Lysine sulfonamides as novel HIV-protease inhibitors: optimization of the Nepsilon-acyl-phenyl spacer

A series of Nalpha-isobutyl-Nalpha-arylsulfonamido-(Nepsilon acyl) lysine and lysinol derivatives were prepared and evaluated as inhibitors of HIV protease and wild type virus. A simple original synthesis was devised to form Nalpha-(arylsulfonamide)-Nalpha-isobutyl lysine, which could be easily acylated with carboxylic acids at the Nepsilon position. A two-atom spacer was found to be optimal between this acyl group and a phenyl yielding compounds of sub-nanomolar potency on purified enzyme.