2-methylpropan-2-yl [(1S,2aR,5aS)-4-ethyl-1-[({[(1S,2aR,5aS)-4-ethyl-1-{2-[(2-methylprop-2-yl)oxy]-2-oxoethyl}-2,2a,3,5a-tetrahydro-1H-cyclobuta[1,2-a][5]annulen-1-yl]methyl}diazenyl)methyl]-2,2a,3,5a-tetrahydro-1H-cyclobuta[1,2-a][5]annulen-1-yl]acetate