Pyridine Schiff base吡啶席夫碱
crude heavy pyridine base粗重吡啶盐基
refined d pyridine base精练吡啶碱类
refined pyridine base精练吡啶碱类
crude light pyridine base粗轻吡啶盐基
pyridine-containing macrocyclic schiff base含吡啶环大环席夫碱