Synonyms: 5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, 7-amino-3-ethenyl-8-oxo-, diphenylmethyl ester, monohydrochloride,(6R,7R)- (9CI);5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,7-amino-3-ethenyl-8-oxo-, diphenylmethyl ester, monohydrochloride, (6R-trans)-;