5,6-Diaza-8b-azoniaacenaphthylene, 7-[(6R)-6-[[(1,1-dimethylethyl)dimethylsilyl]oxy]heptyl]-1,2,2a,3,4,5,6,8a-octahydro-4-methyl-8-[(2-propenyloxy)carbonyl]-, (2aR,4S,8aS)- AIDS-221575 AIDS221575