(E)-(1R,4S,5R,9R,11S,12S)-5-Isopropyl-1-methoxy-8,12-dimethyl-11-[(E)-3-(1-methyl-1H-imidazol-4-yl)-acryloyloxy]-15-oxa-tricyclo[10.2.1.04,9]pentadeca-2,7,13-triene-2-carboxylic acid