Methods for preparing florfeniol and intermediate thereof

A method for preparing florfenicol using an intermediate (V) of florfenicol, comprising:

• step (1):
• addition reaction
• adding source material SM, compound (I) and tetraethyl titanate to a solvent of tetrahydrofuran, heating the mixture and allowing the resulting mixture to react under an atmosphere of nitrogen and under reflux to form compound (II);
• step (2):
• ring closure reaction
• adding compound (II), ethyl bromoacetate and lithium bis(trimethylsilyl)amide to a solvent of tetrahydrofuran, allowing the resulting mixture to react at a temperature in a range from −50° C. to −78° C. to form compound (III);
• step (3):
• hydrolysis reaction
• adding compound (III) to an ethanol-mixed solvent, and adding hydrochloric acid to hydrolyze compound (III) to form compound (IV);
• step (4):
• ring opening reaction
• subjecting compound (IV) to a ring opening reaction in the presence of an acid to form intermediate (V);
• step (5):
• reduction reaction
• reducing intermediate (V) to compound (VI) by using a reducing agent of sodium borohydride in a solvent of ethanol;
• step (6):
• cyclization reaction
• cyclizing compound (VI) with dichloroacetonitrile in an alcohol to form an intermediate (VII);
• step (7):
• fluorination reaction
• fluorinating intermediate (VII) by using an Ishikawa reagent to form intermediate (VIII);
• step (8):
• ring opening reaction
• hydrolyzing intermediate (VIII) in an acid-containing alcohol solution to form florfenicol (TM);
• wherein the synthetic route for preparing florfenicol (TM) is shown in route (2):