Synonyms: 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 6-[(carboxy-3-thienylacetyl)amino]-3,3-dimethyl-7-oxo-, [2S-[2α,5α,6β(S*)]]-;4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,6-[[(2R)-carboxy-3-thienylacetyl]amino]-3,3-dimethyl-7-oxo-, (2S,5R,6R)- (9CI);6-[D-(-)-α-Carboxy-3-thienylacetamido]penicillanicacid;