benzyl 6β-amino-6α-formamidopenicillanate 1α-oxide

(2S,5R,6R)-3,3-Dimethyl-7-oxo-6-trifluoromethanesulfonylamino-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester

benzyl 6β-penicillanate

(2S,5R,6R)-6-{(R)-2-(3,4-Diacetoxy-phenyl)-2-[(4-ethyl-2,3-dioxo-piperazine-1-carbonyl)-amino]-acetylamino}-6-formylamino-3,3-dimethyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester

(D)-2-(4-ethyl-2,3-dioxopiperazin-1-ylcarbonylamino)-2-(3,4-diacetoxyphenyl)acetic acid