Compounds of formula ##STR1## wherein R.sub.1 is hydrogen, lower-alkyl, or trifluoromethyl;R.sub.2 is lower-alkyl, trifluoromethyl or CH.sub.2 Z where Z is hydroxy, chloro, lower-alkylamino or dilower-alkylamino;R.sub.3 and R.sub.4 are each individually hydrogen or fluoro; andAr is phenyl, an aromatic 5- or 6-membered heterocycle or any of these substituted at one or more positions with lower-alkyl, fluoro, chloro, hydroxy, amino, lower-alkylamino, dilower-alkylamino, carboxy, sulfonamido, lower alkylsulfonamido, methylenedioxy, trifluoroacetamido, lower-alkanoylamino, or carbamoyl; and their pharmaceutically acceptable acid addition salts are useful as anticancer agents.