(3S,6aR,6R)-6-{[(2R)-2-(4-hydroxyphenyl)-2-({[(3R,6aR)-2-[(1Z)-2-hydroxyethylidene]-5-oxo-3,5,6,6a-tetrahydro-2H-azeto[2,1-b][1,3]oxazol-3-yl]carbonyl}amino)acetyl]amino}-2,2-dimethyl-5-oxo-3,5,6,6a-tetrahydro-2H-azeto[2,1-b][1,3]thiazole-3-carboxylic acid