Synonyms: (2S,5R,6R)-3,3-Dimethyl-7-oxo-6-[(phenylacetyl)amino]-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid - pyrimidine (1:1);4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid, 3,3-dimethyl-7-oxo-6-[(2-phenylacetyl)amino]-, (2S,5R,6R)-, compd. with pyrimidine (1:1)