4-Oxa-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 3-(2-hydroxyethylidine)-7-oxo-, sodium salt, (2R-(2-alpha,3Z,5-alpha))- 57943-81-4 58001-44-8 Antibiotic MM 14151 sodium salt BRL 14151 Clavulanic acid sodium salt EINECS 261-032-0 Sodium (2R-(2alpha,3Z,5alpha))-3-(2-hydroxyethylidene)-7-oxo-4-oxa-1-azabicyclo(3.2.0)heptane-2-carboxylate