A new class of phosphoinositide-dependent kinase-1 (PDK-1) inhibitors of formula I: ##STR00001## wherein X is selected from the group consisting of alkyl and haloalkyl; Ar is an aryl radical selected from the group consisting of phenyl, biphenyl, naphthyl, anthryl, phenanthryl, and fluorenyl; and wherein Ar is optionally substituted with one or more radicals selected from the group consisting of halo, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 haloalkyl, azido, C.sub.1-C.sub.4 azidoalkyl, aryl, alkylaryl, haloaryl, haloalkylaryl, and combinations thereof, and R is selected from the group consisting of nitrile, acetonitrile, ethylnitrile, propylnitrile, carboxamide, amidine, tetrazole, oxime, hydrazone, acetamidine, aminoacetamide, guanidine, and urea. Also provided are methods of using the compounds for the treatment and prevention of cancer in humans.