Compounds are provided which are glucokinase activators and thus are useful in treating diabetes and related diseases and have the structure wherein in the ring represents one or two double bonds; R1 is aryl or heteroaryl; R2 is halogen, cycloalkyl, heterocyclyl, aryl, or heteroaryl; R5 is as defined herein; Z is O, S, S(O), S(O)2, or NR5a; X is S, O, N, NR3, or CR3; Y is NCR4 or N4; R3, R4, and R5 are as defined herein; R8 is aryl or heteroaryl; R6 and R7 are independently H, halogen, or alkyl; m is 0 or 1; and n is 0 to 3, or a pharmaceutically acceptable salt thereof. A method for treating diabetes and related diseases employing the above compounds is also provided.