(6R)-3-methyl-8-oxo-7t-[2-(1,4,5,8-tetrahydro-naphthalen-2-yl)-acetylamino]-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid

7-<α-methoxyimino-α-(6-methoxy-3-benzothienyl)acetamido>-3-methyl-3-cephem-4-carboxylic acid

7α-bromo-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7S)-7-methylthio-7-(4-nitrobenzylidene)amino-3-methylceph-3-em-4-carboxylic acid