L-Valinamide,N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanyl-N-[4-[[N-[N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanyl]-L-valyl]amino]-2,3-dihydroxy-6-methyl-1-(2-methylpropyl)heptyl]-, dihydrochloride