(6aR)-6t,12t-bis-(2,6-dimethoxy-benzoylamino)-2,2,8,8-tetramethyl-5,11-dioxo-(6ar,12ac)-octahydro-bisthiazolo[3,2-a;3',2'-e][1,5]diazocine-3c,9c-dicarboxylic acid dimethyl ester
<<(1,4-dihydro-1-methyl-3-pyridinyl)carbonyl>oxy>methyl <2S-(2α,5α,6β)>-3,3-dimethyl-7-oxo-6-(2,6-dimethoxybenzamido)-4-thia-1-azabicyclo<3.2.0>heptane-2-carboxylate
<(3-pyridinylcarbonyl)oxy>methyl <2S-(2α,5α,6β)>-3,3-dimethyl-7-oxo-6-(2,6-dimethoxybenzamido)-4-thia-1-azabicyclo<3.2.0>heptane-2-carboxylate
chloromethyl <2S-(2α,5α,6β)>-3,3-dimethyl-7-oxo-6-(2,6-dimethoxybenzamido)-4-thia-1-azabicyclo<3.2.0>heptane-2-carboxylate
methicillin t. butylcarbonyloxymethyl ester