Synthesis of Carumonam (AMA-1080) and a Related Compound Starting from (2R, 3R)-Epoxysuccinic Acid

In the course of the chemical modification of sulfazecin, several 4-carbamoyl-2-azetidinone-1-sulfonic acid derivatives were synthesized with the aim of improving the antibacterial activity. Among those compounds, (3S, 4S)-3-[2-(2-aminothiazol-4-yl)-(Z)-2-(1-carboxy-1-methylethoxyimino) acetamido]-4-carbamoyl-2-azetidinone-1-sulfonic acid (2) was found to have potent antibacterial activity, comparable to that of carumonam (1, AMA-1080 ; Ro 17-2301), against gramnegative bacteria. Efficient synthetic pathways to prepare 1 and 2 in large quantities were developed based on (2R, 3R)-epoxysuccinic acid (5), an easily accessible fermentation product, as a starting chiral synthon.