The present invention provides thiazole compounds of Formula Iwherein X, Y, Z, X1, X2, X3, X4, X5, R1, R2, R4, R5, R6, R7, and W, are as defined herein, or a stereoisomer, tautomer, pharmaceutically acceptable salt, prodrug, ester or solvate form thereof, wherein all of the variables are as defined herein. These compounds are inhibitors of platelet aggregation and thus can be used as medicaments for treating or preventing thromboembolic disorders.