1(2H)-Pyrimidineacetamide, N-[(1S,3S,4S)-4-[[3-(2,6-dimethylphenyl)-1-oxopropyl]amino]-3-hydroxy-5-phenyl-1-(phenylmethyl)pentyl]tetrahydro-.alpha.-(1-methylethyl)-2-oxo-, (a1S)- AIDS-121172 AIDS121172