AIDS-005322 AIDS005322 Cyclohexanehexamide, .delta.-(acetylamino)-.gamma.-hydroxy-.alpha.-(1-methylethyl)-N-[2-methyl-1-[[(1-oxo-2-pyridinylmethyl)amino]carbonyl]butyl] U-81749E analog psi-[CHOHCH2] cHexAla Val-Ile isostere