(4S,5S,6S)-(pivaloyloxy)methyl 3-((1-(4,5-dihydrothiazol-2-yl)azetidin-3-yl)thio)-6-((R)-1-hydroxyethyl)-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate
(4S,5S,6S)-(pivaloyloxy)methyl 3-((1-(4,5-dihydrothiazol-2-yl)azetidin-3-yl)thio)-6-((R)-1-hydroxyethyl)-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate