, good functional group tolerance, and mild reaction conditions.

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The Lewis acidic B­(C6F5)3 was recently demonstrated to be effective for the C–H alkylation of phenols with diazoesters. The method avoids the general hydroxyl activation in transition-metal catalysis. Ortho-selective C–H alkylation occurs regardless of potential para-selective C–H alkylation and O–H alkylation. In the present study, a theoretical calculation was carried out to elucidate the reaction mechanism and the origin of chemo- and regio-selectivity. It is found that the previously proposed B­(C6F5)3/N or B­(C6F5)3/C bonding-involved mechanisms are not favorable, and a more favored one involves the B­(C6F5)3/CO bonding, rate-determining N2 elimination, selectivity-determining electrophilic attack, and proton transfer steps. Meanwhile, the new mechanism is consistent with KIE and competition experiments. The facility of the mechanism is attributed to two factors. First, the B­(C6F5)3/CO bonding reduces the steric hindrance during electrophilic attack. Second, the bonding forms the conjugated system by which the LUMO energy is reduced via the electron-withdrawing B­(C6F5)3. The ortho-selectivity resulted from the greater ortho-C–C (than para-C–C) interaction and the O–H···O and O–H···F hydrogen-bond interaction during electrophilic attack. The greater C–C (than C–O) interaction and the π–π stacking between the benzene rings of phenol and diazoester concerted contribute to the chemo-selective C–H alkylation.