Compounds of Formula I and Formula II and the pharmaceutically acceptable salts thereof are disclosed The variables A, B, Y, Z, X1, X2, R1-4 and R13-18 are disclosed herein. The compounds are useful for treating cancer disorders, especially those involving mutant IDH1 enzymes. Pharmaceutical compositions containing compounds of Formula I or Formula II and methods of treatment comprising administering compounds of Formula I and Formula II are also disclosed.