[(2,2-dimethylpropanoyl)oxy]methyl (7aR,7R)-7-{[(3Z)-4-(2-{[(3Z,7S)-4-(2-amino-1,3-thiazol-4-yl)-7-[(2R)-4-(6,6-dimethyl-1,5-dioxo-2,4-dioxahept-1-yl)-5-[(1Z)-2-(4-methyl-1,3-thiazol-5-yl)vinyl]-2H,3H,6H-1,3-thiazin-2-yl]-5,8-dioxo-3,6-diaza-2-oxaoct-3-en-8-yl]amino}-1,3-thiazol-4-yl)-5-oxo-3-aza-2-oxapent-3-en-5-yl]amino}-3-[(1Z)-2-(4-methyl-1,3-thiazol-5-yl)vinyl]-6-oxo-2,6,7,7a-tetrahydroazeto[2,1-b][1,3]thiazine-4-carboxylate