Chemistry

Characterization of biochar from fast pyrolysis and its effect on chemical properties of the tea garden soil
The characteristics and application of biochar from conventionally slow pyrolysis have been studied a lot, but biochar, as a byproduct in the bio-oil production process, produced by fast pyrolysis was rarely studied. This work assessed the characterization and utilization of biochars derived from rice husk (RH) and elm sawdust (ES) by fast pyrolysis. Incubation experiment of rice husk biochar (...


Hydrothermal liquefaction of lignite, wheat straw and plastic waste in sub-critical water for oil: product distribution
Product distribution and character of the products during hydrothermal liquefaction of Jingou lignite, wheat straw and plastic waste in sub-critical water are investigated in an autoclave. The effects of blending ratio of lignite, wheat straw and plastic waste, temperature, initial nitrogen pressure and additives on product distributions are also studied. The results indicate that blending rati...
Application of chemometric methods to evaluate the origin of solid fuels subjected to thermal conversion
Biomass is the oldest and currently the most often used renewable source of energy. Increasingly, biomass is used in thermal conversion processes. The presented studies focused on the quality control of solid products (char) from the thermal conversion process of biomass in terms of their contamination with polymeric material. To perform these studies, spectral techniques (FT-IR) were coupled w...


Two new ambuic acid analogs from Pestalotiopsis sp. cr013
Pestalotiopsis is a highly prolific genus with a plethora of diverse secondary metabolites. Pestalotiopsis sp. cr013 was isolated from aeciospores of Cronartium ribicola and subjected to phytochemical investigation based on its special environment. To understand the secondary metabolites of strain Pestalotiopsis sp. cr013, two new compounds 1 and 2 were isolated from solid fermentation products...
Flavanoids from Dalea elegans: Chemical reassignment and determination of kinetics parameters related to their anti-tyrosinase activity
In the first chemical investigation developed on the species Dalea elegans twenty years ago, the occurrence of two prenylated derivatives of pinocembrin was reported: 2′,4′-dihydroxy-5′-(1‴,1‴-dimethylallyl)-6-prenylpinocembrin (6PP) given as a new structure in this family of compounds, and another derivative of already known structure, 6-prenylpinocembrin (6P). In the present paper, ...


New oleanane saponins from Schefflera kwangsiensis
Four new oleanane-type triterpenoid saponins, schefflesides I–L (1–4), were isolated from the aerial parts of Schefflera kwangsiensis. Their structures were established as oleanolic acid 3-O-β-d-glucopyranosyl (1→2) [α-l-arabinopyranosyl (1→4)]-β-d-(6-O-methyl) glucuronopyranoside (1), 22α-hydroxyoleanolic acid 3-O-α-l-arabinopyranosyl (1→4)-β-d-glucuronopyranoside , hederagenin...
In Situ Vesicle Formation by Native Chemical Ligation
Phospholipid vesicles are of intense fundamental and practical interest, yet methods for their de novo generation from reactive precursors are limited. A non-enzymatic and chemoselective method to spontaneously generate phospholipid membranes from water-soluble starting materials would be a powerful tool for generating vesicles and studying lipid membranes. Here we describe the use of native ch...

Construction of Axial Chirality by Rhodium-Catalyzed Asymmetric Dehydrogenative Heck Coupling of Biaryl Compounds with Alkenes
Enantioselective construction of axially chiral biaryls by direct CH bond functionalization reactions has been realized. Novel axially chiral biaryls were synthesized by the direct CH bond olefination of biaryl compounds, using a chiral [Cp*RhIII] catalyst, in good to excellent yields and enantioselectivities. The obtained axially chiral biaryls were found as suitable ligands for rhodium-cataly...
Over 10 000 Peptide Identifications from the HeLa Proteome by Using Single-Shot Capillary Zone Electrophoresis Combined with Tandem Mass Spectrometry
Capillary zone electrophoresis (CZE)–tandem mass spectrometry (MS/MS) has recently attracted attention as a tool for shotgun proteomics. However, its performance for this analysis has so far fallen far below that of reversed-phase liquid chromatography (RPLC)–MS/MS. The use of a CZE method with a wide separation window (up to 90 min) and high peak capacity (ca. 300) is reported. This method...

Hydroboration of Arynes with N-Heterocyclic Carbene Boranes
Arynes were generated in situ from ortho-silyl aryl triflates and fluoride ions in the presence of stable N-heterocyclic carbene boranes (NHCBH3). Spontaneous hydroboration ensued to provide stable B-aryl-substituted NHC-boranes (NHCBH2Ar). The reaction shows good scope in terms of both the NHC-borane and aryne components and provides direct access to mono- and disubstituted NHC-boranes. The fo...
Simultaneous In Situ Quantification of Two Cellular Lipid Pools Using Orthogonal Fluorescent Sensors
Lipids regulate a wide range of biological activities. Since their local concentrations are tightly controlled in a spatiotemporally specific manner, the simultaneous quantification of multiple lipids is essential for elucidation of the complex mechanisms of biological regulation. Here, we report a new method for the simultaneous in situ quantification of two lipid pools in mammalian cells usin...

Oxidative Metalation as a Route to Size-Mismatched Macrocyclic Complexes: Osmium Corroles
Heavy-element corroles are of great interest as optical sensors, near-IR dyes, phosphors, organic light-emitting diodes, and anticancer compounds. Insertion of 5d metals into corroles, however, is often a difficult and unpredictable process. Against this backdrop, oxidative metalation of meso triarylcorroles with [Os3(CO)12]/NaN3 in refluxing 1:2 diethylene glycol monomethyl ether/glycol has pr...
Facile and Scalable Preparation of Pure and Dense DNA Origami Solutions
DNA has become a prime material for assembling complex three-dimensional objects that promise utility in various areas of application. However, achieving user-defined goals with DNA objects has been hampered by the difficulty to prepare them at arbitrary concentrations and in user-defined solution conditions. Here, we describe a method that solves this problem. The method is based on poly(ethyl...
Practical and Highly Selective CH Functionalization of Structurally Diverse Ethers
A trityl ion mediated CH functionalization of ethers with a wide range of nucleophiles at ambient temperature has been developed. The reaction displays high chemoselectivity and good functional group tolerance. The protocol also exhibits excellent regio- and diastereoselectivities for the unsymmetric ethers, thus stereoselectively generating highly functionalized disubstituted 2,5-trans tetrahy...
Metal-Free Enantioselective Electrophilic Activation of Allenamides: Stereoselective Dearomatization of Indoles
The effective and unprecedented chiral BINOL phosphoric acid catalyzed (1–10 mol %) dearomatization of indoles through electrophilic activation of allenamides (ee up to 94 %), is documented. Besides the synthesis of 3,3-disubstituted indolenine cores, a dearomatization/hydrogen transfer cascade sequence is also presented as a new synthetic shortcut toward highly enantiomerically enriched ...