Synthesis of (6R,7S)-7-(2-((S)-2-amino-2-carboxyethyl)thio)acetamido)-7-methoxy-3-(((1-methyl-1H-tetrazol-5-yl)thio)methyl)-8-oxo-5-thia-1-azabicyclo[4.2.0 The general procedure for the sodium salt of ]oct-2-ene-2-carboxylic acid was as follows: 433.1 g of 7β-chloroacetamido-7a-methoxy-3-(1-methyl-1H-tetrazol-5-ylthiomethyl)-3-cephalosporan-4-carboxylic acid was added to 2 L of water, followed by the addition of 30 g of EDTA and 412 g of sodium thiosulfate. The reaction mixture was stirred at 50 °C and the progress of the reaction was monitored by thin layer chromatography (TLC). After completion of the reaction, the mixture was cooled to room temperature and a mixed solution consisting of 1500 mL of ethanol and 500 mL of acetone was added. The resulting precipitate was filtered and dried to give 530 g of cefminox sodium in 97.9% yield. The product was analyzed by high performance liquid chromatography (HPLC) and the purity was 99.5%.
