Synthesis of Dipeptide-Type Human Immunodeficiency Virus (HIV) Protease Inhibitors with a Binding Unit to GP120

Some dipeptide-type human immunodeficiency virus (HIV) protease inhibitors derived from KNI-102, with a N-carbomethoxycarbonylprolyl-phenylalanine benzyl ester (CPF) moiety as a binding site to gp120, were synthesized. Compounds 11a showed 7-100 times higher HIV protease-inhibitory activity (11a; IC50=0.90 μg/ml, 1.1 μM) than the standard compound 3 or 4 (3; IC50=3.7 μg/ml, 7.7 μM, 4; IC50=75 μg/ml, 155 μM). Generally, the compounds substituted at the o-position of the phenoxyacetyl group 7a, 11a, 16a and 12a showed several times higher inhibitory activity than 3.