An efficient, green and atom-economical ironcatalyzed hydroamination of vinylpyridines with azoles has been developed. This reaction works smoothly for adiverse range of vinylpyridines and azoles, including diazoles and triazoles. The reactionw as catalyzed by 5mol % FeCl 3 in toluene at 110 8Cf or 3h to afford the anti-Markovnikov hydroaminationp roductsi nm oderate to excellent yields and excellent selectivities.Scheme1.Catalytic anti-Markovnikov hydroamination of vinylpyridines.
A poly(vinyl alcohol)–cationic cellulose copolymer encapsulated SiO2 HILIC stationary phase is described, which exhibits excellent separation for various analytes.
A hyperbranched stationary phase for hydrophilic interaction liquid chromatography (HILIC) has been prepared by grafting polyethylenimine (PEI) onto silica gel (termed as PEI-Sil). Rich primary, secondary, and tertiary amino groups associated with PEI render its good hydrophility. More importantly, the hyperbranched structure of PEI molecule is greatly helpful in improving interaction with polar analytes. For several kinds of model polar compounds, including organic acids, nucleosides, nucleic acid bases, amino acids, cephalosporins, and non-reducing sugars, PEI-Sil demonstrated excellent separation performance in terms of running stability, reproducibility, and separation efficiency (e.g., plate count ~74,000/m). In addition, PEI-Sil also exhibited much better separation selectivity toward inorganic anions when operated in the mode of ion chromatography relative to a commercial amino propyl-bonded column.
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