Dexamethasone Impurity 18

Chemical Name: 2-((8S,9R,10S,11S,13S,14S,16R)-9-fluoro-11-hydroxy-10,13,16-trimethyl-3-oxo-6,7,8,9,10,11,12,13,14,15,16,17-dodecahydro-3H-cyclopenta[a]phenanthren-17-yl)-2-oxoacetic acid

Synonym: 2,5-dioxopyrrolidin-1-yl ((3R,3aR,6aS)-hexahydrofuro[2,3-b]furan-3-yl) carbonate