A Novel Synthetic Route to 7α-Methoxycephalosporins

Abstract

Treatment of 7β-sulfenamidocephalosporins 7 with an oxidizing agent such as active manganese dioxide gave the sulfenimines 8, which were easily methoxylated to the 7α-methoxy-sulfenamides 9 with lithium methoxide. The 7α-methoxy-sulfenamidocephalosporins 9 were converted to the free amine 10 by reaction with sodium iodide. Acylation of 10 afforded the cephamycin derivative 11. This method was also successfully applied to the penicillin series, leading to the sulfenimine 13, which was methoxylated to furnish the desired 6α-methoxy-penicillin 14 together with the ring-opened product 15.