Practical Large-Scale Synthesis of Cefmatilen, A New Cephalosporin Antibiotic

A practical large-scale process for the synthesis of cefmatilen hydrochloride hydrate (1), a new oral cephalosporin antibiotic, is described. Several impurities are isolated from a bulk drug and identified. Side reactions are discussed in order to prevent them. The conditions were optimized to control the formation of impurities. The process is amenable to a multikilogram-scale preparation. Several kilograms of compound 1 for clinical trials were successfully prepared by this process from the three starting materials (7-aminocephem hydrochloride 4, triethylammonium acetate 5, and triazole 7) on a pilot scale in overall yields of 61−65% (10−14% higher than those for the previous process).