[(Z)-4-[(4-amino-2-methyl-pyrimidin-5-yl)methyl-formyl-amino]-3-[(E)-2-[(4-amino-2-methyl-pyrimidin-5-yl)methyl-formyl-amino]-5-butanoyloxy-pent-2-en-3-yl]sulfanyl-pent-3-enyl] butanoate