(6R)-7t-benzoylamino-4c-ethoxy-3-methyl-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid methyl ester
(6R)-7t-benzoylamino-3-methyl-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid methyl ester
(6R)-7t-benzoylamino-4c-ethoxy-3-methyl-5t,8-dioxo-5λ4-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid methyl ester
2-Mercaptobenzothiazole