3-chloro-3',3'-dimethyl-7'-oxo-3-((phenylamino)carbonyl)spiro(oxirane-2,6'-(4)thia(1)azabicyclo(3.2.)heptane)-2'-carboxylic acid, (2'S-(2'alpha,5'alpha,6'alpha(R*)))-isomer
3-chloro-3',3'-dimethyl-7'-oxo-3-((phenylamino)carbonyl)spiro(oxirane-2,6'-(4)thia(1)azabicyclo(3.2.)heptane)-2'-carboxylic acid, (2's-(2'alpha,5'alpha,6'alpha(r*)))-isomer