Preparation method of S-beflubutamid

The invention discloses a preparation method of S-beflubutamid, and belongs to the field of organic chemical synthesis, the method comprises the following steps: S-beflubutamid is prepared from a key intermediate R-1; wherein the key intermediate R-1 is obtained by carrying out a halogenation reaction on R-2, R1 is C1-C6 alkyl, X is Cl or Br, and in the halogenation reaction, a catalyst is a compound containing pyridine and/or containing a pyridyl substituent. The S-beflubutamid is prepared by using the natural chiral (S)-2-hydroxybutyric acid which can be generated by large-scale fermentation as the raw material, and the method is low in cost, short in route, small in pollution, good in safety, high in yield and high in purity. 本发明公开了一种S-氟丁酰草胺的制备方法，属于有机化学合成领域，该方法包括，所述S-氟丁酰草胺由关键中间体R-1制备；其中，关键中间体R-1由R-2经卤代反应得到其中，R1是C1-C6烷基，X是Cl或Br，所述卤代反应中，催化剂为含有吡啶的和/或包括吡啶基取代基的化合物。本发明使用天然的可大量发酵生成的手性的(S)-2-羟基丁酸为原料制备S-氟丁酰草胺，成本低，路线短，污染小，安全性好，且产率高，纯度也高。