(6R-(6alpha, 7beta))-7-((Formyloxy)phenylacetamido)-3-(((1-methyl-1H-tetrazol-5-yl)thio)methyl)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-(6alpha, 7beta))-7-(Aminophenylacetamido)-3-chloro-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-cis)-3-(Acetoxymethyl)-7-amino-7-methoxy-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-cis)-3-(Acetoxymethyl)-7-methoxy-8-oxo-7-(2-thienylacetamido)-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-cis)-3-Methyl-8-oxo-7-(phenylacetamido)-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-trans)-1-((2-Carboxy-8-oxo-7-((2-thienylacetyl)amino)-5-thia-1-azabicyclo(4.2.0)oct-2-en-3-yl)methyl)pyridinium chloride

(6R-trans)-1-((2-Carboxy-8-oxo-7-((2-thienylacetyl)amino)-5-thia-1-azabicyclo(4.2.0)oct-2-en-3-yl)methyl)pyridinium thiocyanate

(6R-trans)-1-((7-Ammonio-2-carboxylato-8-oxo-5-thia-1-azabicyclo-(4.2.0)oct-2-en-3-yl)methyl)pyridinium iodide

(6R-trans)-3-((Carbamoyloxy)methyl)-8-oxo-7-(2-thienylacetamido)-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-trans)-3-(Acetoxymethyl)-7-((4-chloro-1, 3-dioxobutyl)amino)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-trans)-3-(Acetoxymethyl)-7-amino-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid, mono(toluene-p-sulphonate)

(6R-trans)-3-(Acetoxymethyl)-8-oxo-7-(1H-tetrazol-1-ylacetamido)-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-trans)-3-(Acetoxymethyl)-8-oxo-7-(2-(4-pyridylthio)acetamido)-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid, compound with N, N'-bis(phenylmethyl)ethylenediamine (1:1)

(6R-trans)-3-(Acetoxymethyl)-8-oxo-7-(2-(4-pyridylthio)acetamido)-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid, compound with N, N'-dibenzylethylenediamine

(6R-trans)-7-(Acetylphenoxyamino)-3-methyl-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-trans)-7-Amino-3-(((1-(2-(dimethylamino)ethyl)-1H-tetrazol-5-yl)thio)methyl)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-trans)-7-Amino-3-(((1-methyl-1H-tetrazol-5-yl)thio)methyl)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-trans)-7-Amino-3-(((2-methyl-2H-tetrazol-5-yl)thio)methyl)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

(6R-trans)-7-Amino-3-(((5-(carboxymethyl)-4-methyl-2-thiazolyl)thio)methyl)-8-oxo- 5-thia-1-azabicyclo-(4.2.0)oct-2-en-2-carboxylic acid

(6R-trans)-7-Amino-3-(((5-methyl-1, 3, 4-thiadiazol-2-yl)thio)methyl)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid monohydrochloride