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Three new tyramine-type alkamides (1-3), three new natural products (4-6), five new N-acylated/formylated aporphine alkamides with different ratios of rotational isomers (7-11), and 20 known alkamides (12-31) were isolated from an EtOH extract of the stems and leaves of Piper puberulum. The absolute configurations of compounds 7, 8, and 10 were determined by single-crystal X-ray diffraction analysis. In the biological activity assay, compounds 3, 5, and 10-23 displayed inhibitory effects against lipopolysaccharide-induced NO release in BV-2 microglial cells, exhibiting IC50 values of 0.93-45 μM.

Two pairs of cycloneolignane enantiomers, piperhancins A and B (1 and 2, respectively), along with two enantiomeric pairs of biosynthetic related neolignanes, hancinone C (3) and piperhancin C (4), were isolated from the stems of Piper hancei. Compound 1 is an unprecedented 1',2:1,2'-dicyclo-8,3'-neolignane. Their structures and absolute configurations were elucidated by spectroscopic analyses, X-ray diffraction, and electronic circular dichroism calculations. Among all of the isolates, compounds (+)-1, (-)-1, (+)-2, (-)-2, and (+)-3 could significantly inhibit the production of nitric oxide secreted by lipopolysaccharide (LPS)-induced neuroinflammation in BV-2 microglial cells, with IC50 values of 1.1-26.3 μM. In addition, compound (-)-1 could decrease the mRNA levels of iNOS, IL-6, and TNF-α induced by LPS in BV-2 microglial cells.

Twenty new chebulic acid and brevifolincarboxylic acid derivatives, including eight optically pure or achiral compounds (1–7 and 14) and six pairs of enantiomers (8a/8b–13a/13b), along with nine kn...

Six new quassinoids, named kumulactone F (1), kumulactone G (2), kumulactone H (4), kumulactone I (5), kumulactone J (6), and kumulactone K (7), a pair of undescribed epimers α- and β-nigakihemiacetal G (3), 15 known quassinoids (8-22), and a mixture of the known compounds α- and β-neoquassin (23) were separated from the dried stems of the medical plants Picrasma quassioides. The chemical structures of all of the new compounds were established by spectroscopic data analyses (HR-ESI-MS, 1D and 2D NMR spectroscopy, and electronic circular dichroism (ECD)). Biologically, compounds 9 and 21 showed toxicity toward the Asian citrus psyllid Diaphorina citri Kuwayama with potent activity even equal to that of the positive control (Abamectin), compound 11 exhibited an excellent neuroprotective effect against SH-SY5Y cells which were pretreated by H2O2 with potent activity equal to that of the positive control (Trolox), and none of them showed cytotoxic activity toward the HeLa or A549 cell lines (IC50 > 100 μM).

Photoresponsive complex emulsions are prepared in a three-phase system consisting of two oils: hexane (H) and perfluorooctane (F). An aqueous solution of a mixed surfactant of fluorosurfactant, F(CF2)x(CH2CH2O)yH (Zonyl FS-300), and a synthesized light-responsive surfactant, 2-(4-(4-butylphenyl)diazenylphenoxy)ethyltrimethylammonium bromide (C4AZOC2TAB) was employed as the continuous phase. Complex emulsions with various geometries were prepared by one-step vortex mixing and a temperature-induced phase-separation method. It was noticed that the topology of the complex emulsion was highly dependent on the mass ratio of Zonyl FS-300/C4AZOC2TAB. Light microscopy images showed that phase inversion from an H/F/W- to an F/H/W-type double emulsion via a Janus emulsion was achieved by gradually increasing the mass ratio of C4AZOC2TAB/Zonyl FS-300. Upon UV/blue light irradiation, the topology of complex emulsions was turned to switch from an F/H/W double emulsion to a Janus emulsion to an entirely inverted H/F/W d...

For various applications, it is essential to enhance the colloidal stabilization of carbon nanotube (CNT) dispersions. Here, the polymers with carbazole pendants of poly(4-(N-carbazolyl)methylstyrene-bl-poly(ethylene glycol) methyl ether methacrylate) (PCMS5-b-PAPEG73 and PCMS16-b-PAPEG43) and PCMS30, synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization, were used for noncovalent functionalization of multiwalled carbon nanotubes (MWCNTs) in tetrahydrofuran (THF), offering efficient colloidal stabilization. Meanwhile, the adsorption of polymers onto MWCNTs was investigated. The results showed that the MWCNTs decorated with these three polymers in THF exhibited different colloidal stabilization and adsorption capacity. Moreover, the MWCNT dispersions could be stabilized for days and their colloidal stabilization elevated with the increase of polymer concentrations. The block copolymer PCMS16-b-PAPEG43 exhibited the optimal adsorption and dispersion capability for MWCNTs. The...

Six binary graft copolymers were synthesized, and their graft segregation in bulk was investigated. The copolymers were prepared by a one-pot method involving the quantitative grafting of alkyne-end-functionalized poly(n-butyl acrylate) (PBA-C≡CH) and poly(2-cinnamoyloxyethyl methacrylate) (PCEMA-C≡CH) onto poly(3-azide-2-hydroxypropyl methacrylate) (P(GMA-N3)) via click chemistry. Of these copolymers, three had a total PBA and PCEMA molar grafting density g of ∼20%, and their PBA volume fractions VB among PBA and PCEMA varied between 28% and 57%. VB was constant at ∼57%, while g varied between 9.8% and 29.5% for the other three samples. Bulk films were obtained by slowly evaporating the solvent from cast solutions of these copolymers. These films were then annealed above the glass transition temperatures of PBA and PCEMA to facilitate graft segregation. The graft segregation patterns were examined by performing transmission electron microscopy (TEM) analysis of thin sections of these films. The TEM resul...

Effective separation methods must be developed before bio-oils become a source of chemical products or liquid fuels by further upgrading. Phase separation is one effective pathway to realize an initial isolation of bio-oils. When aqueous salt solutions are added, phase separation of the pyrolysis bio-oil can occur to form two different phases: the upper layer with high contents of water, acetic acid, and water-soluble compounds and the bottom layers with low water content and high lignin pyrolysis compounds [Song, Q.-H.; Nie, J.-Q.; Ren, M.-G.; Guo, Q.-X.Effective phase separation of biomass pyrolysis oils by adding aqueous salt solutions. Energy Fuels 2009, 23 (6), 3307−3312]. In this paper, the salt-induced phase separation of bio-oils with 20 kinds of salt solutions was investigated. On the basis of the dependence of the mass ratio of the bio-oil bottom layer to the whole bio-oil sample upon the salt solution concentrations, it has been demonstrated that the phase separation derives from a normal ionic...

A highly selective decomposition of formic acid in aqueous medium was achieved with immobilized catalysts. In the gas product of all of the experiments, only hydrogen and carbon dioxide were detected. The activity of different immobilized catalysts for the decomposition of formic acid was checked, and the highest turnover frequency (TOF) was observed using Pd–S–SiO2. Moreover, we have found that the addition of sulfates could significantly promote the activities of mercapto-functionalized catalysts by 30–70%, which is attractive for practical applications.

O-Methylation of phenols has been studied as an important organic reaction, and its products, aryl methyl ethers, are valuable intermediates in fine chemicals. The phenolic component is one of the factors leading to the thermal instability of biomass pyrolysis oils. O-Methylation of phenols is helpful to improve the stability of bio-oil. Using dimethyl carbonate (DMC) as a methylation reagent, model O-methylations of three phenols (phenol, guaiacol, and eugenol) have been investigated in an ionic liquid, 1-butyl-3-methylimidazolium chloride ([bmim]Cl), in the presence of water and carboxylic acid, separately. In [bmim]Cl at 130 °C, both hydrolysis of DMC and esterification of acetic acid with DMC would occur and compete with the O-methylation of phenol and decrease the yield of the methylation. However, the esterification of carboxylic acids is helpful for bio-oil upgrading. Under the same reaction conditions, the methylation was performed for a phenolic bio-oil, which is the ether extractive from the bot...