Huaiqing Zhao

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A highly sensitive and selective LC-MS/MS method was developed and validated for the determination of dauricine in human plasma, using protopine as internal standard (IS). The analyte and IS were extracted by liquid-liquid extraction and analyzed by LC-MS/MS. Chromatographic separation was performed on Agilent TC-C(18) column with a mobile phase of(More)
A liquid chromatographic-tandem mass spectrometric method (LC-MS/MS) for the determination of ulifloxacin, the active metabolite of prulifloxacin, in human plasma is described. After sample preparation by protein precipitation with methanol, ulifloxacin and ofloxacin (internal standard) were chromatographically separated on a C(18) column using a mobile(More)
A rhodium(III)-catalyzed carboxylic acid directed decarboxylative C-H/C-H cross-coupling of carboxylic acids with thiophenes has been developed. With a slight adjustment of the reaction conditions based on the nature of the substrates, aryl carboxylic acids with a variety of substituents could serve as suitable coupling partners, and a broad variety of(More)
The ambient-temperature ortho C-H arylation of electron-deficient benzoic acids with aryl iodides has been achieved by using an Ac-Ile-OH-supported Pd catalyst. A wide range of unactivated benzoic acids could cross-couple an array of aryl iodides in moderate to excellent yields. The choice of HFIP as a solvent is crucial to realizing the mild C-H arylation,(More)
Water-binding foldamers have been rarely studied. By orienting both H-bond donors and acceptors toward their interior, two pyridine-derived crescent-shaped folding oligoamides were found to be capable of trapping both conventional and unconventional water dimer clusters in their cavity (∼2.5 Å radius). In the unconventional water dimer cluster, the two(More)
A new catalytic methodology has been developed for the synthesis of heteroaryled pyridines via a rhodium(III)-catalyzed dehydrogenative cross-coupling reaction. This protocol features a good substrate scope with a broad range of functional group tolerance and high regioselectivity of the pyridyl C-H activation.
By using Pd(TFA)(2)/PCy(3) as a catalyst, a broad range of aromatic carboxylic acids, including heteroaromatic carboxylic acids, efficiently underwent decarboxylative coupling with an array of polyfluoroarenes in the presence of stoichiometric amount of silver salts to generate biaryls. Silver salts were adjusted to the reactivity of aromatic carboxylic(More)
Hollow tubular aquapores inside aquafoldamers can be created via the "sticky" end-mediated formation of 1D chiral helical stacks involving same-handed helices, and are capable of aligning H-bonded water molecules in a chain-like fashion. These aquapores uniquely feature a small cavity of ∼2.8 Å in diameter, a size identical to that of the water molecule and(More)