(12Z,16E)-(3S,6S,7R,8S,15S)-3,7-Bis-(tert-butyl-dimethyl-silanyloxy)-15-hydroxy-4,4,6,8,16-pentamethyl-17-(2-methyl-thiazol-4-yl)-5-oxo-heptadeca-12,16-dienoic acid