(6R)-7t-((R)-5-amino-5-carboxy-pentanoylamino)-3-carbamoyloxymethyl-7c-methoxy-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2 ene-2-carboxylic acid
N-(tert-butyloxycarbonyl) azide
(6R)-7t-((R)-5-tert-butoxycarbonylamino-5-carboxy-pentanoylamino)-3-carbamoyloxymethyl-7c-methoxy-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2 ene-2-carboxylic acid
1-methyl-5-mercaptotetrazole
diazodiphenylmethane