The present invention is directed to compounds of formula (I) or a pharmaceutically acceptable salt thereof; wherein A is (1); X is selected from CH, CF and N; R5 is selected from H, C.sub.1-C.sub.6 fluoroalkyl, and --OR12; R9 is selected from H --NR13C(O)R14 and --C(O)NR10R11; R12 is selected from H, C.sub.1-C.sub.6 alkyl and C.sub.3-C.sub.6 cycloalkyl, for use as inhibitors of the DPP-IV enzyme in the treatment or prevention of conditions including Type II diabetes.