The synthesis and biological evaluation of Z- and E-1-methyl-2-(1-hydroximinoethyl)-6-methoxy-3,4-dihydro-naphtha len e (Z-1 and E-1) as nonsteroidal inhibitors of 17 alpha-hydroxylase-C17,20-lyase (P450 17, CYP 17) is described. Z-1 and E-1 were separated by column chromatography and identified by 1H NMR. The synthesis of the key compound 3 was accomplished by a new reaction acetylating the 1-methyl-6-methoxy-3,4-dihydronaphthalene compound 2 under Friedel-Crafts conditions. Compound 2 was obtained from the 1-tetralone via Wittig reaction. Using a microsomal fraction of human testicular enzyme, Z-1 and E-1 inhibited the target enzyme only marginally.