How can you get good Thiamphenicol

  How can you get good Thiamphenicol? This metal is strange to many people, and here's the introduction to it:
  A white to white crystalline powder or crystal. Melting point (178-180 ℃) (spin), 164-166 (right). The chemical formula for [R - (R * R *)] N - [1 - (hydroxy methyl) - 2 - hydroxy - 2 - [4 - (methyl sulfonyl) phenyl] ethyl] - 2, 2 - dichloro acetamide, easily dissolved in dimethyl formamide, slightly soluble in anhydrous ethanol, slightly soluble in water. Clinically, it is mainly used for the treatment of intestinal surgery, gynecology, obstetrics and gynecology, etc., especially for mild infection.