(4S)-3-{[(3R,6S)-2,2-dimethyl-6-{[(5-methyl-3-phenylisoxazol-4-yl)carbonyl]amino}-5-oxo-3,5,6,6a-tetrahydro-2H-azeto[2,1-b][1,3]thiazol-3-yl]carbonyl}-2-(carboxy{[(5-methyl-3-phenylisoxazol-4-yl)carbonyl]amino}methyl)-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid