77 research outputs found

    Correlation of hydrogen bond length and log<i>RBA</i> of <i>A</i>-ring and <i>B</i>/<i>C</i>-ring derivatives.

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    <p>The hydrogen bond length data were shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0074615#pone-0074615-t001" target="_blank"><b>Table 1</b></a>. The amino acids shown in the up right corner of each indicated that the hydrogen bonds were formed between 3-hydroxyl groups of the <i>A</i>-ring or <i>B</i>/<i>C</i>-ring derivatives and this specific amino acid in the binding pocket. The curve regression was performed according to the Inverse First Order equation y = y<sub>0</sub>+ a/x.</p

    Chemical structures of the bioflavonoids used in this study.

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    <p>The structure of flavone is enlarged to show the numbering of different carbon positions.</p

    Dehydration of Glucose to 5-Hydroxymethylfurfural Using Combined Catalysts in Ionic Liquid by Microwave Heating

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    <p>The dehydration of glucose into 5-hydroxymethylfurfural (HMF) was catalyzed by NKC-9 (a macroporous sulfonated polystyrene ion-exchange resin) combined with metal oxides (TiO<sub>2</sub>, ZrO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub> calcined at different temperatures). In the combined catalytic system, Al<sub>2</sub>O<sub>3</sub> calcined at 550°C exhibited excellent catalytic activity, when the dosage of NKC-9 was kept constant. Four parameters (catalyst dosage, reaction temperature, reaction time, and initial glucose amount) were optimized by employing response surface methodology (RSM), with HMF yield as the response parameter. The maximum HMF yield of 62.09% was obtained at catalyst 0.07 g, temperature 140°C, time 20 min, and glucose 0.01 g. The catalytic activity of the binary catalyst (NKC-9 and Al<sub>2</sub>O<sub>3</sub>) for the conversion of glucose into HMF did not show significant decrease after five-times uses at 140°C for 20 min.</p