p. 599 - 603
(2007/10/02)(6R,7R)-3-Acetoxymethyl-7-[5-tert-butoxycarbonylamino-5-(2,2,2-trichloro-ethoxycarbonyl)-pentanoylamino]-7-methoxy-8-oxo-5-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester
(6R,7R)-3-Acetoxymethyl-7-(5-tert-butoxycarbonylamino-5-carboxy-pentanoylamino)-7-methoxy-8-oxo-5-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester
(6R,7R)-7-Benzoylamino-8-oxo-3-(2,2,2-trichloro-acetylcarbamoyloxymethyl)-5-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester
(6R,7R)-3-Acetoxymethyl-7-benzoylamino-7-methoxy-8-oxo-5-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester
(6R,7R)-7-Benzoylamino-3-(2-chloro-acetoxymethyl)-8-oxo-5-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester