4-nitro-benzoic acid 1-{7-[4-(3-ethoxycarbonyl-allyl)-6-methoxy-tetrahydro-pyran-2-yl]-3-methyl-2-triisopropylsilanyloxy-octa-3,5-dienyl}-3-methoxy-2,4,8-trimethyl-9-(2-methyl-oxazol-4-yl)-nona-4,6,8-trienyl ester