Refining method of midbody of latamoxef sodium

A refining method of a midbody of latamoxef sodium with the midbody of (6R,7R)-7-Amino-7-methoxy-3-[(1-methyl-1H-tetrazol-5-ylthio)methyl]-8-oxo-5-oxa-1-aza bicyclo[4.2.0]oct-2-ene-2-carboxylic acid, the refining method comprising the following steps:

• (1) dissolving (6R,7R)-7-Amino-7-methoxy-3-[(1-methyl-1H-tetrazol-5-ylthio)methyl]-8-oxo-5-oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid in dichloromethane and washing with an acid solution, to divide into a dichloromethane layer and a water layer;
• (2) extracting the dichloromethane layer, adding a NaHCO3 solution to stir, to divide into an organic layer and the water layer, removing the water layer by liquid separation, to leave the organic layer;
• (3) stirring, crystallizing and filtering the organic layer in the step (2) in turn, to obtain a filtrate;
• (4) extracting the water layer in the step (1) and adding hydrochloric acid, adjusting a pH value of 4-5 by using sodium hydroxide, performing crystal cultivation and suction filtration after performing cooling, and then performing vacuum drying under a temperature of 40-45° C., to prepare a first powder;
• (5) stirring the filtrate in the step (3) under conditions of a catalyst and a normal temperature, washing with a NaCl solution and drying with anhydrous sodium sulfate, to prepare a second powder;
• (6) combining the first powder and the second powder to prepare the midbody of latamoxef sodium:
• (6R,7R)-7-Amino-7-methoxy-3-[(1-methyl-1H-tetrazol-5-ylthio)methyl]-8-oxo-5-oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid;
• and wherein
• the catalyst comprises any two of Ph2SiH2, RhH(CO)(PPH3)3 and RhH(PPH3)4 that are mixed in any proportion thereof, and a weight ratio of the catalyst to the filtrate is 0.01-0.03:1.