3,5-Pyridinedicarboxylic acid,4-[2-[2-[[2-[[2-[[3-(2-cyanophenoxy)-2-hydroxypropyl]amino]ethyl]amino]-2-oxoethyl]amino]-2-oxoethoxy]-5-nitrophenyl]-1,4-dihydro-2,6-dimethyl-, diethyl ester, (S)-