AIDS-005332 AIDS005332 Cyclohexanehexamide, .delta.-[[(1-naphthyloxy)acetyl]histidinyl]amino]-.gamma.-hydroxy-.alpha.-(1-methylethyl)-N-[2-methyl-1-[[(2-pyridinylmethyl)amino]carbonyl]butyl] U-81749E analog psi-[CHOHCH2] His-cHexAla Val-Ile isostere