Synonyms: 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid,6-[[(2R)-(3,4-dihydroxyphenyl)[[(4-ethyl-2,3-dioxo-1-piperazinyl)carbonyl]amino]acetyl]amino]-6-(formylamino)-3,3-dimethyl-7-oxo-,monosodium salt, (2S,5R,6R)- (9CI);4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,6-[[(3,4-dihydroxyphenyl)[[(4-ethyl-2,3-dioxo-1-piperazinyl)carbonyl]amino]acetyl]amino]-6-(formylamino)-3,3-dimethyl-7-oxo-,monosodium salt, [2S-[2a,5a,6b(S*)]]-; BRL 36650; Fomidacillin sodium