(6R)-3-(2-ethoxycarbonyl-vinyl)-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid tert-butyl ester
(6R)-3-(trans-2-cyano-vinyl)-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid
(6R)-3-(cis-2-cyano-vinyl)-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid
(6R)-3-(2-ethoxycarbonyl-vinyl)-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid
(6R)-3-(trans-2-cyano-vinyl)-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid tert-butyl ester