Synonyms: potassium(2s,3s,5r)-3-(chloromethyl)-3-methyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate 4,4-dioxide;BL P2013;AC1Q1U44;79634-05-2;AR-1L1637;BL-P 2013;2beta-(Chloromethyl)-2alpha-methylpenam-3alpha-carboxylic acid 1,1-dioxide;Potassium 2beta-(chloromethyl)-2alpha-methylpenam-3alpha-carboxylate 1,1-dioxide;4-Thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 3-(chloromethyl)-3-methyl-7-oxo-, 4,4-dioxide, potassium salt, (2S-(2alpha,3beta,5alpha))-